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ABSTRACT Attributions of rainfall anomalies to weather systems and their spatio‐temporal variability in Victoria, southeast Australia are investigated with a multimethod weather type dataset and two popularly used gridded daily rainfall datasets for the period 1979–2015. The rainfall anomalies before, during and after the Millennium Drought (1997–2009) are compared to quantify the temporal variability of rainfall responses to weather type changes. The results show: (1) Three weather systems (Front, Cyclone and Thunderstorm) and their combinations contribute 89% of total rainfall; (2) Contributions of weather types to rainfall vary from month to month with winter season rainfall coming from more diverse weather types than summer rainfall; (3) The contributions of weather types to rainfall in three periods show temporal variabilities and there is a clear shift of contribution pattern after the Millennium Drought, such as front‐thunderstorm (FT) is now the largest contributor to rainfall compared with cyclone‐frontal‐thunderstorm (CFT) before and during the Millennium Drought; (4) A seasonal shift in the post‐drought period is found with higher rainfall in February and March and lower rainfall in September and October. The increased rainfall in February mainly results from Front–Thunderstorm (FT) and Thunderstorm‐only (TO), while rainfall declines in September from all weather types; (5) Several rainfall characteristics that are important for streamflow generation, such as rainfall intensity, probability of rainfall occurrence, number of rainfall days and the maximum daily rainfall, do depend on the weather types; (6) The results are similar with different rainfall datasets, but differences do exist, especially at the local scale. The conclusions of this study are drawn from an Australian case study but have implications for other regions to investigate the attributions of rainfall characteristic changes to weather systems. [ABSTRACT FROM AUTHOR]

Sea ports play a major role in the transport of goods worldwide, and knowledge of wind characteristics in these areas is vital to maintaining safety. However, coastal wind flow can be highly complex and turbulent, necessitating additional analysis. A Doppler lidar providing continuous wind profiles is deployed in the Port of Genoa, Italy, to characterize the mean wind velocity and turbulence properties within the coastal surface layer (40–250 m above ground level). Weather conditions, reanalysis data, and transient wind profiles are combined to analyze wind field characteristics on a day which experienced a thunderstorm. We also utilize a method to identify and categorize sources of turbulence through analysis of lidar derived quantities such as wind shear, turbulent kinetic energy, and vertical skewness. Seasonal variations in the wind properties are investigated by selecting data from June (summer) and December (winter). Differences are found in dominant wind direction and the associated frequency of convective mixing, with onshore winds most common in summer and offshore winds in winter. The measured lidar velocity is also compared against Monin–Obukhov similarity theory predictions, showing satisfactory agreement at low heights but struggling to reproduce observations of the stable atmospheric conditions present during winter. Plain Language Summary: Approximately 40% of the world's population lives in the coastal regions. Similarly, seaports host about 80% of the global maritime transport and therefore play a major role in the transportation of goods and services. However, coastal regions and ports are also windy places due in part to strong temperature differences between land and sea. This study uses a remote sensing instrument—Doppler lidar—to measure mean wind velocity and turbulence characteristics in the Port of Genoa, Italy, between 40 and 250 m above the ground. The study first provides a detailed investigation of a case (7 June 2020) that was characterized by variable weather that included rain, thunderstorms, and intermittent sunshine. Seasonal variations in the wind characteristics above the Port of Genoa are investigated by focusing on June (summer) and December (winter) months. Winds that blow from sea to land are most common in summer whereas the winds that blow from land to sea are dominant in winter. The wind measurements are compared against theoretical predictions that are often employed in numerical weather prediction models. A varying degree of similarity between the measured and predicted values is found. Key Points: Analyses of wind variability during a thunderstorm and seasonal wind patterns using Doppler lidar measurements in the Port of Genoa, ItalyClassification of turbulent sources using lidar‐derived quantities and comparison of wind profiles against theoretical predictionsSeasonal analysis of surface heating induced convective‐mixing sources and their frequency [ABSTRACT FROM AUTHOR]

The electrical alignment signatures of ice crystals in the middle and upper parts of a thunderstorm have a physical connection with the strong electric fields within the cloud. By taking advantage of the high spatio‐temporal resolution of an X‐band dual‐polarized multiparameter phased array radar, this paper employs negative KDP signatures to investigate the variation of electric fields in an isolated thunderstorm within its evolution, and the relationship between the negative KDP signatures and intracloud (IC) lightning activity. The results show that the radar‐inferred strong electric fields distributed in a region of about 8.5–10 km during the developing stage, then extended from about 10 km to the cloud top during the mature stage, with an increasing IC lightning flash rate before the end of the mature stage. Subsequently, the electric fields weakened associated with a large amount of IC lightning discharges. The qualitative analysis results indicate that the evolution of the radar‐inferred electric fields associated with the upper charge regions is consistent with the electrification process in the isolated thunderstorm, inferred by the IC lighting activity. In addition, there is a tendency for the increased IC lightning rate as the decrease in average composite KDP in the middle and upper layers of the thunderstorm, with a time lag of about 5.5 min between the minimum average composite KDP and the peak IC lightning rate, while a good correlation between the negative KDP volume and the IC lightning flash rate at a lag of approximately 9 min. Plain Language Summary: By using an X‐band dual‐polarized multiparameter phased array radar with high temporal and spatial resolution, this study investigates the electrical alignment signatures of ice particles related to the strong electric fields in the middle and upper parts of an isolated thunderstorm. The results indicate the potential use of electrical alignment signatures of ice crystals for evaluating the evolution of radar‐inferred electric fields within the thunderstorm lifecycle. Moreover, well correlations are observed between negative KDP volume, average composite KDP, and intracloud lightning flash rate. Key Points: The composite KDP could be used as an indicator of intracloud (IC) lightning potential in isolated thunderstormsThe negative KDP volume and average composite KDP show well correlations with the IC lightning flash rate in an isolated thunderstormThe vertical structure of total electric field in the upper parts of an isolated thunderstorm could be explored by negative KDP signatures [ABSTRACT FROM AUTHOR]

Congenital long QT syndrome (LQTS) is a genetic heart disorder, which may lead to life-threatening arrhythmias, especially in children. Here, we reported two children who were initially misdiagnosed with epilepsy and experienced Torsades de Pointes (TdP) cardiac electrical storm (ES). Through whole exome sequencing (WES), we identified two Potassium voltage-gated channel subfamily H member 2 (KCHN2) mutations (c.1841 C > T and c.1838 C > T) respectively in a 6-year-old boy and a 13-year-old girl. Clinical data indicated that the QT interval was significantly prolonged, the T-wave pattern of chest V5-V6 leads and limb leads were inverted. Our study suggests that patients with epilepsy, especially those refractory epilepsy with atypical features, need comprehensive evaluation of cardiovascular function. KCNH2 mutation in pore region, QT interval prolongation and T wave inversion are high risk factors for ES. For LQT2 patients with ES, Nadolol and left cardiac sympathetic denervation are indicated, sometimes with an ICD. [ABSTRACT FROM AUTHOR]

The accurate prediction of lightning is crucial for forecasters to respond effectively to its related hazards. The rapid development and confined spatial extent of convective storms, in which lightning frequently occurs, pose considerable challenges for accurately predicting their locations using numerical weather prediction (NWP) models. Lightning occurrence is often prognosed using thermodynamic parameters, convective available potential energy (CAPE), the severe weather threat index (SWEAT), the lifted index (LI), etc. A high-resolution NWP model provides a prediction of these thermodynamic parameters at high spatiotemporal resolution with high accuracy for a few hours. However, a complicated algorithm is required to handle all the useful high-resolution variables from the NWP model. The recently emerging machine learning technique can solve this issue by properly handling these "big data" without any model distributional assumption. In this study, we developed a random forest algorithm for nowcasting and very short-range forecasting (useful for ~6 h), named LightningRF. LightningRF was trained by using lightning occurrence as a response variable and characteristic parameters from the NWP as predictors. It was also applied to analysis and forecast fields, showing a high probability of lightning within the observed lightning regions. This highlights the potential of helping forecasters improve their lightning forecasting skills using real-time probabilistic forecasts from a trained model. [ABSTRACT FROM AUTHOR]

