Flash Flood Warning 1, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
300 PM EDT Mon May 12 2025

.SYNOPSIS...
Low pressure will move slowly northeast across the Tennessee River
Valley tonight and Tuesday then over the Ohio River Valley in mid
week.  Numerous showers and thunderstorms will continue across our
region through Tuesday with the heavy rain resulting in some
flooding through tonight, mainly over the eastern side of the
mountains. Drier high pressure moves over our area Thursday then a
cold front stalls to our north for the weekend with scattered to
numerous showers and thunderstorms and above normal temperatures
across our region.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 200 PM: A virtually stacked low pressure system is seen on
water vapor imagery and sfc analysis, centered over the Mississippi
Delta region. A broad region of SE'ly flow is occurring over the
Carolinas/Georgia on the warm side of this system; isentropic
lift generally will persist through tonight. Weak in-situ cold air
damming persists over the region, having developed Sunday. Difficult
to pick out exactly where the wedge boundary is, but it appears
to be well south of the CWA. The edge of more stratiform clouds
now west of the Savannah River appears aligned with the leading
edge of a midlevel dry slot which will shift slowly east over the
area over the next 12 hours. Differential heating along that cloud
edge and slightly cooler air aloft have led to development of a
band of convection gradually shifting into the area. The wedge may
slowly erode along this boundary via mixing. Some breaks are also
seen in the SC Midlands as a result of diurnal warming. LCLs are
already low, but surface-based convection will become increasingly
possible with any low-level clearing. A few hundred J/kg of SBCAPE
is progged over the eastern areas with more than 1000 possible near
the Savannah River. Although winds aloft are not especially strong,
with sfc winds being backed at SE to E, low-level shear and helicity
are fairly high: 0-1km shear of 25-30 kt and 0-3km SRH exceeding
200 m2/s2. Bands of showers/storms with weak circulations have
been observed on radar at numerous times today and with increasing
instability, the tornado threat will increase.

Elevated PWATs and the potential for multiple rounds of
showers/storms suggest the threat of excessive rainfall is
nonzero. CAM output has gradually trended toward lower total QPF
and less supportive of hourly rates near flash-flood guidance. No
changes have been made to the extent of the previously issued Flood
Watch, with the focusing mechanism of the Blue Ridge Escarpment
in the persistent southerly flow regime being the most concerning
element; it looks well placed in that regard.

Slow northward movement of the low will veer low-level winds
tonight, weakening moisture flux; dry slot will also shift over
the area. Shear parameters will diminish during the evening;
surface-based storms also will become less likely. Hence the tornado
threat too is expected to diminish. PWATs decline from west to
east between approx. 03z-09z tonight as the dry slot expands
over the area. The heavy rain threat likely will taper off in
that timeframe as well. There won't be much of a wedge erosion
mechanism, so whatever is left could remain into morning until
diurnal insolation can work to thaty effect. The closed portion
of the 500mb low will drift north over TN/KY by that time, so we
will see 700-500mb lapse rates increase to near 7C/km during peak
heating Tuesday. Profiles will not be saturated thru a deep layer
like today/tonight, but should be supportive of deep updrafts. For
now have kept PoPs mostly in the scattered to low likely range
(the latter over the mountains). Can't completely rule out severe
weather, with 0-6km shear of 30+ kt supportive of multicells
producing a wind or marginally severe hail threat.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 1225 PM Monday: The upper low will be departing from the area
at the beginning of the short range period with ridging asserting
itself across the region by Thursday. This will lead to a shift in
the low level flow to more westerly/southwesterly and more diurnal
showers/storms each day with overall lighter rainfall amounts. High
temperatures are expected to be around normal on Wednesday climbing
to several degrees above normal on Thursday.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 1235 PM Monday: The upper ridging pattern will shift quickly
to the east by Friday and then off the coast by the weekend. An
upper low over the Great Lakes states will create an active storm
pattern across the Ohio and Tennessee Valleys for Friday into the
weekend. A northwest flow pattern that will set up between the low
and ridging to our southwest, causing some of these storms to make a
run at our area during the extended period. Thus, will maintain the
chance of showers/storms through the extended period.

