Case of the Follow-On Short Wave: A WES (Weather Event Simulator) Case from the March 2-5, 2004 Winter Storm

摘要

Determining the timing and intensity of major winter storms can be quite a challenge when a pair of systems interact with each other. This was the case in the first week of March 2004. As documented in a previous TA-Lite (Meyer 2004), a welldefined cutoff low off the southern California coast was expected for several days to move east along the U.S.-Mexico border as an upstream kicker system passed across the southern Great Basin. This lead system had all the desirable characteristics of a decent southern Arizona winter storm: slow movement, moderate to strong dynamics, a southern track along the international border, sufficient moisture, and a slight negative tilt. Scattered showers developed on schedule over south central Arizona on the evening of March 2nd, and increased in earnest by afternoon on the 3rd as the low began to move east. This part of the storm was well anticipated. Outlooks were issued 4 days ahead of precipitation onset, and Winter Storm Watches were issued with over 36 hours of lead time for mountain snow accumulations up to 18 inches. By the morning of the 3rd, 12 inches of snow had already fallen on Kitt Peak, which is located about 50 miles west of Tucson.