What forecasters said that day
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Greenville-Spartanburg, SC wrote its last area forecast discussion before the first event at Sep 9, 7:21 PM EST, 2 hours 9 minutes earlier.
Area forecast discussion, Sep 9, 7:21 PM EST, 2 hours 9 minutes before
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
821 PM EDT Sat Sep 9 2023
.SYNOPSIS...
A cold front remains stalled in the area for the weekend keeping
shower and thunderstorm chances in place with below normal
temperatures. The front slides east Monday with slight drying
and near normal temperatures, although a few showers and storms
will remain possible until a stronger front passes Wednesday. Dry,
mild early fall-like weather is expected to end next week.
&&
.NEAR TERM /THROUGH SUNDAY/...
As of 5:55 PM EDT Saturday: Sct showers and thunderstorms continue
to make their way northward over the area early this evening. Most
of these cells have been fairly weak, with only a few requiring a
Special Wx Statement (SPS). Convective activity is expected to
continue well into tonight and could persist into the overnight.
Otherwise, deep upper ridge over the SW CONUS has allowed for NWLY
flow aloft to filter in across the central CONUS. An embedded upper
shortwave has carved into a closed upper low downstream of the flow
aloft and has become mostly stationary across the OH/TN Valleys.
This sets up the CWA on the lee-side of the trough, where upper
and mid-level SLY flow continues to move an abundance of moisture
from the Atlantic across the region thru the fcst period. Soundings
support a more pronounced hydro threat compared to severe, but the
severe threat is certainly nonzero, with the main threat being an
isolated wet microburst despite lower DCAPE values (<1000 J/kg).
Otherwise, PWAT values between 1.50"-1.80" supports a very saturated
profile, while tall skinny CAPE and a deep warm cloud layer (10,000+
FT) provides even more evidence of a flash flood potential to become
realized. On top of that, MBE velocities (5-10 kts) are weak through
peak heating suggesting the potential for training cells to go along
with convectively enhanced rain rates with any thunderstorm. All of
that to say, a flash flood threat is in store, especially in urban
areas and locations in the NC Piedmont/foothills that have received
multiple days of heavy rainfall. 24-hour probability-matched mean
QPF through tonight indicate scattered 1-3" of rain with isolated
higher amounts, which further supports the Flood Watch issued for
this area through 2AM Sunday. CAMs show the possibility of lingering
showers and thunderstorms to continue overnight, but that will be
dependent on how overworked the atmosphere becomes after the
activity that forms this afternoon/evening dissipates. Highs this
afternoon will be at or slightly below normal with elevated PoPs and
cloud cover in the forecast.
Maintained chances PoPs through the overnight, especially in the
zones where the Flood Watch is in effect as this is the area with
the best moisture convergence to go along with continued upper
forcing from the closed low. Model guidance show the closed low
opening up as the trough axis remains to west of the CFWA on Sunday.
In this case, another round of showers and thunderstorms will be in
the works, mainly during peak heating Sunday. Continued upper
support and enhanced terrain-induced convection will allow for good
overall coverage of convection to develop over the NC mountains
during the afternoon, with some of that activity marching east
through the evening. Slightly better deep layer shear parameters
could provide an uptick in the severe potential Sunday, but hydro
will remain the primary threat due to the antecedent conditions with
heavy rainfall from the past couple of days across a decent chunk of
the CFWA. With extensive cloud cover and isolated rain coverage
continuing overnight, lows will be near normal. Stubborn low stratus
Sunday morning to go along with additional rainfall chances and
continued cloud cover will keep highs on Sunday a few ticks below
normal.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
As of midday Saturday: The upper low will open up and weaken Sunday
night while also beginning to progress east. Although some low-level
convergence will persist near the stalled front, it too will become
progressive and the flow will veer in its wake. Combined with the
relatively meager instability left over from the previous afternoon,
this suggests convection will diminish by late evening. Any airmass
change will be subtle, and on Monday southerly flow will be
reestablished. Accordingly chance PoP will remain warranted over the
mountains, particularly those areas nearer the Blue Ridge Escarpment.
Temps trend warmer, mainly due to lesser cloud cover vice Sunday.
