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A Soggy Cinco de Mayo Across the Southeast

5 May 2013, 11:43 am

Hola! Hope you’re enjoying this Cinco de Mayo Sunday, despite record-busting rains into the Tennessee Valley and Southern Appalachians. A pesky cut-off low pressure system has plagued the region with flash flooding and damp, dreary skies.

Why do we call it a “cut-off” low pressure system? Typically, weather systems are steered across the globe by the jet stream, which is a channel of fast winds flowing high up in the atmosphere. This particular low has slipped away from the main jet stream flow and is drifting aimlessly across the Deep South.

This blocking pattern is keeping our cut-off low from progressing toward the Atlantic, which means the rain all falls in the same spot. It’s called an “Omega Block” from it’s signature Omega shape (Omega is a letter in the Greek alphabet).

But back to the rain! A solid soaking has taken place across the Southeast over the past 48 hours, and some daily rainfall records were broken in the area.

In just 24 hours, over 3 inches of rain fell across southeastern Tennessee and northern Georgia — when it rains, it pours!

As this storm continues to spin, the rain will continue to come down. New rain totals vary a bit between our in-house Adonis forecast model and the ECMWF (European) forecast model. I’ll show you both forecasts to give you an idea of the spread (total accumulation through Tuesday morning):

All of this rain continues to fall on the already-saturated soil, which contributes to our flooding concerns throughout the area. Flood Watches and Warnings are shown below, where travel could be difficult through some of the low-lying areas. Remember, don’t drive through flooded areas — Turn Around, Don’t Drown!

How long until we dry out again? The Climate Prediction Center is forecasting continued rainfall in the Southeast for the upcoming week ahead.

And finally, our National temperature map got a festive upgrade today! Notice a warming trend through the Plains, which have been trending below average recently — soon we will feel more spring-like from Minnesota down to Missouri.


Hope your weekend is muy bueno! -Meteorologist Miranda Hilgers

One response to “A Soggy Cinco de Mayo Across the Southeast

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