Flash Flood Warning 13, NWS Greenville-Spartanburg, SC

628 
WGUS72 KGSP 120632
FFSGSP

Flash Flood Statement
National Weather Service Greenville-Spartanburg SC
232 AM EDT SAT AUG 12 2017

SCC023-120638-
/O.CAN.KGSP.FF.W.0013.000000T0000Z-170812T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester SC-
232 AM EDT SAT AUG 12 2017

...THE FLASH FLOOD WARNING FOR NORTHEASTERN CHESTER COUNTY IS
CANCELLED...

LAT...LON 3491 8087 3490 8088 3487 8088 3486 8087
      3484 8087 3483 8090 3482 8090 3482 8114
      3491 8107 3500 8090 3497 8088 3496 8087
      3494 8086

$$

SCC091-120800-
/O.CON.KGSP.FF.W.0013.000000T0000Z-170812T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
York SC-
232 AM EDT SAT AUG 12 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 AM EDT FOR
SOUTHEASTERN YORK COUNTY...

At 228 AM EDT, Doppler radar indicated the heavy rain producing 
showers and thunderstorms had moved east of the warning area and 
largely dissipated. However, high water conditions continue along 
and just west of the Interstate 77 corridor in southeastern York 
County. The Flash Flood Warning will continue at least until 3 AM in 
case new flooding develops along or near Stony Fork Creek, Fishing 
Creek, or around low lying areas of Lesslie, Catawba or Rock Hill. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Most flood deaths occur in vehicles. Do not attempt to cross
water-covered roadways, bridges, or low-level crossings. Only a few
inches of rapidly flowing water can carry away your vehicle. It is
not worth the risk. Please TURN AROUND, DON'T DROWN.

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

When it is safe to do so, please report flood waters or landslides
flowing over roads or threatening property to the National Weather
Service by calling toll free, 1, 800, 2 6 7, 8 1 0 1, by posting on
our Facebook page, or via Twitter using hashtag NWSGSP. Your message
should describe the event and the specific location where it
occurred, including roadways, nearby cross streets, stream names and
other landmarks.

&&

LAT...LON 3491 8087 3490 8088 3487 8088 3486 8087
      3484 8087 3483 8090 3482 8090 3482 8114
      3491 8107 3500 8090 3497 8088 3496 8087
      3494 8086

$$

HG

031 
WGUS72 KGSP 120656
FFSGSP

Flash Flood Statement
National Weather Service Greenville-Spartanburg SC
256 AM EDT SAT AUG 12 2017

SCC091-120705-
/O.CAN.KGSP.FF.W.0013.000000T0000Z-170812T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
York SC-
256 AM EDT SAT AUG 12 2017

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN YORK COUNTY IS
CANCELLED...

The heavy rain has ended and flood waters continue to recede. 
Additional flooding is no longer expected to pose a threat and the 
Flash Flood Warning for York County has been cancelled.

LAT...LON 3491 8087 3490 8088 3487 8088 3486 8087
      3484 8087 3483 8090 3482 8090 3482 8114
      3491 8107 3500 8090 3497 8088 3496 8087
      3494 8086

$$

HG

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1029 PM EDT Fri Aug 11 2017

.SYNOPSIS...
A moist cold front will drop southeast into the region and become
stationary over the weekend. Waves of low pressure will then ride
east along the front beginning Monday continuing the chance of
locally heavy rainfall. Drier air will mix in from the northeast by
the middle of next week.

&&

.NEAR TERM /THROUGH SATURDAY/...
As of 1025 PM: Scattered to numerous showers extending from the
southern NC and GA mtns through the NW NC Piedmont continue to
gradually diminish in coverage and intensity. Meanwhile, new
convection is firing along remnant/outflow reinforced sea-breeze
boundary across our eastern Piedmont areas. So far, nothing
nothing too intense has developed, but as activity continues to
develop northwest into the urban corridor along I-77, rain rates
will have to be monitored closely for potential hydro issues.
Fortunately, antecedent conditions in these areas are not especially
dire (1-hr FFGs over 2"), and it's not at all clear that the hydro
threat will be anything beyond localized, so do not see a need to
issue a watch at this time, but will continue to mention the threat
for flash flooding along the I-77 corridor through the night.
Meanwhile, the severe convective threat, such as it was, has passed.
Min temps will be above climo, with plenty of stratus and patchy fog
expected to develop prior to daybreak.

