... A warm front will lift northward across the region today. A cold front will approach the southern Appalachians from the northwest tonight and then cross the area on Monday. Dry high pressure will build over from the north as the high center moves from the Great Lakes to the Mid-Atlantic coast Monday night into Tuesday. Unsettled weather returns from the west Tuesday night into Wednesday morning. Another low pressure system may affect the southeast Friday into Saturday.
NEAR TERM /THROUGH TONIGHT/... As of 935 am: Dense fog became more widespread after sunrise, but has since begun to improve again, although pockets linger across the southern NC and eastern SC Piedmont. These should improve to above 1/4 mile by 11 am or so, but lingering reduced visby will likely linger through the morning. A Special Weather Statement for dense fog remains in effect for about another hour.
The forecast area will remain in a sw/ly flow regime this afternoon and evening ahead of an approaching cold front. Good mixing will enable low-end gusts with moderate gusts likely across the higher mtn elevations persisting thru the overnight period. A look at theta charts indicate weak isent lift ahead of the front coupled with low-end available moisture. So, think the best relative chance of light rainshowers will occur across the srn NC mtns and BR escarpment in mech lift throughout the day. However, the latest short term guidance depicts some modest instability...generally 500-1000 J/kg of sbCAPE developing over southern Piedmont areas, and the convection-allowing models are beginning to respond with some spotty showers...mainly across the eastern SC Piedmont this afternoon. A slight chance pops has therefore been introduced there.
The front will take it/s time reaching the NC mtns, likely aft 08z, when stronger sfc forcing and a llvl jet begin to generate higher precip rates over the wrn NC mtns. Not anticipating any hydro threats thru the near term period, but the lingering rainfall into the short range may create isol and minor flooding over the far srn NC mtns, mainly in wrn Graham Co thru late morning Mon.
Widespread low stratus and fog is causing some consternation regarding max temps today, especially in light of the fact that lingering in-situ cool pool is at least partially responsible. However, anomalously high thickness values will result in a rapid warm up in areas that see thinning cloud cover, which should be observed in most areas by afternoon. The forecast was cooled a bit to around 70 closer to the Blue Ridge, but lower/mid 70s still appear to be a good bet across much of the Piedmont, with even some upper 70s likely across the lower SC Piedmont. The mountain valleys will reach the u60s to arnd 70 F. Mins tonight will also remain well abv normal with readings likely ranging from the l50s over the mtn valleys to the u50s south of the I-85 corridor.
SHORT TERM /MONDAY THROUGH WEDNESDAY/... As of 235 am EST Sunday: A progressive northern stream trough will cross the eastern U.S. on Monday, steadily pushing the passing surface cold front south of the region through the day. Anticipate mainly morning rainfall along the passing frontal zone, with precipitation rates and coverage decreasing as the moisture exits the lower Piedmont during the afternoon. Brief upslope showers could also linger into the afternoon along the TN border counties, but still anticipate that basins can handle the event without any flooding of note, so no Flood Watches are expected at this time. Temperature trends will be hard to pin down Monday with the fropa. Expect falling mountains temperatures through the day there in the post fropa cold advection, but with a modest Piedmont spike in midday temps with downslope warming and drying east of the mountains.
Deep-layer drying will continue from the northwest Monday night as the surface boundary settles off to the south. A southern stream closed upper low over the southern Plains Monday night will lift eastward through the lower MS River Valley on Tuesday. Meanwhile, surface high pressure moving from the Midwest to New England will permit cooler and drier air to spill southward into the region on Tuesday. Upglide moisture could begin to return to our region through late Tuesday. As forcing and better moisture with the southern stream system reach the southern Appalachians Tuesday night, mixed precipitation types may develop over the mountains, especially at onset of the steadier precipitation. Profiles over the high terrain suggest that snow may develop along the ridges Tuesday evening, with ptypes transitioning to more of a mixed bag overnight into Wednesday morning. The forcing and moisture should move east of the forecast area by early Wednesday as the associated surface low passes through Midlands of SC toward the NC coast. An HWO mention for the mixed ptypes could be needed for the NC mountains for Tuesday night/Wed morning. Temps should rebound at least a category on Wednesday afternoon with better insolation returning.
LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... As of 245 am EST Sunday: Deep-layer northwest flow and modestly building heights will set up Wednesday night through Thursday ahead of yet another southern tier closed low pressure system moving east across Texas during the period. Temperatures will rebound again into the 60s east of the mountain by Thursday afternoon.
The latest GFS solution has trended toward the ECMWF camp of opening up the southern stream system across the lower MS River Valley and Deep South and bringing more modest forcing through the southeast Friday night. Recent runs of the GFS have trended drier with this late week system, but will keep solid chance PoPs going in a nod to the wetter, more consistent ECMWF solutions. The ECMWF 850 mb and surface low center tracks would be interesting for northern tier snow potential, but this remains a long way off so no HWO mention will be made for now. Saturday will be the chilly day of the extended forecast, but with other days within a category or so of climatology.