Flash Flood Warning 39, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
339 AM EDT Thu Oct 7 2021

.SYNOPSIS...
An upper level Low pressure over the lower Mississippi Valley will
focus a very moist southerly flow off the Gulf of Mexico into our
region for another day before it moves toward the Great Lakes.
Expect periods of widespread showers and locally heavy rainfall
through Friday especially for the mountains and foothills. As this
low and its associated front moves east of our area this weekend,
dry high pressure will be in place into early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 335 AM EDT: A deep upper low will slowly move north from the
Mid-South into the Mid-West through the period. A series of short
waves will rotate around the low and across the area today. Much
weaker short waves are expected tonight. Good upper divergence
expected today as a jet streak rotates across the area. The
divergence weakens overnight as the jet streak moves away from the
area. Deep moisture remains in place over the area through the
period with PW values generally 1.5 inches or higher. Weak
instability remains in place as well along with good warm cloud
precip processes and isentropic lift. The one limiting factor is the
low level jet. While H85 winds will be southeasterly today, they
remain less then 30 kts. The synoptic and CAM guidance all respond
with widespread precip coverage over the western CWFA with lower
coverage over the east. The Flash Flood Watch looks well placed and
basically in line with QPF and Excessive Rainfall forecast from WPC.
That said, can't rule out flooding outside of the watch, especially
along the Upper Savannah River valley of the northern Blue Ridge.
Another warm and muggy day expected.

With forcing diminishing tonight as the upper low moves north,
expect precip coverage and intensity to diminish. This is in line
with both synoptic and CAM guidance. Deep moisture and weak upslope
flow will keep a chance of showers across the area overnight, but
the threat of new flooding greatly decreases. Therefore, the current
end time of the Watch still looks good. Will be another warm and
muggy night.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
As of 300 am Thursday: Arcing upper trough associated with filling
upper low/transitioning open wave over the Midwest at the start of
the period will push steadily through the forecast area Fri into Fri
night. With in-situ cold air damming likely all but dissipated
during that time and plenty of lingering low level moisture...part
of which will be supplied from easterly flow north of tropical
disturbance off the Carolina Coast. Numerous showers and scattered
storms are therefore expected to flare up once again on Friday,
warranting likely PoPs across the entire area. There will be a
continued threat of locally excessive rainfall, with local antecedent
hydro conditions likely being the primary driver of any developing
runoff issues on Friday.

With low level moisture continuing to circulate around the
disturbance off the coast, PoPs will linger across primarily the
eastern half of the area Fri night into Saturday, but with a gradual
draw-down in probabilities to less than 20% by Saturday evening. Min
temps will remain above climo through the period, while maxes will
steadily warm to the tune of a couple of degrees above climo by
Saturday afternoon.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 245 am Thursday: Establishment of a long wave trough across
the western Conus will result in downstream ridging over the East by
the early part of the medium range, and this regime is forecast to
more or less persist into the middle part of next week. This will
result in dry and unseasonably warm conditions through much of the
period, with temps likely averaging around 5 degrees above climo.
Additionally, dewpoints will be anomalously high for early/mid
October, and in fact, wouldn't completely rule out some spotty
diurnal mountain showers early next week. Overall, it's not going to
feel especially fall-like.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
At KCLT and elsewhere: Despite some VFR across the area, expect
deteriorating conditions this morning as moist upslope flow
continues, along with copious low level moisture. Expect MVFR cigs
to become widespread with IFR/LIFR cigs by daybreak then continuing
through the morning. Expect MVFR vsby to develop across much of the
area with TEMPO IFR vsby in heavier showers. NE wind continues
through the morning, S at KAVL. Expect slow improvement to MVFR cigs
and VFR vsby in the mid-afternoon. Showers will continue through the
period, so have prevailing or VCSH continues. TSRA will be possible
during the afternoon, so PROB30s have been included for that. Expect
cigs to drop back into the IFR range during the evening with some
MVFR vsby. NE wind, S at KAVL, continues through the period.

Outlook: A wet pattern is expected to continue into Friday, with
occasional periods of widespread showers and frequent occurrence of
flight restrictions expected. Finally, some drier air will try to
work in from the west this weekend, but low-level moisture may
linger, keeping a chance of low cigs and fog, especially late
night/early mornings.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Flash Flood Watch through this evening for GAZ010-017.
NC...Flash Flood Watch through this evening for NCZ052-053-059-
     062>065-505-507-509.
SC...Flash Flood Watch through this evening for SCZ001>003.

&&

SYNOPSIS...RWH
NEAR TERM...RWH
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...RWH

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
514 AM EDT Thu Oct 7 2021

GAZ018-026-028-029-NCZ033-048>051-058-068-501>504-506-508-510-
SCZ004>008-010>013-019-080915-
Stephens-Franklin-Hart-Elbert-Avery-Madison-Yancey-Mitchell-Swain-
Graham-Cleveland-Caldwell Mountains-Greater Caldwell-Burke Mountains-
Greater Burke-Eastern McDowell-Greater Rutherford-Eastern Polk-
Greater Oconee-Greater Pickens-Greater Greenville-Spartanburg-
Cherokee-Anderson-Abbeville-Laurens-Union SC-Greenwood-
514 AM EDT Thu Oct 7 2021

This Hazardous Weather Outlook is for northeast Georgia, piedmont
North Carolina, western North Carolina and upstate South Carolina.