High temperatures through the extended period look to average around
5 degrees above normal.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Where precip does not occur this afternoon,
mostly MVFR to low VFR stratocu will prevail thru early evening;
wholesale deterioration in cigs is expected tonight. Multiple rounds
of convective precip (SHRA) however are likely at all terminals
through tonight with a chance of TSRA. Any flavor of precip will be
capable of bringing IFR cig, with isolated +SHRA or TSRA potentially
resulting in IFR to LIFR vsby. Utilized TEMPO for relatively higher
confidence fcst of restrictions per radar/obs trends early in the
period, with PROB30 generally handling less certain development
in the late aftn/evening. TSRA most likely between issuance and
sunset, although can't be ruled out in the first few hrs of the
night. Precip becoming less likely late tonight from S to N. IFR
to LIFR cigs thru daybreak with low vsby particularly likely where
precip does end. Scattering cigs in some areas by late morning
Tue with MVFR to low VFR bases. Diurnally driven SHRA or even TSRA
could develop after 18z Tue which prompted another PROB30 at KCLT.

Outlook: SHRA/TSRA gradually taper off Tue night. Drier conditions
return by mid-week, but sufficient moisture will likely remain to
support at least scattered diurnal showers and thunderstorms.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Flood Watch through Tuesday morning for NCZ033-035-049-050-
     063>065-501>510.
SC...Flood Watch through Tuesday morning for SCZ102-103.

&&

SYNOPSIS...DEO
NEAR TERM...Wimberley
SHORT TERM...SCW
LONG TERM...SCW
AVIATION...Wimberley

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
411 AM EDT Mon May 12 2025

NCZ036-037-048-051>053-056>059-062-068>072-082-130815-
Iredell-Davie-Madison-Swain-Haywood-Buncombe-Catawba-Rowan-Graham-
Northern Jackson-Macon-Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-
Union-
411 AM EDT Mon May 12 2025

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

.DAY ONE...Today and tonight.

Waves of showers and a few thunderstorms today and tonight will
produce periodic heavy rainfall that may result in isolated minor
flooding of some urban and poor drainage areas. Elevated stream
levels can be expected.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

The heavy rainfall threat will continue through early Tuesday with
some isolated areas of nuisance to minor flooding possible.

Otherwise...hazardous weather is not expected.

.SPOTTER INFORMATION STATEMENT...

None.

NCZ033-035-049-050-063>065-501>510-130815-
Avery-Alexander-Yancey-Mitchell-Southern Jackson-Transylvania-
Henderson-Caldwell Mountains-Greater Caldwell-Burke Mountains-
Greater Burke-McDowell Mountains-Eastern McDowell-
Rutherford Mountains-Greater Rutherford-Polk Mountains-Eastern Polk-
411 AM EDT Mon May 12 2025

...FLOOD WATCH IN EFFECT FROM 10 AM EDT THIS MORNING THROUGH TUESDAY
MORNING...

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

.DAY ONE...Today and tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Flood Watch.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Flood Watch.

.SPOTTER INFORMATION STATEMENT...

None.

GAZ010-017-018-026-028-029-SCZ008>014-019-101-104>109-130815-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Cherokee-York-Anderson-
Abbeville-Laurens-Union-Chester-Greenwood-Oconee Mountains-
Greater Oconee-Greater Pickens-Central Greenville-
Southern Greenville-Northern Spartanburg-Southern Spartanburg-
411 AM EDT Mon May 12 2025

This Hazardous Weather Outlook is for northeast Georgia and Upstate
South Carolina.

.DAY ONE...Today and tonight.

Waves of showers and a few thunderstorms today and tonight will
produce periodic heavy rainfall that may result in isolated minor
flooding of some urban and poor drainage areas. Elevated stream
levels can be expected.

Stronger thunderstorms this afternoon and early this evening may pose
an additional threat for a isolated brief, weak tornado.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

The heavy rainfall threat will continue through early Tuesday with
some isolated areas of nuisance to minor flooding possible.

.SPOTTER INFORMATION STATEMENT...

None.

SCZ102-103-130815-
Pickens Mountains-Greenville Mountains-
411 AM EDT Mon May 12 2025

...FLOOD WATCH IN EFFECT FROM 10 AM EDT THIS MORNING THROUGH TUESDAY
MORNING...

This Hazardous Weather Outlook is for Upstate South Carolina.

.DAY ONE...Today and tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Flood Watch.

Additionally, a few isolated, weak tornadoes are possible this
afternoon and early this evening.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Flood Watch.

.SPOTTER INFORMATION STATEMENT...

None.

