Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
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191 FXUS62 KGSP 102028 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 428 PM EDT Fri May 10 2024 .SYNOPSIS... Strong storms are possible thru this evening southeast of Interstate 85. Dry high pressure will keep most areas dry through the weekend, with mild temperatures. An unsettled pattern will take shape late Monday, with rain chances returning and lasting through Wednesday. && .NEAR TERM /THROUGH SATURDAY/... As of 415 PM...Minor tweaks to the PoPs to reflect latest radar trends. A boundary is sagging south into Union and Chester counties in SC. With Cherokee, York and Union, NC north of the boundary with less CAPE, have canceled the SVR Tstm Watch for those counties. Still a severe storm in Chester County. The severe threat should slowly wane as the boundary continues to to push south and east. Activity across the mountains has weakened, with mainly just scattered showers and occasional general thunderstorm. Otherwise, convection ongoing across the ern Piedmont associated with a sfc bndry will continue active this afternoon. Soundings across the area indicate sbCAPE values reaching arnd 1200 J/kg while latest mesoanalysis shows 0-6 bulk shear on the order of 30-35 kts moving in from the west. So, a few of these storms could become quite strong to severe with large hail and damaging outflows being the main threats. A secondary bndry will push in from the northwest this afternoon arnd 22z and this could help maintain tstm activity into the evening hours, altho direr llvl air will also be accompanying this bndry, which could hinder convec development. Winds outside the storm areas will become low-end to moderately gusty and lessen after sunset. No great chance of fog overnight as drier air mixes into the llvls, yet some mtn locales could see spotty dense fog. Upper heights fall thru the day Sat as an upper wave approaches from the northwest. This wave will bring it/s own moisture and will likely instigate a few showers across the NC mtns during the afternoon into the evening. Lows tonight will drop a little below normal and highs Sat will also be held a couple degrees below normal as the new airmass mix begins to modify warmer. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of midday Friday: Confluent upper flow between NE CONUS closed low, and a ridge in the lower MS Valley, will allow dry sfc high pressure to build into the CWA beginning Saturday night. This looks to suppress diurnal convection Sunday. Mild, near-normal temps, fairly low humidity, and light winds look to make for a nice Mother`s Day. Ridge will migrate east and sfc high will set up just off the East Coast by Monday morning. Southerly flow will develop atop it within moisture plume on warm side of occluded low moving into the Ozarks; surface front still looks likely to be well south of the CWA. Models vary in how quickly they develop precip; some do so Monday and others Monday night. The setup could foster in-situ CAD once precip develops. With increased cloud cover temps Monday should be a little cooler than Sunday. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 200 PM Fri: Low pressure will track into the lower Ohio Valley Tuesday, and PWATs will peak that afternoon or early evening as southerly moisture flux comes to a head in advance of the low. Main shortwave trough likely will be centered over west-middle TN during the afternoon, but some degree of DPVA could be present to further enhance lift. How well CAD becomes entrenched may be critical, as by the same token SBCAPE could creep into our lower Piedmont. GFS soundings are rather skinny and not indicative of much more impact than convectively enhanced rainfall rates. Per NAEFS and EPS member soundings, a few hundred J/kg could overlap with around 40 kt of deep layer shear, so a strong to severe thunderstorm is not completely out of the question. That said, leaned slightly toward the low end of guidance given potential CAD. Tuesday likely will be the coolest day of the week with highs in the mid-70s, but if CAD does form highs may stay in the 60s. Low-level flow will turn westerly and some upslope driven precip is possible Tue night into Wed near the TN border. The shortwave itself will cross the CWA Wednesday morning. Temps will rebound above normal for Wed with skies clearing and downslope winds east of the mountains. Gradient aloft will be weaker and near-sfc winds more veered, so less shear will be present but stronger CAPE. As such scattered t-storms look somewhat more likely but severe threat probably lesser. Precip chances diminish Wed night as another ridge moves overhead behind the shortwave. Dry weather will last until the next low approaches from the west and warm front lifts over the area. That currently looks likely to occur Thursday night or Friday, but as a nod to the few solutions depicting it earlier, PoPs tick upward again Thu afternoon. Thursday temps also will be a little above normal. && .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/... At KCLT and elsewhere: An upper wave will cross the area this afteroon and evening which will bring a nw/ly wind shift outside the mtns. Some precip will be associated with this wave, but instability looks suspect for a great thunder threat. So have included a TEMPO -TSRA for CLT aft 22z til 00z. Otherwise, VFR conds persist and north to northwesterly gusty winds will prevail this afternoon across most sites and weaken overnight. No great chance of fog in the morning with the drier air mixing in. Outlook: VFR conditions continue this weekend. Moisture returns late Monday with active weather possible by Tuesday. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...Wimberley NEAR TERM...ARK/SBK SHORT TERM...Wimberley LONG TERM...Wimberley AVIATION...SBK