textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

No major changes to the forecast.

KEY MESSAGES

1. Cooler high temperatures return this weekend into early next week as cold air damming lingers over the forecast area. Temperatures slowly rebound through midweek ahead of the next frontal system. 2. Rain chances return by the middle of next week as a low pressure system approaches from the west.

DISCUSSION

Key message 1: Cooler high temperatures return this weekend into early next week as cold air damming lingers over the forecast area. Temperatures slowly rebound through midweek ahead of the next frontal system.

A backdoor cold front will move south of our area today as a robust 1030+mb surface high settles over New England. Cooler, relatively dry air will filter into the low-levels while mid to upper level clouds increase today. This will help keep high temperatures near normal with some low-end wind gusts this afternoon. The low-level dry air should keep the better moisture transport to our south, while any forcing from the upper shortwave to our west remains weak. As such, most of the deterministic and ensemble guidance continues to show mostly dry conditions across our CWA thru the weekend and early next week. Some of the latest CAMs continue to spread light showers over our area on Sunday and Monday, but much of this will likely fall as virga. Thus, precip chances remain isolated at best across our area thru Tuesday. The CAD is expected to be in place across our area on Sunday, resulting in the coolest day of the fcst period with most locations being at or slightly below normal for afternoon highs. Any lingering CAD/wedge should gradually erode early next week, allowing temperatures to steadily warm back above normal.

Key message 2: Rain chances return by the middle of next week as a low pressure system approaches from the west.

Upper ridging will amplify over the Southeast early next week, as a broad/deep upper trof moves over the western CONUS. This upper trof will approach our area by mid-week and eventually push the upper ridge off the Atlantic Coast. As the upper trof approaches, it will likely close off into a low and begin to lift NE. At the sfc, a deepening cyclone will develop over the Central Plains, while a secondary low forms over the Southern Plains and lower half of the MS River Valley. An attendant cold front will gra- dually move eastward and approach our area by early Wed. At the same time, the surface high over the NE moves out over the NW Atlantic, while SLY return flow brings increased moisture into our area ahead of the frontal system. The overall timing/progres- sion of the front differs amongst the guidance, but the bulk of it indicates that we should get some precipitation by mid-week with the best chances on Thursday. In addition, thunderstorms and even severe weather can't be ruled out with this setup as deep layer flow will likely be enhanced. Most of the current guidance shows minimal amounts of instability as the cold front moves across the CWA Wed into Thurs. However, we are talking about days 5 and 6, so confidence wrt to these details is low.

AVIATION /19Z SATURDAY THROUGH THURSDAY/

At KCLT and elsewhere: Expect dry, VFR conditions to continue thru the 18z TAF period. High clouds will continue to stream across the region as a backdoor cold front pushes further south. Outside the mtns, winds should remain NE to ENE thru the period with low-end gusts this afternoon (except at KHKY), with more low-end gusts expected tomorrow at the Upstate sites. At KAVL, winds will be light and favor a SELY direction this aftn/evening. They will go light and VRB to calm later this evening and pick up again from the SE later tomorrow morning.

Outlook: Mostly dry and VFR thru Tuesday. I cannot entirely rule out a few showers and associated restrictions early next week, but confidence is low. Otherwise, rain and associated restrictions are expected to return during the middle of next week. With ample cloud cover expected this weekend into much of next week, any mtn valley fog should be limited.

GSP WATCHES/WARNINGS/ADVISORIES

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