Great AFD:
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
The mid-week mess maker will be moving east of the area by early
Thursday, leaving us in the relative foul weather nadir for the
week. This occurs as we fully enter the warm sector of a low that
will be rapidly spinning up to our west. This means warm advection
again holds sway and as 850 mb temperatures approach +10C, even with
sub-optimal mixing profiles during the diurnally favorable period,
much of the area should again return into the 50s.
A fantastically strong cold front looks to follow the warm Thursday
across the area Thursday night into early Friday. Fall off of about
25C at 850 mb can be noted across this front between here and lower
Michigan as it approaches. This represents a veritable wall of a
density discontinuity, and it indicates that forcing for ascent
along the front itself should be very impressive. If we combine this
with the presence of a couple hundred J/kg of MUCAPE, steep lapse
rates above the 0C isotherm, and solidly negative theta-e lapse
rates from 850 up toward 500 mb, it would seem a rumble or two of
thunder would also be possible along the front. This is unusual for
February, but the low CAPE/high shear environment really is not.
Further, the deep dive of the dynamic tropopause to below 700 mb on
the ECMWF in the wake of the front yields further confidence in
impressive lift along the front.
Another implication of the suppression of the tropopause and the
presence of the 2 PVU surface below 700 mb will be the propensity
for solid mixing in the dry slot behind the frontal passage. The NAM
and GFS both feature 50-60 kts at 850 immediately post-frontal.
Soundings don`t favor the best mixing until daytime Friday in the
post-frontal air mass, however, which would already be beyond the
time when the best tropopause undulation has moved by. Nevertheless,
a period of high winds seems likely overnight Thursday night into
Friday. The favored areas on WSW flow east of Lake Erie and Ontario,
including the Buffalo/Niagara Falls area, would likely see gusts of
50 to 55 mph in this set up even as it stands now. High end
advisories from KBUF to KROC look very plausible...with at least a
chance for warning criteria winds. Climatologically (rapidly
deepening cyclone passing to northwest and strong post frontal
subsidence)...this event is looking more and more threatening. Stay
tuned.