Area Forecast Discussion
Issued by NWS Greer, SC

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921 FXUS62 KGSP 230220 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 1020 PM EDT Sat Jun 22 2024 .SYNOPSIS... Hot and humid air will remain over the area this weekend and into the middle of next week. A weak yet active cold front tracks across the area Sunday into Monday before drier air returns on Tuesday. Another moist and stormy frontal system should push in Tuesday night and slowly cross the area through Thursday. && .NEAR TERM /THROUGH SUNDAY/...
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As of 1003 PM Saturday: No major changes. It`s quiet across the area but for a couple isolates showers over the extreme western NC/GA mountains. Further activity looks unlikely with the sun set. Otherwise...over the next 24 hours, the effects of the old upper anticyclone will finally come to an end as it relocates to the srn Plains and we come underneath a broadly sagging cyclonic flow aloft with a nrn stream upper system over the upper Great Lakes. Altho this might seem favorable, there is a distinct lack of support for convection. That little swirl you see along the GA coast will not be able to make it close enough to our forecast area. The slight increase in westerly flow aloft by Sunday afternoon should allow temps to warm a few degrees above what we had today, making Sunday feel like the hottest day of the season thus far. Fortunately, the RH will merely be like usual summer, so the Heat Index will fall well short of Heat Advisory criteria. The arrival of the cyclonic flow should also eliminate the cap finally, so expect a bit better coverage of showers and storms in the late afternoon, similar to climo.
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&& .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... As of 120 PM Sat...A weak ulvl wave will cross the area Sun night and bring a decent chance of precip, mostly rain across the NC mtns thru daybreak. Not much of a chance east of the mtns and maintained slight PoPs there thru the afternoon as h5 heights rebound and forcing wont be enuf to overcome the warm mlvl cap. Canadian high pressure mixes in thru the day and winds become n/ly to nw/ly. However, this airmass will be rather warm so little CAA, if any, can be expected and temps shud have no problem rising to the m90s east of the mtns and u80s mtn valleys. Will be close to heat indices reaching 105 F across NE GA and the western Upstate Lakeland region as sfc dewpts will mix out the least compared to other areas. A Heat Adv may be needed for Mon. The pattern remains quite warm and supressive Mon night into Tue as upper heights continue to rise while a subTrop high becomes more dominant. Soundings show parcels possibly breaking the cap across the mtn ridges Tue afternoon for brief -shra/tstms, but most areas will remain dry. Still, another hot day in store with temps similar to Mon yet a little better dewp mixing may hold heat index values shy of advisory criteria across the FA. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... As of 155 PM Sat...No major changes were made to the ext range fcst. The latest guidance is still at odds with the development and evolution of an upstream trof / frontal system Tue night thru Thu. The GFS is a moist outlier with better h92-h85 moist adv off the wrn GOM and is much faster and energized than the other op models. The GFS dProg/dt trends have been holding consistent however, so the latest run has been given good weight in the fcst. The ECMWF on the other hand is slower and only develops isol precip across the NC mtns Wed and reluctantly develops more widespread activity on Thu as the sfc front likely stalls. So, backed off the NBM PoPs east of the mtns for Wed and Thu, yet still have low likely chances across the mtns and mid chance PoPs east each afternoon. The upper levels remain quite warm thru the period and with limited shear or forcing, most storms shud remain below severe criteria. Wednesday will be another hot one before temps cool a little Thu and Fri. Could need a heat advisory Wed for the srn zones as higher dewpts are pooled north ahead of the Tue night cold front. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... At KCLT and elsewhere: It`s essentially a persistence forecast from this time yesterday; widespread cu field but virtually no rainfall anywhere apart from extremely isolated showers over the Balsams. SE winds and VFR at all the terminals and should stay that way through the period, with the notable exception of another round of MVFR ceilings expected around daybreak at KCLT. No restrictions are advertised at KAVL given they didn`t appear this morning, and the guidnace is even less enthused by the possibility of valley fog/stratus than it was yesterday. Thunderstorms will be a possibility for much of the terminal forecast area by tomorrow afternoon...but coverage will be isolated and severe risk will be low. For the NC terminals, we`re now carrying PROB30s for TSRA after 18z. Outlook: Outlook: Expect a return to more typical scattered convection across the region Monday. Slight drying may follow for Tuesday, but humidity goes back up for Wednesday. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...SBK NEAR TERM...MPR/PM SHORT TERM...SBK LONG TERM...SBK AVIATION...MPR