Severe Thunderstorm Warning 89, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
131 PM EDT Wed May 14 2025

.SYNOPSIS...
Low pressure will move slowly northeast to the Mid-
Atlantic Coast tonight then off the coast on Thursday. Drier
high pressure moves over our area Thursday with a weak
cold front moving south across our area over the weekend then
the front becomes stationary.  Above normal temperatures will
continue through the weekend and into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 923 AM Wednesday: An early morning cluster of convection has
weakened as it continues to lift northeast across the I-77 corridor.
Here, showers will continue for another hour or two before all
precipitation shifts out of the area. The ongoing forecast captures
this well and no significant changes were needed. Morning low clouds
will also lift and scatter by early afternoon with a warm and humid
day as temperatures climb into the mid 70s to low 80s.

The aforementioned low pressure system is expected to continue
its northeastward trek today while the upper low opens up into
a negatively tilted wave over the Upper Ohio Valley/Mid-Atlantic
regions. The passage of the mid/upper trof axis is expected this
morning, and that will carry one batch of shower activity away to
the E/NE while weakening in the middle part of the day. Thereafter,
the CAMs suggest the bulk of the afternoon will be relatively
quiet, which makes some sense as the environment won't be quite
so favorable in the wake of the upper wave. However, there is
good indications that we should be able to destabilize thru the
afternoon to the tune of 1500-2000 J/kg of sfc-based CAPE mainly
outside the mtns. Then, things might get interesting. Guidance
suggests that late in the afternoon into the evening the deep
layer shear across northeast GA into the western Upstate will climb
into the 30-40 kt range, which should be a sufficient to allow for
supercell thunderstorms. That is, if we manage to develop storms
at all. Note the 00Z CAMs are not particularly interested in
making anything more than widely scattered storms. That suggests
our severe weather potential is very conditional upon developing
enough of a storm to acquire supercell characteristics. If that can
happen, the Marginal Risk on the new Day 1 makes sense for wind
and hail. Something to keep an eye on. Otherwise, temps will be
back to normal. The convection might not exactly diminish in the
way we might normally expect, as there are indications that the
stronger NW flow might continue to organize storms upstream and
drive them southeastward into the early morning hours in a loosely
organized band that translates eastward over western NC. That
is still somewhat sketchy but also worth keeping track. The fcst
doesn't really indicate that for the moment, so don't be surprised
by a big increase in precip probs late tonight if the model trend
holds. Lows tonight will be mild once again.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY/...
As of 300 AM Wednesday: Relatively quieter weather expected Thursday
and Friday, as an upper ridge builds into the Southeast. The
ridging, combined with an elevated mixed layer (EML) in the profiles
will work to largely cap the atmosphere of deep convection. The
exception will be mainly in the northern NC mountains, which may
see some diurnal mountaintop activity Thursday aftn, which should
be sub-severe. Friday looks basically completely capped thru the
day, with NAM soundings showing over 100 J/kg of CINH with over
4000 J/kg of sbCAPE. The GFS has less CINH, but also a lot less
CAPE. Not surprisingly, the deterministic guidance has little to
no QPF response across the CWFA either day. Temps will continue a
warming trend, with highs about 5-8 deg above normal Thu and 8-12
deg above normal Friday.

