Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
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577 FXUS62 KGSP 051753 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 153 PM EDT Sun May 5 2024 .SYNOPSIS... The weather pattern will have a summerlike look to it through Wednesday, keeping scattered thunderstorm chances around each afternoon. A strong cold front will approach out of the west on Thursday before tracking across the western Carolinas on Friday, leading to better coverage of thunderstorms towards the end of the workweek. Highs will remain above normal through the workweek but will climb well above normal Tuesday through Thursday. && .NEAR TERM /THROUGH MONDAY/... As of 150 PM EDT Sunday: Convection developing across the mountains where differential heating and warming have caused sbCAPE to increase. sbCAPE increasing elsewhere but slowest over the NW Piedmont and northern foothills. DCAPE slow to develop with the slower heating from continued low clouds. These clouds will continue to lift and scatter through the afternoon, so instability should develop, along with DCAPE. That said, the latest CAMs have backed off on the idea of mountain convection holding together and moving southeast across the rest of the area. Can`t rule out some cells following this patter, so have retained the higher PoP for the mountains with lower PoP elsewhere. An isolated strong to severe storm, with damaging wind gusts, will also be possible where core heights can become strong or elevated. Convection diminishes this evening but a short wave and occluding cyclone, with associated remnant warm conveyor belt/moisture plume is forecast to move in from the west toward daybreak. The guidance has slowed the progression of this feature, limiting better shower chances to the mountains. Show these trends in the hourly PoP forecast. Lows will be around 10 degrees above normal. Guidance shows the short wave/frontal feature crossing the area on Monday with an increase in PoP through the day. Have continued this trend in the forecast as well. The increase in shear forecast seems likely given the stronger winds moving in with the feature, but the instability increase on some models is more uncertain. This is due to the development of morning cloud cover limiting heating, and better overall precip chances. Therefore, while there will be scattered thunderstorms, the chance of severe storms looks to be limited unless better instability actually develops. Highs will be a few degrees above normal. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... As of 1220 PM EDT Sunday: Diurnally enhanced deep convection will have the potential to be maintained well into Monday night as subtle s/wv energy ripples eastward atop the region. Otherwise a mild night is expected with Tuesday morning minimums around 10 deg F above the early May climo. Lower level warming expected on Tuesday will boost lower elevation maximums into the middle 80s. As sfc dwpts creep upward in the lower 60s, weak to moderate instability is fcst. Thunderstorms have the potential to become numerous in the mountains and perhaps gusty, within the upper diffluent flow along the backside of the eastern seaboard subtle ridge axis. Further warming is slated for Wednesday with Piedmont upper 80s, again, around 10 deg F above normal. The pattern will continue to progress toward a more dynamic look featuring increasingly deep SW flow. Within the increasingly sheared environment, tstms will have the potential to produced locally damaging wind gusts. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... As of 110 PM EDT Sunday: An eastward progressing cold front is progged to be moving toward the Tenn Valley to start off the period before sagging into the cwfa on Thursday. Along and east of this boundary, sensible wx will feature numerous showers and strong tstms within the unstable and moderately sheared environment. Thanks to clouds and showers we will be stepping away from the midweek heat although pretty solid lower 80s are expected acrs lower elevations. As the frontal zone gets hung up as it becomes parallel to upper flow on Friday, another piece of energy will rotate through the mean trough, extending shower chances at least one more day. A considerably drier post frontal airmass should settle atop the SE CONUS on Saturday. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... At KCLT and elsewhere: Convection developing over the mountains with restrictions hanging on at KAND and KHKY. The cigs should lift to low VFR or scatter out soon. Guidance has backed off on chance of convection for all but KAVL and KHKY. Since it`s already ongoing near KAVL, have a TEMPO to start there, and at 20Z for KHKY. Can`t rule out a cell moving over the other sites, but chance now too low for the TAF. Isolated SHRA will be possible through the night, but the developing MVFR then IFR cigs the bigger story. MVFR to IFR vsby possible as well. Vsby improves by mid morning but IFR cigs hold on until near noon with MVFR thereafter. Better chance of SHRA except for KCLT where TSRA develops during the afternoon. PROB30s in place for that. NW wind at KCLT and KHKY becomes SW later in the afternoon with S to SW wind elsewhere. Light and variable wind overnight becomes S to SW on Monday. Outlook: Enhanced moisture will combine with a weak/stalled front through the middle of next week, resulting in a period of active/mainly diurnal convective weather each day. There will also be the potential for restrictions associated with widespread fog and/or low clouds each morning. A cold front moves in for later in the work week with continued chances of diurnal convection. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...CSH NEAR TERM...RWH SHORT TERM...CSH LONG TERM...CSH AVIATION...RWH