Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
739 FXUS62 KGSP 141017 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 617 AM EDT Tue Oct 14 2025 .SYNOPSIS... A coastal low will drift offshore through mid week as dry and warmer high pressure builds in across the region. This will allow for a return of above normal temperatures through Wednesday. A backdoor cold front moves through the area Thursday bringing a brief cool down before temperatures warm again over the weekend. The next chance for rain may come on Sunday as an upper trough crosses our region. && .NEAR TERM /THROUGH TONIGHT/... As of 1128 PM Monday: A rather quiet and benign pattern will continue today as upper ridging dominates the scene from the Southern Plains to the Appalachians. The ridge is forecast to amplify through the period as a potent trough digs down the west coast and slides into the Great Basin. Rising heights and warming low-level temperatures will promote warm afternoon highs in the mid 70s to low 80s. Heading into tonight, temperatures will fall into the mid 40s to mid 50s with the only weather of note being the potential for mountain valley fog. Here, temperatures are expected to cool to at or several degrees below the afternoon crossover which will favor ribbons of fog in the usual valleys. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... As of 100 am Tuesday: A highly amplified upper air pattern will evolve across the Conus during the short term, with the axis of a massive ridge forecast to extend from the Deep South through the Great Lakes by the end of the period. This will support continued dry but very warm conditions on Wednesday, with max temps of 5-7 degrees above normal expected. By Thursday, 1020+ mg surface high pressure beneath confluent flow downstream of the ridge axis will begin building into the northeast Conus and northern Mid-Atlantic, effectively pushing a dry backdoor cold front through our forecast area by afternoon. This will shave several degrees off high temps, with near-normal highs expected across much of the CWA Thursday. The relatively dry air mass will support a large diurnal temp range Wed/Wed night, with near-normal min temps expected Thu morning. Even cooler conditions are forecast in the wake of the front Fri morning, with perhaps some patchy frost in the high valleys of the northern NC mountains. && .LONG TERM /FRIDAY THROUGH MONDAY/... As of 110 am Tuesday: A highly amplified, yet fairly progressive upper air pattern will be in place atop the Conus through the extended, with increasingly cyclonic flow developing over our area as a ridge axis pushes east of the CWA by the end of Saturday. Inverted surface ridge and associated high pressure in place at the beginning of the period will therefore weaken and move east early in the weekend, resulting in a return of above normal temps and increasing humidity Saturday/Sat night. A deepening upper trough...which is expected to attain an increasingly neutral, and perhaps eventually negative tilt...will approach the East on Sunday, with attendant frontal zone expected to cross the forecast area by the end of the day. With surface ridge extending into the Gulf from an anticyclone over the western Atlantic, moisture return ahead of the front will be along a rather narrow axis...and even drawing 60s surface dewpoints into the CWA may prove to be a bit of a tall task...significantly limiting the destabilization potential. The precipitation potential will therefore be largely dictated by the degree of forcing/how far south the upper jet digs on Sunday, which is still the subject of some debate in the latest deterministic guidance. As such, we take a conservative approach on PoPs... generally advertised in the 30-50% range Sunday afternoon. A return of dry and mostly clear conditions will return behind the front Sun night, with a regime of near-normal max temps and below normal mins returning to end the period. && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... At KCLT and elsewhere: VFR conditions will prevail at all terminals through the TAF period. A few ribbons of mountain valley fog are apparent in early morning satellite imagery, but remain confined to the lower French Broad Valley and the Little Tennessee Valley with no impacts at KAVL. A few high clouds may stream across the area today with mainly light winds out of the north/northeast, although another day of gusts can be expected at KAVL. Valley fog will once again be the main focus tonight with a better setup favoring a more widespread event. Have thus introduced a TEMPO at KAVL for restrictions early Wednesday morning. Outlook: Expect mostly dry, VFR conditions to persist thru the week, except for the potential for mountain valley fog and/or low stratus each morning. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO/JDL NEAR TERM...TW SHORT TERM...JDL LONG TERM...JDL AVIATION...TW