Storm Ciarán was an extremely damaging windstorm which affected southern Britain, the Channel Islands and northern France on 1/2 November 2023. Storm force winds with gusts in excess of 90mph (81kn) widely affected Jersey, along with a severe thunderstorm bringing heavy precipitation, large hail and a severe tornado. Due the development of the storm, warnings were issued well in advance giving the island time to prepare. In many ways, Storm Ciarán was comparable to the Great Storm of 1987, both of which left severe damage across Jersey including widespread damage to homes and infrastructure across the island. [ABSTRACT FROM AUTHOR]

This study explores gulf-breeze circulations (GBCs) and bay-breeze circulations (BBCs) in Houston–Galveston, investigating their characteristics, large-scale weather influences, and impacts on surface properties, boundary layer updrafts, and convective clouds. The results are derived from a combination of datasets, including satellite observations, ground-based measurements, and reanalysis datasets, using machine learning, changepoint detection method, and Lagrangian cell tracking. We find that anticyclonic synoptic patterns during the summer months (June–September) favor GBC/BBC formation and the associated convective cloud development, representing 74% of cases. The main Tracking Aerosol Convection Interactions Experiment (TRACER) site located close to the Galveston Bay is influenced by both GBC and BBC, with nearly half of the cases showing evident BBC features. The site experiences early frontal passages ranging from 1040 to 1630 local time (LT), with 1300 LT being the most frequent. These fronts are stronger than those observed at the ancillary site which is located further inland from the Galveston Bay, including larger changes in surface temperature, moisture, and wind speed. Furthermore, these fronts trigger boundary layer updrafts, likely promoting isolated convective precipitating cores that are short lived (average convective lifetime of 63 min) and slow moving (average propagation speed of 5 m s−1), primarily within 20–40 km from the coast. [ABSTRACT FROM AUTHOR]

The use of meteorological radars in monitoring current weather conditions is crucial regarding the observation of the evolution and dissipation of thunderstorms. Thus, Doppler velocities being measured in each radar scan and velocity vectors derived from Numerical Weather Prediction (NWP) models—that are usually not as highly resolving as radar scans—are combined, as a monitoring utility during the evolution of a convective weather event. The objective of this study is to develop a new method that allows the implementation of a thunderstorm movement velocity estimation technique combining block matching and optical flow techniques. This new method constitutes a nowcasting (NWC) application that enables the use of a single Doppler radar without the need of using NWPs. The method relies on the estimation of the thunderstorm movement vector velocities (Doppler velocity) for each constant altitude plan position indicator (CAPPI) and through correction for aliasing errors to obtain 3D vector velocity fields for convective systems. The performance of the method is evaluated for selected case studies of convective thunderstorms under different synoptic scale conditions over Greece, a geographical area with challenges in forecasting due to its sharp relief and the need for optimization of the use of radar products. [ABSTRACT FROM AUTHOR]

Thunderstorm and Desire under the Elms exhibit striking similarities in thematic elements and the portrayal of female characters, which suggests the two playwrights, Cao Yu (1910-1996) and Eugene O’Neill (1888-1953), shared aesthetic vision in their creative writings. Prior studies of these plays have often focused on the characterisation of the protagonists, thereby overshadowing gender as a critical factor in shaping tragedies. This paper argues that the tragedies in these works are not merely personal misfortunes but are deeply embedded in gendered dynamics, specifically the oppressive force of phallocentrism. It posits that the central cause of tragedy is the conflict between societal constraints and the female characters’ aspirations for power, equality, freedom, and spiritual autonomy. A comparative study of these plays reveals that both Cao Yu and Eugene O’Neill crafted an affective space where the female protagonists, Fanyi and Abbie, despite their different social contexts, share a fundamental human essence. This comparison not only underscores the essence of tragedy within diverse national frameworks but also highlights the commonalities in how the two playwrights perceive and portray women’s destinies and existential predicaments. [ABSTRACT FROM AUTHOR]

In this study, we evaluate mesoscale convective system (MCS) simulations in the second version of U.S. Department of Energy (DOE) Energy Exascale Earth System Model (E3SMv2). E3SMv2 atmosphere model (EAMv2) is run at the uniform 0.25° horizontal resolution. We track MCSs consistently in the model and observations using PyFLEXTRKR algorithm, which defines MCSs based on both cloud top brightness temperature (Tb) and surface precipitation. Results from using only Tb to define MCSs are also discussed to understand the impact of different MCS tracking algorithms on MCS evaluation and provide additional insights into model errors in simulating MCSs. Our results show that EAMv2 simulated MCS precipitation is largely underestimated in tropical and extratropical regions. This is mainly attributed to the underestimated MCS genesis and underestimated precipitation intensity in EAMv2. Comparing the two MCS tracking methods, simulated MCS precipitation is increased if MCSs are defined with only cloud top Tb. The Tb‐based MCS tracking method, however, includes cloud systems with very weak precipitation. This illustrates the model issues in simulating heavy precipitation even though the convective cloud shield is overall well simulated from the moist convective processes. Furthermore, sensitivity experiments are performed to examine the impact of new cloud and convection parameterizations developed for EAMv3 on simulated MCSs. The new physics parameterizations help increase the relative contribution of convective precipitation to total precipitation in the tropics, but the simulated MCS properties are not significantly improved. This suggests that simulating MCSs still remain a challenge for the next version of E3SM. Plain Language Summary: Mesoscale convective systems (MCSs) are one of the largest forms of deep convective storms, which play an important role in the earth system. It is imperative for global climate models to reasonably simulate MCS properties. This study aims to evaluate simulated MCS properties in the second version of U.S. Department of Energy (DOE) Energy Exascale Earth System Model (E3SMv2). We utilized two different approaches to define MCSs in the model and observations for consistent comparisons. Our results show that the E3SMv2 model underestimates MCS precipitation in the tropical and subtropical regions. The too few MCSs and overly weak precipitation intensity in individual MCSs are the primary reasons for this MCS precipitation bias. The simulated MCS precipitation becomes more comparable to the observations when surface precipitation is not included in the MCS definition. However, many cloud systems with very weak precipitation characteristics are included. This comparison illustrates the model issues in precipitation formation while convective cloud structures are overall well simulated. In addition, by examining the impact of new physics parameterizations that are developed for the next generation of E3SM model on the MCS simulation, we find simulating MCSs will remain a challenge for the next version of E3SM model. Key Points: Simulated mesoscale convective system (MCS) precipitation is substantially underestimated in E3SMv2 due to insufficient MCS genesis and rain rate in individual MCSsUtilizing different MCS tracking methods provides a more complete picture about the model capability in simulating MCSsMCS properties in E3SMv2 are not significantly improved with the new cloud and convection parameterizations developed for E3SMv3 [ABSTRACT FROM AUTHOR]

