644 FXUS62 KGSP 131028 AFDGSPArea Forecast Discussion National Weather Service Greenville-Spartanburg SC 628 AM EDT Mon Oct 13 2025
.SYNOPSIS... A coastal low will slowly drift offshore through mid week as dry high pressure builds in across the region. This will allow for a return of above normal temperatures through Wednesday. A backdoor cold front drops across 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 a potent system swings across the country.
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.NEAR TERM /THROUGH TONIGHT/... As of 625 am EDT Monday: Stacked/occluding cyclone just off the SC coast is forecast to finally accelerate to the east later today, as "kicker" low travels from the northern Great Plains to Hudson`s Bay. Shield of stratocu is expected to lift/scatter as it gradually moves east through the morning. As such, most locations should see no worse than mostly sunny conditions by afternoon, with increasing thickness values/rising heights allowing max temps to warm to around 5 degrees above normal across much of the area. Less cloud cover and the relative dryness of the air mass brought about by N/NW low level flow along with decoupling surface winds are expected to allow tonight`s lows to settle to near normal. The better radiational cooling conditions should also pave the way for more fog/low stratus in the mountain valleys Tue morning.
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.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... As of 1142 PM Sunday: The synoptic pattern will become increasingly amplified through mid week as an upper ridge builds from the Southern Plains through the Mississippi Valley. Farther upstream, a potent trough will be sliding across the Great Basin and lifting through the Rockies while a northern stream trough drops across the Great Lakes and into New England. Rising heights across the Southern Appalachians on the eastern flank of the upper ridge will promote warm temperatures in the mid 70s to low 80s both Tuesday and Wednesday. Otherwise, the forecast remains dry through the short term.
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.LONG TERM /THURSDAY THROUGH SUNDAY/... As of 1202 AM Monday: By Thursday, sprawling surface high pressure dropping across the Great Lakes and into New England will send a backdoor cold front through the area. This will in turn result in temperatures falling back to or just below seasonal averages Thursday and Friday. Heading into the weekend, the upper trough axis is progged to traverse the Appalachians with a slight warmup on Saturday. The forecast becomes much more interesting on Sunday as the first in a series of potent troughs ejects across the Northern Plains and across the Midwest into the Great Lakes/Ohio Valley. Forecast confidence quickly wanes, however, as considerable differences in timing, location and evolution of the wave are apparent across the suite of guidance. Rain chances may eventually return to the area, so will leave the forecast in line with the national model blend for now until there`s better agreement.
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.AVIATION /12Z MONDAY THROUGH FRIDAY/... At KCLT and elsewhere: Lingering MVFR cigs at KCLT are expected to lift to VFR by 12Z...or shortly thereafter. Meanwhile, fog/low stratus has developed in the mountain valleys W=>N of KAVL, and is not expected to impact the TAF sites this morning. Otherwise, drier air filtering into the Terminal Forecast Area on developing NNW winds will result in clouds lifting/scattering at most sites by around noon, with FEW/SCT cumulus of 050-060 likely continuing into the afternoon before SKC conditions develop. restrictions will be in the valleys to the W and N of KAVL. NNE winds are expected to gradually turn toward NNW by afternoon, with speeds generally expected to be 5-8 kts during the daylight hours, except for 10-12 kts at KCLT this morning. Speeds should drop off to around 5 kts at most sites this evening. Conditions should be favorable for mountain valley fog/low stratus to be a little more widespread early Tuesday. Having said that, confidence is low on timing/ magnitude of any restrictions at KAVL, mainly due to the expectation that an up-valley wind may prevent the necessary cooling. For now, 5SM/FEW005 is advertised at KAVL after 10Z.
Outlook: VFR conditions are expected to persist thru the week, except for the continued potential for mountain valley low stratus and/or fog each morning.
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.GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None.
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SYNOPSIS...TW NEAR TERM...JDL SHORT TERM...TW LONG TERM...TW AVIATION...JDL
NWS GSP Office Area Forecast Discussion