Rosman, North Carolina Weather Forecast Discussion

785
FXUS62 KGSP 300606
AFDGSP
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
206 AM EDT Tue Sep 30 2025
.SYNOPSIS...
A moist easterly flow of moisture will continue thru midday, but
should gradually end later today as Imelda moves off to the east
toward Bermuda. From tonight onward, dry high pressure ridging
down from the northeast will control our weather, bringing cooler
temperatures for Thursday and Friday, but normal temperatures and
fair weather for the upcoming weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 1:45 AM EDT Tuesday: Ragged and (mostly) weak shower bands
will continue across mainly the northern half of the forecast area
overnight. Current mesoanalysis shows a nice 850mb-700mb Atlantic
Fetch over the region in accordance with the shower activity. The
sfc high parked over the Lower Great Lakes region will support a
wedge-like configuration over the area, bringing in stable NELY flow.
Aloft, the trof axis to our west supports a nice jet streak on the
leeside, which is helping to stream mid-to upper-level clouds in
association with Tropical Storm Imelda, which is currently located
over the Bahamas and is helping to filter in better moisture as the
coastal front retrogrades towards the area. With multiple features
assisting to provide good forcing, expect the shower activity to
linger thru the overnight period. Very stable airmass suggests that
rainfall rates will remain on the lighter side, which should keep
most of the area from receiving a complete wash out. With extensive
cloud cover and elevated rain chances, expect overnight lows to run
about 5 degrees below normal.
Tropical Storm Imelda is expected to start making a right turn
further out to sea as it induces the Fujiwhara effect with Hurricane
Humberto as it slides just west of Bermuda and begins to track NE
today. Deeper low-level subsidence begins to cutoff the Atlantic
Fetch as a result, while overall forcing begins to weaken as well.
With that being said, shower coverage will begin to dwindle during
the day today, but with the trof axis still hovering over the area,
additional shower and thunderstorms activity can`t be ruled out,
mainly across the mtns and foothills. Afternoon highs will be de-
pendent on how quick cloud cover can sct out, but nothing suggests
that this process will occur quickly, especially in the western
Piedmont of NC where the better available low-level moisture will
be located. Expect temperatures to remain 5 to 10 degrees below
normal, with the exception of the Upper Savannah and Little TN
Valley where better insolation could lead to warmer temps compared
to the rest of the CWA.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
As of 1201 AM EDT Tuesday: By daybreak Wednesday, the threat of
Imelda should be a fading memory as that system moves away to the
east well out over the Atlantic. What is left behind over much
of the area east of the MS River will be a slowly evolving rex
blocking pattern aloft. The upper anticyclone will drift slowly
east across the Midwest while the weak upper low will drift slowly
west across the Deep South, with our region in-between and under a
relatively deep E/NE flow. The pattern supports a parent sfc high
ridging down from the northeast with the high center moving from
Quebec to the southern New England Coast starting on Wednesday
and continuing thru at least Friday. Profiles start out relatively
stable and the static stability only goes up from there thru the
end of the work week as a formidable subsidence inversion builds
across the region. This will effectively put the fcst area under
a dry cold air damming wedge, with a breezy northeast wind each
day. Fortunately, there should be enough residual moisture to keep
afternoon RH from bottoming out and causing problems. Temps look
normal for Wednesday as the wedge air mass doesn`t get established
until late in the day, but with cold/dry advection taking hold
Wednesday night, high temps for Thursday and Friday should be
on the order of five degrees below normal. Elevations above 6K
feet might not get out of the low/mid 50s. Low temps look close
to normal still Wednesday night, but also about five under climo
for Thursday night. The summit of Mt Mitchell will flirt with 32F
at daybreak Friday. Autumn will definitely be here.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
As of 1230 AM EDT Tuesday: Nothing controversial in the medium
range...just more fair early Autumn weather for the weekend as
the rex blocking pattern devolves as the upper high and low dance
around each other. By Saturday, the upper anticyclone should migrate
to the Mid-Atlantic region while the upper low moves to AR/LA/MS,
then both slowly fill thereafter. The pattern supports a weakening
sfc high drifting down along the coast of southern New England to
the Mid-Atlantic and still controlling our weather through at least
the weekend, and possibly all the way thru Tuesday. The cold air
damming wedge weakens over the weekend, but never really goes away
in the GFS solution, especially as some moisture returns from the
south over the top and results in some light rain chances Monday
and Tuesday. The air mass should slowly modify back to normal over
the weekend and stay there.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Sct light-to-moderate showers continue
to move across the fcst area from the east overnight. Most of
the activity is currently confined to the NC Piedmont and foot-
hills, but some of these showers will likely spread further west
over the next few hrs. Most sites are reporting either IFR or
low-end MVFR cigs within this moist regime, yet some mtn sites
(including KAVL) still have low-end VFR cigs. There are fewer
visby restrictions, but a handful of terminals are reporting
MVFR visby. The low cigs will likely persist into the afternoon
with most sites not likely to see VFR-level cigs until later
this evening. While visby should remain MVFR or better thru
the morning, it could drop lower in any heavier showers. We
could another round of showers later this morning/early after-
noon, but the timing still remains fairly uncertain. As such,
I kept PROB30s for -SHRA and/or VCSH at most sites thru the
afternoon and into the early evening. After that, any lingering
showers should be few and far between. Winds will remain NELY
thru the taf period with speeds around 9 to 12 kts thru the
afternoon with some intermittent low-end gusts in the 16 to 22
kt range. Speeds will taper off later this evening.
Outlook: Drying high pressure is expected to spread over the region
from the north on Wednesday and linger into the weekend. Expect VFR
conditions to prevail, with the exception of patchy early morning
fog and low stratus in the mtn valleys each day.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...PM
NEAR TERM...JPT
SHORT TERM...PM
LONG TERM...PM
AVIATION...JPT

NWS GSP Office Area Forecast Discussion