Round 2 Tuesday/Wednesday(4/4-5/23)

[nWo]

We could see a multi-day event next week, strong surface intensifying low-pressure system is forecast to proceed across the central Great Plains into the Upper Midwest Tuesday through Tuesday night, in response to a significant short trough emerging from the Intermountain West.  It still appears that, as the center of the deepening low pressure system migrates from the north central Kansas vicinity through eastern Nebraska and western Iowa during the late afternoon and early evening, a trailing dryline advancing across the Missouri/Kansas border vicinity might provide one focus for intense thunderstorm initiation.  

 A period of sustained, long track discrete supercell development may be possible, as strong southwesterly deep-layer winds  moves cells away from the dryline through the moist warm sector.  This probably would be accompanied by potential for strong tornadoes and large hail.  Thereafter, as a trailing cold front overtakes the dryline and surges eastward across the lower Missouri/middle Mississippi Valleys, an organizing squall line may be accompanied by strong, damaging wind gusts and a few tornadoes. As the occluding surface cyclone continues across and northeast of the Upper Midwest/Great Lakes region on Wednesday, there may be at least some continuing risk for severe thunderstorm development across parts of the lower Great Lakes/upper Ohio Valley and perhaps parts of the northern Mid Atlantic. However, due to a number of lingering uncertainties, this remains much more unclear at the  present time. Storms could refire during the day on Wednesday. The Storm Prediction Center already has 30%(Enhanced Risk) area covering the entire state of Missouri and a majority of Illinois. A 15%(Slight Risk) area covers portions of Kentucky to about I-75. This includes the Cincinnati/NKY area. At the time of this posting the instability looks to be more prevalent that what some went through this past Friday. Keep checking back for updates.

The following maps illustrate what I'm talking about.

Trough

 

Dryline

EHI

 

Supercell

 

[nWo]

Just to show how things can change quickly in weather forecasting. I've had to change this post in the middle of making it.  The Storm Prediction Center has a majority of Kentucky in a Level 2 Slight Risk Area for Wednesday. This change is primary due to the slowing upper trough, and the westward expansion of severe probabilities. Lower 70s F dewpoints and heating ahead of a cold front is expected to support scattered storms during the day into the lower MS Valley, where mainly hail and damaging gusts will be possible.   Destabilization remains a bit uncertain, based on the latest model output, with perhaps considerable warm sector cloud cover inhibiting insolation.  Based on ensemble output, the NAM might be a bit of an outlier indicating sizable instability developing across southern lower Michigan and adjacent portions of Indiana/Ohio by early Wednesday afternoon. If it becomes more apparent  in subsequent model output that this environment will materialize, severe probabilities will probably need to be increased, with the risk including at least a bit more appreciable potential for a couple of strong tornadoes.