The cold front that swept through the mid Mississippi Valley Wednesday has stalled out to the south. It is expected to lift north as a warm front later tonight.
An area of low pressure is also expected to develop over the central Plains this afternoon. The computer models are projecting the surface low to quickly deepen (strengthen) starting overnight tonight through Friday evening. The track of the surface low takes it generally speaking from Springfield, Missouri (6am CT Friday) to Champaign, IL (12pm CT Friday) to Detroit, Michigan (6pm CT Friday).
Thunderstorms could fire later tonight along the warm front . The Storm Prediction Center has included southeast Missouri, southern Illinois, western Kentucky, western Tennessee and northeast Arkansas in a “Slight Risk” area for severe thunderstorms in their outlook that is valid through 6am CT Friday.
The main threat from these thunderstorms will be large hail, but damaging wind and an isolated tornado can’t be ruled out.
Attention then turns to the main event coming Friday. SPC has all of southeast/east Missouri, east Arkansas, southern Illinois, Indiana, Ohio and Kentucky in a “Slight Risk”. The “Slight Risk” includes cities such as St. Louis, Springfield (Mo & IL), Cape Girardeau, Memphis, Lafayette (IN) and Paducah.
There is a heightened threat for parts of south-central Indiana, southwest Ohio, western/central Kentucky, central Tennessee, northeast Mississippi and northern Alabama. That is why they have those areas in a “Moderate Risk” for severe weather from 6am CT Friday through 6am CT Saturday. However, the action will likely occur during the afternoon and late evening hours.
The “Moderate Risk” includes cities such as Bloomington (IN), Columbus (IN & OH), Cincinnati, Indianapolis, Evansville, Louisville, Lexington, Nashville and Birmingham (AL). The main threat within the “Moderate Risk” are is damaging winds, strong tornadoes and hail.
The jet stream appears to be very favorable for lifting. Diverging winds at 25,000-30,000 feet will create a void and aid thunderstorm development over southeast Missouri, southern Illinois, western Kentucky, northwest Tennessee and northeast Arkansas. This feature moves in around 5am CT Friday.
I think what we are likely to see is individual thunderstorms developing along the warm front overnight tonight in southeast Missouri, southern Illinois, western Kentucky, northwest Tennessee and northeast Arkansas. These would primarily be “hailers”.
Later Friday morning we will see thunderstorms fire up near the Mississippi River and quickly form a line. The thunderstorms will move to the east at a quick pace. They will begin to mature as they move in to south-central Indiana/central Kentucky and be capable of producing damaging winds and tornadoes.
Thunderstorms can happen at any time of the day and at any time of the year. I saw a message on Twitter yesterday that was perfect… “Tornado season starts January 1 and ends December 31.” This is why I can’t stress enough how important it is to have a working NOAA weather radio at home. Yesterday’s storms proved that. They hit between 3am and 6am. Ask yourself, “If it is the middle of the night how would I know there is a warning?” In my opinion, weather radios are just as important as a smoke detector. EVERY home, school and business should have one. Don’t think about it, just get one!