Forecast Discussion
Summary
SYNOPSIS
... Dry high pressure will remain over the region for the remainder of the weekend and into much of the upcoming workweek. This will allow above normal temperatures to continue through late next week. A cold front will approach out of the west on Thursday before tracking across the area sometime Friday into early Saturday. The front may bring rain chances back into the forecast, but confidence on this is low.
NEAR TERM /THROUGH TONIGHT/... As of 1030 am EDT Sunday: The western Carolinas and northeast Georgia will remain on the eastern periphery of a robust 500 mb ridge axis stretching over the Mississippi and Ohio River Valleys today. Stratocu lingers this morning...mainly near the southern Blue Ridge escarpment. This is expected to diminish somewhat into the afternoon, but some degree of stratocu or fair cumulus is expected to linger. Meanwhile, northeasterly flow from surface high pressure centered over the eastern Great Lakes will contribute to a slight drop in low-level thicknesses east of the Appalachians today, with maximum temperatures perhaps a category shy of those observed on Saturday - but still some 5 to 8 degrees above climatology. Cannot rule out some very shallow instability in the southwest NC mountains this afternoon, but any sources of lift will be very hard to find and profiles will exhibit strong capping aloft. No PoPs will thus be featured.
The upper ridge axis will retrograde slightly westward tonight. Nocturnal stratocumulus should be a bit less and thus more potential for mountain river valley fog should return. Minimum temperatures will remain about 4 to 7 degrees above normal early Monday morning.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... As of 130 AM EDT Sunday: No changes this update....which leads to a discussion about as dry as the weather. An omega blocking pattern will be in place on Monday before gradually breaking down Monday night into Tuesday. This will keep upper ridging over the eastern CONUS through the short term. At the sfc, high pressure will remain parked over the eastern US. This will lead to continued warm and dry weather. Both highs and lows will be around 5-8 degrees above climo through the period.
LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 145 AM EDT Sunday: Upper ridging remains over the eastern CONUS Wednesday before gradually pushing into the western Atlantic Thursday as an upper longwave trough pushes east. Meanwhile, at the sfc, high pressure will gradually push off the East Coast as a cold front approaches out of the west. Global models all agree that the southwestern periphery of the sfc high will continue to extend across the Carolinas and northeast Georgia through Thursday. This will allow dry and warm conditions to continue the first half of the long term. Highs will remain around 5-8 degrees above climo on both Wednesday and Thursday. Lows Wednesday night will be around 4-7 degrees above climo, becoming 7-10 degrees above climo Thursday night as cloud cover increases ahead of the front.
Upper troughing will track across the eastern CONUS the second half of the long term. This will allow the aforementioned cold front to push across the forecast area sometime Friday into early Saturday. The 00Z GFS shows a faster FROPA and wetter conditions compared to the 12Z ECMWF. The ECMWF keeps rain confined to the mountains and has the FROPA pushing into the CWA Friday night into early Saturday. The GFS shows the front pushing into the CWA Friday afternoon, and has rain across much of the area. With the latest global model guidance still not in agreement regarding the timing of the front or the amount of moisture available, maintained slight chance PoPs across the western zones Friday and Saturday. Highs on Friday may end up around 5 degrees above climo, potentially becoming near climo on Saturday behind the front. Lows Friday night could remain several degrees above climo depending on the timing of the front.