... Widespread rain will gradually move south of Interstate 85 tonight and out of the area as sunny skies return on Friday. Cold and dry high pressure will move east across the Mid Atlantic Friday and Saturday bringing much below normal temperatures. Temperatures return to above average next week with dry weather persisting into mid week.
NEAR TERM /THROUGH TODAY/... As of 1245 am EST: Main precip band, associated primarily with right rear quadrant of jet streak has largely shifted southeast of the CWA early this morning, with just a couple of bands of light precip lingering across our Piedmont and foothills. Lingering precip will gradually shift southeast/taper off thru the next 1-3 hours. Temps remain below freezing on some of the ridgetops, and profiles suggest snow would be predominant there assuming precip occurrence. Can't rule out some brief flakes across the high elevations over the next hour or two, but this probability will quickly diminish in the very near term as drier air overtakes the southern Appalachians. Temperatures will fall more sharply toward daybreak in response to increasing cold advection, but lows are expected to remain above normal.
Drier air will move in early in the day, followed by developing downslope flow which will scatter out any lingering clouds by afternoon. It won't be enough to save the high temp fcst, which should once again be on the order of five degrees below normal.
SHORT TERM /TONIGHT THROUGH SUNDAY/... As of 210 PM EST Thursday: Heights slowly rise Saturday behind the departing trough. Heights then fall again Sunday as a weak trough moves in from the west. Cold and dry surface high pressure builds in on Saturday. The center of the high moves off shore Monday with a weak east-west ridge remaining over the area. There will be some moisture return and clouds over the area Monday, but any precip remains to our east closer to a weak inverted trough over the coast and better isentropic lift. Decent radiational conditions develop Friday night with clear skies and diminishing winds. With the cold air mass, lows drop to around 10 degrees below normal. Highs Saturday will also be around 10 degrees below normal. The air mass moderates Sunday with developing southerly flow. Lows Saturday night will be a few degrees below normal. Highs Sunday will be near normal outside of the mountains where clouds develop and around 5 degrees above normal across the mountains with more sun.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... As of 105 PM EST Thursday: A progressive pattern sets up for the medium range as a series of short wave troughs and ridges cross the area. None are especially deep or strong which helps keep the features moving. High pressure moves into the area Monday and to the east on Tuesday, with dry conditions initially then a weak moisture return developing late Tuesday night. The guidance then diverges with their solutions for Wednesday and Thursday. A weak front crosses the area Wednesday on the GFS with dry high pressure through Thursday. The ECMWF has a frontal system slowly approaching from the west Wednesday then moving across the area late Wednesday night or early Thursday. Both models agree that precip would be all liquid and with only light to moderate QPF. Given the differences, have gone with the lower end of the model blend. This results in chance PoP west and slight chance PoP east Wednesday and Wednesday night then chance PoP on Thursday. Of course, confidence is low and the precip timing may change over time. Both models agree on warm temps with above normal temps Monday and a warming trend through the week.