textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Low to moderate confidence in the potential for very light snow to occur across portions of the foothills and Piedmont Wednesday evening into early Thursday morning.

KEY MESSAGES

1. Warmer temperatures return allowing for decent melting of lingering snowpack. Dry conditions continue through Tuesday for most areas, although rain chances will increase across the North Carolina mountains starting late Tuesday afternoon. 2. A front crosses the area Tuesday night through Wednesday bringing precipitation back to the area with light snow possible Wednesday night. 3. A brief round of mountain snow is possible Friday night, otherwise temperatures return to seasonal averages through the weekend.

DISCUSSION

Key message 1: Warmer temperatures return allowing for decent melting of lingering snowpack. Dry conditions continue through Tuesday for most areas, although rain chances will increase across the North Carolina mountains starting late Tuesday afternoon.

Most locations will see temperatures rise above freezing this afternoon, but some of the higher elevations in North Carolina mountains will remain below freezing through Tuesday morning before finally rising above freezing early Tuesday afternoon. Highs this afternoon will climb into the mid 30s to mid 40s across the lower elevations, with the higher elevations only reaching into the upper 20s to lower 30s. Highs on Tuesday will be even warmer ranging from the mid 40s to lower 50s across the lower elevations and the mid 30s to lower 40s across the higher elevations. Visible satellite loops this afternoon show lingering snowpack across much of the forecast area but warmer temperatures will allow for decent melting each day. Per usual, shaded areas will take longer to melt despite warmer temperatures.

Any moisture that is left behind from melting snow on roadways, sidewalks, driveways, parking lots, bridges, and overpasses will quickly refreeze after sunset as temperatures will once again fall below freezing this evening into tonight. Thus, patchy black ice will be a concern again tonight into mid-morning Tuesday, especially on bridges and overpasses as well as untreated roadways. Will hold off on the issuance of a Special Weather Statement for patchy black ice for now as this will be highly dependent on how much snow melts prior to sunset. Lows tonight will not be as cold as last night, but will still be cold, ranging from the upper teens to mid 20s.

Dry conditions linger across most locations through Tuesday thanks to surface high pressure, but precipitation chances will increase across the North Carolina mountains ahead of an approaching front. For now it appears that areas along the NC/TN border will have the best chance to see precipitation develop late Tuesday afternoon into early Tuesday evening. Temperatures will be warm enough for mostly rain, but some of the higher elevations will see temperatures drop near to below freezing allowing for a rain/snow mix or even a full transition to snow at the highest peaks. Snow accumulations will remain light through 00Z Wednesday.

Key message 2: A front crosses the area Tuesday night through Wednesday bringing precipitation back to the area with light snow possible Wednesday night.

By tomorrow night, a tall ridge will extend up the West Coast with a piece of Pacific energy diving down the eastern flank into the Great Plains. Ahead of this feature, a broad swath of westerlies is forecast to extend from the Deep South into the Carolinas in the base of a mean trough. With time, this flow will shift to out of the southwest as the upstream trough digs over the Southern Plains. At the surface, a cold front will be progressing from the Mississippi Valley towards the Appalachians in advance of a 1035mb high spilling into the Plains. At least some precipitation will likely be ongoing across the mountains at the start of tomorrow night with this activity spreading east through the overnight into Wednesday morning. Guidance continues to depict profiles that are too warm for wintry weather east of the mountains with the greatest chance for snow to be across the highest elevations of the mountains, generally above 4000ft. The upper trough remains positively tilted with only modest forcing, which throws some question as to how much precipitation makes it east of the mountains. At least isolated to widely scattered showers seem likely, but coverage and amounts of rainfall appear rather limited.

Heading through the day Wednesday, the latest suite of models continues to depict a surface low developing along the advancing cold front within an inverted surface trough extending from the coast up I-26. The surface low then slides east roughly along the I- 20 corridor through the evening and into early Thursday morning. In response, light QPF blossoms across portions of the North Carolina foothills and Piedmont along a weak band of mid-level frontogenesis. How far south any QPF makes it into the Upstate remains uncertain. At the same time, cold air will be arriving behind the boundary and could allow some of this moisture to fall as light snow. If this were to occur, accumulations would be minimal and generally less than 1". Forecast confidence remains low to moderate right now pending better model agreement and amount of moisture and cold air to work with.

Key message 3: A brief round of mountain snow is possible Friday night, otherwise temperatures return to seasonal averages through the weekend.

The next feature of interest will be a strong clipper dropping out of the Great Lakes region Friday into Saturday morning. There's an impressive slug of moisture with this system, moreso than we would typically see with a clipper. Most of the precipitation will remain well to our north, but a period of northwest flow snow showers will be possible across the mountains along the immediate Tennessee border Friday night. Will need to watch model trends and see how far south sufficient moisture can make it as to the magnitude of snowfall, if any, that may occur. Otherwise, temperatures finally return to or just shy of seasonal averages for early February.

AVIATION /18Z MONDAY THROUGH SATURDAY/

At KCLT and elsewhere: Dry and VFR with light winds through the 18Z TAF period. Wind direction will remain NW at KAVL through Tuesday morning before turning S/SE Tuesday afternoon. Winds east of the mountains will generally S/SW through Tuesday but will go light and VRB to calm at times, especially this evening into early Tuesday morning. Cirrus will gradually become BKN to OVC from west to east overnight into Tuesday morning.

Outlook: A cold front brings precipitation and restrictions back Tuesday night into Wednesday night. Dry conditions return Thursday into the weekend for most of the terminals, outside of some northwest flow snow along the NC/TN border Friday night into early Saturday morning. Gusty winds develop Friday in association with a cold front and will linger across the mountains through Saturday, but will gradually taper off east of the mountains Friday evening.

CLIMATE

RECORDS FOR 02-02

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 76 1989 16 1908 52 1988 -2 1917 KCLT 80 1989 29 1908 61 1923 10 1917 KGSP 77 1989 28 1951 60 1923 9 1900

GSP WATCHES/WARNINGS/ADVISORIES

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