Extreme rainfall events (EREs) caused by convection are a major prediction challenge and can lead to deadly flash flooding. This study investigates EREs from 2003 to 2023 over the central and eastern United States using high‐resolution (4‐km) Stage IV precipitation analyses. EREs were defined where 12‐hr accumulations exceeded the 10‐year average recurrence interval thresholds. Summertime (June–August) EREs exhibited pronounced interannual variability, but with statistically significant increasing trends in annual frequency, particularly among those caused by mesoscale convective systems. Significant relationships were also found between summertime convective EREs over the central United States and enhanced poleward moisture transport, consistent with a westward expansion of the climatological North Atlantic Subtropical High. This relationship may aid in medium‐ and long‐range forecasting. However, the spatial scale of EREs often included localized or narrow bands of extreme accumulations, revealing significant challenges in the accurate representation of EREs in weather and climate models. Plain Language Summary: Extreme rainfall events often result from slow‐moving thunderstorms that drop heavy rain over the same area for several hours, which can cause deadly flash flooding. This study defines an extreme rainfall event where the 12‐hr accumulation would only exceed that amount once every 10 years on average, with a focus on the summer months over the central and eastern United States from 2003 to 2023. Our results show a significant increasing trend in the number of extreme events, especially those caused by larger, longer‐duration storms. Our use of a high‐resolution rainfall data set also revealed that extreme rainfall often occurs due to nighttime thunderstorms producing heavy rainfall over highly localized areas or narrow (20–40 km wide) swaths. These characteristics present a challenge for global weather and climate models. The frequency of these summertime extreme events also significantly varied from year to year. Summers with more extreme events were associated with a greater northward transport of moist air around the western edge of an area of high pressure that extends westward from the Atlantic Ocean. The relationship between this flow pattern and extreme rainfall suggests a possible path for improving forecasts of extreme rainfall. Key Points: High‐resolution rainfall data reveal an increasing trend in extreme summertime rainfall, especially from mesoscale convective systemsMore events occurred during summers with greater southerly moisture transport driven by differences in the North Atlantic Subtropical HighThe relatively small scale of extreme convective rainfall presents a challenge for representing these events in weather and climate models [ABSTRACT FROM AUTHOR]

Four parameterizations, distinguishing between land and ocean, have been developed to simulate global distributions of thundercloud streamer corona discharges (also known as Blue LUminous Events or BLUEs) mainly producing bluish optical emissions associated with the second positive system of N 2 accompanied by no (or hardly detectable) 777.4 nm light emission. BLUEs occur globally about 12 times less frequently than lightning flashes. The four schemes are based on non-linear functions of the cloud-top height (CTH), the product of the convective available potential energy (CAPE) and total precipitation (TP), the product of CAPE and specific cloud liquid water content (CLWC), and the product of CAPE and specific cloud snow water content (CSWC). Considering that thunderstorms occur on hourly timescales, these parameterizations have been tested using hourly ERA5 data (except for CTH, not available in ERA5) for the meteorological variables considered, finding that the proposed BLUE schemes work fine and are consistent with observations by the Atmosphere–Space Interactions Monitor (ASIM). Moreover, the parameterizations have been implemented in a global chemistry–climate model that generates annual and seasonal global distributions for present-day and end of 21st century climate scenarios. Present-day predictions are in reasonable agreement with recent observations by the ASIM. Predictions for the end of the 21st century suggest BLUE occurrence rates that range between 13 % higher (∼ 3 % K -1) and 52 % higher (∼ 13 % K -1) than present-day average occurrences of BLUEs. [ABSTRACT FROM AUTHOR]

This study examines the differences related to microphysical properties of ice in thunderstorms over the Amazon and Congo Basin using the Precipitation Feature (PF) data sets derived from passive microwave and radar observations from the Tropical Rainfall Measuring Mission and Global Precipitation Mission Core Satellites. Analysis reveals that Amazon thunderstorms are likely composed of ice crystals smaller but more numerous than those in the Congo Basin, resulting in half as many flashes per PF on average in the Amazon, for similar Ice Water Content (IWC) or Area of 30 dBZ at −10°C (Acharge). The increase of the flash count following an increase of the IWC (Acharge) is only 72% (61%) as effective in the Amazon as it would be in the Congo Basin area. PFs with similar 30 dBZ radar echo top heights exhibit lower Brightness Temperatures (TBs) in the 85/89, 165, and 183 GHz frequencies over the Amazon, indicating more numerous smaller ice particles compared to those over the Congo Basin, which tend to show colder TBs at 37 GHz, possibly due to more numerous large graupel or hail particles. Comparisons of TBs in PFs with similar 30 dBZ echo top temperature between the Amazon and 3 × 3º global grids show that the median TB in Amazon is higher than that in most oceanic areas but is comparable to areas having high oceanic lightning activity (e.g., South Pacific Convergence Zone). It suggests that systems in the Amazon have similarities with maritime precipitation systems, yet with distinct characteristics indicative of land systems. Plain Language Summary: A comparison is made between Amazon (AM) and Congo Basin (CB) thunderstorms with similar reflectivity values seen by either TRMM or GPM, versus other variables that can help us understand the ice microphysics of these storms (IWC, area of 30 dBZ at −10C, Flash count, TBs). The radar reflectivity being driven by number and size (to the sixth power) of hydrometeors, the hypothesis is that for two storms with a same reflectivity value, one in AM and one in CB, the reflectivity value measured is driven by a higher concentration of large ice particles in CB (i.e., driven by size), while it is driven by a higher concentration of smaller ice particles in AM (i.e., driven by number). We quantify the lightning count difference between the two areas as a function of the amount of ice in the thunderstorm. It shows that AM produces significantly less lightning than CB on average for a similar ice content. Radiometers from TRMM and GPM are then used to compare the median TBs observed in the Amazon with the rest of the globe, to emphasize once again that AM is producing systems that are neither of land nor oceanic nature, but somewhere in the middle. Key Points: Amazonian systems are principally composed of smaller and more numerous ice crystalsIncreasing the Ice Water Content (IWC) and/or core size of thunderstorms in the Amazon demonstrates lower effectiveness in boosting lightning activityAmazonian systems present brightness temperatures unlike land or oceans but similar to oceanic regions with greater lightning activity [ABSTRACT FROM AUTHOR]

The dynamical environment of the stratosphere, during the summer over North America, provides a natural integrator of the impact of convection in the lower stratosphere, as air can be confined for periods of a few days to more than a week. In situ data obtained during the NASA Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) field campaign show increasing water vapor mixing ratios in background air as a function of time the air parcel spent within the North American Monsoon Anticyclone region. We find that water vapor added to the stratosphere by convection decreases with altitude and tends to drop below detectable limits by the 415 K isentrope in 2021 and the 430 K isentrope in 2022. Integrating between potential temperatures of 380 and 460 K we find that convection added between 20 and 32 Tg per summer to the stratosphere in 2021 and 2022. While the total amount is only 1%–4% of the amount ascending in the tropics across the tropical tropopause, small changes in the annual flux of water can have a significant effect on the radiation budget of the atmosphere. Locally, over North America we find that convection increased the water vapor mixing ratio at 380 K by as much as 40%. Tropopause‐penetrating convection is part of the yearly cycle of stratospheric water vapor and we suggest that it must be included in extratropical models to accurately predict future trends in stratospheric water vapor. Plain Language Summary: Water vapor in the stratosphere is important for regulating Earth's climate and also influences the amount of ozone in the stratosphere. Most air rises into the stratosphere through the tropical tropopause where the excess water freezes out leaving very dry air. But air and water can also be injected into the stratosphere via strong convective storm systems. During the summer months, strong storms over the Sierra Madre Occidental and the central United States are known to produce many overshoots that can be seen with radar and satellite. A recent NASA airborne campaign called Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) aimed to study this region. The aircraft was equipped with 12 different sensors measuring gases, aerosols, and meteorological variables. We use these measurements to look at the cumulative effect these storms have on the background air in the stratosphere and specifically calculate the amount of water vapor added by convection as a function of altitude above the tropopause. We find that water added by storms over North America is 1%–4% of the total amount ascending in the tropics. Over North America convection may account for as much as a 40% increase in lower stratospheric water vapor. Key Points: Deep convection over North America lofts significant amounts of water to the lower stratosphereThe North American Monsoon Anticyclone (NAMA) provides a natural integrator of convective perturbations to the stratosphereConvective detrainment of water vapor and ice is quantified by looking at changes in background air as a function of time spent in the NAMA [ABSTRACT FROM AUTHOR]

A large tornado and severe hailstorm struck Jersey, Channel Islands, just before midnight on 1–2 November 2023. Radar data are analysed to explore the morphology of the parent supercell thunderstorm. A tornado debris cloud was evident in polarimetric fields, collocated with a reflectivity ‘debris ball’. The debris cloud comprised a small region of exceptionally low correlation coefficient (<0.8) collocated with differential reflectivity ≤0dB. In vertical section, the debris signature comprised a column of low correlation coefficient and high reflectivity that tilted north‐northeast with height and extended to at least 2km above ground level. [ABSTRACT FROM AUTHOR]

