textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Rain amounts have trended slightly higher for Wednesday night.

The aviation forecast was updated to reflect the recent 12Z TAF issuance.

KEY MESSAGES

1. Unseasonably warm and humid conditions are expected for the remainder of the week, with shower and thunderstorm chances increasing today and lingering through Friday.

DISCUSSION

Key message 1: Unseasonably warm and humid conditions are expected for the remainder of the week, with shower and thunderstorm chances increasing today and lingering through Friday.

A modestly active period ensues through at least Friday as trough located west of the area begins to lift toward the northeast, increasing rain and thunderstorm chances. For Wednesday, a weakening frontal boundary approaches from the west with showers and thunderstorms. Ahead of the front, some instability builds in during the afternoon but remains limited due to the anticipated cloud cover. Guidance also hints at weak shear as the front occludes and moves into the area. These less than favorable factors decreases confidence in severe weather coverage. However, cannot rule out an isolated strong to severe storm later today into tonight. Given the southeasterly surface winds, there could be an isolated flash flood risk especially along the Escarpment and foothills. Confidence remains low on in this though. Rain amounts vary in range with this frontal passage with 0.25"-1.5", with the higher amounts likely in the far western NC mountains and portions of Upstate SC and northeast GA.

Behind the front, the CWA remains in a steady southeasterly surface wind regime, funneling moisture into the region and keeping rain chances around. Aloft, a secondary low weakens from the breakdown of the decaying omega block and swings toward the Ohio/TN Valley. Rain chances look to be in the 30-40% for Thursday and increase in the NC Piedmont for Friday as the last bit of forcing pushes through. Guidance has a 20-30% chance for rain totals of 1" or higher for Friday in the eastern zones, which means confidence is lower that rain amounts with the second wave are minimal. Behind this last system, drier air pushes in as surface high pressure spills from the north and spreads into the region.

By Saturday, forecast looks to dry out and have cooler temps closer to normal. Overnight temps for the weekend and into the beginning of next week dip into the 30s for the mountains and upper 30s and 40s elsewhere.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

At KCLT and elsewhere: A very busy TAF period is ongoing and will continue through much of the forecast period. A cold front is approaching the area from the west and drawing moisture into the region. This has fueled the development of widespread MVFR to IFR stratus this morning that will persist through much of the morning hours. A few instances of patchy fog are also ongoing, but should remain fairly limited in light of more widespread cloud cover. A few terminals may see a brief return to VFR this afternoon as ceilings slowly lift, but this will be rather short lived as a band of showers and a few TSRA push into the area. This precipitation will move through this evening into the overnight bringing associated visibility and ceiling restrictions. Behind the precipitation, ceilings are forecast to crash again with more widespread MVFR and IFR heading into Thursday morning.

Outlook: Consistent improvement is not expected until Friday, when the cold front moves to our east and ushers in VFR conditions for the weekend.

GSP WATCHES/WARNINGS/ADVISORIES

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