Saturday, the upper trough begins to deamplify as it crosses the
Appalachians. Meanwhile, a cold front should push into the NC
mountains during the AFTN. There is a big question mark on how
unstable we will be able to get due to all the convective
overturning today into tonight. But if the models are right with
1000-2000 J/kg of SBCAPE. There may be a marginal severe threat, as
bulk shear remains elevated, especially across the northern third of
the CWFA. Drier air will start to filter in from the west, so heavy
rain threat should start to diminish. I took the SUPERBLEND pop as a
first guess, but if we don't get as unstable as the models depict,
these pops may be overdone. Temps will be below normal under plenty
of cloud cover.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 230 PM EDT Friday: The pattern will remain intact through the
rest of the weekend and to start next week, with a broad upper trof
across the region that will have weak short wave trofs and ridges
moving through it. The entire period lacks a strong synoptic-scale
signal or forcing, so expect a diurnal nature to be slightly
more dominant. A weak boundary is expected to slip southeast on
Saturday evening which should allow for some nw flow drying and
diurnal weakening of convection, thus the precip probs drop off
to the slight chance range. Sunday still looks more uncertain as
we lack a lot of forcing and the strength of moist southerly low
level upslope flow is questionable. The guidance blends still
point toward a high chance/low likely probability so that will
be kept in the fcst. Precip chances were kept Sunday night in
spite of the drying out on the GFS, mainly out of continuity and
agreement with neighbors. On Monday, the models show a slightly
improved environment as a weak upper wave moves through. That
should provide a small extra boost, so precip prob will be kept
in the likely range, with some categorical near the Blue Ridge
Escarpment. The lack of real air mass change suggests a continued
low-end severe and flash flood threat through the period. Temps
will remain near, if not slightly below, normal as well.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 150 PM EDT Friday: The ulvl trof slowly lifts and moves east
thru the period while a ridge axis begins to advance and cross the
area by late Wed. At the sfc...not expecting much change in the
airmass as a wavy frontal zone remains parked along the srn
periphery of the FA. This bndry will likely waft north/south a bit
thru the first part of the period...before becoming suppressed south
by llvl ridging early Thu. Tue and Wed look to be fairly active with
sct -shra/tstms each afternoon as sbCAPE values reach moderate
levels. Some measure of ulvl lift and bulk shear will be present
mainly across the nrn zones. Thus...the better chance for stg/svr
tstms shud be across nrn half of the FA...with more general thunder
south. On Thu...the aforementioned high pressure begins to build in
with the parent high center tracking east across the mid/Atl region
and off the coastline. This will enable a wedge of high pressure to
develop over the area...which looks to become less defined and more
insitu/like as the period progresses. Plenty of h85 Atl moisture
flux will be in play to expect a reinforcing moist wedge. A distinct
instability gradient is noted in the guidance which gives the wedge
favored wrn/srn zones the best chance for tstm development both Thu
and Fri afternoons. Max temps will be rather steady state a few
degrees below normal thru the period...with mins remaining a couple
degrees above normal due to a high moisture environ.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Numerous showers and storms are becoming
increasingly focused across the mtns and foothills this evening, thus
the best chances for convection and restrictions in the very near
term will be at KHKY/KAVL, where tempos are included for TSRA (at
KHKY) or SHRA (at KAVL). However, showers could redevelop at just
about anytime near the other terminals, and most get another period
of tempos for SHRA during late evening through the early part of the
overnight, while VCSH is carried everywhere through much of the
night. The other concern will be timing the development of low
stratus and BR, which seems a virtual certainty in the extremely
moist environs, with most terminals seeing dewpoint depressions of
less than 5 degrees already this evening. In fact, feel there is a
pretty good chance of IFR conditions developing at the Upstate SC
terminals and KAVL during the first six hours of the period, and
tempos have been included for such. Otherwise, all terminals should
settle into IFR/LIFR conditions btw 06Z and 09Z, with visby ranging
from 1-3SM at times. Conditions will gradually improve Saturday
morning, with VFR anticipated by early afternoon. More convection is
expected during the afternoon, and all terminals receive accordingly
receive a PROB30.

Outlook: A moist and unsettled pattern will dominate through the
weekend into early next week.  With that, expect possible shra/tsra
associated restrictions each day, while low clouds and fog remain
a possibility each morning with the best chances in the mtn valleys
as well as for sites that experienced recent rainfall.

