LWX
.LONG TERM /FRIDAY THROUGH MONDAY/...
Uncertainty remains wrt the temp forecast Friday into Saturday due
to where a frontal boundary will stall. Models continue to show a 20-
30 degree spread in high temps during this period. With the front
stalled nearby, a sfc low will track along the front. Some guidance
shows a wedge of stable/cool air to the east of the Alleghenies with
highs only staying in the 50s north of I-66 on Friday, however some
guidance erodes the wedge rather quickly. Ensemble guidance and the
NBM show the most likely solution at this time is the front stalls
somewhere near the FA and a gradient in temperatures exists with
near 70 across the southern areas and upper 50s along the Mason-
Dixon.
Should a warmer scenario come to fruition, the potential for enough
instability rooted in the boundary layer to result in surface-based
convection/thunderstorms, especially during the Saturday period as
the strong sw trough moves through. Given favorable mid-level lapse
rates of 6-7C/km coupled with 60-70 kts in the 850-700 mb layer,
there could be the attendant risk for severe weather if this scenario
works out given the strong dynamics and shear at play.