Flash Flood Warning 17, NWS Greenville-Spartanburg, SC

944 
WGUS72 KGSP 210047
FFSGSP

Flash Flood Statement
National Weather Service Greenville-Spartanburg SC
847 PM EDT SUN MAY 20 2018

NCC159-210053-
/O.CAN.KGSP.FF.W.0017.000000T0000Z-180521T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Rowan NC-
847 PM EDT SUN MAY 20 2018

...THE FLASH FLOOD WARNING FOR NORTHWESTERN ROWAN COUNTY IS
CANCELLED...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 3564 8066 3578 8066 3579 8054 3579 8052
      3578 8051 3578 8049 3567 8045

$$

Krentz

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
525 PM EDT Sun May 20 2018

.SYNOPSIS...
A moist air mass will remain atop the region through at least
Tuesday. This will result in a continued high chance of showers and
storms each afternoon and evening.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 521 PM EDT: PoPs have been adjusted up east of the
mountains with sbCAPE values running 3000 J/kg+ and outflows
triggering new convection farther east. Locally very  heavy rainfall
will be the biggest threat, and scattered trees down with the
ouflows and improving piedmont DCAPE. Any 55 dBZ or better cores
into the mid to upper 20kft feet range may produce marginally large
hail, but profiles remain very warm and wet. The storms should fade
in the early evening as the instability is consumed.

It remains difficult to differentiate one day to the next in this
air mass as very little changes in the synoptic scale over the next
24 hours or so. Persistence looks like a good forecast. Still think
convection will mostly ash out in the mid/late evening and then we
will have a lull during the pre-dawn hours through mid-morning
Monday. We could end up with some patchy dense fog in places that
have good rain this afternoon. Low temps will be seasonally mild
once again. On Monday, destabilization will depend on when any
lingering convective debris moves away or dissipates, but in general
it should be fairly early in the day over the mtns. The model
guidance is not terribly keen on developing convection across the
western Piedmont and Upstate on Monday afternoon, however. Will not
make major changes to the precip probability in that regard, but
will trend a bit downward over the east in the afternoon. High temps
will be just above normal.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 245 PM EDT Sunday: The forecast area will be between a weak
upper low over GA and a subtropical anticyclone off the Southeast
Coast on Tuesday. This will keep a deep, moist southerly flow over
the area as surface high pressure sits off the Southeast coast as
well. Instability will be weak, but the southerly flow and moist air
mass will create conditions favorable for diurnal convection. Given
the weak instability and moist profiles, expect heavy rainfall would
be the greater threat than severe storms. Highest PoP will be across
the mountains, western Upstate, and NE GA, but the rest of the area
will see good chance values. The upper low washes out Wednesday and
the subtropical anticyclone is suppressed as a short wave trough
passes by to our north. This short wave does push a frontal boundary
into the area on Wednesday. The short wave also creates increasing
lapse rates with cooling mid level temps. Dry mid level air filters
in as well increasing surface delta theta-e values. DCAPE values
remain modest, but expect severe chances to creep up with the
moderate instability and drier mid levels. That said, heavy rainfall
cannot be ruled out given the good coverage and frontal boundary.
Lows remain nearly steady 5 to 10 degrees above normal. Highs near
normal Tuesday rise to around 5 degrees above normal Wednesday.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 235 PM EDT Sunday: The medium range forecast period begins
Wednesday night, as an overall unsettled weather pattern remains on
tap through into next week. With the Bermuda High once extended into
the Southeast retreating back to the east and an upper trough slowly
exiting from the NE and Canada off to the east, weakening upper
ridge is progged to move out of the central plains and over the
eastern half of the US on Thursday. As sfc high manages to build
south into the OH Valley before being pushed eastward and out to
sea, a weak sfc trough looks to meander around and just south of the
FA Thursday into early Friday. With a very moist airmass in place as
PWATs remain well above one inch, low-level SW flow returns on
Friday as weak upper ridging returns to the north. Expect diurnal
convection to be a daily occurrence as dewpoints remain in the mid
to upper 60s and severe weather parameters, while not overly
impressive, remain somewhat on the map of interest. Thus, would not
entirely rule out an isolated severe storm any of the days, but the
bigger concern will be the continued potential threat for periods
heavy rainfall and localized flash flooding.