Confidence Table...

            02-08Z        08-14Z        14-20Z        20-00Z
KCLT       High  94%     Med   67%     High  85%     High 100%
KGSP       Med   73%     Med   68%     High  85%     High 100%
KAVL       Med   77%     Med   69%     High  92%     High 100%
KHKY       High  92%     Med   71%     High  85%     High 100%
KGMU       High  83%     Med   75%     High  87%     High 100%
KAND       High  88%     Low   51%     High  91%     High 100%

The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:

www.weather.gov/gsp/aviation

&&

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

&&

SYNOPSIS...SBK
NEAR TERM...ARK/JDL
SHORT TERM...PM
LONG TERM...SBK
AVIATION...JDL

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
1036 PM EDT Fri Aug 11 2017

GAZ010-017-018-026-028-029-NCZ033-048>053-058-059-062>065-068-
501>510-SCZ001>008-010>013-019-130245-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Avery-Madison-Yancey-
Mitchell-Swain-Haywood-Buncombe-Graham-Northern Jackson-Macon-
Southern Jackson-Transylvania-Henderson-Cleveland-Caldwell Mountains-
Greater Caldwell-Burke Mountains-Greater Burke-McDowell Mountains-
Eastern McDowell-Rutherford Mountains-Greater Rutherford-
Polk Mountains-Eastern Polk-Oconee Mountains-Pickens Mountains-
Greenville Mountains-Greater Oconee-Greater Pickens-
Greater Greenville-Spartanburg-Cherokee-Anderson-Abbeville-Laurens-
Union-Greenwood-
1036 PM EDT Fri Aug 11 2017

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

.DAY ONE...Tonight.

A thunderstorm or two will remain possible across the area overnight.
The main threats will be from occasional cloud to ground lightning
and locally heavy rainfall.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

..Saturday...No hazardous weather is expected at this time.
..Sunday...No hazardous weather is expected at this time.
..Monday...No hazardous weather is expected at this time.
..Tuesday...No hazardous weather is expected at this time.
..Wednesday...No hazardous weather is expected at this time.
..Thursday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

NCZ035>037-056-057-069>072-082-SCZ009-014-130245-
Alexander-Iredell-Davie-Catawba-Rowan-Lincoln-Gaston-Mecklenburg-
Cabarrus-Union-York-Chester-
1036 PM EDT Fri Aug 11 2017

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

.DAY ONE...Tonight.

Scattered to numerous thunderstorms heavy rain showers and a few
thunderstorms are expected along and near the I-77 corridor through
the overnight hours. Slow movement of the showers and storms, along
with the potential for multiple heavy showers and storms to move
over the same areas will pose a threat of localized excessive
rainfall and flash flooding, particularly in urbanized areas.
Occasional cloud to ground lightning can occur with any
thunderstorm.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

..Saturday...No hazardous weather is expected at this time.
..Sunday...No hazardous weather is expected at this time.
..Monday...No hazardous weather is expected at this time.
..Tuesday...No hazardous weather is expected at this time.
..Wednesday...No hazardous weather is expected at this time.
..Thursday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

LANE

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1127 PM EDT FRI AUG 11 2017

GAZ010-017-018-SCZ001-002-004-005-120415-
Rabun GA-Stephens GA-Habersham GA-Pickens Mountains SC-
Greater Pickens SC-Greater Oconee SC-Oconee Mountains SC-
1127 PM EDT FRI AUG 11 2017

...THUNDERSTORM WITH TORRENTIAL RAINFALL WILL IMPACT NORTHEASTERN
STEPHENS...NORTHEASTERN HABERSHAM...EASTERN RABUN...WEST CENTRAL
PICKENS AND OCONEE COUNTIES UNTIL 1215 AM EDT...

At 1126 PM EDT, Doppler radar was tracking thunderstorm with
torrential rainfall 9 miles west of Walhalla, or 7 miles east of
Tallulah Gorge State Park, moving east at 10 mph.

Locations to be impacted include...
Walhalla, Seneca, Westminster, Tallulah Falls, Salem, Lake Keowee,
Devils Fork State Park, Keowee Toxaway State Park, Tallulah Gorge
State Park and Oconee State Park.

Very heavy rainfall rates up to 2 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 3473 8347 3500 8311 3497 8292 3484 8279
      3453 8318
TIME...MOT...LOC 0326Z 273DEG 10KT 3476 8323

Carroll