textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

A Cold Weather Advisory was issued from 6 PM this evening through 9 AM Monday for portions of western North Carolina and portions of the South Carolina Upstate as very cold wind chills could result in hypothermia or frostbite if precautions are not taken.

A Special Weather Statement was issued for the entire GSP forecast area as widespread black ice will lead to hazardous road conditions this evening into Monday morning.

KEY MESSAGES

1. Lingering snowpack combined with cold temperatures will lead to black ice as well as very cold wind chills this evening into Monday morning. Black ice will lead to hazardous road conditions and very cold wind chills could result in hypothermia or frostbite if precautions are not taken. 2. Temperatures gradually warm through early next week with dry conditions returning across the region. Precipitation chances return by mid week.

DISCUSSION

Key message 1: Lingering snowpack combined with cold temperatures will lead to black ice as well as very cold wind chills this evening into Monday morning. Black ice will lead to hazardous road conditions and very cold wind chills could result in hypothermia or frostbite if precautions are not taken.

Dry high pressure lingers over the region through Monday night keeping dry and cold conditions around. Temperatures will remain below freezing across most locations through Monday morning before rising above freezing Monday afternoon. However, higher elevations in the North Carolina mountains will likely see temperatures remain below freezing through Monday night. Despite most locations remaining below freezing today, plentiful sunshine will help melt some of the snowpack. However, once the sun sets, any moisture left behind will quickly refreeze onto roads, parking lots, sidewalks, driveways, bridges, and overpasses this evening into tonight leading to widespread black ice through Monday morning. If traveling, be prepared for hazardous road conditions, especially on bridges and overpasses as well as on untreated roadways. Use extra caution when walking on sidewalks, driveways, and in parking lots.

Gusty winds will linger across the mountains through late this afternoon before gradually diminishing late this evening into daybreak Monday. Lingering snowpack will lead to cold temperatures tonight, with lows falling into the single digits. Cold temperatures combined with lingering wind gusts will allow very cold wind chills of 5 to 12 degrees below zero to develop this evening into Monday morning across the northern and central North Carolina mountains. Thus, a Cold Weather Advisory was issued for these zones from 6 PM this evening through 9 AM Monday. Breezy winds will linger east of the mountains through late this afternoon before diminishing early this evening. Light winds combined with mostly clear skies and lingering snowpack will allow for great radiational cooling conditions. With temperatures expected to fall into the single digits to lower teens leading to wind chills as low as 5 degrees, a Cold Weather Advisory was also issued for the North Carolina foothills and Piedmont as well as the southern and eastern South Carolina Upstate from 6 PM this evening through 9 AM Monday. Wear appropriate clothing, a hat, and gloves. Make frequent checks on older family, friends, and neighbors. Ensure portable heaters are used correctly. Do not use generators or grills inside.

Key message 2: Temperatures gradually warm through early next week with dry conditions returning across the region. Precipitation chances return by mid week.

Flat shortwave ridging will be translating across the Ohio Valley and the Appalachians by Tuesday morning while a piece of Pacific energy dives down the eastern flank of a tall west coast ridge. This will carve out a positively tilted trough over the Southern Plains with a broad zone of southwest flow extending from the Gulf states into the Carolinas. A surface cold front will also be dropping across the Midwest and into the Ohio Valley/Tennessee with a broad zone of precipitation ahead of the boundary. The leading edge of the precipitation encroaches on the mountains late Tuesday evening where rain chances are the highest. Guidance has come into better agreement with struggling to maintain much coverage of precipitation east of the mountains as the positive trough orientation and lack of stronger forcing and a well developed surface low will prove hostile to maintenance of the precipitation band. Guidance has also trended warmer with overnight temperatures with even fewer ensembles members cold enough for wintry weather east of the mountains, the majority of which remain dominated by the GEPS. Thus, will confine any rain/snow mix to the mountains with just rain elsewhere. A few members of guidance have hinted at the potential for a surface low to try and develop along the coastal baroclinic zone Wednesday night as the main trough axis crosses the region. There are also indications that an inverted surface trough may extend up I-26 from the coast. Guidance that favors this solution attempts to blossom another bout of anafrontal precipitation into cold air overnight into Thursday morning. This is a very low confidence scenario, so will keep the forecast to just rain and then drying. Temperatures make a run at returning to near seasonal average by late week.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

At KCLT and elsewhere: Dry and VFR through the 18Z TAF period. Gusty winds (25-33 kts) will linger at KAVL through late this afternoon before gradually tapering off this evening into tonight. Low-end, intermittent wind gusts (15-20 kts) can be expected east of the mountains through late this afternoon before tapering off early this evening. Wind direction will remain NW at KAVL through the period. Winds east of the mountains will remain W/NW through tonight, before gradually turning SW Monday. Upper cirrus will increase this evening into tonight before brief clearing develops ahead of another round of cirrus Monday morning into Monday afternoon.

Outlook: Dry and VFR through Tuesday. A cold front brings precipitation and associated restrictions back Tuesday night into late Wednesday.

CLIMATE

RECORDS FOR 02-01

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 74 1950 22 1898 55 1950 4 1909 KCLT 76 1950 27 1900 55 1896 10 1900 KGSP 73 1957 30 1980 56 1969 9 1900 1936 1950 1916

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...Cold Weather Advisory from 6 PM this evening to 9 AM EST Monday for NCZ033-035>037-049-050-053-056-057-065-068>072- 082-501>510. SC...Cold Weather Advisory from 6 PM this evening to 9 AM EST Monday for SCZ008-009-011>014-019-103-106>109.