More Severe Storms Out West – Ridge Keeps The Tennessee Valley Mostly Dry

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The severe weather threat will continue across the Plains, portions of the Midwest and Ohio River Valley this afternoon.  Yesterday there were over 150 severe weather reports with 16 tornado reports.  Today the threat for severe weather remains in many of the same areas, including Moore, Oklahoma and other hard hit communities from tornadoes over the past couple of weeks.  Below is the Day 1 Convective Outlook, with hail and wind being the main threats with any storms that develop.

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Tomorrow the severe threat is even higher, especially for tornadoes. The Storm Prediction Center has already highlighted part of southern Nebraska, central Kansas and central/western Oklahoma in a ‘Moderate Risk’ for severe storms. There also remains a large flooding and flash flooding threat in parts of the Midwest, especially in Iowa, Missouri and Illinois due to significant rain over the past couple of days and the chance for more storms and heavy rain.  Below is the Day 2 Convective Outlook with many of the same areas with a risk for severe storms, including the I-35 corridor.  There will be the potential for more severe storms in part of the plains and Midwest through the end of the work week.

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So is this severe weather headed our way?  Thankfully for the Tennessee Valley we are on the northern edge of a strong ridge of high pressure that will keep the severe storms to our west for much of the week.  Also surface high pressure is centered off of the eastern seaboard near Bermuda, what meteorologists often refer to as a Bermuda High. We typically see a Bermuda High more often in the summer months, which can persist for weeks, causing extremely hot and dry conditions.  You can easily see where the ridge of high pressure is just by looking at the satellite and radar image and surface map below, showing a mostly sunny sky over much of the Southeast, with clouds and storms to the north and west.

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As moisture continues to surge into the area, the chance for an afternoon pop-up shower or storm will slowly rise through the end of the week as the ridge of high pressure starts to shift east.  Not everyone will see rain, we are only expecting widely scattered storms if any. Remember this type of pop-up, summertime storms are the kind in which you may see it raining right down the road from where you are, but it may not rain directly over your location. Significant rain chances do not return to the Tennessee Valley until early next week, when a cold front approaches the region.

This may have wondering about drought conditions and rainfall. Year-to-date Huntsville still has a higher than five inch surplus of rain (5.36”). So far in the month of May along we have received 6.60” of rain.  Muscles Shoals is somewhat less, but still has a year-to-date surplus just over two inches (2.06”), and a month-to-date total of 4.14”. By this time last year, we had already been experiencing excessively warm and dry conditions through April and May, with rainfall deficits and drought conditions increasing in the Tennessee Valley.  Below is a look at the U.S. Drought Monitor valid May 21st, 6:00 am CDT and the U.S. Drought Monitor about one year later on May, 22 2013.

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Thankfully this year, due to the high amount of rain and cooler temperatures, we are not expecting to experience the extreme drought conditions like last year.

- Jennifer Watson

Twitter: @JWatson_Wx

Facebook: Jennifer Watson WHNT