Flash Flood Warning 33, NWS Greenville-Spartanburg, SC

267 
WGUS72 KGSP 201235
FFSGSP

Flash Flood Statement
National Weather Service Greenville-Spartanburg SC
835 AM EDT Wed May 20 2020

GAC147-SCC007-045-201600-
/O.CON.KGSP.FF.W.0033.000000T0000Z-200520T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hart GA-Greenville SC-Anderson SC-
835 AM EDT Wed May 20 2020

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL NOON EDT FOR
CENTRAL HART...EAST CENTRAL GREENVILLE AND CENTRAL ANDERSON
COUNTIES...

At 830 AM EDT, heavy rain and flash flooding is occurring all across 
the warned area.  Storm total rainfall across parts of Northern 
Anderson and Central Greenville counties in exceeding 5 inches in 
spots.  Widespread stream, creek and roadway flooding will continue 
to develop, especially where the rain has been heaviest, from 
Piercetown to Powdersville and throughout the city of Greenville. 
Floodwaters will be threatening numerous roads and select structures 
within the warned area!

HAZARD...Life threatening flash flooding. Heavy rain producing flash 
         flooding.

SOURCE...Radar indicated.

IMPACT...Life threatening flash flooding of creeks and streams, 
         urban areas, highways, streets and underpasses.

Some locations that will experience flooding include...
Greenville Downtown, Anderson, Hartwell, Greenville Eastside, West
Greenville, Greer, Mauldin, Taylors, Berea and Welcome.

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.

Numerous roads, parking lots and bridges will be threatened by heavy
rain and rapidly rising streams and creeks. Please pay close
attention to road signs indicating a flood-prone area. Obey all
barricades, even if water is not currently over the road. Barricades
are in place for your protection and indicate areas where flooding
can occur rapidly and without warning.

&&

LAT...LON 3437 8310 3448 8302 3447 8300 3463 8283
      3471 8271 3482 8249 3489 8250 3499 8234
      3495 8222 3484 8223 3451 8264 3427 8296

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
401 AM EDT Wed May 20 2020

.SYNOPSIS...
A large upper low will linger over the Tennessee Valley Region today
and tonight, generating several rounds of moderate to heavy rain
across much of our region. This pattern has the potential to produce
significant rainfall and flooding over parts of the region. The low
will finally start to move away on Thursday and Thursday night. On
Friday, one more disturbance will move across the region. We should
see a return to more typical late spring weather over the weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 325 AM EDT Wednesday: Some heavier showers have made their
way up and over NE Georgia and parts of the Western Upstate over
the past couple of hours. We have yet to see any lighting in the
more reflective cells, but I wouldn't be surprised if we saw a
handful of strikes over the next few hours. A Flash Flood Watch
remains in effect for most of the CWA with a handful of flood
warnings currently in effect. Please see latest Public Information
Statement regarding the increasing threat for landslides and
debris flows across the mountains and foothills over the next
few days. In addition, we coordinated with WPC wrt the latest
fcst QPF and the decision to increase portions of our CWA to a
High Risk for excessive rainfall for today and tonight. Please
see the Hydrology Section below for more details regarding the
potential impacts from the excessive rain.