.DAY ONE...Today and tonight.

Numerous to widespread showers along with isolated thunderstorms
are expected off and on through tonight. The main threat will be
from locally heavy rainfall. Isolated flash flooding could develop in
areas that see multiple rounds of heavy rainfall. Locations that have
received heavy rainfall in previous days will be most susceptible to
developing flash flooding. Occasional cloud to ground lightning will
also be possible with any thunderstorms.

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

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

GAZ010-017-NCZ052-053-059-062>065-505-507-509-SCZ001>003-080915-
Rabun-Habersham-Haywood-Buncombe-Northern Jackson-Macon-
Southern Jackson-Transylvania-Henderson-McDowell Mountains-
Rutherford Mountains-Polk Mountains-Oconee Mountains-
Pickens Mountains-Greenville Mountains-
514 AM EDT Thu Oct 7 2021

...FLASH FLOOD WATCH IN EFFECT THROUGH THIS EVENING...

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

   Flash Flood Watch.

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

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

NCZ035>037-056-057-069>072-082-SCZ009-014-080915-
Alexander-Iredell-Davie-Catawba-Rowan-Lincoln-Gaston-Mecklenburg-
Cabarrus-Union NC-York-Chester-
514 AM EDT Thu Oct 7 2021

This Hazardous Weather Outlook is for piedmont North Carolina and
upstate South Carolina.

.DAY ONE...Today and tonight.

Isolated to widely scattered thunderstorms are expected across the
Piedmont today, mainly this afternoon and evening. The primary
threats from any storms will be from cloud to ground lightning and
locally heavy rainfall.

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

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

Lane

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
338 AM EDT Thu Oct 7 2021

GAZ010-017-018-NCZ062>064-SCZ001-070815-
Rabun GA-Stephens GA-Habersham GA-Transylvania NC-
Southern Jackson NC-Macon NC-Oconee Mountains SC-
338 AM EDT Thu Oct 7 2021

...THUNDERSTORMS WITH HEAVY RAINFALL WILL IMPACT NORTHWESTERN
STEPHENS...HABERSHAM...RABUN...SOUTHEASTERN MACON...SOUTHWESTERN
TRANSYLVANIA...SOUTH CENTRAL JACKSON AND NORTHWESTERN OCONEE COUNTIES
UNTIL 415 AM EDT...

At 332 AM EDT, Doppler radar indicated numerous rain showers and
scattered thunderstorm producing heavy rainfall across northeast
Georgia, extreme northwest South Carolina, and extreme southwest
North Carolina.

Locations to be impacted include...
Clayton, Clarkesville, Demorest, Mount Airy, Highlands, Mountain
City, Tiger, Dillard, Sky Valley and Tallulah Falls.

Heavy rainfall rates of 1 to 2 inches per hour are expected in these
areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall may flood areas with poor drainage, such as
ditches and underpasses. Avoid these areas and do not cross flooded
roads. Water levels of small streams may also rise rapidly. Seek
higher ground if threatened by flood waters.

As additional heavy showers and storms continue to develop over
these areas through the morning, the potential for flash flooding
will steadily increase. Stay tuned to local media outlets or NOAA
Weather Radio for later statements, advisories, or potential
warnings.

&&

LAT...LON 3473 8362 3476 8363 3478 8366 3489 8364
      3491 8363 3492 8360 3494 8360 3495 8355
      3499 8355 3500 8348 3500 8352 3502 8352
      3504 8356 3510 8359 3512 8359 3508 8293
      3451 8347 3455 8362 3462 8364 3465 8366
TIME...MOT...LOC 0732Z 204DEG 10KT 3471 8351

LANE

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
547 AM EDT Thu Oct 7 2021

SCZ005-006-010-071030-
Greater Pickens SC-Anderson SC-Greater Greenville SC-
547 AM EDT Thu Oct 7 2021

...A THUNDERSTORM WITH TORRENTIAL RAINFALL WILL IMPACT CENTRAL
GREENVILLE...NORTHEASTERN ANDERSON AND EAST CENTRAL PICKENS COUNTIES
UNTIL 630 AM EDT...

At 547 AM EDT, Doppler radar was tracking a thunderstorm with
torrential rainfall 10 miles south of Easley, or 5 miles northwest of
West Pelzer, moving northeast at 10 mph.

Locations to be impacted include...
Easley, Greenville Downtown, West Greenville, Welcome, Powdersville
and Piedmont.

Torrential rainfall rates up to 3 inches per hour will be possible in
these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall may flood areas with poor drainage, such as
ditches and underpasses. Avoid these areas and do not cross flooded
roads. Water levels of small streams may also rise rapidly. Seek
higher ground if threatened by flood waters.

&&

LAT...LON 3457 8254 3461 8265 3490 8256 3481 8238
TIME...MOT...LOC 0947Z 206DEG 9KT 3468 8255

LANE