Canopy leaf abundance of Amazon rainforests increases in the dry season but decreases in the wet season, contrary to earlier expectations of water stress adversely affecting plant functions. Drivers of this seasonality, particularly the role of water availability, remain debated. We introduce satellite-based ecophysiological indicators to demonstrate that Amazon rainforests are constrained by water during dry seasons despite light-driven canopy greening. Evidence includes a shifted partitioning of photosynthetically active radiation toward more isoprene emissions and synchronized declines in leaf and xylem water potentials. In addition, we find that convective storms attenuate light-driven ecosystem greening in the late dry season and then reverse to net leaf loss in the wet season, improving rainforest leaf area predictability by 24 to 31%. These findings highlight the susceptibility of Amazon rainforests to increasing risks of drought and windthrow disturbances under warming. [ABSTRACT FROM AUTHOR]

The global energy budget is pivotal to understanding planetary evolution and climate behaviors. Assessing the energy budget of giant planets, particularly those with large seasonal cycles, however, remains a challenge without long-term observations. Evolution models of Saturn cannot explain its estimated Bond albedo and internal heat flux, mainly because previous estimates were based on limited observations. Here, we analyze the long-term observations recorded by the Cassini spacecraft and find notably higher Bond albedo (0.41 ± 0.02) and internal heat flux (2.84 ± 0.20 Wm−2) values than previous estimates. Furthermore, Saturn's global energy budget is not in a steady state and exhibits significant dynamical imbalances. The global radiant energy deficit at the top of the atmosphere, indicative of the planetary cooling of Saturn, reveals remarkable seasonal fluctuations with a magnitude of 16.0 ± 4.2%. Further analysis of the energy budget of the upper atmosphere including the internal heat suggests seasonal energy imbalances at both global and hemispheric scales, contributing to the development of giant convective storms on Saturn. Similar seasonal variabilities of planetary cooling and energy imbalance exist in other giant planets within and beyond the Solar System, a prospect currently overlooked in existing evolutional and atmospheric models. Global energy budgets of planets are important to understand their climate system. Here, the authors show long-term multi-instrument observations from Cassini spacecraft, which reveals dynamical imbalances of Saturn's global energy budget. [ABSTRACT FROM AUTHOR]

Data recorded by several infrasound sensor arrays deployed in the southeastern United States during the spring of 2018 have been analyzed during a period when a storm front passed through and spawned several tornado touchdowns. The tornadoes ranged from EF-0 to EF-2. Accurate bearings have been obtained, corresponding to tornadoes at ranges up to more than 100 km. Earlier in the day, a convective storm cell passed and triggered a tornado warning but no verified tornado touchdowns. During this earlier passage, a weaker signal was detected with bearings that tracked this convective storm cell. The analyses reveal that on the systems deployed, the dominant band of coherent infrasound measured from the tornadic storms was between 2 and 6 Hz. Atmospheric conditions are known to have a significant influence on signal detection because of propagation effects and local wind noise conditions. Propagation modeling and wind noise analysis were undertaken and are observed to be consistent with signal detection from the tornadoes. Because of the static sources, as well as the multiple strong cells that were in the region simultaneously, it was necessary to use array signal processing methods that are capable of resolving multiple sources. [ABSTRACT FROM AUTHOR]

This investigation builds upon and extends prior lightning research in the Bangkok Metropolitan Region (BMR) through the reconstruction of thunderstorm distribution, utilizing a novel lightning tracking algorithm. Five years (2016–2020) of lightning stroke data from the Global Lightning Dataset (GLD360) were used to identify 52 608 thunderstorms. Optimized hotspot analyses, track densities, and analyses of thunderstorms with respect to winds, landcover, and seasons were performed. Our findings suggest that significant modification of thunderstorm distribution within the region was due to urban landcover impacts on the local environment. Thunderstorm intensity, as measured by stroke counts and track length, also appeared to be sensitive to the urban environment. The thunderstorm distribution also highlighted areas prone to hazards such as flash flooding. By visualizing thunderstorms grouped by winds, thunderstorm initiation hotspots and track density corridors were identified. These corridors of augmented thunderstorm production tended to occur during specific months given the seasonal monsoon wind regime occurring across the BMR. As urbanization within the BMR continues, geospatial assessment of thunderstorms is important to inform forecast meteorologists, urban planners, government officials, and others who play a critical role in developing strategies, policies and insfrastructure that could mitigate thunderstorm impacts. [ABSTRACT FROM AUTHOR]

Thunderstorms are among the most extreme meteorological phenomena that can cause widespread destruction and loss of life. Their occurrence varies significantly across different regions and times of the year. Despite various studies on thunderstorm activity across Central Europe, direct analyses based on data from the Slovak territory still need to be made available. Given Slovakia's diverse natural conditions, there is a need for detailed knowledge about the frequency and spatial distribution of thunderstorms in this region. To address this knowledge gap, we analysed the frequency and spatiotemporal distribution of days with thunderstorm occurrences in Slovakia between 1984 and 2023, utilising climatological data from the Slovak Hydrometeorological Institute. We limited our analysis to data of days with close thunderstorms (thunderstorms occurring within 3 km of the monitoring station). Our findings reveal a significant variation in thunderstorm occurrences across Slovakia, with peak activity in the summer, especially in June and July. However, the spatial distribution of thunderstorms differed significantly across the country, with the highest frequency observed in mountainous regions and the east-central part of Slovakia. We found significant deceasing signals of the thunderstorm activity trends during the studied period, including analyses during the colder part of the year. Furthermore, our results underscore the critical role of synoptic situations in shaping these trends, where changes in certain atmospheric patterns were closely aligned with variations in thunderstorm frequency. The interaction between these synoptic conditions and regional topography was particularly evident, reinforcing the notion that topographical and environmental complexities substantially contribute to the observed thunderstorm distribution. [ABSTRACT FROM AUTHOR]

The three-body scatter spike (TBSS), an echo artifact in radar imagery, manifests as a weak, linear echo extending radially from a core of high reflectivity. Adequately, though not indispensably, indicating the presence of large hail in convective storms, the automatic identification of the TBSS proves advantageous in significantly improving the effectiveness of hailstorm detection. This study introduces an algorithm that synergizes Jensen–Shannon divergence (JSD) and support vector machine (SVM) for rapid TBSS detection in two decades' worth of single-polarization radar data across China. The algorithm, tested on data from 50 S-band China Next Generation Weather Radar (CINRAD) in central and eastern China, utilized reflectivity factor images for sample extraction. An application in Chenzhou, China, demonstrates the algorithm's efficacy in improving hailstorm detection resolution. Significance Statement: In recent years, China's hail recordkeeping, primarily based on manual observations at national surface meteorological stations, has suffered from limited spatial and temporal detail. However, the advent of the China Next Generation Weather Radar (CINRAD) network offers a new avenue for hailstorm detection. TBSS, a secondary but significant indicator for large hail in S-band radar, presents an opportunity for enhanced hail warning capabilities. By automating TBSS detection in radar archives spanning two decades, this research significantly enhances the resolution of hailstorm climatology, contributing to more effective hail disaster mitigation and management. [ABSTRACT FROM AUTHOR]

