textproduct: Greenville-Spartanburg

SYNOPSIS

Warmer temperatures expected Thursday even as rain chances continue. Fair afternoon skies and exceptionally warm weather end the week. A cold front brings shower and thunderstorm chances on Sunday, with drier and cooler conditions through the middle of next week.

NEAR TERM /THROUGH TODAY/

As of 155 AM EDT Thursday: Upslope showers continue to develop and track north into the NC mountains. This shower activity may linger along the Blue Ridge Escarpment through the overnight hours. Otherwise, expect cloudy skies and temperatures staying elevated, as a wedge gradually erodes with very warm temps just to our south. Temps, dewpts, winds, sky, and PoPs were all updated to reflect the latest obs and trends thru this morning.

Otherwise...Despite the surface high moving far enough offshore that it won't really be in position to actively sustain the wedge any longer, there won't be a mechanism to erode it; rather, there will be the usual nighttime inversion and moist southeasterly flow keeping the boundary layer saturated...which all but guarantees the murky conditions will persist through the night. Lows will struggle to fall below the upper 50s or lower 60s. The daylight hours on Thursday will feature slow clearing...as daytime heating very slowly mixes the residual wedge. Temps today are tricky...since the temperature trend will be highly dependent on how quickly the wedge scatters out. The NBM and a consensus of the 12z CAMs are forecasting highs in the upper 70s or even lower 80s...but think actual highs could wind up cooler since these models may be clearing out the wedge unrealistically fast.

SHORT TERM /TONIGHT THROUGH SATURDAY/

As of 150 PM Wed: Upper ridge starts out over the area then slowly moves eastward as a trough digs into the Midwest. The moist upslope/ upglide weakens Thursday evening bringing an end to any showers. Despite the ridge in place Friday, there looks to be enough moisture and weak instability for isolated to scattered showers across the mountains during the afternoon and early evening as a front moves south toward the area but stalls just to our north. An isolated ridge top shower can't be ruled out Saturday afternoon, but overall chance of precip is low with less in the way of moisture and instability as the front moves north away from the area and a surface ridge reasserts itself. Thicknesses and heights remain high under the ridge. This puts record highs in jeopardy both days. Lows will be around 20 degrees above normal.

LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/

As of 210 PM Wed: The upper trough mentioned at the end of the short range moves east and pushes a cold front into the area Sunday. There will be plenty of forcing and shear, along with high PW values, associated with the front. There will be some instability, but the amount is uncertain. Therefore, there is a low severe and excessive rainfall threat which we'll keep an eye on as the event approaches. A wave forms along the front slowing its eastward progression Monday. This will keep a chance of lingering showers across the area, but any severe and flood threat will have moved eastward.

A weak secondary front/clipper type low may cross the area Tuesday, but the guidance keeps shifting from low chance precip to dry. Have kept the forecast dry for now. Dry and cooler high pressure moves in Wednesday.

Temperatures are cooler but still above normal Sunday and falling to near normal Monday. Temps drip below normal for Tuesday and Wednesday. This brings a frost concern for the non-mountain areas of the Upstate and NE GA and the NC southern foothills and Piedmont, where the growing season has started.

AVIATION /06Z THURSDAY THROUGH MONDAY/

At KCLT and elsewhere: A wedge lingers across the Escarpment and adjacent foothills, with all sites in the wedge or near the wedge boundary, except for CLT. Those site may see LIFR cigs and possibly some vsby restrictions during the pre-dawn hours. The wedge is expected to erode, bringing winds out of the S and improve the vsbys. The LIFR cigs will take a while to mix out, however. All sites will likely have IFR cigs this morning and possibly into early aftn, with guidance showing cigs may not get to VFR until early to mid aftn. A few showers may form again during the day, but are expected to be mostly near the Escarpment and too isolated for a TAF mention at this time. MVFR to IFR cigs may form again tonight after 06z. Winds will be out of the south at all sites, once the wedge fully erodes, picking up with some low-end gusts by late morning or midday, then weakening again late aftn into this evening.

Outlook: IFR to MVFR cigs may return again late tonight and linger into Friday morning. Drier conditions return Friday night into Saturday night before another cold front brings shower and thunderstorm chances, and associated flight restrictions, back on Sunday.

CLIMATE

STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 88 1963 31 1936 64 1946 23 1936 KCLT 90 1946 42 1915 62 1986 26 2021 1946 KGSP 87 1967 44 1901 62 2014 27 2021 1963 1993 1946 1902

RECORDS FOR 04-04

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 83 1999 33 1891 61 1893 22 1936 1978 KCLT 87 1999 43 1911 63 1986 29 1936 1899 1945 1934 KGSP 88 1963 44 1936 62 1999 25 1975 1934

RECORDS FOR 04-05

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 86 1909 30 1891 60 2023 20 1944 1910 KCLT 88 1942 38 1891 62 1910 26 1891 KGSP 90 1934 43 1899 60 2023 25 1904 1888

RECORDS FOR 04-06

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 88 1967 36 1950 64 2023 22 1898 KCLT 90 2010 43 1931 67 2023 28 1891 1929 KGSP 88 2010 47 1950 65 2023 26 1904 1945

GSP WATCHES/WARNINGS/ADVISORIES

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