textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

No significant changes from the previous forecast. Only minor tweaks to the daily precipitation probabilities and temperatures.

Forecast was updated to reflect 18z TAF issuance.

KEY MESSAGES

1. Summerlike pattern continues. Temperatures stay well above normal, and chances for spotty afternoon showers increase through Friday night. 2. Warm with mainly diurnal convection Saturday into the middle of next week.

DISCUSSION

Key message 1: Summerlike pattern continues. Temperatures stay well above normal, and chances for spotty afternoon showers increase through Friday night.

Some pesky low-level stratocu is still in place from this morning, mainly south of I-85, but is looking more and more anemic from satellite imagery. A 6-12kt wind is being reported at most ob sites, with intermittent gusts as daytime mixing sets in. The pattern remains starkly summerlike and quite unusual for early March, with the Bermuda high settled into place across the western Atlantic beneath subtropical ridging aloft. As a result, anomalously warm temperatures within a weak WAA regime will continue, and a weak but steady influx of low-level moisture will continue unabated through the rest of the week. A shallow subsidence inversion advected in from the eastern Gulf Coast / Florida Peninsula will largely inhibit any showers from developing today, so we can expect to remain dry through tonight. Based purely on persistence...one would expect another round of patchy fog and a deck of low stratus to develop somewhere in the SC Upstate and NC Piedmont around daybreak Friday...though guidance doens't feel great about how far north this feature will make it before morning sun begins scattering it out.

On Friday, daytime mixing should once again develop across the area, and with mid-level forecast profiles depicting less/no subsidence, the case for at least spotty convection is more convincing. Parcels don't look to reach their convective temps here, so most activity will likely take place across the mountains, where mechanical forcing can give parcels the nudge they need to start rising. However, the majority of the 12z CAMs, as well as the morning RRFS run and many of its ensembles, support more widespread initiation over the Deep South (mainly Alabama and central Georgia) on Friday afternoon, and depict residual showers making a run at the western Upstate and Smokies/Balsams sometime well into Friday night. Any associated precipitation would mainly be light, producing very little accumulation.

Key message 2: Warm with mainly diurnal convection Saturday into the middle of next week.

A summer-like pattern remains in place into the weekend with a Bermuda high in the Atlantic and southwesterly flow aloft over our area. This keeps plenty of moisture over the area with PW values over 200% of normal. Instability remains on the weak side given the deep moisture and warm mid levels. Any forcing on Saturday will be limited but some shortwave energy does move through the flow and across the area Sunday. A weak frontal boundary also crosses the area Sunday. As a result, expect better convective chances on Sunday. That said, some guidance does show better instability and shear on Saturday, with the potential for isolated severe storms. Confidence is low and uncertainty is high, so keep an eye on the forecast for later updates. Either way, precip chances will be higher across the mountains. Despite the front washing out south of the area, PW values remain high with more shortwave energy moving through the flow over the area, keeping the potential for scattered convection in place. The Bermuda high reasserts itself Tuesday and Wednesday with southwesterly flow returning. This keeps the warm and moist airmass in place along with scattered diurnal convection. Temps will remain well above normal each day potentially threatening record highs, especially on Tuesday.

A stronger frontal system may move into the area Thursday as a deep closed low ejects out of northwestern Mexico and starts to approach our area from the west. This would lead to increased precip chances and cooler but still above normal temps.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

At KCLT and elsewhere: A continuation of dry, mainly VFR conditions expected for today and tonight. Still dealing with some pesky MVFR ceilings across the southern Upstate, with occasional obs from GSP, GMU, and AND all reporting cloud bases in the FL020-025 range. Satellite suggests this cloud cover is rapidly thinning and likely to scatter out entirely in the next hour. Thereafter, expect mainly FEW/SCT cumulus this afternoon, giving way to higher clouds overnight. Intermittent SW gusts should taper off by this evening and give way to a light SW breeze overnight. Expect another deck of low stratus to make a run at the Upstate and eastern Piedmont Friday morning; how far north this deck makes it before the sun comes up is uncertain, with many of the raw models suggesting it'll be less extensive than this morning's...but was confident enough for TEMPO MVFR at CLT and AND just based on persistence. Whatever fog/stratus develops should scatter out by mid-morning Friday, giving way to another day of scattered cu and very isolated afternoon showers.

Outlook: The spring-like weather pattern will persist over the next several days. Patchy fog/low stratus expected each morning. A stalling front will likely bring showers and associated flight restrictions over the weekend.

CLIMATE

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

RECORDS FOR 03-11

MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 79 1967 29 1924 55 2016 14 1934 1925 KCLT 83 2015 37 1960 60 1986 22 1969 2009 1934 1990 KGSP 84 2009 34 1960 60 1986 17 1969

GSP WATCHES/WARNINGS/ADVISORIES

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