Based on the significant weather report, CG lightning, composite radar reflectivity, and ERA5 reanalysis data, we first studied the spatiotemporal distribution characteristics of four types (only severe convective wind (SCW); SCW and hail; SCW and short-duration heavy rainfall (SDHR); and SCW, hail, and SDHR) of convective weather events related to SCW during the warm season (May to September) from 2011 to 2018 in North China. Second, severe convective cases producing SCW were selected to statistically analyze the initiation, decay, lifetime, and organizational characteristics of convective systems. Finally, using ERA5 reanalysis data and conventional surface observation data, preconvective soundings were constructed to explore the differences in environmental conditions for initiating convective systems between SCW and non-SCW. The results indicate that mixed-type of SCW and SDHR events occur more frequently over plains, while other types of convective weather occur more frequently over mountains. The frequency peak of SCW occurs in June, while mixed convective weather peaks in July. The initiation time of convective systems is concentrated between 1000 and 1300 BST, with apeak at 1200 BST. Over mountains, the daily peaks of ordinary and significant SCW generally occur at 1700–1800 BST and 1600–1700 BST, respectively, while over plains, the peak of ordinary SCW typically lags behind that of mountains by 1–2 hours. Additionally, SCW systems are mainly initiated over mountains, with most lifetimes lasting 7–13 hours. Nonlinear convective systems produce the most SCW events, followed by trailing-stratiform convective systems. The convective available potential energy (CAPE), downdraft convective available potential energy, and the temperature difference between 850 and 500 hPa can all distinguish between SCW systems and non-SCW systems occurring over plains. Compared to non-SCW convective systems, SCW convective systems over mountains are more likely to occur in environments with less precipitable water, while SCW convective systems over plains are more likely to occur in environments with higher CAPE and stronger deep-layer wind shear. [ABSTRACT FROM AUTHOR]

This document provides a summary of the weather patterns and extreme events that occurred in the United States during the months of May and June 2024. In May, there were contrasting weather conditions across the country, with record-low temperatures in the Northwest and record-high temperatures in the Southwest. Severe thunderstorms and tornadoes occurred throughout the month, causing fatalities and damage. May was the 13th-warmest and 13th-wettest on record for the contiguous United States. In June, there was record-breaking heat in various parts of the country, with some areas experiencing daily-record highs. The Southwest and Southeastern states saw extreme heat, while the Northwest had cool temperatures. There were also significant rainfall and flooding in parts of the West and South. June 2024 was the second-hottest and 41st-driest June in the past century for the contiguous United States. The summary provides factual information about the temperatures, precipitation, and extreme events without any personal opinions or biases. [Extracted from the article]

This article provides a trend analysis of rainfall in the Tlawng River basin of Mizoram, India from 1984 to 2023. The study finds that while there is an increasing trend in annual rainfall, it is not statistically significant. However, there are statistically significant increasing trends in the monsoon and winter seasons. The article emphasizes the importance of understanding rainfall patterns for effective water resource management. It also references two articles on the Northeast Monsoon in South Asia and the application of trend analysis to study rainfall variability in the Mahanadi River basin. These articles may be useful for library patrons researching meteorology, monsoons, rainfall variability, and statistical analysis. [Extracted from the article]

Previous research has suggested that the frequency and intensity of surface hazards associated with thunderstorms and convection, such as severe convective winds (SCWs), could potentially change in a future climate due to global warming. However, because of the small spatial scales associated with SCWs, they are unresolved in global climate models, and future climate projections are uncertain. Here, we evaluate the representation of SCW events in a convection-permitting climate model (Bureau of Meteorology Atmospheric Regional Projections for Australia, BARPAC-M) run over southeastern Australia for the months of December–February. We also assess changes in SCW event frequency in a projected future climate for the year 2050 and compare this with an approach based on identifying large-scale environments favourable for SCWs from a regional parent model (BARPA-R). This is done for three different types of SCW events that have been identified in this region, based on clustering of the large-scale environment. Results show that BARPAC-M representation of the extreme daily maximum wind gust distribution is improved relative to the gust distribution simulated by the regional parent model. This is due to the high spatial resolution of BARPAC-M output, as well as partly resolving strong and short-lived gusts associated with convection. However, BARPAC-M significantly overestimates the frequency of simulated SCW events, particularly in environments having steep low-level temperature lapse rates. A future decrease in SCW frequency under conditions with steep lapse rates is projected by BARPAC-M, along with less frequent favourable large-scale environments. In contrast, an increase in SCW frequency is projected under conditions of high surface moisture, with more frequent favourable large-scale environments. Therefore, overall changes in SCWs for this region remain uncertain, due to different responses between event types, combined with historical model biases. [ABSTRACT FROM AUTHOR]

Most damage to buildings across the contiguous United States of America (USA) is caused by gusts in convective events associated with thunderstorms. Design rules for structures to resist these events rely on the integrity of meteorological observations and the methods of assessment. These issues were addressed for the US Automated Surface Observation System (ASOS) in six preliminary studies published in 2022 and 2023, allowing this present study to focus on the analysis and reporting of gust events observed between 2000 and 2023 at 642 well-exposed ASOS stations distributed across the contiguous USA. It has been recently recognized that the response of buildings to convective gusts, which are non-stationary transient events, differs in character from the response to the locally stationary atmospheric boundary gusts, requiring gust events to be classified and assessed by type. This study sorts the mixture of all observed gust events exceeding 20 kn, but excluding contributions from hurricanes and tropical storms, into five classes of valid meteorological types and two classes of invalid artefacts. The valid classes are individually fitted to optimal sub-asymptotic models through extreme value analysis. Classes are recombined into a joint mixture model and compared with current design rules. [ABSTRACT FROM AUTHOR]

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Thunderstorms are known to have the potential to cause damage to the population. In Mexico, these weather events can bring threats such as lightning, hail, damaging winds, and even tornadoes. Various parameters and indices have been developed for mid‐latitude regions to improve forecasting and reduce the potential damage from thunderstorms; however, they do not consider the specific conditions of tropical and subtropical environments. This research used a comprehensive set of thunderstorm reports and the proximity‐sounding approach using ERA5 reanalysis data to examine five important instability indices commonly used for thunderstorm forecasting regarding their spatial and temporal characteristics. The results reveal significant variations in the values of the instability indices during thunderstorm events associated with different atmospheric systems in both the high‐activity and low‐activity seasons. The above suggests that no single index can reliably predict thunderstorms throughout Mexico and during all seasons. Analyses provide forecasters with a more comprehensive understanding of the various atmospheric conditions under which thunderstorms develop in the country, which can lead to more accurate forecasting and better disaster risk management for these natural phenomena. [ABSTRACT FROM AUTHOR]

The evolution of charge structure involved in lightning discharge of a thunderstorm over the central Tibetan Plateau is investigated for the first time, based on the data from very high frequency interferometer, radar and sounding. During the developing‐mature stage, the TP thunderstorm exhibited a tripolar charge structure evolved from an initial inverted dipole. At the mature stage, a bottom‐heavy tripole charge structure is clearly presented, with a strong lower positive charge center (LPCC) at temperatures above −10°C, a middle negative charge region between −30°C and −15°C, and an upper positive charge region at T < −30°C. As the LPCC was depleted, the charge structure evolved into a normal tripole with a pocket LPCC. The merging between different convective cells resulted in the formation of two adjacent negative charge regions located directly and obliquely above the LPCC, and horizontally arranged different charge regions were simultaneously involved in the same lightning discharge. Plain Language Summary: Tibetan Plateau thunderstorms usually exhibit special convective structures. Using the data from the accurate lightning VHF interferometer, electric field mill, fast/slow antenna and C‐band radar, the evolution of the charge structure of thunderstorms and their influence on lightning discharges are investigated. Our observation for the first time revealed the charge structure evolution of the central‐TP thunderstorm which involved in the lightning discharge, exhibiting a bottom heavy tripole charge structure with a large LPCC in the mature stage evolved from an initial inverted dipole and the usual tripole in the dissipating stage of the thunderstorm. Under different magnitudes of the LPCC, different types of lightning discharges including ‐IC, +IC and ‐CG flashes were generated, indicating the crucial effects of LPCC on the lightning discharge types. Key Points: The charge structure of the TP thunderstorm evolves from an initial inverted dipole to a mature stage tripole with a strong LPCCHorizontally distributed negative charge zones from cell merger are simultaneously involved in the discharge of a single lightning flashDifferences in the relative magnitude of LPCC leads to various types of lightning discharges [ABSTRACT FROM AUTHOR]

