Just got done checking all the latest data from the 06Z models. Not much has changed as far as the event is concerned. I ran some forecast soundings through BUFKIT, and things are really looking good for severe weather. ETA 06Z run indicates the best timeframe will be between 18Z-21Z FRI. Bufkit momentum transfers are showing that 60KNT wind gusts wills will be able to mix down in the afternoon, and that isn't even in the convection. I do believe this is overdone, and that non-convective wind gusts to 50KNTS will be possible (~60MPH).
One big concern for tomorrow is instability. Regardless of instability, a squall line will likely develop, with damaging winds the obvious threat. However, bufkit indicates 0-3km helicity is over 350m2/s2 between 18-21Z, with extreme speeed shear between the SFC and 700MB. The problem is, we must have a CAPE of at least 1150J/KG to get any supercells to sustain themselves. The morning forecast discussion from DTX explains this situation well. Its hard to say at this point, but if sun does break through (ETA strongly suggests it does), than temps will near 70F, and with dewpoints in the mid 50's, will help to bring more instability. The biggest factor in determining the instability though, is the 500mb cold core. If the 500mb temps are a degree or two lower, than instability will be higher...ETA has been indicating a bit colder at 500mb for the past few runs, which is why it is showing more instability.
If for some reason we do end up with less instability, below 750J/KG...Then I would expect mainly a low topped and narrow squall line, possibly thunderless...With a pretty good threat of damaging winds.
Robert
