... Strong gusty wind areawide, and scattered showers and thunderstorms are expected by afternoon with a cold front. Dry weather returns Sunday under high pressure.
NEAR TERM /UNTIL 6 PM THIS EVENING/... Warm-frontal induced rain is moving quickly east this morning, leaving a short dry interlude for the CWA. A few vorticity- induced scattered showers may redevelop during the mid to late morning period.
Wind gusts of around 45 MPH were reported at the airport sensor at Connellsville, so the early wind advisory start time for the downslope-prone areas of Indiana, Westmoreland, and Fayette appears to be working well. Will maintain other ongoing wind advisories for the rest of the area. Wind gusts of 30 to 40 MPH are already being reported in several areas, and these should start to approach and exceed wind criteria as mixing improves by midday. Think that, for the most part, any possible high wind warning-type gusts will be more associated with convection starting around midday and continuing into the afternoon.
Regarding this convection, concerned about potential for severe gusts with convection that forms ahead/along the crossing cold front later today, with lift forced by further increases in vorticity advection. While MUCAPE values are likely to top out at around 500 J/kg this afternoon, effective bulk shear values of 50-60 knots and cold temperatures aloft could support a few low-topped supercells during the early to mid afternoon hours. 60 to 70 knot wind between 5 and 10 thousand feet could easily be tapped by these storms to create severe surface gusts. In addition, a low-end tornado risk exists across the northern CWA, which could possibly be realized by deviant right-moving storms given expected hodographs. Some hail is also possible given the shear and the temperatures aloft. This severe threat will largely end by late afternoon with the departure of the cold front. SPC is maintaining a marginal severe risk for now.
With mixing, and the area in the warm sector this afternoon, highs in the 60s to lower 70s are expected.
SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... The cold front will complete its passage by early evening as the surface low continues its track through Ontario. Advisory level wind gusts should continue for several hours after FROPA, so extended the ending time of the Wind Advisory through 11 PM. Wind should diminish overnight as the surface pressure gradient relaxes, and mixing decreases. Dry weather is then expected through Sunday night as shortwave ridging builds across the Upper Ohio Valley region.
A shortwave trough in nearly zonal flow aloft is expected to cross the region Monday and Monday night, as an associated weak surface low tracks across the Mid Atlantic region. Rain chances return then, and some snow could mix in north of PIT Monday night before the trough and surface low exit.
LONG TERM /TUESDAY THROUGH FRIDAY/... A shortwave in quasi zonal flow aloft is expected track across the region Tuesday, maintaining rain chances in the forecast. A deep Western CONUS trough is progged to track slowly eastward, reaching the Central CONUS by the end of the week. Increasing warm, moist advection in southwest flow ahead of the trough will return rain chances again by Thursday night and Friday.