... High pressure will dominate the area through the weekend. Moisture moving inland from the Atlantic to the southern Appalachians will produce scattered showers and thunderstorms each afternoon and evening over the weekend. A cold front will move slowly across the area on Monday before stalling just southeast of the region on Tuesday. Despite rebuilding high pressure, moisture returning over the front should lead to scattered afternoon and evening showers and thunderstorms the rest of the week.
NEAR TERM /THROUGH SATURDAY/... Surface based CAPE has increased over the wrn zones and a few showers and weak tstms have developed across the NC mtns. Convection will increase in coverage, while a few storms could become fairly strong and produce gusty outflows and small hail thru this evening.
Convection wanes by late evening due to loss of heating and little forcing outside of weak upslope flow. Spotty and shallow showers will likely linger across the high terrain into the overnight period. Not expecting much of a fog threat outside the lower NC mtn valleys as upper cloud cover increases from the northwest. With weak se/ly flow abv the sfc combining with a shallow sfc ridge...morning StCu looks likely again, which may linger thru mid-morning. Another near normal temp day is in store for Sat as the airmass remains mostly unchanged and the mean BL flow continues se/ly. Expect afternoon showers and a general tstms to develop, generally across the mtns and higher elevations of SC and GA as weak triggering is provided by upslope lift in a destabilizing atmos.
SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 200 pm EDT Friday: A 594 dm 500 mb ridge will remain centered over the Mississippi River Valley, with a ridge axis nosing eastward to the Atlantic Coast thorugh the latter half of the weekend. Mainly diurnal mountain showers and thunderstorms are expected Sunday afternoon and evening under the ridge, with minimum temperatures about a category above climatology in the morning, and maxes near climo late in the day.
A modest breakdown in the eastern portion of the ridge is expected Sunday night through Monday as a vigorous wave moves east across the Great Lakes and eastern Canada. Meanwhile, a surface cold front will move southeast through the Ohio Valley lay over into the southern and central Appalachians Monday morning. The boundary will slowly slip southeast through the forecast area the rest of Monday through Monday night, however, recent trends are toward the boundary stalling just southeast of the area. Will feature robust high chance to likely PoPs for mainly daytime Monday. Clouds ahead of the boundary should limit instability and any significant severe thunderstorm threat.
LONG TERM /TUESDAY THROUGH FRIDAY/... As of 200 pm EDT Friday: A broad and shallow eastern U.S. trough will set up briefly on Tuesday, as a recently passed surface cold front stalls just southeast of the forecast area. The trend toward the boundary stalling very near the area is leading to less drying of boundary-layer moisture and a quicker return of southerly flow moisture over the front. The combination of clouds, scattered showers, and cooler post-fropa thicknesses will lead to maximum temperatures some 5 to 10 degrees below normal Tuesday afternoon.
Resurgent Bermuda high pressure will combine with the persistent southern/central CONUS ridge to modestly raise heights again atop the area for Wednesday through Friday. Lingering low-level moisture in southerly flow will produce diurnal precipitation chances Wednesday through Friday. Below climo temperatures on Wednesday will rebound to a category above climo by Friday as the airmass modifies.