Into the weekend, as it has been mentioned over the past few days,
things could get interesting and even more complicated. While
another system looks to move into the upper midwest and gradually
approach the area just past the medium range forecast period,
guidance continues to hint at the possibility of a developing
tropical system. However, plenty of discrepancy remains between the
models so nothing is set in stone. Whether it develop in the GOM or
on the east coast of FL, or not at all, moisture will continue to
infiltrate into the area, and thus the continuation of an unsettled
weather pattern.

Temperatures each day will climb into the low to mid 80s (cooler
across the mountains), with overnight lows above normal.

&&

.AVIATION /22Z SUNDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Thunderstorm coverage has been ramped up
around all foothill/piedmont TAF sites through early evening, along
with strong gusty winds of 35kt or better. Expect LIFR visibility
with any torrential downpours along with generally MVFR clougs. KAVL
will only see lingering showers. The showers and storms should
diminish fairly early this evening with only convective debris
beyond about 00Z. Locations that see rain this afternoon/evening
will have a good chance at a fog restriction in the pre-dawn hours
Monday if recent past is any indication. All sites get a short
window of MVFR visibility around daybreak to account for this.
Otherwise, Monday looks to be nearly a copy of today. Wind should
remain light S/SW apart from thunderstorm outflows today, then
light/variable overnight, and SW again Monday.

Outlook: The unsettled weather pattern will continue into the first
half of the week with flight restrictions possible each day around
isolated/scattered showers and storms.

Confidence Table...

            21-03z        03-09Z        09-15Z        15-18Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High  81%     High  87%
KAVL       High 100%     High 100%     High  81%     High 100%
KHKY       High 100%     High 100%     High  94%     High 100%
KGMU       High 100%     High  98%     Med   72%     High  87%
KAND       High 100%     High  96%     Med   61%     Med   79%

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...ARK
NEAR TERM...HG/PM
SHORT TERM...RWH
LONG TERM...SGL
AVIATION...HG/PM

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
335 PM EDT Sun May 20 2018

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-211945-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Avery-Alexander-
Iredell-Davie-Madison-Yancey-Mitchell-Swain-Haywood-Buncombe-Catawba-
Rowan-Graham-Northern Jackson-Macon-Southern Jackson-Transylvania-
Henderson-Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-Union-
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-York-
Anderson-Abbeville-Laurens-Chester-Greenwood-
335 PM EDT Sun May 20 2018

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

.DAY ONE...Tonight.

Scattered thunderstorms will continue into the evening across the
area. Brief heavy rain with localized flash flooding, small hail,
and lightning are possible. Gusty winds from thunderstorms could
blow down a few trees due to saturated soils.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

..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.
..Friday...No hazardous weather is expected at this time.
..Saturday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
526 PM EDT SUN MAY 20 2018

GAZ028-SCZ005>007-010>012-202200-
Hart GA-Greater Pickens SC-Laurens SC-Anderson SC-Abbeville SC-
Spartanburg SC-Greater Greenville SC-
526 PM EDT SUN MAY 20 2018

...A CLUSTER OF THUNDERSTORMS WILL IMPACT NORTHERN HART...
NORTHWESTERN LAURENS...SOUTHEASTERN GREENVILLE...WEST CENTRAL
SPARTANBURG...ANDERSON...SOUTHEASTERN PICKENS AND CENTRAL ABBEVILLE
COUNTIES UNTIL 600 PM EDT...

At 526 PM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from 14 miles east of
Greenville Downtown to 5 miles southeast of Hartwell, and moving
south at 30 mph.

Locations to be impacted include...
Greenville Downtown, Anderson, Easley, Hartwell, Clemson, Greenville
Eastside, West Greenville, Greer, Mauldin and Taylors.

Wind gusts up to 40 mph and half inch hail 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.

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 3443 8308 3448 8302 3447 8300 3460 8286
      3461 8286 3462 8284 3463 8285 3500 8239
      3485 8195 3421 8261
TIME...MOT...LOC 2126Z 343DEG 27KT 3478 8215 3431 8284

SGL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
527 PM EDT SUN MAY 20 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0445 PM     HAIL             4 ESE EASLEY            34.80N 82.52W
05/20/2018  E0.75 INCH       ANDERSON           SC   PUBLIC

&&

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
542 PM EDT SUN MAY 20 2018

NCZ035>037-056-057-068>072-202215-
Rowan NC-Davie NC-Gaston NC-Iredell NC-Cleveland NC-Lincoln NC-
Mecklenburg NC-Cabarrus NC-Alexander NC-Catawba NC-
542 PM EDT SUN MAY 20 2018

...A CLUSTER OF THUNDERSTORMS WILL IMPACT NORTHWESTERN CABARRUS...
CATAWBA...DAVIE...SOUTHEASTERN ALEXANDER...LINCOLN...IREDELL...
NORTHWESTERN MECKLENBURG...ROWAN...CENTRAL CLEVELAND AND NORTHERN
GASTON COUNTIES UNTIL 615 PM EDT...

