Conditions will become more favorable for severe thunderstorms Wednesday as the main upper storm system finally moves into the central / southern plains. Slight Risk could be upgraded to Moderate Risk for northern Oklahoma!
Last couple of days minor upper ridge in place over Oklahoma with warm mid level temps, limited atmospheric forcing, weak convergence on surface boundaries. However, this will all change on Wednesday as upper wind energy spreads over Oklahoma increasing the atmospheric forcing and surface convergence to overcome warm mid level temps leading to thunderstorm development! Here's a look at the 500mb(25,000ft) flow showing the stronger upper trough moving into the plains Wednesday evening.
Even though the center of the upper trough tracks north of Oklahoma expect at least isolated to scattered thunderstorms to develop along dry line across western and northwestern Oklahoma and then track east northeast across northern Oklahoma and central / eastern Kansas. Here's one forecast model showing thunderstorms forming along dry line in northwestern Oklahoma and then moving east northeast.
As it stands right now it's a Slight Risk for severe weather. But let me tell you after looking at all the new data coming in this evening I think there is chance that the Slight Risk could be upgraded to a Moderate Risk for northern Oklahoma northward into central / eastern Kansas. Regardless, any thunderstorms that develop could become severe with the main threats very large hail, damaging winds, lightning and tornadoes! As the storm system pushes east the threat for severe weather will shift into far eastern and southeastern Oklahoma on Thursday. I'll talk more about Thursday after we get through Wednesday.
Here's my quick hand drawn severe weather potential map for Wednesday. This is basically a snapshot of how I see things at 6pm Wednesday evening. Thunderstorms form near dry line in northwestern Oklahoma between 5-7pm and track east northeast across northern Oklahoma and central / eastern Kansas through 11pm. Other more isolated thunderstorms could develop south ahead of dry line across western Oklahoma and move east toward central Oklahoma by 11pm. I am expecting the most coverage north with less coverage south as you can see the 80% chance north compared to 40% over central Oklahoma. I have added an X where I think the most likely area for tornado formation is through 8pm. Keep in mind all modes of severe weather are possible in this situation! Also keep in mind that this just my forecast and is NOT meant as exact science.
Bottom line it's a heads up for Oklahoma severe weather Wednesday evening / night. I know you already have your severe weather safety plan ready to go, right? I know you have already talked to your family and loved ones, right? I know everybody knows where everyone is going to be tomorrow evening, right? Great! That's the way we roll in Oklahoma. Prepare for the worst and hope for the best.