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The transition region between the North Equatorial Band (NEBn) and North Tropical Zone (NTrZ) in Jupiter is home to convective storms, systems of cyclones and anticyclones and atmospheric waves. A large anticyclone formed in the year 2006 at planetographic latitude 19N and persists since then after a complex dynamic history, being possibly the third longest-lived oval in the planet after Jupiter's Great Red Spot and oval BA. This anticyclone has experienced close interactions with other ovals, merging with another oval in February 2013; it has also experienced color changes, from white to red (September 2013). The oval survived the effects of the closely located North Temperate Belt Disturbance, which occurred in October 2016 and fully covered the oval, rendering it unobservable for a short time. When it became visible again at its expected longitude from its previous longitudinal track, it reappeared as a white large oval keeping this color and the same morphology since 2017 at least until the onset of the new convective disturbance in Jupiter's North Temperate Belt in August 2020. Here we describe the historic evolution of the properties of this oval. We use JunoCam and Hubble Space Telescope (HST) images to measure its size and its internal rotation. We also used HST and PlanetCam-UPV/EHU multi-wavelength observations to characterize its color changes and Junocam images to unveil its detailed structure. The color and the altitude-opacity indices show that the oval is higher and has redder clouds than its environment but has lower cloud tops than other large ovals like the GRS, and it is less red than the GRS and oval BA. We show that in spite of the dramatic environmental changes suffered by the oval during all these years, its main characteristics are stable in time and therefore must be related with the atmospheric dynamics below the observable cloud decks.

Moist convective storms in Jupiter develop frequently and can trigger atmospheric activity of different scales, from localized storms to planetary-scale disturbances including convective activity confined inside a larger meteorological system. In February 2018 a series of convective storms erupted in Jupiter's South Temperate Belt (STB) (planetocentric latitudes from -23$^{\circ}$ to -29.5$^{\circ}$). This occurred inside an elongated cyclonic region known popularly as the STB Ghost, close to the large anticyclone Oval BA, resulting in the clouds from the storms being confined to the cyclone. The initial storms lasted only a few days but they generated abundant enduring turbulence. They also produced dark features, possibly partially devoid of clouds, that circulated around the cyclone over the first week. The subsequent activity developed over months and resulted in two main structures, one of them closely interacting with Oval BA and the other one being expelled to the west. Here we present a study of this meteorological activity based on daily observations provided by the amateur community, complemented by observations obtained from PlanetCam UPV/EHU at Calar Alto Observatory, the Hubble Space Telescope and by JunoCam on the Juno spacecraft. We also perform numerical simulations with the EPIC General Circulation Model to reproduce the phenomenology observed. The successful simulations require a complex interplay between the Ghost, the convective eruptions and Oval BA, and they demonstrate that water moist convection was the source of the initial storms. A simple scale comparison with other moist convective storms that can be observed in the planet in visible and methane absorption band images strongly suggests that most of these storms are powered by water condensation instead of ammonia., Comment: 73 pages, 18 figures, manuscript available online in Icarus

Small-scale waves were observed along the boundary between Jupiter's North Equatorial Belt and North Tropical Zone, ~16.5{\deg} N planetographic latitude in Hubble Space Telescope data in 2012 and throughout 2015 to 2018, observable at all wavelengths from the UV to the near IR. At peak visibility, the waves have sufficient contrast (~10%) to be observed from ground-based telescopes. They have a typical wavelength of about 1.2{\deg} (1400 km), variable-length wave trains, and westward phase speeds of a few m/s or less. New analysis of Voyager 2 data shows similar wave trains over at least 300 hours. Some waves appear curved when over cyclones and anticyclones, but most are straight, but tilted, shifting in latitude as they pass vortices. Based on their wavelengths, phase speeds, and faint appearance at high-altitude sensitive passbands, the observed NEB waves are consistent with inertia-gravity waves at the 500-mbar pressure level, though formation altitude is not well constrained. Preliminary General Circulation Model simulations generate inertia-gravity waves from vortices interacting with the environment and can reproduce the observed wavelengths and orientations. Several mechanisms can generate these waves, and all may contribute: geostrophic adjustment of cyclones; cyclone/anticyclone interactions; wind interactions with obstructions or heat pulses from convection; or changing vertical wind shear. However, observations also show that the presence of vortices and/or regions of convection are not sufficient by themselves for wave formation, implying that a change in vertical structure may affect their stability, or that changes in haze properties may affect their visibility., Comment: Astronomical Journal, accepted