974
FXUS62 KGSP 260129
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
929 PM EDT Sat May 25 2024

.SYNOPSIS...
Temperatures will remain above normal through the holiday weekend
with a chance of afternoon and evening thunderstorms. A cold front
brings another chance of showers and thunderstorms on Monday. Cooler
and drier conditions move in behind the front and remain through the
end of the week.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 926 PM EDT Saturday: A generally quiet overnight period is
expected with isolated showers and storms from this afternoon having
dissipated with loss of daytime heating. Nudged overnight low
temperatures down a couple degrees owing to expected radiational
cooling. Patchy fog will be possible, especially for areas that saw
rain today and this evening.

Warm and humid airmass continues on Sunday as convection across
the Plains and Midwest gradually travel east. This will likely
generate an MCV that will slip into the OH Valley, which will
push south and east towards the CFWA via CAMs. Deep layer shear
won`t be great, but an increasing LLJ (20-30 kts) with 40-50 kts
of mid-level flow will begin to filter in across the region late
Sunday afternoon just as convection gets into the region. A westerly
component to the mid-level winds will allow for some type of dry
air entrainment. This will help to create a damaging wind threat,
especially if a cold pool can become generated and the convection
ingest some form of upscale growth. Best locations will be the
NC zones and the northern Upstate, but the timing may slip into
the beginning portions of the short-term, meaning that the onset
isn`t expected until after 18Z in the NC mountains before pulling
east across the rest of the CFWA. Afternoon highs should be able
to reach the upper 80s to near 90 as morning convection is not
expected, so there should be less cloud debris until peak heating
arrives and convection pops off.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 145 PM EDT Saturday: Weak ridging with diffluent flow aloft
will be in place over the Eastern Seaboard as we move into the short
term Sunday evening, with an upper trough dragging a surface low and
attendant front across the MS/OH Valleys. Some timing differences
especially with the GFS wanting to bring some warm frontal precip in
overnight, but by and large guidance is in fairly good agreement
with the front pushing in on Memorial Day. Temperatures will again
climb into the mid and upper 80s across the Piedmont with SBCAPEs
well over 2000J/kg and deep layer shear >40kts, and if you believe
the NAM, possibly higher. Steep low-level lapse rates and mid level
dewpoint depressions that would allow for dry air entrainment
accompany these parameters on forecast soundings, supportive of
damaging wind gusts. SPC Slight Risk for Day 3 covers a chunk of the
NW NC Piedmont, with marginal elsewhere. Main threats will be
damaging winds and perhaps large hail especially as the storms form
into a line, but cannot rule out isolated tornadoes if any storms
are able to get going ahead of the line, which certainly can`t be
ruled out. There might be enough shear with the system for embedded
weak tornadoes (there always seems to be something like that in our
area anyway) but again primarily damaging winds.

Front moves through Monday night into Tuesday and even with the
drier dewpoints, competition with downsloping at the base of the
upper trough will bring temperatures up just as high on Tuesday as
Memorial Day (but just not quite as oppressive right?). Can`t rule
out a couple of showers in the NW flow across the mountains Monday
night but have a dry forecast for now.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 215 PM EDT Saturday: Upper trough remains in place over East
Coast as we move into the extended, with ridging in place over the
Plains. A dry pattern sets up with gradual cooling behind the front,
bringing temperatures back towards seasonal normals. A shortwave
moves across the flow Wednesday night into Thursday which should
serve to increase cloud cover just a tad, but for now have kept the
forecast dry. The Plains ridging begins to gradually shift east as
we approach the end of the period but timing on global guidance
varies on how quickly this occurs, so current forecast remains near
seasonal normals as finish out the work week.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: VFR conditions will continue this evening
across the area as a lingering thunderstorm in the vicinity of KCLT
drift southeast over the next hour or two. Thereafter, a quiet
overnight period is expected with the main focus shifting to fog/low
stratus potential, especially for terminals that saw rain today.
Confidence in visibility restrictions is the highest at KAVL and
KHKY, although a brief period of shallow ground fog cannot be ruled
out at any location around sunrise. Any fog will quickly mix out
following sunrise with a cumulus field expected to develop heading
into the afternoon. Another batch of showers and thunderstorms is
expected to move into the area Sunday afternoon and evening and
could bring temporary restrictions.

Outlook: A unsettled pattern will linger thru the rest of the
weekend and into early next week, allowing for diurnal shower and
thunderstorm chances each day and at least patchy fog development
each night/morning.

&&

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

&&

$$

SYNOPSIS...TDP
NEAR TERM...CAC/TW
SHORT TERM...TDP
LONG TERM...TDP
AVIATION...TW