textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Updated PoP today based on radar and latest high resolution guidance.

KEY MESSAGES

1. Showers and a few storms this morning. Drying this afternoon. Convection returns ahead of a cold front on Wednesday. 2. After a few quiet days late this week, the next active system will arrive Friday night into Saturday. Though it doesn't look like a great setup for severe weather, it should provide a much- needed round of rainfall for most of the forecast area.

DISCUSSION

Key message 1: Showers and a few storms this morning. Drying this afternoon. Convection returns ahead of a cold front on Wednesday.

Convection associated with an MCS crosses the area this morning. Latest guidance agrees on convection entering the mountains then weakening as it moves east and south. They disagree on the coverage of the convection outside of the mountains. Better chances will be along and north of I-85, and over the Upper Savannah River valley. The QPF coverage shows a similar pattern with any rainfall being beneficial but not drought busting. A few strong to possibly a severe storm may move into the mountains, but they weaken very quickly as they move east. Dry but lingering clouds for the afternoon with highs near to a little below normal.

Another MCS moves into the area late tonight or Wednesday morning with more convection. Precip chances look better overall with this along with higher QPF. Not enough for a flood threat but potentially beneficial amounts for many. A cold front moves into the area during the afternoon. The guidance differs on convective coverage with the front itself. They do seem to favor NC and the eastern Upstate. There could be enough heating for sbCAPE to develop with isolated severe storms for the above mentioned area. SPC has a Marginal severe risk for this area. Lows tonight around 10 degrees above normal with highs Wednesday a few degrees above normal.

Key message 2: After a few quiet days late this week, the next active system will arrive Friday night into Saturday. Though it doesn't look like a great setup for severe weather, it should provide a much- needed round of rainfall for most of the forecast area.

A cold front will cross the area from the west on Wednesday night, driving a somewhat cooler air mass into the Carolinas. Gusty winds are expected in the immediate vicinity of the front overnight, and may persist into the first part of Thursday, but postfrontal CAA looks weak, and even the most aggressive ensemble members depict only isolated, high-elevation areas approaching Advisory criteria...so impacts should be limited at best. The most noticeable impact will therefore be cooling...with highs back near or slightly below normal on Thursday...and at least two categories below normal on Friday. Dry, unperturbed conditions are anticipated during this time beneath mostly flat, unperturbed upper flow.

By late Friday, operational models depict a z500 trough ampliflying over Texas and New Mexico. This trough will eject into the southern Great Plains and phase with another shortwave diving across the Midwest...resulting in surface cyclogenesis somewhere over the Gulf coast Friday night. Rapid onset of isentropic ascent appears likely after 00z Saturday...meaning another round of rainfall. Given the time of day and the placement of the low, long-range ensemble guidance is in good agreement that little to no surface-based instability will develop, but LREF profiles depict at least a little elevated instability...so can't rule out some embedded thunder.

The low should lift northeast, shifting off the Carolina coast by Saturday night and ushering in another broad surface high. Dry conditions should then persist through the end of the seven-day forecast period.

AVIATION /06Z TUESDAY THROUGH SATURDAY/

At KCLT and elsewhere: Low VFR clouds increase early this morning ahead of an area of convection. MVFR cigs and this convection move in near daybreak with IFR cigs and MVFR vsby possible. Confidence in SHRA is high enough for TEMPOs for all but KGSP where PROB30 continues. Can't rule out some TSRA, but the chance is too low for now. The convection moves east of the area by noon, but the MVFR cigs linger into the afternoon before lifting or scattering out late in the afternoon. S to SW wind picks up with the convection continuing into the afternoon. KAVL sees winds turn NW behind the convection. Can't rule out low end gusts at any location, but confidence not high enough for the TAFs for now. Low VFR continues into the evening, but MVFR returns overnight with of another round of convection ahead of a cold front.

Outlook: The cold front keeps rain and associated restrictions into Wednesday. Dry and VFR conditions may return Wednesday night into Friday before another disturbance brings rain chances and associated restrictions over the weekend.

GSP WATCHES/WARNINGS/ADVISORIES

GA...None. NC...None. SC...None.