Otherwise, the wet and unsettled weather pattern will continue to
bring waves of showers and a few thunderstorms thru the near-term
period as a large h5 low spins over the TN Valley with a slight move
eastward expected today. At the sfc, the latest analysis depicts a
fairly weak sfc low near the area with a nearly stationary bndy
located right over the CWA. With plenty of available moisture in
place along with some limited instability and shear, we can't rule
out a few thunderstorms becoming stronger this afternoon (mainly
across the Upstate). The primary threat will be damaging winds with
an isolated tornado also possible. Otherwise, the main story will
be the ongoing flood threat, with moderate to heavy downpours at
times and training of storms. Since Monday, some areas have already
received 3 to 6 inches of rainfall, with a few locations approaching
7 inches. With the hybrid wedge remaining in place, temperatures
will stay well below normal again today, with highs struggling to
reach the low 60s across the lower terrain.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 321 AM EDT Wednesday: The model guidance shows the cutoff
low finally but slowly on the move away from the fcst area, altho
we will remain under the influence of its cyclonic flow. More
importantly, at daybreak on Thursday, the plume of tropical moisture
will also be on the move across the western Piedmont/foothills of
NC. Unfortunately, this might be too late, and one might anticipate
the Flash Flood Watch to be extended over parts of the fcst area
through the daylight hours on Thursday to account for what looks
like an ongoing threat at least over the area east of Highway
321 in the morning. Very high precip probs will be maintained in
that area, and across the rest of the mtns as well as wraparound
moisture/precip remain across that region well into the day. We
should finally see the threat wane late Thursday as the mid/upper
level dry air wraps in across the rest of the fcst area while the
upper low moves toward the OH Valley. Temps should rebound but
remain below normal. On Thursday night, we might finally get a
break with the forcing having exited to the northeast, so precip
probs tail off considerably, but not entirely. Friday looks like
yet another busy day, what with so much lingering moisture to work
with. The guidance shows a short wave coming through an upstream
ridge Thursday night and then getting entrained into the cyclonic
flow around the departing upper low on Friday. That scenario brings
this forcing overhead during peak heating, which would support
numerous showers/storms across the mtns/foothills and a chance
everywhere else. Fortunately, buoyancy appears to be rather limited,
so we do NOT appear to have an appreciable chance at strong/severe
storms. Temps should climb back to normal. Finally, in the wake of
this short wave Friday night and the upper low having moved even
farther away, dare we say that we might start to briefly dry out
after midnight? One can hope at that point.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 140 AM EDT Wednesday: We are still on track for a weather
regime change once we finally get rid of the old upper low that
has plagued our region for the better part of the week thus
far. Altho the models differ in their placement of the upper low
Saturday morning, the effect is the same, that being an upper
ridge building in from the west to bring back our springtime. The
models are in general agreement that once the upper low moves
away, the pattern will reamplify with a ridge axis building over
the southeast/Carolinas/upper OH Valley regions. We are going
to feel this pattern as something almost summerlike because of
the humidity that will remain relatively high, thanks to all the
water that will have been dumped across our region this week, and
temps that should make it well into the 80s over the weekend. This
pattern will also support mainly diurnal showers and thunderstorms
through the medium range period. The precip probs are expected to be
above climo for the weekend as at least one weak short wave moves
over the region. We may drop back to mainly mtn convection early
next week if the ridge cuts off into an upper level anticyclone
and depending where the center of the anticyclone is located. The
building upper anticyclone may support a building sfc high off the
Canadian Maritimes that ridges all the way back down the east side
of the mtns, which would moderate the temps somewhat. Altho the
fcst right now shows temps dropping back toward climo for early
next week, there is a good chance this is underdone if we don't
develop or maintain a connection to that cooler sfc high.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and Elsewhere: With the hybrid wedge in place, IFR conditions
are expected to continue thru most of the 06z TAF period. Shower activity
will likely increase after roughly 11Z from SW to NE with KCLT on the
later end of the time frame. PROB30s for TSRA were kept at all sites
for the late aftn thru the evening, however some sites likely won't see
much in the way of thunder as instability still appears minimal thru
the period. As has been the case for the past couple of days, visby
will likely bounce around quite a bit thru the taf period as bands of
precip continue to move across the area. Winds will remain out of the
NE thru the period with some low-end gusts expected over most sites.

Outlook: Unsettled weather with associated restrictions will continue
well into Thursday before improving by the weekend, however diurnally
driven SHRA/TSRA will be possible over the weekend.

Confidence Table...

            08-14Z        14-20Z        20-02Z        02-06Z
KCLT       Med   78%     Med   74%     High  93%     High  84%
KGSP       High  94%     High  91%     High  94%     High  83%
KAVL       Med   73%     High  82%     High  90%     High  89%
KHKY       Med   71%     Med   63%     High  93%     High  97%
KGMU       High  89%     High  91%     High  90%     High  81%
KAND       High  85%     High  87%     Med   76%     Med   75%

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

www.weather.gov/gsp/aviation

&&

.HYDROLOGY...
Very wet near-term antecedent conditions are setting the stage
for a hydrologically active Wednesday with widespread forecasted
rainfall of 2-4+" expected over saturated upper soils following
several rounds of heavy rain since Monday.  The heavy rainfall
already observed, exceeding 5 inches in some locations along and
near the Blue Ridge Escarpment, has caused significant rises on
area stream.  While most small streams have receded, flows remain
elevated heading into Wednesday.  Though much of the area was dry
over the two weeks leading up to this event, the entire region
has seen a wet winter and early spring with above-normal rainfall.
Given these antecedent conditions and forecasted rainfall, WPC's
Moderate Risk and a High Risk for excessive rainfall today is well
placed and warranted.

With a lower threshold for excessive runoff and embedded rainfall
rates exceeding 3 inches per hour within bands of training
shower/convective activity on Wednesday, new rapid stream rises and
higher crests will be easier to achieve with any heavy rainfall that
occurs for the remainder of this multi-phased event.  Therefore,
confidence is increasing that widespread Minor flooding will occur,
especially along the Blue Ridge Escarpment and adjacent foothills
of North and South Carolina during the day on Wednesday and near
the Charlotte Metro area later Wednesday.  Isolated to scattered
areas of more significant (Moderate) flooding potentially impacting
several homes and businesses are likely, especially along and
adjacent to the Escarpment from Henderson and Polk counties north
to Avery and Caldwell counties, but such impacts cannot be ruled
out further east and south into the Piedmont, especially near
urban areas, including Charlotte.

