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000
FXUS62 KGSP 111615
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1215 PM EDT Thu Apr 11 2024

.SYNOPSIS...
A cold front moves east and off the Carolina coast tonight as drier
air filters into our region from the west and northwest. Very windy
conditions develop Friday into Saturday. Dry and warm weather
returns for the weekend into the middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1210 PM EDT Thursday: Rain chances continue across mainly the
western third of the forecast area this afternoon. Have seen a lull
in lightning activity since the precious AFD update. Areas that saw
some breaks cloud cover are starting to fill back in. Made a few
minor tweaks to both PoPs and thunder again based on the latest
trends. Also made some tweaks to winds through tonight. Otherwise,
the forecast remains on track.

A strong low pressure system will lift NE across the TN Valley
today. HREF depicts shower and thunderstorm simulated reflectivity
through early afternoon, with the higher activity concentrated
across the mountains and eastern NC Piedmont. Moving into the
afternoon period, severe chances look low but remain non-zero. The
HRRR and NAM do show some redevelopment of sbCAPE of at least 500
J/kg, but this will greatly depend on if afternoon clouds can break
and allow for daytime heating. Additionally, if this instability can
materialize, the better forcing from the front is expected to push
into the region at that time. The RAP and NAM indicate a strong
upper jet with 60-70 kts of EFF shear. DCAPE also has the potential
to be high, between 600-800 J/kg, which could lead to gusty and
possible damaging winds should any storms develop. SPC keeps the CWA
in a Day 1 MRGL as well. If these ingredients can align, the main
concern for the afternoon period will be strong, damaging winds from
the outflow of any severe storm. Cloud-to-ground lightning could
also be a concern. But again, this is all contingent on the
instability and better forcing aligning this afternoon. Once the
FROPA clears the CWA through tonight, precip chances will be wiped
out for the most part as the drier air behind the boundary filters
in. Aloft, the low pressure system strengthens over the Great Lakes
and tightens the pressure gradient, increasing wind speeds and gusts
late this afternoon and through the end of the period. Latest
guidance does not have gusts reaching wind advisory criteria,
therefore one is not planned to be issued. Expect gusts around 30-40
mph across most of the CWA through at least midnight and decreasing
through early Friday morning for a brief period before picking back
up in the short term. Overall, storm chances and winds will be the
main story for this period. Temperatures will be warm today with
overnight temps dipping into the 40s across the mountains and low
50s in the Piedmont.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 325 AM Thursday: A strong short wave rotates through the area
Friday with deep NW flow over the area. Deeper moisture lingers over
the mountains, so expect scattered convection there with the forcing
and upslope flow. Isolated convection will spread east across the NC
foothills and Piedmont during the afternoon where moisture and
forcing move through. NE GA and the Upstate will remain dry due to
downslope flow and lack of forcing. The bigger story will be the
wind. Deep mixing and strong H85 flow will allow wind gusts to 50
mph across much of the mountains and up to 40 mph elsewhere. A Wind
Advisory will likely be needed for the mountains, but is more
uncertain elsewhere. Any uptick in expected wind speeds would put at
least some of the non-mountain counties into Advisory criteria.

Convection diminishes Friday evening as moisture and forcing
diminish. Winds also taper off outside of the mountains, but gusts
to 50 mph will linger across the higher elevations. Windy conditions
continue across the mountains Saturday with breezy conditions
elsewhere. A high elevation Wind Advisory may still be needed. Winds
taper off all areas Saturday night.

Highs Friday will be near normal outside of the mountains and up to
10 degrees below normal across the mountains. Highs rise to slightly
above normal across the mountains Saturday and up to 5 degrees
elsewhere. RH values drop into the 25 to 30 percent range outside of
the mountains Friday and 20 to 25 percent range most locations
Saturday. With the very gusty winds, fire weather could become a
concern, especially if fuels dry out. Lows will be near normal
Friday night then rise a couple of degrees Saturday night.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 240 AM Thursday: A weak short wave crosses the area in NW flow
on Sunday. An upper ridge builds in through Tuesday as an upper low
moves from the Desert SW to the Midwest. A back door cold front
drops south toward the area Sunday and Monday then lifts back
northward on Tuesday. Expect a dry forecast to continue as moisture
and forcing remain sparse. Highs will be 10 to 15 degrees above
normal with lows rising into that range as well. Windy to breezy
conditions linger on Sunday, but winds won`t be as high as previous
days. Some weak short wave energy may cross the area Wednesday
rotating around the upper low. A cold front approaches from the west
but stalls west of the Appalachians. Therefore, expect the dry
forecast to continue. Highs will remain nearly steady on Wednesday.

&&

.AVIATION /16Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: A busy TAF period continues with showers and
TS moving in ahead of a cold front approaching from the west. Winds
start off light, but are expected to pick up after 12z across all
sites. Expect winds to turn from S/SE this morning to SW/W by at
least 00z at all sites. The front comes through after 00z and moves
eastward, turning winds at KAVL NW and WSW/W at all other terminals
by the end of the TAF period. There still remains some guidance
suggesting LLWS as a few sites, so kept LLWS for KCLT/GSP/GMU/AVL to
account for the 40-50kt speed change after sunrise and lasting
through the early afternoon. CIGS are expected to remain MVFR, with
all terminals dipping into IFR with low level stratus and widespread
BR lingering through mid-morning. Conditions should improve with
more convective showers and storms this afternoon, with temporary
restrictions possible. If instability can form during the day, TSRA
is possible at KCLT. CIGS will improve to VFR after midnight with
drier air behind the front.

Outlook: Gusty winds linger Thursday night into Friday, with the
strongest winds expected on Friday. VFR conditions persist Friday
into the weekend as high pressure builds across the terminals.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

$$

SYNOPSIS...DEO
NEAR TERM...AR/CP
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...CP