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
519 PM EDT Mon May 12 2025

GAZ028-029-122200-
Elbert GA-Hart GA-
519 PM EDT Mon May 12 2025

...A STRONG THUNDERSTORM WILL IMPACT ELBERT AND SOUTHERN HART
COUNTIES THROUGH 600 PM EDT...

At 519 PM EDT, Doppler radar was tracking a strong thunderstorm 5
miles west of Elberton, moving north at 15 mph.

HAZARD...Wind gusts up to 40 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to outdoor objects is
         possible.

Locations impacted include...
Dewy Rose, Bowman, Rock Branch, Nuberg, Hartwell, Elberton, Sweet
City, Vanna, and Ruckersville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3401 8291 3401 8294 3403 8294 3404 8298
      3410 8304 3411 8303 3415 8306 3416 8309
      3420 8309 3422 8308 3423 8309 3437 8304
      3438 8287 3431 8279 3428 8276 3398 8281
      3399 8283 3398 8286
TIME...MOT...LOC 2119Z 201DEG 14KT 3411 8295

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

CP

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
530 PM EDT Mon May 12 2025

SCZ103-106-122215-
Central Greenville SC-Greenville Mountains SC-
530 PM EDT Mon May 12 2025

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN GREENVILLE COUNTY
THROUGH 615 PM EDT...

At 530 PM EDT, Doppler radar was tracking a strong thunderstorm 11
miles northwest of Greenville Downtown, or near Slater-Marietta,
moving northeast at 25 mph.

HAZARD...Wind gusts up to 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Tigerville, North Saluda Reservoir, Glassy Mountain, Pleasant Ridge
State Park, Cleveland, Slater-Marietta, and Travelers Rest.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3500 8254 3501 8254 3502 8255 3516 8250
      3518 8246 3517 8245 3516 8246 3517 8244
      3519 8242 3521 8239 3518 8237 3519 8235
      3519 8232 3520 8229 3520 8225 3511 8224
      3492 8246
TIME...MOT...LOC 2130Z 210DEG 22KT 3500 8247

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

CP

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
605 PM EDT Mon May 12 2025

GAZ029-SCZ011-122245-
Elbert GA-Abbeville SC-
605 PM EDT Mon May 12 2025

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN ELBERT AND
SOUTHWESTERN ABBEVILLE COUNTIES THROUGH 645 PM EDT...

At 605 PM EDT, Doppler radar was tracking a strong thunderstorm 12
miles southeast of Elberton, or near Nancy Hart State Park, moving
north at 20 mph.

HAZARD...Wind gusts up to 40 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to outdoor objects is
         possible.

Locations impacted include...
Lowndesville, Calhoun Falls, Fortsonia, Richard B Russell Dam, Nancy
Hart State Park, Middleton, Lake Strom Thurmond, Russell State Park,
Rice Town, and Lake Russell.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3398 8264 3399 8265 3398 8270 3398 8281
      3399 8283 3421 8284 3421 8274 3424 8264
      3420 8250 3407 8254 3401 8260 3399 8258
      3398 8259
TIME...MOT...LOC 2205Z 201DEG 19KT 3398 8271

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

CP

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
658 PM EDT Mon May 12 2025

GAZ028-029-SCZ010-011-122345-
Elbert GA-Hart GA-Anderson SC-Abbeville SC-
658 PM EDT Mon May 12 2025

...A STRONG THUNDERSTORM WILL IMPACT ELBERT...SOUTHEASTERN HART...
SOUTH CENTRAL ANDERSON AND ABBEVILLE COUNTIES THROUGH 745 PM EDT...

At 658 PM EDT, Doppler radar was tracking a strong thunderstorm 14
miles east of Elberton, or near Calhoun Falls, moving north at 30
mph.

HAZARD...Wind gusts up to 40 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to outdoor objects is
         possible.

Locations impacted include...
Broad River Campground, Fortsonia, Bobby Brown State Park, Starr,
Nuberg, Lake Strom Thurmond, Russell State Park, Rice Town, Bobby
Brown State Recreation Area, and Ruckersville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3398 8261 3397 8264 3399 8265 3397 8278
      3399 8283 3398 8286 3401 8291 3402 8294
      3438 8289 3439 8262 3436 8231 3434 8233
      3433 8233 3408 8247 3408 8248 3407 8253
      3401 8260 3396 8257
TIME...MOT...LOC 2258Z 199DEG 24KT 3407 8262

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

CP