847 FXUS62 KGSP 150607 AFDGSPArea Forecast Discussion National Weather Service Greenville-Spartanburg SC 207 AM EDT Wed Oct 15 2025
.SYNOPSIS... After another warm day, a dry backdoor cold front moves through the area Thursday, bringing cooler temperatures before another warm-up on Saturday. Another cold front will approach the area by Sunday and bring the next chance of rain for portions of the area.
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.NEAR TERM /THROUGH TONIGHT/... As of 1137 PM Tuesday: Another benign "copy and paste" forecast as the synoptic pattern remains largely unchanged. A tall and amplified ridge resides over the Mississippi Valley with a potent upstream trough sliding across the Great Basin while a downstream trough slides across the Great Lakes and into New England. This will continue to promote a monotonous forecast with yet another day of high temperatures in the mid 70s to low 80s with mostly sunny skies. Surface high pressure drops into the Great Lakes tonight and sends a dry backdoor cold front through the area with overnight lows falling into the mid 40s to mid 50s. Otherwise, a few instances of mountain valley fog cannot be ruled out this morning and tomorrow morning, especially in most favored and sheltered valleys.
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.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... As of 130 am EDT Wednesday: A highly amplified pattern will persist across the Conus through the short term, with a strong upper ridge that will progress from the Miss River Valley at the start of the period, to the Appalachians by Saturday morning. Confluent flow between the ridge and an upper low off the northeast coast will support 1020+ mb surface high pressure across the northeast quadrant of the country that will push an effective dry backdoor cold front through the forecast area early Thursday. This will spell a week-ending cooling trend, with temps expected to cool to near-normal on Thursday, and even a couple of degrees below normal Thu night and Friday. Otherwise, conditions will be comfortably dry, with surface dewpoints generally in the 40s and afternoon RH dipping into the 30-35% range in most locations.
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.LONG TERM /SATURDAY THROUGH TUESDAY/... As of 145 am EDT Wednesday: Upper flow over the Southeast will turn increasingly cyclonic over the weekend, as a strong upper low/increasingly negative tilt trough and associated cold front sweeps across the East on Sunday. The deeper forcing associated with this feature is forecast to pass north of the CWA, as a consensus of global model guidance now indicates the upper jet will pass across or just north of the area. Meanwhile, moisture return ahead of an approaching cold front will occur along a fairly narrow axis due to the presence of a surface ridge extending into the Gulf from an anticyclone over the western Atlantic. As such, it will be a bit of a struggle to advect 60s+ dewpoints into the CWA on Sunday...limiting the destabilization potential. Additionally, moisture advection may be further disrupted due to potential organized convection in the upstream area of the Gulf Coast. All things considered, any convective band accompanying the cold front into the forecast area on Sunday may struggle to be maintained, especially as the frontal band moves off the Blue Ridge. Likely PoPs will therefore be limited to the mountains Sunday afternoon, with chances tapering to 30-40% outside the mountains. After a period of above-normal conditions ahead of the front Saturday/Sat night, temps are forecast to dip a little below normal Sun night through Mon night, before rebounding to near-normal to end the period.
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.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... At KCLT and elsewhere: VFR conditions are expected to prevail at most terminals through the TAF period. Quiet weather continues through the period with the only focus being the potential for mountain valley fog through the early morning hours. Temporary visibility restrictions cannot be ruled out at KAVL. Otherwise, winds will be light out of the north/northeast.
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.
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.GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None.
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SYNOPSIS...JDL NEAR TERM...TW SHORT TERM...JDL LONG TERM...JDL AVIATION...TW
NWS GSP Office Area Forecast Discussion