textproduct: Greenville-Spartanburg

SYNOPSIS

High pressure keeps dry conditions over the area through Wednesday night before a cold front brings precipitation chances back Thursday into Thursday night. Drier conditions return behind the front Friday into the weekend as high pressure builds in from the northwest.

NEAR TERM /THROUGH WEDNESDAY/

As of 1:05 PM EDT Tuesday:

Key Message: Warming trend continues thru Wednesday with dry conditions persisting.

Broad sfc high pressure currently centered over our area will continue to migrate eastward thru the near-term period. This pattern will keep us dry with plenty of sunshine today as tem- peratures rebound from their well-below normal values the past few days. Dewpts have been stubborn to rebound across the region, but the persistent S to SW low-level flow should help them in- crease later this evening and more so tomorrow. Nonetheless, a Fire Danger Statement remains in effect for our NE Georgia counties until 7 PM this evening. Otherwise, expect high temps today to reach the 50s at most locations, with the NC Piedmont remaining cooler than most of our Upstate counties and our NE Georgia counties. Low temps early Wed are expected to bottom- out near freezing, if not slightly below, for most sites. High temps tomorrow will continue to rebound, with values in the mid to upper 50s across most of our fcst area. Dewpts should also gradually increase thru the day/evening with minimum RH values expected to remain above 30% for most zones tomorrow. We could see some low-end wind gusts of 15 to 25 mph tomorrow morning/aftn across the Upstate and Piedmont, but this will largely depend on whether or not a weak, low-level jet can effectively mix down to the sfc. In addition, the jet appears stronger just to our north and east.

SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/

As of 1125 AM Tuesday:

Key Message #1: Precipitation chances and gusty winds return Thursday into Thursday night

By tomorrow night, an intense Pacific jet will extend from the Pacific Northwest through the Great Basin and will help carve out a potent trough over the Great Plains by Thursday morning. The trough will deepen and take on a neutral to negative tilt as it swings across the Mississippi Valley and eventually lifts across the Appalachians by early Friday morning. Robust wind fields in response to the deepening cyclone will advect a plume of deeper moisture across the region with PWATs rising to around or just above 1". Showers are expected to increase in coverage within the warm advection regime on Thursday, especially along the southern Blue Ridge escarpment and within a low-level convergence zone in the vicinity of the Piedmont. A band of showers will likely accompany the front Thursday night, but guidance is split as to the degree of coverage, but ample forcing should promote at least likely probabilities for measurable rainfall. Better surface moisture recovery appears to remain limited to the coastal plain, so not expecting any severe weather, which is good as shear profiles are rather concerning otherwise.

Key Message #2: Cooler and dry weather returns Friday with gusty winds

Any lingering showers should quickly clear the area Friday morning with a surface cold front pushing across the region. This will usher in a cooler airmass with temperatures back to around seasonable normals for late December. Winds will also be gusty in the cold advection regime, especially across the mountains and the most favorable ridges. Although gusts should remain below advisory levels.

LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/

As of 1205 PM Tuesday:

Key Message #1: Dry conditions continue Saturday with uncertain rain chances this weekend into early next week

The region will be situated beneath quasi-zonal flow by Saturday as the previous trough lifts across New England and a broad/flat trough evolves over the Northern Plains. This trough will slide east through the weekend across the Great Lakes and into New England, but the better upper jet dynamics and forcing are displaced north of the area over the Ohio Valley into the Mid-Atlantic. A subsequent surface cold front gets nudged south towards the southern Appalachians, but the timing and progress of the front is uncertain as it will be oriented parallel to the upper flow. This, combined with an overall dearth of synoptic ascent, casts considerable uncertainty as to whether any precipitation chances can return over the weekend into early next week. Will maintain a slight chance for showers over the mountains as a small handful of ensemble members do maintain wetter solutions, but confidence is lower than normal. Temperatures quickly rebound to back above normal through the weekend.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

At KCLT and elsewhere: Expect dry, VFR conditions to prevail thru the 18z taf period with high pressure remaining over the area. Mostly clear skies will give way to high clouds spreading over the area from the west beginning tomorrow morning. Outside of the mtns, winds will remain S to SW thru the taf period with some sites going light and VRB later tonight. Speeds will pick back up later tomorrow morning with low-end gusts likely at most terminals except KHKY. At KAVL, winds will remain NWLY this aftn/ evening with a TEMPO for some low-end gusts this aftn due mostly to channeling effects down the French Broad Valley. They should go light and VRB to calm later this evening and remain light thru 18z tomorrow.

Outlook: VFR conditions prevail thru Wednesday night. Showers and associated restrictions are expected Thursday into Friday, with VFR returning by Friday aftn.

GSP WATCHES/WARNINGS/ADVISORIES

GA...Increased Fire Danger until 7 PM EST this evening for GAZ010- 017-018-026-028-029. NC...None. SC...None.