*Updated from my previous post*
As numerical weather models continue to update and change, my overall thinking has somewhat stayed the same, at least for Monday. The GFS model has slowed down considerably compared to previous runs just a few days ago. This will keep severe storm chances in the Central/Southern Plains until Wednesday morning.
Monday (April 8th)
One thing all the models have been consistent with is the strong capping inversion from southeastern KS, down through central-north TX on Monday. There will not be enough dynamical lift to break the cap from this line, eastward. The points of concern will be southwest KS, south-central KS, northwest OK, north-central OK, west-central OK, and possibly northwest TX. However, my current thinking is that the cap won’t break over northwest TX, at least not on Monday. Models continue to consistently show CAPE values over 2000 J/kg from west-central OK, through south-central KS. Assuming the cap breaks everywhere else, storms initiation will be tough to pinpoint. If you strictly look just at the forecast models, EURO and GFS have storms forming in west-central OK and north-central OK, respectively. The 04/06 12z EURO model even has storms developing in south-central KS just before sunset. The cap would be much weaker in KS, so if this were to occur, this area would be the best area for storm initiation. the 04/07 00z GFS (and previous runs) have storms starting out in northern OK and moving into KS by sunset. If or once storms do fire, they will be in an environment for supercell structure. Very large hail, damaging winds and a couple of tornadoes will be possible. The dryline will be set up in western OK and likely retreat westward after sunset.
Tuesday (April 9th)
Still a lot of questions to be answered as far as Tuesday’s severe weather outlook is concerned. Recent runs by the GFS have slowed down the upper-level trough/low that will dig towards the OK/KS area, and then quickly lift northeast by Wednesday. GFS is in somewhat of agreement with the latest EURO as far as timing, with GFS still being a little faster. This would indicate an active severe weather Tuesday for central OK, northern TX, and southern/southeast KS, during the day and early evening. It is still tough to say when and where exactly storms will initiate on Tuesday. The slower EURO suggests storms would fire just after noon from south-central KS, down to northern TX and continue through the early evening hours. If this holds true, storms will likely be discrete and isolated. Because of stronger lift, any cap present would easily break, unlike Monday’s scenario. This could be very interesting if this model holds true. Meanwhile the faster GFS hints at morning convection from southwest OK through central OK. If this occurs, they will likely be elevated thunderstorms. It has the surface-based convection developing in the late afternoon hours in northern TX and eastern OK and into eastern KS. I’m still leaning toward the slower EURO, at this time.
Wednesday (April 10th)
Though there is still low confidence in where and when severe weather will occur on Wednesday, a better idea now exists. A squall line will likely form from an advancing cold front that will be sweeping through southern KS, central OK and northern TX. This squall line will stretch from IL to northeast TX by early Wednesday morning. Though tornadoes aren’t the biggest threat with squall lines, large hail and damaging winds are. This is where computer forecast models really differ. The faster GFS has the squall line centered from southern IN to northeast TX. By sunset, GFS has the squall extended from northern IN to southwest LA. It is very possible that isolated storms will fire a head of this squall line. If they do, these isolated, discrete cells will have the greatest opportunity to develop tornadoes. As far as the slower EURO, it has a squall line developing in northwest OK Tuesday night. It takes all day for this line to reach eastern OK, western AR and northeast TX. Strong storms will also extend to northern IL by Wednesday evening. However, EURO has a broken line and possibly a more isolated severe threat for MO and points northward. This will have to be looked into with upcoming model runs.
Below is a graphic, made by a friend of mine, Cory Mottice. You can check out his Facebook page here. You can also follow him on Twitter: @EverythingWX