Severe Thunderstorm Warning 2, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
947 PM EST Thu Feb 6 2025

.SYNOPSIS...
Well above normal temperatures continue through the weekend. A
cold front will push through the area late Sunday, ushering in
much cooler temperatures Monday. Unsettled weather conditions will
likely persist through most of next week, as a front stalls over
the region.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 945 PM...

Key Messages:

1) Supercell thunderstorms are moving thru East TN and will pose
a severe threat at least to the immediate NC/TN border 11 PM
to midnight.

2) Scattered showers or even an isolated t-storm may occur between
midnight and 4 AM across our Piedmont zones. This activity likely
will be elevated in nature and severe threat will be small but
nonzero.

3) Well Above Normal Temperatures Continue Friday

Flat upper trough will swing thru the Great Lakes tonight, ushering
in just subtle height falls across the forecast area. An associated
cold front will lay over the area from the north overnight,
and may stall roughly half way thru the forecast area by daybreak
Friday. The sfc cold front is in middle TN now, and within the warm
sector ahead of it, about 500 J/kg are analyzed in the Knoxvlle
area, along with ~200 m2/s2 of ESRH, and a couple of supercells
are present there. This activity is timed to reach the NC/TN
border around 1030-11 PM, but will encounter increasingly weak
instability as it moves toward the mountains. Effective shear will
persist but the storms would appear likely to become elevated. At
the very least a severe hail and strong to severe wind threat
may develop from Haywood to Yancey counties. Not confident any
threat would extend further east, but given the strong organization
particularly of the storm now over Knoxville, can't completely rule
it out. Scattered remnant showers and perhaps an isolated elevated
t-storm are expected in the lee of the mountains, southeast to
about the I-85 corridor where most guidance allows the activity
to fizzle. PoPs will fall below slight-chance by daybreak. Temps
still look to be about 20-25 degrees above normal overnight under
mostly cloudy skies.

Most guidance depicts more of a lull in activity in the morning
than we previously advertised, so PoPs were reduced below slight
chance 6 AM to about 10 AM. The front is forecast to stall roughly
along the SC/NC border Friday, as flow remains zonal aloft. Westerly
downslope flow should help scour out any stratus that forms Friday
morning, with some cumulus lingering across the southern half of
the forecast area into the aftn hours. A few showers may develop
in the southern zones, but overall, it is expected to be dry. Highs
will be 15-20 deg above normal.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 213 PM EST Thursday...

Key Messages:

