National Weather Service United States Department of Commerce

Mississippi Valley Summer Heat Wave; Severe Thunderstorms and Flooding Possible to the North

A dangerous summer heat wave will continue much of the Plains, Mid/Lower Mississippi Valley, Southeast U.S. today and Thursday. Areas of severe thunderstorms may occur today and again on Thursday from parts of the northern/central Rockies and High Plains into the Ohio Valley and Carolinas. Excessive rainfall over similar areas may bring flash flooding today and Thursday. Read More >

July 22-24, 2010: Heavy Rain & Flooding

 

Ring-of-Fire Storms and Floods

72 Hour Precipitation Map ending at 7:00 am Sunday
Map of 72 hour precipitation ending on July 25

Meteorological Setup:

A large sub-tropical ridge developed early in the week across Texas and drifted east towards the Southeastern United States. (Fig. 1)  As the 500hPa ridge drifted east, a series of weak low pressure systems traversed the Central Plains northeast into the Upper Midwest. A by-product of the 500hPa positioning on 22Jul2010, was a steady feed of Gulf of Mexico moisture to the Northwest of the ridge. (Fig. 2) 

Strong convective activity is commonly found when subtropical ridges occur, especially during the warm seasons. Galarneau and Bosart (2006) coined the term "ridge rollers" for convective systems 

500hPa Ridge 20Jul10-24Jul10
Figure 1. 500hPa-ridge across the Southwest United States becoming centered across the Southeast United States 22July 2010.

 

Precipitable Water
Figure 2. GFS Precipitable water anomalies.

 

Total Rainfall
Figure 3. Multi-sensor estimated rainfall for the period of 21-24 July 2010.