SPC increases severe weather risk for Mid-South Thursday

Yesterday, we discussed the possibility of severe weather on Thursday evening. Today, we update that post with the latest information and a little more detail.  Below you see the latest convective outlook graphics from the Storm Prediction Center, as issued early this afternoon. The Mississippi Valley, from St. Louis to Greeneville, MS, including the Memphis metro, has been upgraded to a Moderate Risk of severe weather, which is somewhat uncommon on the Day 2 forecast. A Day 2 Moderate Risk indicates a fair amount of certainty in the likelihood of severe weather. (Read: What do the SPC risk areas mean?)

A Moderate Risk zone covers the metro for Thursday afternoon/evening.

In fact, as indicated in the second graphic, SPC places us in a “45% hatched” area, as we say in the business.  This means that there is at least a 45% chance that severe weather will occur within 25 miles of any point in that area, given the current forecast data.  The “hatched” region is where there is a 10% or greater risk of significant severe weather.  Significant severe weather is defined as EF-2+ tornadoes, 75+ mph wind, or 2″+ hail.

A 45% hatched area covers the metro, indicating a 45% chance of severe storms and a 10% risk of significant severe weather within 25 miles of any point.

What to expect in the Memphis metro:

Most of Thursday (during the day) will be like the past couple of days – windy, warm, and muggy with highs in the lower 80s and an isolated shower. By mid to late afternoon (probably after 3-4pm), a few thunderstorms could develop ahead of a squall line that will be moving across Arkansas. These early storms will grow in a very unstable and humid environment and could quickly become severe. Any discrete cells pose a risk of hail, damaging wind, and tornadoes.

By early evening (5-7pm), the squall line will move into the metro from west to east.  The main threat from the line of storms will be damaging straight line wind and perhaps large hail.  Isolated tornadoes are also a possibility in the line. Rain, perhaps heavy at times, will follow the squall line for a few hours with most precipitation done by midnight or shortly thereafter.

Plan ahead

Mid-Southerners should have their severe weather safety plans ready and reviewed prior to severe weather occurring.  Know where yo will go and what you will do if severe weather strikes while you are at work, home, or on the road.  Most storms should occur after school hours, though rush hour could be affected. If you have outdoor plans Thursday evening, plan appropriately. Most outdoor activities should probably be proactively cancelled due to expected heavy rain and lightning.

You should also know where you will get your severe weather information given your plans and the timing. We will be nowcasting all severe weather on our social channels listed below. Also plan to have your cell phones charged before heading home from work. If you have the MemphisWeather.net mobile app, now is the time to go ahead and spend the few extra dollars to add StormWatch+ to your app in the Alerts tab, then program in the locations you want alerts for. You’ll automatically receive push notifications as soon as a watch or warning is triggered for your SPECIFIC location(s). Links to our apps are available below as well.

Be prepared not scared!
Erik Proseus, MWN Meteorologist

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