... Canadian high pressure will spread across the region today and linger through mid-week. Another front will then lift across our area from the southwest on Thursday and bring widespread rainfall to the region for Thursday and Friday. Drying high pressure will eventually build back across the Southeast on Sunday.
NEAR TERM /THROUGH TONIGHT/... As of 1001 AM...Still seeing evidence of some weak upslope rain showers in the NW flow on the TN side of the mtns, and some orographic cirrus surging eastward in the lee of the mtns. As for wind, an initial post-frontal surge moved through during the early morning hours and after a lull before sunrise, many locations across the western Upstate and NC foothills have seen renewed gusts in the last hour or so. No reason yet to expand the wind advisory any further, but will revisit this by the next near-term update.
The wind will be the main concern through the day, as high pressure builds in from the NW on the strength of a deep NW flow aloft. A strong height gradient and pressure gradient courtesy of deep low pressure moving past to our north today should bring enough wind this far south to provide for frequent gusts across the entire fcst area through the afternoon hours. Although the better potential for significant wind gusts will be to our north, and the winds aloft will gradually weaken in the afternoon, think it prudent to have an Advisory near the Blue Ridge Escarpment into the afternoon hours. Upslope showers will continue along the TN border this morning, but the NW flow will become less productive in the afternoon as the moisture becomes more shallow and eventually pulls out. Temps will be cooler than previous days, but not that far off normal because of strong downslope. For tonight, expect clear sky and a light NW/N wind, which may help to keep patchy frost at bay. Temps will be about five degrees below normal. If we can get the wind to calm down enough we might be able to get decent coverage of frost across at least the higher terrain. As it stands right now, the fcst does not support a Frost Advisory, but we often struggle at this time of year with temps getting lower than expected, so this will be revisted with the afternoon forecast package.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... As of 325 AM EDT Tuesday: The short-term fcst picks up at 12z on Wednesday with upper trofing lifting off the Atlantic Coast and morphing into a large, closed h5 low. At the same time, heights will increase over the Southeast as upper ridging briefly builds over the region. At the surface, broad Canadian high pressure will be in place over the region as the period begins early Wednesday. The high is expected to linger over the area thru Wednesday and then lift northeast as a large low pressure system develops over the Southern Plains and lifts a warm front over our area on Thurs. The low will linger just to our northwest for the remainder of the period keeping precip chances at solid chance to likely from Thurs onward. Temps will start out near-normal on Wed and cool to below normal by Thurs.
LONG TERM /FRIDAY THROUGH MONDAY/... As of 305 AM EDT Tuesday: The extended fcst picks up at 12z on Friday with upper ridging moving off the Southeast Coast as a massive, closed upper low moves over much of the Eastern CONUS. The low is expected to eventually open back up and lift NE during the latter half of the weekend with flat upper ridging building back over the region to end the period. At the sfc, a large low pressure system will be centered to our NW and over the Ohio River Valley. The low will gradually lift NE and up over New England by Sunday. In its wake, broad high pressure will spread over the SE and dry things out for the remainder of the period. No major changes were made to the sensible fcst, with solid chance to likely PoPs over most of the CWA thru Sat and decent QPF for Thurs and Fri. We may have some hydro issues by the end of the week if the QPF amounts trend higher. Otherwise, temperatures are expected to start out well-below normal on Friday and rebound to near-normal by early next week.