textproduct: Greenville-Spartanburg

SYNOPSIS

High pressure will dominate our weather for the next several days as temperatures go through a warming trend between today and the end of the week. Fair and warm weather is expected over the weekend. The next low pressure system could affect our region early next week.

NEAR TERM /THROUGH WEDNESDAY/

Key Messages:

1) Slippery road conditions expected tonight across areas that received accumulating snowfall.

2) Colder temps stick around with intermittent gusty winds across the mountains.

As of 1210 PM EDT Tuesday: High pressure resumes over the southeast as the upper trough lifts out of the area and flow aloft becomes more quasi-zonal. Toward the end of the period, a moderate ridge out west turns upper winds NW as another trough dips southward from Canada, but surface high pressures keeps the area dry. The bigger story are the rebounding temperatures as the airmass modifies throughout the period. Guidance has a weak shortwave traversing across the CWA on Wednesday and continues to the drier air trend. Limited moisture and unimpressive forcing keeps the shortwave from producing any weather of mention. Winds across the mountains should decrease throughout the day and pick up again overnight. The trough off to the north skirts through the mid-Atlantic region, edging a tighter pressure gradient toward the northern and high elevations of the CWA. Regardless, winds remain below any advisory criteria. As for temperatures, expect overnight lows to be somewhat warmer with most of the locations east of the mountains reaching at or just above freezing. Mountain regions dip below freezing tonight. Any areas that received snowfall, could see black ice concerns tonight on sidewalks or roadways where melting occurred during the day. However, with most of the mountain areas getting well above freezing and gusty winds, this is expected to assist the melt/evaporation process. The areas of most concern for any ice on roadways are at the higher elevations (above 3500 feet) where accumulations were higher and temps are colder today. By Wednesday, daytime highs quickly rebound and warm to just below normal.

SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/

As of 1039 AM EST Tuesday: The rest of the week looks relatively quiet and dry with a warming trend. The upper pattern doesn't change much with our area underneath a broad and deep NW flow between the trof axis that moved off the East Coast and the upstream ridge axis over the Rockies through Friday. Might still be a little breezy Wednesday night with the passage of a weak reinforcing front, but the pressure gradient relaxes quickly Thursday morning. Behind the front, sfc high pressure will settle over the mtns and temps will continue their steady warmup. Lows might still be on the cool side of normal because of good radiational cooling conditions and the dry air mass, but highs will go from near normal on Thursday to a category above normal on Friday. The afternoon RH could be problematic assuming the apparent usual NBM bias toward keeping the dewpoint too high on good mixing days, so we will expect some RH below 30 percent in the afternoons over the Piedmont/Upstate.

LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/

As of 1050 AM EST Tuesday: Once we get out to the end of the week, the upper pattern starts to become slowly progressive once again. The upper ridge axis over the Plains holds its position briefly over the weekend while the next low pressure system moves over the Southwest/Great Basin. That should keep us in the broad WNW flow aloft and under warm and dry high pressure, making for a lovely weekend, in theory. There is the matter of some moisture dropping down in this flow that model guidance picks up on Sunday along another weak front. The model blend keeps some low-end precip probs for Sunday and Sunday night over the western part of the mtns, but this looks somewhat dubious. The trend is toward delaying and decreasing the precip prob, so it wouldn't be surprising to see this eventually dry up completely until the next system arrives from the west early next week. Meanwhile, the temps will climb up again to 5-10 degrees above normal. If there is any controversy, it would be with the handling of the western system expected to come off the Rockies out onto the Plains Sunday night and into Monday. The models are having some big differences of opinion as to how much the system will deamplify Monday into Tuesday and where the trof will move, with the 06Z GFS showing the strongest wave coming toward our region on Tuesday. Hard to say which way this one will trend...more toward the low end because of poor moisture return and forcing well to the north...or more toward the high end with better moisture return and maybe even another round of strong storms. For now, Tuesday will feature a chance over the mtns with temps falling back to around normal. No cold air, so all precip will be liquid even at the highest elevations.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

At KCLT and elsewhere: VFR conditions prevail through the period. No vsby or cig restrictions as high pressure moves in. As for the winds, expect gusty conditions to continue at KCLT/KGMU/KAND through the remainder of the afternoon. Though a low-end gust at KAVL is possible, the general trend is for the winds to decrease throughout the day and into part of the overnight hours. Expect winds to increase again overnight and into Wednesday morning. There could also be 35kt LLWS at KAVL and KAND tonight as well. If any LLWS develops, it should diminish by 14z.

Outlook: VFR conditions prevail through the remainder of the week. Lighter winds return by Thursday, increasing the chance for mountain valley fog/low stratus each morning.

GSP WATCHES/WARNINGS/ADVISORIES

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