Vashti, North Carolina Weather Forecast Discussion

990
FXUS62 KGSP 290601
AFDGSP
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
201 AM EDT Mon Sep 29 2025
.SYNOPSIS...
A stalled frontal boundary will drift westward and back over
our area today allowing for a return of showers and possibly
a few thunderstorms. Meanwhile, Tropical Storm Imelda will drift
north of the Bahamas. The system is expected to slow down and
turn east and away from the Florida coast by late Tuesday.
The system will then move further out over the Atlantic as
broad high pressure builds over our region from the north.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1235 AM EDT Monday: Other than a few light showers
over southwest NC drifting off toward the west, radar was
quiet. Satellite imagery shows lingering clouds over the mtns at
this late hour, which should act to hinder the usual fog/low stratus
development. Meanwhile, high level clouds were streaming northward
from Imelda in a jet streak on the east side of the upper level
trof axis just to our west. Most of that higher level cloudiness
will cover the eastern half or 2/3 of the fcst area for the rest
of the overnight and the better part of Monday. Min temps will
be on the order of five degrees above normal. Toward daybreak,
we should see a developing easterly flow start to bring low level
moisture in from the Atlantic, but precip is not expected to arrive
until after sunrise.
For today, the situation is somewhat-weak-wedge-like with a sfc
high pressure ridge on the east side of the mtns, but with a weak
mid/upper low lingering over the Carolinas. The main feature of
interest will be a low level inverted trof that moves in from
the Atlantic and moves westward to the mtns in the afternoon. Low
level convergence where the flow veers from NE to E will help to
force what looks like a wide, ragged, incoherent band of mostly
showers that gradually pushes westward across the fcst area thru
the day. On the one hand, some periodic upper divergence under the
outflow jet and some decent low/mid level isentropic lift will
make the situation more favorable for precip, but on the other
hand the buoyancy for sfc-based parcels will be poor. Expect a
gradient in precip probs from chance to likely between the mtns
and the western Piedmont/nrn Upstate for the day, but will keep any
categorical probs east of I-77 for the time being. The CAMs are more
enthusiastic than the model blend, but aren`t doing particularly
well with the coverage as of 04Z along the coast, FWIW. That being
said, if anything, our forecast is probably under-doing the coverage
by the end of the day. The increasing clouds and precip coverage
will limit the high temps to the 70s, with the cooler readings to
the east where precip arrives earliest. Prolonged easterly flow may
keep shower activity going along/east of I-26 thru the evening and
well into the overnight as Imelda gets as close as it is going to
get, but still south of 30 deg N latitude. However, the forcing
gradually weakens, and without a convective component, rainfall
rates/amounts are expected to be quite modest. In the end, the
rain that falls will be more the beneficial kind than anything. Low
temps will once again be around five degrees above normal.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
As of 1:25 AM EDT Monday: The short-term forecast picks up at 12z
on Tuesday with TC Imelda expected to be centered north of the Ba-
hamas and beginning to turn eastward as it reaches hurricane strength.
At the same time, Hurricane Humberto will be tracking northward and
pulling away from Imelda. Over the next couple of days, both of these
systems are expected to track E/NE and further away from the East
Coast. We can still expect some amount of lingering wrap-around
moisture across our fcst area on Tuesday with relatively dry pro-
files by early Wednesday. Overall, fcst precip amounts on Tuesday
continue to trend lower for most of our CWA with excessive rain-
fall no longer a concern for our fcst area beyond roughly 12z Tues.
We can still expect some marginally gusty N to NE winds both Tues
and Wed. Most of the gusts are expected outside of the mountains,
with speeds in the 20 to 30 mph range.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 1:05 AM EDT Monday: The extended forecast picks up at 12z on
Thursday with TC Imelda moving further out in the Atlantic and away
from the East Coast. At the same time, robust sfc high pressure from
Canada will be spreading southward over the Eastern CONUS. The high
will dominate our synoptic pattern the rest of the week and into the
weekend. By late next weekend, the long-range guidance has the high
shifting east and beginning to move off the Atlantic Coast as deeper
moisture begins to spread back over our area from the south. Overall,
we can expect dry conditions thru most of the period with low-end
chances for precip by the end of the period early next week. We can
also expect some lingering low-end NELY wind gusts on Thursday out-
side of the mountains. Otherwise, temperatures start out 1 to 2 ca-
tegories below normal on Thursday and warm to near-normal by late
weekend.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Starting out VFR at all terminals and
that should hold thru daybreak. Lingering VFR-level clouds over
the mtns may preclude the usual fog/low stratus restrictions in
the mtn valleys around KAVL. Meanwhile, a plume of high level
clouds will stream northward from the western Atlantic. We will
be watching a developing easterly flow of Atlantic moisture at
low levels thru daybreak. Shower activity and a low cloud ceiling
restriction are expected to move in from the east by 10Z-12Z at
KCLT, but the timing could easily slip. Through the day, flight
conditions are expected to deteriorate as a broad band of showers
moves westward and brings broken MVFR to IFR ceilings. Will handle
with an initial PROB30 because of uncertainty with arrival time,
then go to a TEMPO mainly for IFR ceiling. Eventually, by late
afternoon, most terminals will end up IFR. Won`t rule out periods
of LIFR into Monday evening. Wind will increase from the NE as
the gradient between high pressure to the north and Imelda well to
our southeast improves from mid-morning onward. Occasional gusts
can be expected.
Outlook: Flight restrictions may persist through Tuesday as an
easterly flow of Atlantic moisture remains across the region. Most
likely this will be in the form of a low cloud ceiling at MVFR or
IFR levels. From Wednesday onward, VFR expected, with the exception
of early morning fog and low stratus in the mountain valleys.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...JPT
NEAR TERM...PM
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...PM

NWS GSP Office Area Forecast Discussion