Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
389 FXUS62 KGSP 170556 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 1256 AM EST Mon Nov 17 2025 .SYNOPSIS... High pressure will bring very dry air and near-normal temperatures early this week. Conditions will become very warm again during the latter half of the week ahead of the next cold front, which may bring rain chances next weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 1200 AM EST Monday: Deep layer northwesterly flow sticks around through tonight and during the daytime period. Surface high gradually building in from the northwest will allow for a very dry airmass to set up shop across the CWFA. Boundary layers will struggle to fully decouple overnight with lingering gap winds, which will keep occasional low-end gusts. CAA from the departing cold front from earlier will settle in as overnight lows end up a few ticks below normal with mostly clear skies. Center of the surface high will be over the OH/TN Valleys during the daytime period as the very dry air mass remains in place. Expect RH values to dip below 25%, even into the teens for a period of time by the afternoon hours for most locations. Fire weather concerns will be elevated despite lower winds as the pressure gradient fully relaxes. Will likely need another Increased Fire Danger Statement for portions of the CWFA. Afternoon highs will be a few ticks above normal and closer to normal values across the higher terrain. Good radiational cooling conditions are expected overnight Monday as the surface high fully situates over the area with mostly clear skies and light winds. As a result, overnight lows will be up to 5 degrees below normal. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... As of 1215 pm Monday: A consensus of the latest short term guidance has trended stronger and farther south with a compact upper low that will move from the Corn Belt through the Mid-Atlantic during the first half of the period. Resultant surface wave development/baroclinic zone activation should result in precip development across the region...primarily across the central Appalachians and Mid-Atlantic. Nevertheless, the farther south trend in guidance warrants an increase in PoPs Tue night across the mountains (50-60%) and along the I-40 corridor east of the escarpment (20-30%). Any rainfall should it occur be very light...around a tenth of an inch or less. Otherwise, the pattern will support establishment of a broad warm sector across the Southeast, while heights will be on the rise as an upper ridge builds to our west. Temps will soar on Wed as a result, with maxes forecast to be almost 15 degrees above climo. Otherwise, low level moisture/precipitable water values will steadily increase through the period as S/SW return flow becomes established. One more day with critical or near-critical RH is expected Tue afternoon, but RH should increase significantly during mid-week. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 1235 AM Monday: A complex, quite amplified split flow upper air pattern is forecast to evolve during the extended period, with perhaps a bit of a Rex block becoming established across the West. Timing of speed maxima ejecting through a long wave trough across the southwest quadrant of the country will potentially have major implications on the sensible weather across our area late in the week, but this is very uncertain given the complexity of the pattern...confirmed by rather disparate solutions regarding the short wave details among the various deterministic global models. Nevertheless, the potential for showers will steadily increase from the west through the period, with general 40-60% chances advertised across the mountains by Saturday...and mainly token chances elsewhere. Otherwise, heights over the Southeast will be anomalously high through the period, resulting in forecast temps 10-15 degrees above normal through the period. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... At KCLT and elsewhere: VFR conditions expected through the forecast period. Mostly clear skies overnight as most sites will see gusts fully subside outside of KAVL. Winds remain north-northwesterly through the morning hours. Winds should turn west to southwesterly by the afternoon before going light and variable after sunset, remaining that way through the rest of the night. KAVL maintains a northwesterly component with low-end gusts through most of daytime period before gradually diminishing after sunset. Mostly clear skies through the daytime period with some coverage of cirrus moving into the area by the evening and early parts of the overnight. Outlook: A low pressure system may bring scattered showers and associated restrictions on Tuesday, possibly lingering into Wednesday. Dry high pressure returns briefly on Thursday, before another cold front potentially brings showers and restrictions on Friday and over the weekend. && .FIRE WEATHER... Winds will be lower for today, but RH values will dip below 25% for most of the area as a very dry air mass remains in place. Increased fire danger conditions are expected once again as Fire Danger Statements will likely for portions of the CWFA for this afternoon and evening. Humidity and temperatures are expected to steadily increase tonight through mid-week. One more afternoon of critical RH is likely Tuesday, but minimums are expected to be more in the 20-25% range. Although RH is expected to be well above critical levels for the remainder of the week, very warm days are also expected, so some degree of wildfire risk is likely to continue in light of low 10- hour fuel moisture. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...JDL NEAR TERM...CAC SHORT TERM...JDL LONG TERM...JDL AVIATION...CAC FIRE WEATHER...CAC/JDL