textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Temperatures were warmed a bit over the weekend. Precip chances are delayed until next Thursday.

KEY MESSAGES

1. Lingering showers will taper off by evening as drier starts moving in, but patchy dense fog is possible through late tonight. Otherwise, temperatures remain cool Friday before returning to normal through the weekend.

DISCUSSION

Key message 1: Lingering showers will taper off by evening as drier starts moving in, but patchy dense fog is possible through late tonight. Otherwise, temperatures remain cool Friday before returning to normal through the weekend.

Cool temperatures will continue through the afternoon with extensive low cloudiness and lingering patches of light rain, especially over the western Piedmont. Afternoon high temps were lowered over much of the region east of the mtns based on temp trends at midday. Meanwhile, locations not affected by the cold air damming wedge, such as the Smokies and southwest part of NC should have scattered to numerous showers aided by weak buoyancy of 500 J/kg over the ridgetops.

The wedge should start breaking down as we get into this evening and the upper low over WV this past morning rotates southeastward across the Carolinas through the end of the day. Once this happens, the flow backing more northerly and northwesterly will drain the cool pool east of the mtns and that will be it, with most of the sky becoming clear by daybreak. The only minor problem could be the potential for some dense fog to develop as the dry air comes in aloft first and we have plenty of lingering moisture at the sfc. Many times in similar situations, we get a period of a few hours where patchy dense fog develops, sometimes to the point where a Dense Fog Advisory needs to be issued. The guidance doesn't support it right now, but the possibility exists and we will monitor for fog development after dark.

From Friday onward, it looks like smooth sailing. The models show us trapped under a cool and dry cyclonic N to NW flow aloft through at least Monday, which will preclude any rain. Temps stay cool on Friday with highs around five degrees below normal, and perhaps downright chilly for low temps early Saturday morning with lots of places dropping down to 45-50 degrees. Ridgetops above 5000 feet could get down in the upper 30s! The sfc high responsible for this cool-down will be stuck to our north through the weekend as it will be blocked by the big cutoff low over the northeast, so as a result the air mass will remain in-place and should slowly modify with temps returning to seasonal normals over the weekend. It should be spectacular early autumn weather. The pattern gets un-stuck during the middle part of the week with warmer temperatures, but by then, model differences inject a great deal of uncertainty into the forecast. Eventually as we get into the latter half of the next week, rain chances will return as moisture comes back up from the south, but details are very sketchy.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

At KCLT and elsewhere: Starting out with widespread MVFR ceiling restrictions. Most of the light rain has moved east and ended, but a few patches remained around KCLT with associated IFR ceiling restrictions, thus the TEMPO for the first few hours. That can probably be amended away before 20Z. Wind will be NE with occasional gusts at most places outside the mtns. As we start to lose daytime heating, and the low level flow backs more northerly, the low cloud decks should scatter out and then dissipate by late evening. That could set us up for a period of fog, owing to the lingering moisture near the sfc and the dry air moving in aloft. For now, only the mountain valleys like KAVL and places over the NC Foothills like KHKY get it, but other terminals have a chance at the fog restriction. Once that mixes out Friday after sunrise, VFR and clear everywhere with a light NE wind.

Outlook: VFR should persist into the middle of next week, though mountain/river valley fog/stratus could still develop before daybreak each day.

GSP WATCHES/WARNINGS/ADVISORIES

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