Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
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213 FXUS62 KGSP 090806 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 406 AM EDT Thu May 9 2024 .SYNOPSIS... Widespread shower and thunderstorm activity will continue through this morning, with severe storms expected. The cold front will push east Thursday night into early Friday morning allowing for drier conditions. Another system approaching out of the south may bring shower and thunderstorm chances back to the region on Friday. Drier conditions and below normal temperatures return for the weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 400 AM EDT Thursday: The Tornado Watch for northeast Georgia and the SC Upstate was allowed to expire at 4 AM. The line of strong to severe storms have mostly pushed south and east of the forecast area, but an isolated strong to severe storm may continue grazing far southern NE GA and the far southern SC Upstate the next hour or so. What`s left behind the main line is stratiform rain with embedded thunder at times. The severe threat will be lower through the rest of the morning due to the atmosphere being worked over from earlier activity. However, CAMs depict another line of convection making a run for the forecast area around between roughly 6am-8am. The SPC mesoanalysis page shows SBCAPE values climbing back to 500- 1500 J/kg across the forecast area by 9am. With deep layer shear expected to increase to 40-50 kts by mid to late morning ahead of an approaching cold front, the strong to severe storm potential may return later this morning, but confidence on this remains low and will be highly dependent on how much the atmosphere can recover before the next batch of convection. The flooding threat will gradually ramp up through the morning hours as rainfall totals pile up. However, with only a one Flood Advisory currently in place, a Flood Watch looks unlikely at this point as mainly nuisance flooding in low-lying/poor drainage areas is expected. With activity expected to linger through the late morning hours, have likely to categorical PoPs area-wide through this morning. With activity expected to gradually come to an end from west to east this afternoon, capped PoPs to chance through the afternoon hours. Highs this afternoon will be a few degrees cooler than yesterday, and around 3-6 degrees above climo. Breezy winds can be expected this afternoon and early evening as a cold front tracks across the forecast area. Cloud cover will linger through most of the day, but should gradually clear out from west to east late this afternoon into this evening. Lows tonight will remain around 10 degrees above climo thanks to returning cloud cover. Dry conditions should linger through tonight. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... As of 317 AM EDT Thursday: We begin Friday with a wildcard, that being whether or not there is an MCS remnant moving past to our south which some of the guidance indicates. For what it`s worth, the NAM is quiet and the HRRR keeps what remains to our south. Once that is out of the way, the next item of interest is a potent-looking short wave dropping in from the WNW late in the day. It won`t be able to keep our temps from climbing a deg or two above normal for highs, but this wave will bring some decent forcing that should be able to generate some scattered shower/storm activity at least across the mtns. The wave will drive a reinforcing boundary through overnight. Could be some upslope shower activity, but the chances are too low for now. The main effect will be to drop temps about five degrees, back to below normal for Saturday. A slug of moisture in the NW flow aloft behind the wave could result in scattered showers over the nrn tier, especially near the TN border, late in the day. High pressure should build in Saturday night, with temps falling to roughly five degrees below normal. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 1252 am EDT Thursday: The rest of the upcoming weekend looks like it should be quiet, with a mid/upper ridge axis to our west supporting weak sfc high pressure on Sunday. Temps should be right around normal into Monday. The ridge axis moves overhead early Monday and then things start to go downhill. The next system moving over the Plains on Monday will begin to spread moisture back in from the southwest by late in the day, although the models do not agree on when precip might develop up from the southwest. Be that as it may, the pattern favors a quick moisture return with sfc high pressure off the Mid-Atlantic coast, so if precip doesn`t develop by sunset on Monday, it will overnight. The rest of the early half of the week look busy again as the upper system slowly approaches then moves past Tuesday night and into Wednesday. Precip probs climb up into the Likely range, but we have removed the categorical for the time being. Temps will stay on the cool side on Tuesday owing to extensive cloudiness and precip. We should get another brief break in the action in the wake of this system, probably on Wednesday, but afterward we remain in a busy looking part of the flow with perhaps another upper feature moving in by the end of the period. Temps could pop back up about five degrees above normal on Thursday, but there is much uncertainty. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... At KCLT and elsewhere: Widespread SHRA and TSRA are tracking over the terminals this morning leading to mainly LIFR to MVFR restrictions. With the strongest activity expected to continue through the next few hours, went with TEMPOs for TSRA from 06Z-10Z for all terminals. Strong, gusty winds can be expected within stronger thunderstorms. From 10Z-15Z have SHRA with a PROB30 for TSRA as thunder should become more isolated once the main line of activity pushes east. Should see drier conditions develop by the late morning to early afternoon, which should allow restrictions to lift across the terminals. Wind direction will generally be variable through daybreak with shower and thunderstorm activity around, but should eventually pick up out of the SW around sunrise. Winds will remain SW through this afternoon before turning WNW across the mtns and WSW east of the mtns this evening into tonight. Low-end gusts are expected to develop this afternoon as a cold front track over the western Carolinas. Dry conditions should linger through tonight. Outlook: A system lifting out of the south my increase shower and thunderstorm chances again on Friday, but confidence on this remains low. Drier conditions can be expected this weekend. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...AR NEAR TERM...AR SHORT TERM...PM LONG TERM...PM AVIATION...AR