203
FXUS62 KGSP 202321
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
721 PM EDT Mon May 20 2024

.SYNOPSIS...
Warm high pressure will persist across the region through the
middle of the week. A cold front approaches from the northwest on
Thursday, bringing a chance of showers and storms mainly to the
mountains. The front will stall over the area Friday, keeping rain
chances through weekend and into early next week.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 600 PM EDT Monday: Finally seeing some isolated showers
develop across the mountains this evening. No lightning is currently
present in this activity, but thunder will remain possible through
sunset. Cumulus that developed this afternoon is dwindling in
coverage since it`s past peak heating. Thicker cloud cover continues
across portions of the North Carolina mountains this evening. Main
change needed was the tweaking of PoPs, cloud cover, and winds
through the near term period. Otherwise, the forecast remains on
track.

Persistence looks like a really good forecast over the next 24
hours as the salient features don`t change much. We continue to
enjoy a positively-tilted mid/upper ridge that supports weak high
pressure to our northeast. As a result, expect another round of
mountain valley low stratus/fog late tonight, with some locally
dense. Once that mixes out in the middle-part of the morning, the
day should be quiet again east of the mtns, but ridgetop showers
can be expected in the mid/late afternoon. High temps will nudge
upward a bit, maybe a category above normal Tuesday afternoon.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 200 PM EDT Monday: An upper ridge axis starts out the period
over the area. The axis slowly moves east and becomes suppressed by
the end of the period as some weak short waves top move through the
flow. The result Is a very low chance of diurnal mountain convection
Wednesday, then a better chance on Thursday as the cap erodes
allowing sbCAPE to be realized. For now, chance PoP on Thursday is
limited to the mountains and I-40 corridor, with isolated PoP south
of there to the I-85 corridor. Highs will be well above normal both
days, making a run at 90 for the CLT Metro, Upstate, and NE GA. Lows
5 to 10 degrees above normal as well.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 215 PM EDT Monday: An active pattern returns for this period
as a series of short waves move east across the area. These will
push a series of low pressure/frontal systems across the area as
well. Expect good to numerous, mainly diurnal, convective coverage
each day, with the highest PoP favoring the mountains. Still to
early to be certain on the severe storm chances given the potential
for limited instability, even though forcing and shear will be
decent. Heavy rain potential may eventually creep up as well,
especially if the better coverage hits the same areas day after day.
Highs will drop a few degrees on Friday then remain nearly steady
through the period. Lows rise a few degrees then remain nearly
steady.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Daytime cumulus have dissipated as of 00Z but
stratocu continues across the mountains as well as the western SC
Upstate. This is mainly impacting the SC Upstate terminals, KAVL,
and KHKY as KCLT has clear skies in place. Dry conditions are noted
east of the mountains, lingering through the remainder of the 00Z
TAF period. Isolated showers continue over portions of the North
Carolina mountains this evening, mainly impacting KAVL. Thus, have
VCSH mentioned through 03Z at KAVL. Lightning remains possible the
next few hours, but confidence on this is low as no lightning has
developed yet within this activity. Mountain valley fog should
develop again overnight into daybreak Tuesday, mainly impacting
KAVL. Went with prevailing IFR vsbys by 0700Z with a TEMPO for LIFR
vsbys and cigs from 0900Z-1200Z. Patchy fog could briefly develop
again at KHKY around daybreak, so maintained the VFR fog mention.
Fog should mix out shortly after sunrise. Another round of VFR
cumulus should develop Tuesday afternoon and evening, although KAVL
may see low-end MVFR cumulus develop. KAVL will likely see another
round of isolated SHRA/TSRA late Tuesday afternoon into early
Tuesday evening, so have VCSH at the terminal starting at 2100Z.
Winds are expected to be calm this evening into daybreak Tuesday,
picking up out of the S/SE by Tuesday afternoon.

Outlook: High pressure remains over the terminals through Wednesday
but isolated mountaintop convection is expected each afternoon.
Showers and thunderstorms, along with restrictions, may return with
a cold front late Thursday into Friday.

&&

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

&&

$$

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