Synoptic-Scale Precursors to Significant Cold-Season Precipitation Events in Burlington, Vermont.

Several classes of significant cold-season precipitation events occurring in Burlington, Vermont (KBTV), during the 33-yr period from 1963 to 1995, are studied with the objective of identifying large-scale circulation precursors to the more extreme events. Several physically interesting and unique features that correspond to 24-h totals of 25 to 50 mm of precipitation are found. Preferential southerly and more maritime surface geostrophic flow occur in the heavier cases, in association with a strong cyclone (anticyclone) to the west (east) of KBTV. The 1000–500-hPa positive thickness anomaly corresponds to a depth-mean virtual temperature anomaly of +10.5°C in the heavy events. Additionally, statistically significant negative thickness anomalies, responsible for triggering these significant precipitation events, can be traced westward to a position in the Pacific Ocean at least 6 days prior to the event. Significantly heavier precipitable water amounts and preferentially strong water vapor transports from maritime regions are also associated with the heavier cold-season precipitation events. [ABSTRACT FROM AUTHOR]