textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

PoPs are virtually unchanged for Friday, but have trended a touch lower, especially for the Piedmont on Saturday. Likely pops remain in the forecast for Sunday.

KEY MESSAGES

1. Well above-normal to record temperatures expected through the period. 2. Showers chances increasing starting on Friday and continuing through the weekend and into early next week.

DISCUSSION

Key message 1: Well above-normal to record temperatures expected through the period.

Summer-like Bermuda high will stagnate through the period as an upper ridge builds, with increasing thicknesses and low-level WAA leading to well above-normal to record temperatures through the period. The upper ridge will flatten somewhat over the weekend with the wave moving through but little change in overall thicknesses, and it will re-amplify into early next week as a stronger wave digs out of the Rockies into the Southern Plains. With this, highs are forecast to be 15-20 degrees above normal, generally only a few degrees below records. The exception is with current forecast highs on Friday where GSP and AVL are just a smidge below records and the 81 forecast at CLT would break it...but will see how subsequent NBM runs handle this anomalously warm airmass. Dewpoints remain high enough in the moist low-level WAA to keep RHs from reaching critical levels.

Key message 2: Showers chances increasing starting on Friday and continuing through the weekend and into early next week.

Persistent flow around Bermuda hipres will gradually advect higher PWAT values into the Southern Appalachians over the next several days. By Friday, richer dwpts combined with near record warmth is expected to promote a weakly unstable atmosphere to support scattered diurnally enhanced showers and a few tstms, especially in the mtns which are closer to the western periphery of the deep layered anticyclone. The atmosphere becomes a touch less suppressed on Saturday as eastward moving weakening baroclinic zone sags toward the mtns and upper ridge flattens a tad. The sensible weather will feature showers becoming numerous in the mountains, but development could struggle SE of I-85 which is further from the deep moisture and weaker synoptic scale lift. Within the flat SW flow aloft, weak s/wv energy and persistent southerly llvl flow is expected to continue to promote shower development throughout Sunday with blended model probabilities increasing to likely regionwide. The warm but unsettled pattern will linger into the first half of next week with mean southerly flow through the deep layer continuing all across the SE CONUS although it may take until the end of the forecast period, with the approach of a moderately forced s/wv, for more than token shower chances to be realized.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

At KCLT and elsewhere: VFR today into tonight, but MVFR to at least low VFR cigs will lift into the area from the south in the pre-dawn hours Thursday. Have included tempo mention at KGSP/KGMU/KHKY, with prevailing MVFR at KAND. SW winds through the period generally 5- 10kt both afternoons, decreasing towards lgt/vrb overnight.

Outlook: Springlike weather pattern over the next several days. Cannot rule out patchy overnight fog/stratus each night. A weak front will bring showers and associated restrictions for the weekend.

CLIMATE

RECORDS FOR 03-05

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 78 1955 20 1960 60 2004 5 1960 KCLT 84 1955 31 1960 62 1955 12 1960 1880 KGSP 80 1976 31 1960 61 2004 12 1960 1905 1976 1961

RECORDS FOR 03-06

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 78 1908 28 1960 58 1961 5 1960 KCLT 80 2022 33 1901 62 1961 10 1960 KGSP 79 1974 37 1948 63 1961 16 1960 1915 1901

RECORDS FOR 03-07

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 82 1974 23 1920 61 1956 15 1960 KCLT 85 1974 30 1899 63 2022 14 1899 1956 KGSP 83 1974 36 1920 62 1961 13 1901 1901 1956

RECORDS FOR 03-08

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 81 1974 23 1996 57 1921 8 1920 KCLT 84 1974 36 1989 59 1946 16 1920 KGSP 84 1974 35 1899 56 1921 14 1901 1899

RECORDS FOR 03-09

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 80 1974 22 1932 57 1964 8 1996 KCLT 83 2009 30 1960 62 1925 16 1996 1974 1921 1925 KGSP 85 2009 29 1960 60 2009 16 1996 1921

RECORDS FOR 03-10

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 76 1974 29 1932 58 1903 10 1996 1932 KCLT 82 1974 36 1924 59 1903 17 1932 KGSP 84 1974 39 1924 58 2009 17 1932 1997

GSP WATCHES/WARNINGS/ADVISORIES

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