... Canadian high pressure slowly builds into the region through Saturday. A weak cold front moves toward the area on Sunday then stalls over the area Monday and moves north as a warm front on Tuesday.
NEAR TERM /THROUGH TONIGHT/... As of 10:15am EDT Thursday: Minor touch-up of temperatures is the only change to the forecast at this time. Patchy fog appears to have burned-off in the few areas that had it, with skies mostly clear for the balance of today, and temperatures warming this afternoon back up to near normal. Northerly to northwesterly winds will gradually relax through the day following a few gusts to 15kts late this morning.
With sfc high pressure dominating the weather pattern through the forecast period, upper trough will continue to swirl off the Mid- Atlantic coast today as upper ridge to the west amplifies as it extends down through the MS River Valley, gradually shifting eastward tonight. Situated in between these two features, NW flow will persist down through to the sfc, allowing for NNW winds today to be breezy at times with intermittent higher gusts as well. Any gusts will subside this evening. With plenty of sunshine in store and the occasional batch of thin cirrus, downsloping flow will allow for max temperatures to climb to around normal this afternoon.
Expect clear skies tonight with min temperatures slightly below normal and NW winds 3 to 5 kts outside of the mountains. With this fcst, patchy frost will be possible across portions of the NC Piedmont as well as Chester and York counties in SC. Given lower confidence and patchy nature, a frost advisory is not warranted attm.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... As of 245 AM EDT Thursday: Ridging surface and aloft start the period over the area and slowly move east by the end of the period. A lingering pressure gradient between an off shore low and the building high will keep breezy conditions over the area Friday. This relaxes for Saturday. A weak cold front does approach from the west Saturday night, but moisture is limited and the forecast remains dry. Highs Friday will be around 5 degrees above normal then rising a degree or two on Saturday. Lows near normal Friday night rise to around 5 degrees above normal Saturday night. Can't rule out some isolated frost over the northern foothills/NW piedmont Friday night, especially in sheltered normally cooler locations. Should be too warm for frost Saturday night.
LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 320 AM EDT Thursday: The upper ridge over the eastern CONUS weakens and flattens allowing weak short waves to cross the area from time to time. At the surface, a weak frontal system moves into the area Sunday and stalls through Monday. The front moves back north Tuesday with weak southerly flow developing through Wednesday. The result is a weakly forced but increasingly moist atmosphere. Have isolated to low chance PoP, favoring the mountains, Sunday and Monday. Chance increases to likely over the mountains with good chance elsewhere Tuesday, dropping back into the chance range for Wednesday. Although there will be a few thunderstorms, severe storms look unlikely. Moderate QPF will be possible across the mountains. Highs will range from 5 to around 10 degrees above normal with lows 10 to as much as 20 degrees above normal.