At 542 PM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from 9 miles north of
Statesville to 13 miles northwest of Huntersville to 10 miles
northeast of Shelby, and moving south at 10 mph.

Locations to be impacted include...
Huntersville, Kannapolis, Salisbury, Statesville, Shelby, Newton,
Lincolnton, Mocksville, Downtown Concord and Gastonia.

Wind gusts up to 45 mph and half inch hail 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.

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 3588 8042 3586 8039 3584 8039 3585 8042
      3583 8043 3583 8049 3577 8045 3574 8046
      3573 8043 3544 8056 3519 8151 3550 8168
      3572 8121 3606 8095 3604 8049 3606 8046
      3601 8042 3599 8042 3596 8038 3589 8037
TIME...MOT...LOC 2142Z 342DEG 8KT 3592 8082 3556 8101 3542 8147

SGL

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
558 PM EDT SUN MAY 20 2018

GAZ028-SCZ006-010>012-202230-
Hart GA-Laurens SC-Anderson SC-Abbeville SC-Greater Greenville SC-
558 PM EDT SUN MAY 20 2018

...A CLUSTER OF THUNDERSTORMS WILL IMPACT NORTHEASTERN HART...
NORTHWESTERN LAURENS...SOUTHEASTERN GREENVILLE...ANDERSON AND
NORTHWESTERN ABBEVILLE COUNTIES UNTIL 630 PM EDT...

At 558 PM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from 16 miles north of
Laurens to 12 miles southeast of Anderson, and moving southeast at 20
mph.

Locations to be impacted include...
Anderson, Hartwell, Homeland Park, Piedmont, Belton, Williamston,
Northlake, Honea Path, Iva and Lake Secession.

Wind gusts up to 40 mph and pea size hail 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.

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 3429 8277 3429 8278 3437 8296 3473 8249
      3465 8210 3420 8260
TIME...MOT...LOC 2158Z 304DEG 15KT 3472 8212 3437 8250

SGL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
600 PM EDT SUN MAY 20 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0540 PM     TSTM WND GST     5 ENE MAULDIN           34.82N 82.22W
05/20/2018  E45 MPH          GREENVILLE         SC   NWS EMPLOYEE

            45 MPH WINDS ESTIMATED DUE TO SMALL LIMBS DOWN.

&&

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
613 PM EDT SUN MAY 20 2018

NCZ036-037-056-057-068>072-SCZ009-202245-
Rowan NC-Davie NC-Gaston NC-Iredell NC-Cleveland NC-Lincoln NC-
Mecklenburg NC-Cabarrus NC-Catawba NC-York SC-
613 PM EDT SUN MAY 20 2018

...A CLUSTER OF THUNDERSTORMS WILL IMPACT CABARRUS...SOUTHEASTERN
CATAWBA...SOUTHERN DAVIE...LINCOLN...SOUTHERN IREDELL...
MECKLENBURG...ROWAN...CENTRAL CLEVELAND...GASTON AND NORTHEASTERN
YORK COUNTIES UNTIL 645 PM EDT...

At 613 PM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from 8 miles north of
Salisbury to 4 miles east of Huntersville to 6 miles southeast of
Shelby, and moving southeast at 30 mph.

Locations to be impacted include...
Gastonia, Uptown Charlotte, Huntersville, Kannapolis, Downtown
Concord, Salisbury, Statesville, Shelby, Newton and Lincolnton.

Torrential rainfall, wind gusts up to 45 mph and half inch hail 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.

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 3505 8075 3500 8084 3508 8091 3502 8090
      3501 8091 3522 8151 3541 8170 3543 8170
      3580 8103 3595 8056 3584 8043 3583 8047
      3584 8048 3583 8049 3579 8048 3577 8045
      3574 8046 3572 8042 3572 8034 3558 8029
TIME...MOT...LOC 2213Z 330DEG 28KT 3578 8044 3542 8076 3523 8144

SGL