Erin Strengthens to a Hurricane; Heavy Rainfall Possible in Puerto Rico and the Virgin Islands, the Upper Midwest, South Texas

Hurricane Erin may bring isolated flash and urban flooding, landslides or mudslides, and possible tropical storm conditions to Puerto Rico and the U.S. Virgin Islands this weekend. Scattered thunderstorms and heavy rainfall may bring areas of flooding this weekend over the Upper Midwest. A tropical disturbance will bring locally heavy rain and mainly urban flash flooding to far southern Texas. 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 America 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.

Figure 2. GFS Precipitable water anomalies.

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

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