Blue corona discharges are often generated in thunderclouds penetrating into the stratosphere and are the optical manifestation of narrow bipolar events (NBEs) observed in radio signals. While their production appears to depend on convection, the cause and nature of such discharges are not well known. Here we show the observations by a lightning detection array of unusual amounts of 982 NBEs during a tropical storm on the coastline of China. NBEs of negative polarity are predominantly observed at the cloud top reaching the stratosphere, and positive NBEs are primarily at lower altitudes. We find that the dominant polarity changes with the typical time of development of thunderstorm cells, suggesting that the polarity depends on the phase of the storm cells. Furthermore, we find that the lightning jump of negative NBEs is associated with above-anvil cirrus plumes of ice crystals and water vapor in the lower stratosphere. We propose that variations in updrafts induce changes in the altitude and charge concentrations of the cloud layers, which lead to the polarity transition. Our results have implications for studies of the chemical perturbations of greenhouse gas concentrations by corona discharges at the tropopause. NBEs are intracloud lightning discharges with both positive and negative polarities. Here, the authors show that the dominant polarity of NBEs in the overshooting cloud depends on the phase of the storm cells. [ABSTRACT FROM AUTHOR]

Lightning generated electromagnetic impulses propagating in the magnetospheric plasma disperse into whistlers – several seconds long radio wave signals with decreasing frequency. Sometimes, multiple reflections form long echo trains containing many whistlers with increasing dispersion. On January 3, 2017, two necessary prerequisites – a pronounced lightning activity and a magnetospheric plasma duct – allowed for observations of a large number of whistler echo trains by the high-latitude station in Kannuslehto, Finland. Our investigation reveals that the duct existed for nearly eight hours. We show that causative lightning sferics arrived to the duct entry from three different winter thunderstorms: a small storm at the Norwegian coast, which produced energetic lightning capable to trigger echo trains in 50% of cases, and two large storms at unexpectedly distant locations in the Mediterranean region. Our results show that intense thunderstorms can repetitively feed electromagnetic energy into a magnetospheric duct and form whistler echo trains after subionospheric propagation over distances as large as 4000 km. When lightning generated whistler waves echo multiple times, they are called whistler echo trains. Here, the authors show lightning strokes from three thunderstorm systems responsible for long-lasting and intense whistler echo trains. [ABSTRACT FROM AUTHOR]

Hailstorms are analyzed across the United States using explicit hailstone size calculations from convection-permitting regional climate simulations for historical, mid-century, and end of twenty-first-century epochs. Near-surface hailstones <4 cm are found to decrease in frequency by an average of 25%, whereas the largest stones are found to increase by 15–75% depending on the greenhouse gas emissions pathway. Decreases in the frequency of near-surface severe hail days are expected across the U.S. High Plains, with 2–4 fewer days projected—primarily in summer. Column-maximum severe hail days are projected to increase robustly in most locations outside of the southern Plains, a distribution that closely mimics projections of thunderstorm days. Primary mechanisms for the changes in hailstone size are linked to future environments supportive of greater instability opposed by thicker melting layers. This results in a future hailstone size dichotomy, whereby stronger updrafts promote more of the largest hailstones, but significant decreases occur for a majority of smaller diameters due to increased melting. [ABSTRACT FROM AUTHOR]

Due to their severity and lack of predictability, understanding and forecasting extreme precipitation events (EPEs) is critical for disaster risk reduction. The present work documents the large‐scale environment of tropical EPEs based on a 42‐year data set combining dense rain‐gauge networks that cover several tropical small islands and coastal regions. Approximately 10%–30% of EPEs are associated with a tropical storm or cyclone (TC), except for Reunion, for which its high topography makes it reach 55%. TCs multiply the EPE probability by a factor of 4–15, especially during TCs of category 1 or higher. A composite analysis demonstrates that the remaining large part of EPEs occurs within large‐scale and strong moist, convective, and cyclonic wind anomalies resulting from the superimposition of intraseasonal, seasonal‐to‐annual, and interannual timescales. These intense anomalies come essentially from intraseasonal variability, and lower frequencies improve the effect of intraseasonal events in creating a favorable environment for EPEs. Plain Language Summary: Floods and landslides, mainly caused by extreme precipitation events (EPEs), are severe disasters that affect populations and economies. However, their prediction, especially in tropical areas, is challenging. Here, we study the main atmospheric configurations leading to EPEs using rain‐gauge data densely sampling several tropical small islands and coastal regions, covering the period 1979–2021. In areas prone to tropical storms and cyclones (TCs), these systems account for 10%–30% of EPEs, except for Reunion, whose high topography increases it up to 55%. TC‐related EPEs are also more intense than non‐TC‐related EPEs. TCs multiply the EPE probability of occurrence by 4–15 times, depending on the region and the TC category. Non‐TC‐related EPEs are shown to occur within specific large‐scale weather patterns in which moisture is highly increased, and convective storms are more active. These patterns involve phenomena occurring at intraseasonal (2–90‐day periods), seasonal‐to‐annual (91–365‐day periods), and interannual (periods above one year) timescales. The intraseasonal variability helps the most to develop this environment favorable to the occurrence of EPEs. Slower signals build a background on which intraseasonal variability can have more effects. The real‐time monitoring of these different features should improve EPE forecasting capabilities and deliver more early warnings. Key Points: Over most of the studied tropical small islands, only 10%–30% of extreme precipitation events occur near a tropical storm or cycloneTropical storms and cyclones favor heavier rainfall and raise the probability of occurrence of extreme precipitation by a factor of 4–15The other largest part of events occur in a large‐scale, intense, moist, and convective anomaly driven mainly by the intraseasonal timescale [ABSTRACT FROM AUTHOR]

We simulate the Madden‐Julian oscillation (MJO) over an aquaplanet with uniform surface temperature using the multiscale modeling framework (MMF) configuration of the Energy Exascale Earth System Model (E3SM‐MMF). The model produces MJO‐like features that have a similar spatial structure and propagation behavior to the observed MJO. To explore the processes involved in the propagation and maintenance of these MJO‐like features, we perform a vertically resolved moist static energy (MSE) analysis for the MJO (Yao et al., 2022, https://doi.org/10.1175/jas‐d‐20‐0254.1). Unlike the column‐integrated MSE analysis, our method emphasizes the local production of MSE variance and quantifies how individual physical processes amplify and propagate the MJO's characteristic vertical structure. We find that radiation, convection, and boundary layer (BL) processes all contribute to maintaining the MJO, balanced by the large‐scale MSE transport. Furthermore, large‐scale dynamics, convection, and BL processes all contribute to the propagation of the MJO, while radiation slows the propagation. Additionally, we perform mechanism‐denial experiments to examine the role of radiation and associated feedbacks in simulating the MJO. We find that the MJO can still self‐emerge and maintain its characteristic structures without radiative feedbacks. This study highlights the role of convective MSE transport in the MJO dynamics, which was overlooked in the column‐integrated MSE analysis. Plain Language Summary: We conduct simulations of the Madden‐Julian oscillation (MJO) using a computer model that can explicitly simulate deep convective clouds. The simulated MJO behaves similarly to what has been observed in the real world in terms of its spatial structure and propagation. We then delve into the detailed mechanisms behind the MJO, using a method that analyzes how energy and moisture move vertically through the atmosphere, rather than just averaging these properties across the whole atmosphere. This novel analysis shows that radiation, convection, turbulence in the atmospheric boundary layer, and large‐scale atmospheric flows all play roles in sustaining the MJO and affect its eastward propagation. Interestingly, the MJO can still develop and maintain its unique features without the influence of radiation, indicating other processes are also key. This research underscores the importance of understanding the vertical transport of energy and moisture by convective storms in studying the MJO, an aspect previously underappreciated in some simpler models and diagnoses. Key Points: We have successfully simulated the Madden‐Julian Oscillation (MJO) using the Energy Exascale Earth System Model‐multiscale modeling framework over an aquaplanet with uniform surface temperatureVertically resolved analyses of moist static energy highlight the role of convection in the maintenance and propagation of the MJOMechanism‐denial experiments show that radiative feedbacks are not essential to simulate the MJO [ABSTRACT FROM AUTHOR]