There is still some hint that an organized cluster of storms or
a full-blown MCS may form and track into the OH/TN Valley late
Friday. It seems the models are trending a little slower with this
activity, with it not reaching the TN/NC border until after 06z
Sat. At that time of day, there may not be enough instability to
sustain the activity thru the mountains. However, depending on
the timing, they could be slow enough to either cross the area
during the day Saturday, or at least lay out an outflow boundary
that triggers storms in the CWFA Saturday. All that to say, the
PoP forecast for Friday night thru Saturday is a low confidence
forecast. Plenty of bulk shear will be in place, thanks to a passing
trough to our north. So severe storms may be possible. The new Day
3 Convective Outlook has a slight risk to our west, with a marginal
just to the TN/NC border. Temps will continue to be about 10 deg
above normal Saturday.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 330 AM Wednesday...An upper trough will pass by to our north,
briefly flattening the Southeastern ridge. A weak cold front will
slip thru the area on Saturday, which depending on the timing,
may bring a round of showers and storms. But not all the guidance
agrees on that, with the GFS in particular, rather dry. In any case,
Sunday looks largely dry as high pres noses in from the north and
the frontal boundary stalls out just to our southwest. The medium
range guidance is not in great agreement on how far south the front
gets shunted, and may start to lift back into the area as early as
Sunday night. Despite the front's close proximity, early next week
doesn't look too active, as we will be in a NWLY flow regime with
a building upper ridge axis over the MS Valley. Temps are expected
to be slightly cooler than Friday and Saturday's forecast highs,
but still above normal.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
At KCLT and elsewhere: Morning stratus has since lifted and
scattered with most ceiling restrictions coming to an end, although
a brief period or two of MVFR cannot be ruled out at any given
terminal. Isolated to widely scattered showers and thunderstorms are
expected this afternoon into the evening, but where these may form
is uncertain. PROB30 groups have been maintained at all TAF sites
accordingly, but will need updating once storms develop and tracks
become more certain. The forecast becomes murky overnight as another
round of showers and storms may drop into the area from the
northwest. Confidence as to whether this actually occurs remains low
and will preclude mention in the TAF at this time. There will also
be the potential for another round of low stratus, which has been
advertised as MVFR for now. Should storms move through the area, fog
and stratus issues would be less likely. Should fog and low stratus
develop, some terminals may see restrictions worse than currently
advertised, potentially as low as IFR/LIFR. Any fog/stratus should
lift/mix out through the morning hours tomorrow with a return to VFR.

Outlook: In general, a summertime pattern is expected through
the end of the week with diurnally driven convective storms each
day. In addition, fog and low stratus will be possible each morning,
primarily in the mtn valleys and in areas that receive appreciable
rainfall the previous day.

&&

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

&&

SYNOPSIS...ARK
NEAR TERM...PM/TW
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...TW

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
443 AM EDT Wed May 14 2025

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ008>014-019-101>109-150845-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Avery-Alexander-
Iredell-Davie-Madison-Yancey-Mitchell-Swain-Haywood-Buncombe-Catawba-
Rowan-Graham-Northern Jackson-Macon-Southern Jackson-Transylvania-
Henderson-Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-Union-
Caldwell Mountains-Greater Caldwell-Burke Mountains-Greater Burke-
McDowell Mountains-Eastern McDowell-Rutherford Mountains-
Greater Rutherford-Polk Mountains-Eastern Polk-Cherokee-York-
Anderson-Abbeville-Laurens-Chester-Greenwood-Oconee Mountains-
Pickens Mountains-Greenville Mountains-Greater Oconee-
Greater Pickens-Central Greenville-Southern Greenville-
Northern Spartanburg-Southern Spartanburg-
443 AM EDT Wed May 14 2025

This Hazardous Weather Outlook is for northeast Georgia, Piedmont
North Carolina, western North Carolina and Upstate South Carolina.

.DAY ONE...Today and tonight.

Scattered showers and thunderstorms are expected to develop across
the area this afternoon into this evening. A severe thunderstorm or
two cannot be ruled out, with large hail and damaging winds as
potential threats.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

ARK

Preliminary Local Storm Report
National Weather Service Greenville-Spartanburg SC
139 PM EDT Wed May 14 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0740 PM     Tornado          3 NE Calhoun Falls      34.12N 82.55W
05/12/2025                   Abbeville          SC   NWS Storm Survey

            A brief and weak EF-0 tornado touched down
            along Old Calhoun Falls Road near Mud Creek
            Road. The tornado moved northeast,
            paralleling Old Calhoun Falls Road, before
            dissipating near the intersection with
            Latimer Road. The tornado snapped multiple
            large limbs and uprooted a couple trees.
            Maximum estimated winds were 65 mph with a
            width of 20 yards.

&&

TW