Monday, November 29, 2010

Update on severe weather and flooding risk for today

A strong frontal system is poised to move through the region this evening. Atmospheric conditions are coming together to create the potential for severe weather over the Lower Mississippi River Valley into parts of the Tennessee Valley, including a portion of the Mid-South. In addition, the risk for flooding in low-lying and urban areas remains as well.

The map above shows the SLIGHT RISK area that the Storm Prediction Center will be closely monitoring today. Storms are expected to increase in intensity by mid-afternoon along the western portion of the slight risk area and move slowly east overnight. As you can see, the Memphis area is now encompassed within the slight risk. The most likely time for severe weather in the metro area will be between 4-10 pm with the main risks being damaging thunderstorm wind and isolated tornadoes.

The second map (above) highlights the tornado risk area for today and tonight. As low pressure develops and moves northeast through Arkansas, areas ahead of the low (in the "warm sector"), mainly SE AR, NW LA, and MS, will be at the most risk of seeing tornadoes. The risk extends north into the metro area though as well, just not as high of a threat. The areas within the hatched blue circle have the greatest threat of significant tornadoes.

Finally, this weather system will be quite the rain-maker as well. The last map above shows the expected 12-hour rainfall totals from noon today until midnight tonight. Most of the area should see anywhere from 1-2" of rain, while isolated areas could see higher amounts. This is the reason for the Flash Flood Watch that is in effect, which could be exacerabted by the heavy rain we received last week. will have full coverage of this developing weather scenario on the web, Twitter (@memphisweather1), and Facebook ( You can also receive severe weather alerts via Twitter for Shelby County by following @shelbyalerts or sign up to receive alerts by e-mail for any metro county as they are issued from the National Weather Service.

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