While the last vestige of the upper trough will fill and/or exit the
area Monday, the longer and more potent upper wave will be steadily
approaching with an attendant cold front. Accordingly we will retain
the southerly flow regime into Tuesday. Those models that depict
lower dewpoints Tuesday, namely the NAM, do so as a result of a
pocket of drier midlevel air advecting in, which would have wrapped
around the by-then dissipated upper low. Kind of a strange
suggestion. Discounting this possibility, the airmass Tuesday will be
comparable to that Monday. Shear and convergence may increase in our
west late in the day as the front nears, so coverage in the mountains
could be better. Some model/ensemble-member spread on how soon the
front arrives, but generally looks like peak precip chances for the
fropa will be either Tuesday night or Wednesday. 0-6km shear may
reach 30-40 kt as the base of the trough passes by, and dependent on
timing (and resultant CAPE) this may produce at least a
marginal-level threat of severe weather. PWATs rebound above climo
ahead of the front so locally heavy rain is also a possibility. Given
the spread in timing and expectation of at least some forcing
lingering throughout the timeframe, will maintain slight-chance to
chance PoPs in most areas Tuesday afternoon to early Wednesday
afternoon. Lower temps Wednesday, perhaps a category below normal,
appear reasonable with lower thicknesses, but if the faster model
solutions verify, max temps could end up being a few degrees below
normal.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
As of 200 PM Sat: A dry, mild fall-like airmass will filter in
Wednesday night following the fropa, via sfc high centered in the
Ohio Valley. Below-normal temps are expected to persist thru next
weekend, but the pattern presently doesn't look like a record-setter
by any means. As the next trough approaches, guidance members
generally develop a plume of precip from the Gulf Coast northward. In
some solutions this reaches the SW Appalachians as soon as Friday,
but consensus is better among deterministic and ensemble members for
this to occur early Saturday. Some solutions however show a broader
sfc high holding off the trough and keeping us dry into Sunday. At
any rate, saw fit to include a slight-chance PoP in our western zones
Saturday.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
At KCLT and elsewhere: Expect intermittent restrictions at most
terminals thru the 00z TAF period. Numerous showers and thunder-
storms will continue across the area thru the evening and into
the overnight. Much of the coverage should dwindle after midnight,
but most of the model guidance keeps some lingering activity going
well into the overnight. Thus, I kept VCSH overnight. The main
concern will be the development of widespread low stratus, which
is expected at all terminals. I kept IFR/LIFR cigs between roughly
09z to 14z at all terminals with this potentially holding on a bit
longer than that. Fog will likely be an issue as well, and is also
mentioned in the prevailing lines. Most of the low stratus/fog
should sct by noon or so on Sunday. Another round of showers and
thunderstorms with associated restrictions is expected during peak
heating on Sunday and hinted at that with PROB30s. Winds will be
mainly E to SE thru tonight, while becoming light and vrb overnight.
Expect a more SLY than ELY shift late Sunday morning and continued
thru the end of the period.
Outlook: A chance of mountain valley fog and associated restrictions
around daybreak continues each night. Diurnal convection and associated
impacts is expected to continue thru the weekend. Drier conditions
expected on Monday, then an uptick in mainly aftn/evening convection
is expected for Tuesday and Wednesday.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Flood Watch until 2 AM EDT Sunday for NCZ035>037-056-057-
068>072-082-501>510.
SC...None.
&&
SYNOPSIS...Wimberley
NEAR TERM...CAC/JPT
SHORT TERM...Wimberley
LONG TERM...Wimberley
AVIATION...JPTHazardous weather outlook, Sep 9, 8:23 PM EST, 1 hour 7 minutes before
Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
923 PM EDT Sat Sep 9 2023
GAZ010-017-018-026-028-029-NCZ033-048>053-058-059-062>065-SCZ008>014-
019-101>109-110130-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Avery-Madison-Yancey-
Mitchell-Swain-Haywood-Buncombe-Graham-Northern Jackson-Macon-
Southern Jackson-Transylvania-Henderson-Cherokee-York-Anderson-
Abbeville-Laurens-Union SC-Chester-Greenwood-Oconee Mountains-
Pickens Mountains-Greenville Mountains-Greater Oconee-
Greater Pickens-Central Greenville-Southern Greenville-
Northern Spartanburg-Southern Spartanburg-
923 PM EDT Sat Sep 9 2023
This Hazardous Weather Outlook is for northeast Georgia, the North
Carolina mountains and the Upstate of South Carolina.
.DAY ONE...Tonight.
Shower and thunderstorm chances will continue through late tonight.
A few of the storms could become strong with gusty winds and cloud-
to-ground lightning being the main hazards. In addition, showers and
thunderstorms will be capable of producing locally heavy rainfall
which may lead to isolated flooding.
.DAYS TWO THROUGH SEVEN...Sunday through Friday.
No hazardous weather is expected at this time.
.SPOTTER INFORMATION STATEMENT...
Spotters are requested to forward any reports of flash flooding to
our office.
NCZ035>037-056-057-068>072-082-501>510-110130-
Alexander-Iredell-Davie-Catawba-Rowan-Cleveland-Lincoln-Gaston-
Mecklenburg-Cabarrus-Union NC-Caldwell Mountains-Greater Caldwell-
Burke Mountains-Greater Burke-McDowell Mountains-Eastern McDowell-
Rutherford Mountains-Greater Rutherford-Polk Mountains-Eastern Polk-
923 PM EDT Sat Sep 9 2023
...FLOOD WATCH IN EFFECT UNTIL 2 AM EDT SUNDAY...
This Hazardous Weather Outlook is for the Foothills and Piedmont of
North Carolina and portions of the North Carolina mountains.