Overshooting convection can significantly impact the chemical and radiative properties of the upper troposphere and lower stratosphere through the transport of various chemical species. These impacts include enhancements of water vapor and ozone‐depleting halocarbons, which both have important consequences for climate change. Therefore, accurate prediction of the Earth's climate system requires convective overshooting to be included. To better understand how convective transport is represented in current state‐of‐the‐art models, approximately 75,000 individual updrafts in the central and eastern United States are analyzed from High‐Resolution Rapid Refresh (HRRR) simulations and NEXRAD radar observations during May and July 2021. Distributions of echo top potential temperatures and heights, as well as diurnal cycles of overshooting frequency, are compared to observations. These distributions show mean, median, and maximum echo tops 2–3 km lower than observations, both in absolute and tropopause‐relative space, with evidence of updrafts losing momentum too rapidly above the tropopause. Diurnal cycles show accurate times of maximum and minimum overshooting, but significant errors at model initialization and evidence that some simulated overshoots continue too late into the overnight hours. Despite these deficiencies, distributions of simulated levels of maximum detrainment show decent agreement with observations. All results, including the severe underprediction of echo top heights, persist at shorter forecast lead times. This indicates a need to improve representation of overshooting storms in weather and climate models, even those that are convection‐permitting, or introduce a transport parameterization. Plain Language Summary: Thunderstorms that are able to extend into the stratosphere can lead to water and pollutants being transported to altitudes where they are not typically found in large quantities. There is evidence suggesting the collective impact of thousands of these storms annually can significantly change the composition of the upper troposphere and lower stratosphere, with subsequent impacts on Earth's climate. The goal of this work is to investigate how well this transport process is captured by the best model available for forecasting thunderstorms today. From an analysis of each simulated storm in the United States during May and July 2021, we find cloud top heights several kilometers lower in the model when compared to radar observations. Forecasts initialized a few hours closer to the time of day when the events generally occur do not change the result. These results indicate that climate simulations are not able to properly represent transport by thunderstorms. Therefore, improvements to the representation of overshooting convection or a separate estimation of its impacts will need to be added to models. Key Points: Echo top heights predicted by the HRRR were generally 2 km lower than observations and up to 4 km lower than the maxima of a previous studyOnly 4% of HRRR overshoots reached the stratospheric overworld, significantly lower than the 35% of observed cases reaching that levelTransport to the upper troposphere was also at lower altitudes than observations, but less biased than echo tops in the lower stratosphere [ABSTRACT FROM AUTHOR]

Background: Catheter ablation (CA) is a well-established treatment in patients with ventricular tachycardia and appropriate implantable cardioverter defibrillator (ICD) therapies. Methods: We enrolled 57 consecutive carriers of ICD undergoing CA for electrical storm (ES). Our aim was to investigate differences in clinical, device-related, and electroanatomic features among patients who had history of appropriate ICD interventions before the ES compared to those who had not. The primary endpoint was a composite of death from any cause and recurrences of sustained VT, ventricular fibrillation, appropriate ICD therapy, or ES. Results: During a median follow up of 39 months, 28 patients (49%) met the primary endpoint. Those with previous ICD interventions had a higher prevalence of late potentials and a greater unipolar low-voltage area at electroanatomic mapping. Patients who met the primary endpoint had a higher prevalence of ATP/shock episodes preceding the ES event. At Cox regression analysis, non-ischemic dilated cardiomyopathy (NIDCM), QRS duration, and previous ATP and/or shock before the ES were associated with arrhythmic recurrences and/or death. At multivariate analysis, NIDCM and previous shock were associated with arrhythmic recurrences and/or death. Conclusions: A history of recurrent ICD therapies predicts worse outcomes when CA is needed because of ES. Although more studies are needed to definitively address this question, our data speak in support of an early referral for CA of ES. [ABSTRACT FROM AUTHOR]

A strong and fast-moving electrical storm occurred in the Southwest Florida region overnight, from 01:00 UTC on 17 April to 07:00 UTC on 17 April 2023. Video recordings were conducted in the region at Latitude N 26.34° and Longitude W 81.79° for 5 h and 15 min, from 01:45 UTC to 07:00 UTC. The camera captured the flashes transforming from pinkish, violet, blue, and then emerald green in the sky twice: the first colored flash lasted 2.0 s, and the second one lasted 0.5 s. The characteristics of the flashes were analyzed using video images integrated with lightning flash data from the Geostationary Lightning Mapper (GLM). To gain deeper insights into the associated atmospheric conditions, the Advanced Baseline Imager (ABI) was also used to help understand the spectral anomalies. Both events had similarities: the same pattern of changing luminous colors in the optical images and the trajectory of the lightning discharges, showing clusters and horizontal distributions. Event 1 occurred mainly over the ocean and featured more intense storms, heavier rain, and denser, higher cloud-tops compared to Event 2, which occurred inland and involved dissipating storms. Moreover, the group energy detected in Event 1 was an order of magnitude higher than in Event 2. We attribute the wavelength of the recorded colored luminosity to varying atmospheric molecular concentrations, which ultimately contributed to the unique spectral line. In this study, we explore the correlation between colored flashes and specific atmospheric concentrations. [ABSTRACT FROM AUTHOR]

Abstract—Numerous publications have appeared in the literature describing a new seismo-electromagnetic effect—the appearance of magnetic pulses with a duration of 1–40 s, which are detected at distances up to ten thousand km a few minutes before earthquakes of even low magnitude. An assumption was made about the universality of the processes responsible for generation of pulsed precursors and the fundamental possibility of a short-term (a few minutes) warning of an approaching earthquake. In this article, the possibility of the occurrence of ultra-low-frequency pulses that precede seismic events with magnitudes M > 5.0 is studied based on the data from a network of induction magnetometers in the Far East. Pulsed disturbances occur regularly in the records by these highly sensitive magnetometers. Some pulses are observed synchronously at several stations, which excludes their origin from local noise. The spectral maximum of about 7–8 Hz of the oscillatory structure, which appears in many pulses, corresponds to the fundamental frequency of the Schumann resonator. A comparison of magnetic observations with data from the World Wide Lightning Location Network (WWLLN) showed that some of the pulses were caused by lightning discharges in the 650 km vicinity of magnetic station. Although some of the impulses are observed immediately before earthquakes, their connection with seismic activity cannot be claimed with certainty. The calculation of the number of pulses within the 5-min interval before and after the seismic shock shows that they are randomly distributed around the time of the earthquake. Apparently, the pulses are mainly due to the ionospheric response to a distant lightning discharge. [ABSTRACT FROM AUTHOR]

With future global warming projections, how lightning activity changes in the warmer world is still a debated and challenging question. During the Indian pre‐monsoon season (March–May), land surface heating and moisture availability due to prevailing winds from the neighbouring oceans provide favourable conditions for thunderstorm formation. Based on 24 years of lightning data from 2000 to 2023 detected by Lightning Imaging Sensor/Optical Transient Detector (LIS/OTD) and Indian Lightning Location Network (ILLN), the trend of lightning flashes over western India (15°–22°N, 72.5°–81°E) has been investigated. Our results demonstrate a steady decline in lightning activity during the pre‐monsoon season over western India, which contradicts the previous studies suggesting an increasing lightning trend over the Indian Subcontinent and other parts of the world. Our analysis has shown a falling trend of lightning activity at a rate of −0.066 flashes·km−2 year−1 from 2000 to 2013 (LIS/OTD) and −0.14 M flashes·year−1 from 2014 to 2023 (ILLN). Our observation and previous research strongly suggested that the pressure difference between the land and the neighbouring oceans during pre‐monsoon and monsoon has been weakening for a long time over the Indian region, and we have found a consistent reduction in wind speed over the study region. Here, we propose that the enhanced Indian Ocean warming potentially weakens the land–sea thermal contrast and, thereby, reduces the horizontal pressure gradient. Further, the decreasing trend in the land–sea horizontal pressure gradient resulted in a declining rate of wind speed over western India, affecting moisture transport over land. Thus, the study emphasizes the impact of the decreased land–sea horizontal pressure gradient on declining lighting activity in western India. [ABSTRACT FROM AUTHOR]