1) Stalled Front on Saturday may lead to a wide range of
temperatures

2) A return to Well Above Normal Temperatures on Saturday

3) Low rain chances outside the mountains for the weekend

More uncertainty than usual for the weekend forecast because of the
presence of a boundary strung out west-east across the region, stuck
under a quasi-zonal flow aloft. Guidance is in decent agreement
with a weak sfc wave moving along the front located across the
southern part of the forecast area Friday evening. Forcing will be
practically nil but moisture will be pooled across the frontal zone,
and some weak low level warm advection/upglide will develop in the
evening, which warrants holding onto a modest precip chance across
most of the region. The model blend appears to be overdone in this
regard, so the fcst undercuts it by 10-20 pct, thinking the NAM
Nest has a good depiction of what to expect. Low temps should be
around 10 degrees above normal. Saturday looks like a tricky temp
fcst. At the sfc, a weak high will move across the Mid-Atlantic and
should ridge down across the area, which ordinarily might suggest a
weak hybrid cold air damming scenario, but the forcing for precip
is nearly non-existant and the models suggest redeveloping the
frontal boundary as a warm front much farther north across VA as a
low pressure system moves up the OH River Valley. That being the
case, warm advection would stream northward across the fcst area
and we might be well above normal. However, remnant cool pools
are notoriously stubborn across the foothills/NW Piedmont at this
time of year and this situation, which would act to keep temps much
cooler. This day could feature a tight gradient in temps from south
to north, which is indicated in our forecast, but areas along/north
of I-85 could see our forecast being off by 10-15 degrees for highs
rather easily. After the low passes, the associated cold front
is expected to run up against the west side of the mtns where it
will get stuck at least temporarily. That yields a tight gradient
in precip chances between likely/categorical on the TN border to
nothing east of the mtns. Will the front get pushed over the mtns
early enough on Sunday to affect the high temps? Guidance says not
and shows high temps well into the 70s again outside the mtns. That
seems to have worked out lately and was generally accepted, but
this too could go right down the tubes if the front moves through
early enough. Assuming it gets warm Sunday, don't get used to it.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 259 PM EST Thursday...looks like Monday might come as a shock
to the system. Revenge of the Wedge. A large continental sfc high
dropping down over the nrn Plains should effectively drive a cold
front across the region either late in the day on Sunday or at least
Sunday night, with isentropic upglide developing to the north of
the front as the high bridges over the mtns and sets up a classic
cold air damming wedge by sunrise Monday. Oh what a difference a
day makes. Monday looks cloudy and wet with temps that struggle to
get out of the 40s across NC and in the 50s across the south...some
15-20 degrees colder than Sunday. A chunk of the parent high scoots
past to the north Monday night and offshore Tuesday, while the old
boundary reactivates and a wave moves along it. Precip chances go
way up and temps stay on the below normal while this sorts itself
out. The timing of this next wave passing to the north and dragging
a cold front across the region is uncertain and would affect the
main high prob time, either Tuesday or Wednesday. A brief break in
the action is likely during mid-week once the first wave passes,
but by this time the srn stream is active and spins up another wave
on the old boundary either over the srn Plains or lower MS valley
late in the week. Precip could redevelop right away Wednesday night
and continue into Thursday, with another cold air damming wedge
possible. All this keeps precip probs high, temps below normal,
and uncertainty high through the period.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: Warm upglide is beginning to generate
stratus near VFR/MVFR threshold near KAND and this may soon expand
east to KGSP/KGMU; some mountain wave stratocu will also be seen
over KAVL this evening but likely VFR for some time. Cold front
now moving thru eastern KY and middle TN will push east of the
NC mountains after midnight. Clouds are expected to lower prior
to the fropa which may induce an MVFR cig. Guidance generally
shows small instability along the front, which will translate to
a chance of SHRA at all terminals, and even a small chance of
TSRA at KAVL/KHKY. Overall precip chance is perhaps a bit low
for a TEMPO, but there is also a possibility of a brief drop
to low MVFR or even IFR along the front, so wrapped both into
TEMPOs. Winds will veer to NW around that time also. Low clouds
will scatter at/after daybreak in the wake of the front so just
FEW-SCT VFR clouds for most of the daytime hrs. Front will stall
by Fri evening and upglide may redevelop over it, so cigs and
possibly restrictions will return after 00z Sat. Confidence not
high enough for a mention of restrictions this far out.

Outlook: Periodic showers possible through early next week and could
bring associated restrictions to visibility along with periods of
low ceilings.

&&

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

&&

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

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
400 PM EST Thu Feb 6 2025

GAZ010-017-018-026-028-029-NCZ062>065-068>072-082-507>510-SCZ008>014-
019-101>109-072100-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Macon-Southern Jackson-
Transylvania-Henderson-Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-
Union-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-
400 PM EST Thu Feb 6 2025

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

.DAY ONE...This afternoon and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

NCZ033-035>037-048>053-056>059-501>506-072100-
Avery-Alexander-Iredell-Davie-Madison-Yancey-Mitchell-Swain-Haywood-
Buncombe-Catawba-Rowan-Graham-Northern Jackson-Caldwell Mountains-
Greater Caldwell-Burke Mountains-Greater Burke-McDowell Mountains-
Eastern McDowell-
400 PM EST Thu Feb 6 2025

This Hazardous Weather Outlook is for Piedmont North Carolina and
western North Carolina.

.DAY ONE...This afternoon and tonight.

Isolated strong to severe storms develop this evening across
portions of western North Carolina, with the severe threat possible
around midnight. The main hazard is damaging wind gusts although
hail near or up to an inch in diameter is possible.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotters are requested to forward any reports of large hail,
damaging winds, tornadoes, or flash flooding to our office.