As always, it will take many hours for streams to rise, crest, and
recede so flooding could persist well after the rainfall ends.
Larger streams will be the last to respond and recede from
excessive runoff; therefore, rivers like the Broad, Catawba,
and SF Catawba may see flooding persist well into Thursday.
Moderate flooding along these mainstem rivers, which includes
structural flooding, is possible so it will be important to monitor
forecasts (https:/water.weather.gov/ahps2/forecasts.php?wfo=gsp)
and Warnings for the latest information if conditions deteriorate.

Given the potential for high rainfall rates and event-total (since
Monday) rainfall amounts exceeding 10 inches in isolated locations
along and adjacent to the Escarpment, the threat for landslides is
also increasing.  Residents in areas prone to landslides are urged
to review the GSP Public Information Statement for preparedness
information and be prepared to act if a Flash Flood Warning is
issued for your area.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Flash Flood Watch through Thursday morning for NCZ033-035>037-
     049-050-053-056-057-064-065-068>072-082-501>510.
SC...Flash Flood Watch through Thursday morning for SCZ002-003-
     005>010-013-014.

&&

SYNOPSIS...PM
NEAR TERM...JPT
SHORT TERM...PM
LONG TERM...PM
AVIATION...JPT
HYDROLOGY...JMP

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
509 AM EDT Wed May 20 2020

NCZ033-035>037-049-050-053-056-057-064-065-068>072-082-501>510-
SCZ002-003-005>010-013-014-210915-
Avery-Alexander-Iredell-Davie-Yancey-Mitchell-Buncombe-Catawba-Rowan-
Transylvania-Henderson-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-
Pickens Mountains-Greenville Mountains-Greater Pickens-
Greater Greenville-Spartanburg-Cherokee-York-Anderson-Union SC-
Chester-
509 AM EDT Wed May 20 2020

...FLASH FLOOD WATCH IN EFFECT THROUGH THURSDAY MORNING...

This Hazardous Weather Outlook is for the western Piedmont, foothills,
and parts of the North Carolina mountains, and parts of 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.

In addition to the heavy rainfall threat, isolated thunderstorms are
possible through tonight. The storms that develop will produce cloud
to ground lightning, torrential downpours, and wind gusts capable of
knocking down trees weakened by the heavy rain and saturated soil.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

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

   Flash Flood Watch.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed. Please relay any information about
observed severe weather to the NWS while following all local, state,
and CDC guidelines.

GAZ010-NCZ048-051-052-058-059-062-063-210915-
Rabun-Madison-Swain-Haywood-Graham-Northern Jackson-Macon-
Southern Jackson-
509 AM EDT Wed May 20 2020

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

.DAY ONE...Today and tonight.

Isolated thunderstorms are possible through tonight. The main
threats from these thunderstorms will be heavy rainfall and cloud to
ground lightning. Some locations could experience minor flooding
where numerous showers and storms occur.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Periods of showers and storms could persist into Thursday morning.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed. Please relay any information about
observed severe weather to the NWS while following all local, state,
and CDC guidelines.

GAZ017-018-026-028-029-SCZ001-004-011-012-019-210915-
Habersham-Stephens-Franklin-Hart-Elbert-Oconee Mountains-
Greater Oconee-Abbeville-Laurens-Greenwood-
509 AM EDT Wed May 20 2020

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

.DAY ONE...Today and tonight.

Numerous of showers and thunderstorms are expected through today and
into tonight. Periods of heavy rain can be expected, perhaps enough
to cause flooding of poor drainage areas and rapid rises on streams
and creeks. Cloud to ground lightning can be expected in
thunderstorms. A few of the storms could produce wind gusts strong
enough to knock down a few trees that have been weakened by the heavy
rain and saturated soil.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

No significant weather is expected.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed. Please relay any information about
observed severe weather to the NWS while following all local, state,
and CDC guidelines.

PM

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
539 AM EDT Wed May 20 2020

SCZ010-011-019-201015-
Anderson SC-Abbeville SC-Greenwood SC-
539 AM EDT Wed May 20 2020

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN ANDERSON...
ABBEVILLE AND NORTHWESTERN GREENWOOD COUNTIES UNTIL 615 AM EDT...

At 539 AM EDT, Doppler radar was tracking a strong thunderstorm 8
miles west of Abbeville, or 7 miles east of Lowndesville, moving
northeast at 35 mph.

Locations to be impacted include...
Abbeville, Honea Path, Ware Shoals, Calhoun Falls, Due West, Donalds,
Hodges, Shoals Junction, Lake Secession and Lake Russell.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 inches per hour will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

The combination of gusty winds and saturated soil conditions will
cause scattered trees and power lines to fall. Seek shelter inside an
interior room.

&&

LAT...LON 3407 8261 3417 8266 3454 8240 3435 8217
      3408 8247 3408 8248 3407 8250
TIME...MOT...LOC 0939Z 215DEG 28KT 3419 8252

MOORE