Area Forecast Discussion
Issued by NWS Greer, SC

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012 FXUS62 KGSP 271447 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 1047 AM EDT Mon May 27 2024 .SYNOPSIS... Strong to severe thunderstorms early this morning with another round possible Monday afternoon with a cold front. Cooler and drier conditions return Tuesday through Saturday. && .NEAR TERM /THROUGH TONIGHT/...
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As of 1045 AM EDT Monday: Severe Thunderstorm Watch 322 is still in effect as the area of showers and thunderstorms continue to push across the southern portions of the Upstate. Will likely cancel the Watch as soon as the activity moves out of the area. MUCAPE (1000- 2000 J/kg) and effective deep layer shear (40-50 kts) suggests that the severe threat is nonzero. The HRRR indicated that the precip would pull out slowly and that`s coming to fruition. Cloud debris from this morning`s convection will keep temperatures at bay this afternoon and will ultimately limit the severe potential for our third and final round this afternoon/evening, ahead of the cold front that`s slipping through the OH/TN Valleys currently. Made a few adjustments to the forecast based on current observations and latest trends. Hard to sleep on the severe threat this afternoon, so if we start to see sunshine with breaks in the clouds, this could be trouble as the kinematics are in place. Otherwise, in the wake of the QLCS remnants, expect widespread debris cloudiness and lingering light rain. Indications are that the precip and clouds will break up early enough in the day to allow some air mass recovery. The RAP still shows muCAPE climbing back up to the 2500-3000 J/kg range in the late afternoon, along with 30-35 kt of deep layer/cloud layer shear. If that is indeed the case, then scattered thunderstorms could develop mainly east of the mtns, and pose a risk of damaging wind gusts and large hail. Coverage on the CAMs is relatively widely scattered, but a few severe storms will not be ruled out. Temps will top out maybe a few deg above normal assuming the clouds break early enough in the day. The deep convection should move off to the east by mid-evening or so. For tonight, we should have more quiet weather. Can`t rule out a few showers in the westerly upslope areas along the TN border. Drying aloft suggests some fog potential, also assuming some locations get the rain late in the day. Low temps should cool off a bit, but still above normal.
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&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... As of 150 AM Monday: Kicking off a quieter stretch Tuesday as the surface cold front heads out to sea and drier air filters in behind. The upper low continues to lift toward the NE. Meanwhile, an omega blocking pattern emerges over the CONUS and keeps trough toward the north of the CWA. The pressure gradient is not anticipated to be tight, so some low-end wind gusts possible across the higher elevations through the end of the period. Guidance from the GFS and Euro does suggest a stray shower across the far northern NC mountains Tuesday afternoon, but models have also been trending drier over the past few forecast cycles. So confidence is very low. Upper flow should start to turn more NW by Wednesday night as the ridge axis over the central plains moves eastward. Will keep non- zero PoPs at this point. Temps will be warmest Tuesday during the short term and decrease closer to climo by Wednesday. Overnight temps will also be on the decline Wednesday night as drier air continues to move in and drop dewpoints. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 155 AM Sunday: By Thursday, a semi-strong omega blocking pattern continues over the CONUS, leaving the CWA in a weakening NW flow regime. Thursday and Friday will remain dry as heights begin to rise gradually as the ridge axis out west approaches the area. By Saturday, the axis will be over the CWA and also dry. Guidance does start to diverge on the next potential chance for showers. The Euro develops a weak upper low and trough that approaches the area by Sunday. However, the GFS keeps this weakened low from really forming and prevents any rainfall from reaching the CWA through the end of the forecast period. Either way, there`s very little confidence in this as we start to transition into a more summer like pattern. So for now, consider the extended forecast dry and warm. Temperatures should remain close to climo. && .AVIATION /15Z MONDAY THROUGH FRIDAY/...
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At KCLT and elsewhere: Area of showers and thunderstorms currently slipping through the Upstate with associated restrictions. Cloud debris continues to produce low VFR cigs across the terminals. Another round of showers and thunderstorms will be possible this afternoon/evening, but depends if the atmosphere can recover. Will continue the PROB30 groups for now, but if trends in latest guidance hold, we may be able to drop most TS mention with later AMDs. Otherwise, a low-VFR cig is expected for most of the day with SW winds picking up with some low-end gusts thru the day. Winds should become light, then toggle to WNW or NW overnight, as a cold front pushes in. Guidance is not too excited about fog and/or stratus, despite decoupling winds and clearing skies. That may be due to a combination of less aftn/eve precip and dry air filtering in behind the front. Outlook: Drier weather is expected Tuesday thru the end of the week with VFR conditions.
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&& .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...CP NEAR TERM...ARK/CAC/PM SHORT TERM...CP LONG TERM...CP AVIATION...ARK/CAC