The autonomic nervous system plays a key role in maintaining body hemostasis through both the sympathetic and parasympathetic nervous systems. Sympathetic overstimulation as a reflex to multiple pathologies, such as septic shock, brain injury, cardiogenic shock, and cardiac arrest, could be harmful and lead to autonomic and immunologic dysfunction. The continuous stimulation of the beta receptors on immune cells has an inhibitory effect on these cells and may lead to immunologic dysfunction through enhancing the production of anti-inflammatory cytokines, such as interleukin-10 (IL-10), and inhibiting the production of pro-inflammatory factors, such as interleukin-1B IL-1B and tissue necrotizing factor-alpha (TNF-alpha). Sympathetic overstimulation-induced autonomic dysfunction may also happen due to adrenergic receptor insensitivity or downregulation. Administering anti-adrenergic medication, such as beta-blockers, is a promising treatment to compensate against the undesired effects of adrenergic surge. Despite many misconceptions about beta-blockers, beta-blockers have shown a promising effect in decreasing mortality in patients with critical illness. In this review, we summarize the recently published articles that have discussed using beta-blockers as a promising treatment to decrease mortality in critically ill patients, such as patients with septic shock, traumatic brain injury, cardiogenic shock, acute decompensated heart failure, and electrical storm. We also discuss the potential pathophysiology of beta-blockers in various types of critical illness. More clinical trials are encouraged to evaluate the safety and effectiveness of beta-blockers in improving mortality among critically ill patients. [ABSTRACT FROM AUTHOR]

The aerodynamic characteristics of the train under the stationary thunderstorm downburst wind were studied. The thunderstorm downburst wind test device was employed to simulate the thunderstorm downburst wind field. Based on the rigid model pressure measurement tests, analyses were conducted on the influence of radial distance on the pressure coefficients on the train surface, the aerodynamic load coefficients of the train section, and the total force coefficients of the middle and head cars. On this basis, combined with the computational fluid dynamics model, further exploration was conducted on the characteristics of the mean pressure on the train surface and the flow field around the train at different radial distances under the stationary thunderstorm downburst wind. The research results show that the train's total aerodynamic coefficients fluctuate with the train's position. The non-uniform distribution of the lateral force coefficient for each train section is primarily caused by variations in the wind yaw angle along the train's longitudinal axis. Variations in the wind attack angle at different radial distances cause the total lateral force coefficient to change accordingly. When the radial distance r/Dj = 0.5, there is no significant vortex-shedding phenomenon in the flow field around the train. However, when radial distance r/Dj = 1 and 1.5, the leeward surface exhibits a regular vortex-shedding phenomenon. Vortex shedding starts at the junction of the leeward surface and the top surface, extending from the middle car along the train's longitudinal axis toward the front and rear. [ABSTRACT FROM AUTHOR]

South‐west Australia has been identified as a global hotspot for the occurrence of meteotsunamis. In this study, a numerical hydrodynamic model (Regional Ocean Modelling System) was configured to investigate the generation of meteotsunamis through propagating thunderstorms. A range of simulations were performed using realistic and synthetic atmospheric forcing to establish the sensitivity of meteotsunami wave heights and waveforms along different parts of the coast to variations in the propagation speed and bandwidths of propagating pressure jumps associated with the thunderstorms. When a pressure jump propagated from the north and north‐west quadrants with a speed (U) of 8–15 ms−1, both the Proudman and Greenspan resonances were possible mechanisms for the generation of meteotsunamis. However, the response changed for different bandwidths of the propagating pressure jump and resulted in different meteotsunami waveforms at the coast. When U > 15 ms−1, long waves were amplified initially through shoaling at the shelf slope, with Proudman resonance enhancing the wave heights at corresponding resonant depths on the shelf, and then propagated as free waves on the continental shelf. The waves were further amplified at the coast through refraction and shoaling effects and resulted in an elevation wave at the coast. Numerical simulations also indicated that edge waves can also be excited near the coast when the incoming free wave wavelengths were equal to or half the edge wave wavelength. The study provides observational and numerical evidence to suggest that the bandwidth of propagating air pressure jumps plays a major role in meteotsunami generation and their waveforms. Plain Language Summary: The numerical simulation results show that meteotsunamis on the southwest Australian coast can be generated over a range of traveling pressure jump speeds and bandwidths, where Proudman resonance, Greenspan edge wave, refraction, and shoaling were responsible for the initial wave amplification. The simulations also revealed that resonance and shoaling amplification were determined by both the speed and bandwidth of the propagating pressure jumps. The pressure jump with constant translational speed can cause significantly different wave heights and waveform meteotsunami when the bandwidths were different. As the wave propagates southward with speeds of 15–28 ms−1, it undergoes subcritical, critical, and supercritical states over the shelf. The findings of this study provide preliminary guidelines for forecasting meteotsunamis generated by summer thunderstorms along the south‐west Australian coastline. Key Points: A range of moving atmospheric pressure jump speeds were conducive to meteotsunami generation on the southwest Australian coastProudman resonance, Greenspan edge waves, refraction, and shoaling were responsible for the generation and amplification of meteotsunamisThe resonance and shoaling amplification were influenced by both the speed of propagation and the bandwidths of the pressure jumps [ABSTRACT FROM AUTHOR]

Aims: Drug‐refractory electrical storm (ES) is a life‐threatening medical emergency. We describe the use of venoarterial extracorporeal membrane oxygenation (VA‐ECMO) in drug‐refractory ES without a reversible trigger, for which specific guideline recommendations are still lacking. Methods and results: Retrospective observational study in four Iberian centres on the indications, treatment, complications, and outcome of drug‐refractory ES not associated with acute coronary syndromes, decompensated heart failure, drug toxicity, electrolyte disturbances, endocrine emergencies, concomitant acute illness with fever, or poor compliance with anti‐arrhythmic drugs, requiring VA‐ECMO for circulatory support. Thirty‐four (6%) out of 552 patients with VA‐ECMO for cardiogenic shock were included [71% men; 57 (44–62) years], 65% underwent cardiopulmonary resuscitation before VA‐ECMO implantation, and 26% during cannulation. Left ventricular unloading during VA‐ECMO was used in 8 (24%) patients: 3 (9%) with intraaortic balloon pump, 3 (9%) with LV vent, and 2 (6%) with Impella. Thirty (88%) had structural heart disease and 8 (24%) had an implantable cardioverter‐defibrillator. The drug‐refractory ES was mostly due to monomorphic ventricular tachycardia (VT) and ventricular fibrillation (VF) (59%), isolated monomorphic VT (26%), polymorphic VT (9%), or VF (6%). Thirty‐one (91%) required deep sedation, 44% overdrive pacing, 36% catheter ablation, and 26% acute autonomic modulation. The main complications were nosocomial infection (47%), bleeding (24%), and limb ischaemia (21%). Eighteen (53%) were weaned from VA‐ECMO, and 29% had heart transplantation. Twenty‐seven (79%) survived to hospital discharge (48 (33–82) days). Non‐survivors were older [62 (58–67) vs. 54 (43–58); P < 0.01] and had a higher first rhythm disorder‐to‐ECMO interval [0 (0–2) vs. 2 (1‐11) days; P = 0.02]. Seven (20%) had rehospitalization during follow‐up [29 (12–48) months], with ES recurrence in 6%. Conclusions: VA‐ECMO bridged drug‐refractory ES without a reversible trigger with a high success rate. This required prolonged hospital stays and coordination between the ECMO centre, the electrophysiology laboratory, and the heart transplant programme. [ABSTRACT FROM AUTHOR]