.DAY ONE...Tonight.
Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.
Flood Watch.
Shower and thunderstorm chances will continue through late tonight.
A few of the storms could become strong with gusty winds and cloud-
to-ground lightning being the main hazards.
.DAYS TWO THROUGH SEVEN...Sunday through Friday.
No hazardous weather is expected at this time.
.SPOTTER INFORMATION STATEMENT...
Spotters are requested to forward any reports of flash flooding to
our office.
AR
In the hours before
Special weather statement, Sep 9, 6:32 PM EST, 2 hours 58 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
732 PM EDT Sat Sep 9 2023
GAZ010-100000-
Rabun GA-
732 PM EDT Sat Sep 9 2023
...A STRONG THUNDERSTORM WILL IMPACT CENTRAL RABUN COUNTY THROUGH 800
PM EDT...
At 731 PM EDT, Doppler radar was tracking a strong thunderstorm over
Clayton. This storm was drifting slowly east.
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...
Clayton, Mountain City, Tiger, and Black Rock Mountain State Park.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
&&
LAT...LON 3482 8345 3491 8346 3495 8334 3480 8333
TIME...MOT...LOC 2331Z 262DEG 4KT 3488 8341
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH
MOORESpecial weather statement, Sep 9, 6:36 PM EST, 2 hours 54 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
736 PM EDT Sat Sep 9 2023
GAZ026-028-100000-
Hart GA-Franklin GA-
736 PM EDT Sat Sep 9 2023
...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL FRANKLIN AND
NORTHWESTERN HART COUNTIES THROUGH 800 PM EDT...
At 735 PM EDT, Doppler radar was tracking a strong thunderstorm 6
miles northwest of Hartwell, or near Bowersville. This storm was
nearly stationary. Another storm is expected to develop to the west
in east central Franklin County.
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...
Lavonia, Canon, and Bowersville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
&&
LAT...LON 3434 8314 3445 8312 3447 8297 3433 8295
TIME...MOT...LOC 2335Z 262DEG 4KT 3440 8302
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH
MOORESpecial weather statement, Sep 9, 7:00 PM EST, 2 hours 30 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
800 PM EDT Sat Sep 9 2023
SCZ104-100030-
Greater Oconee SC-
800 PM EDT Sat Sep 9 2023
...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL OCONEE COUNTY
THROUGH 830 PM EDT...
At 759 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles southwest of Seneca, or 4 miles south of Westminster, moving
and developing toward the west at 10 mph.
HAZARD...Wind gusts up to 40 mph and half inch 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...
Westminster, and Oakway.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
If on or near Lake Hartwell, get out of the water and move indoors
or inside a vehicle. Remember, lightning can strike out to 10 miles
from the parent thunderstorm. If you can hear thunder, you are close
enough to be struck by lightning. Move to safe shelter now! Do not
be caught on the water in a thunderstorm.
&&
LAT...LON 3455 8311 3456 8313 3456 8314 3457 8314
3458 8315 3467 8315 3468 8298 3454 8297
3453 8310
TIME...MOT...LOC 2359Z 087DEG 8KT 3461 8306
MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH
MOORESpecial weather statement, Sep 9, 7:37 PM EST, 1 hour 53 minutes before
Special Weather Statement
National Weather Service Greenville-Spartanburg SC
837 PM EDT Sat Sep 9 2023
NCZ071-082-100100-
Union NC-Mecklenburg NC-
837 PM EDT Sat Sep 9 2023
...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN MECKLENBURG AND
CENTRAL UNION COUNTIES THROUGH 900 PM EDT...
At 837 PM EDT, Doppler radar was tracking a strong thunderstorm 6
miles northwest of Monroe, or near Wesley Chapel, 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...
Monroe, South Charlotte, Matthews, Mint Hill, Indian Trail,
Weddington, Stallings, Wesley Chapel, Lake Park, and Mineral Springs.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
&&
LAT...LON 3491 8052 3489 8071 3516 8082 3521 8055
TIME...MOT...LOC 0037Z 169DEG 13KT 3503 8064
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH
MOORELocal storm report, Sep 9, 9:02 PM EST, 28 minutes before
Preliminary Local Storm Report
National Weather Service Greenville-Spartanburg SC
1002 PM EDT Sat Sep 9 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0945 PM Flash Flood 5 WNW Monroe 35.02N 80.61W
09/09/2023 Union NC 911 Call Center
Reports of stranded vehicles on roadways and
water on roadways.
&&
ARLocal storm report, Sep 9, 9:14 PM EST, 16 minutes before
Preliminary Local Storm Report
National Weather Service Greenville-Spartanburg SC
1014 PM EDT Sat Sep 9 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1010 PM Flash Flood 3 SSE Fairview 35.10N 80.51W
09/09/2023 Union NC Trained Spotter
Chinkapin Creek coming out of its banks and
flooding the roadway.
&&
AR