River Flood Advisory 19, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
259 PM EDT Thu Aug 19 2021

.SYNOPSIS...
A weak upper trough and abundant moisture will continue across the
region into Friday leading to scattered afternoon and evening
showers and thunderstorms. Saturday an upper-level low will meander
around the Ohio Valley and Mid-Atlantic region before lifting
northeast into New England late this weekend into early next week as
a ridge of high pressure to the south nudges eastward. This should
lead to drier conditions for the weekend with only isolated showers
and thunderstorms during the afternoon and evening hours expected.
Highs will remain above climo this week into next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 2:45pm EDT Thursday:  Round of typical diurnal thunderstorms
is underway this afternoon, expected to die out after dark.  Storms
are being enhanced by the passage of a weak upper wave. This shows
nicely as updraft strength in hi-res models. This wave will have
most of its energy east of the region by tomorrow, and while some
thunder will still be possible, the coverage and intensity will be
much reduced from today.  For today, forcing from the wave might
give some severe storms today, despite only 500-1000 j/kg of MLCAPE.
Bulk shear and hodographs are unimpressive, with pulse severe wind
gusts the main threat.  Storm motion is also eastward at 10 to
20kts, which should reduce the risk from hydro issues.  Should mid
and upper clouds clear behind weak surface boundary ahead of upper
wave later tonight, fog could become an issue overnight as surface
layer remains very moist from recent rains, but this is not clear.
Fading tropical air mass will have highs and lows near to a couple
degrees above normal tomorrow.  Winds are fairly light around weak
frontal boundary, and will be lighter on Friday as surface high
behind boundary moves in.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 215 PM EDT Thursday...A ridge of high pressure will continue
to dominate across the southern United States through the short term.
Meanwhile an upper-level closed low will meander around the Ohio
Valley and Mid-Atlantic region Friday night into Saturday. This low
will be forced to lift northeast into New England as the ridge of
high pressure in the southern CONUS nudges eastward Saturday night
into early Monday. As a result of this ridge pushing east into the
western Carolinas and northeast Georgia, flow will be mainly
northerly and northwesterly. This will lead to limited moisture
across the CWA this weekend. Capped PoPs to a slight chance to
chance for the entire period as only isolated showers and
thunderstorms look possible. Highs this weekend should be a couple
degrees above climo.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
As of 215 PM EDT Thursday...The closed low keeps lifting northeast
out of New England into Nova Scotia during the first half of the
extended term forecast period. This will allow the ridge to remain
over the southeastern CONUS through the middle of next week. Towards
the end of the forecast period, this ridge should start to
retrograde back west of the CWA. Meanwhile, a surface trough looks
to linger along the Southeast coast throughout the extended. Monday
and Tuesday are looking like the drier days as the eastern periphery
of the ridge will remain over the area. Capped PoPs to a slight
chance to chance for this reason. Wednesday into Thursday moisture
associated with this trough could push further inland as the high
retreats west. This would increase the moisture influx. Both the GFS
and ECMWF have PWAT values increasing Wednesday into Thursday. As a
result, have PoPs at chance for the end of the forecast period.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
At KCLT and elsewhere:  Thunderstorms now spreading across the area
from west to east.  Expect a typical diurnal pattern with storms
dying out just after sunset.  Upper trough crossing the area will
assist storm development today with some severe.  Weak surface
boundary has generally SW winds of 5 to 10 kts.  As this boundary
moves eastward, surface high comes in, and winds become light and
VRB overnight, becoming more NW to northerly on Friday.  Opted to
keep in some mention of fog at all locations as some possible
clearing overnight above a still moist surface layer and light
winds, will create good conditions for fog formation at some level.
For KCLT, have kept in a PROB30 for thunder tomorrow afternoon,
though storms will be much more widely scattered than today.

Outlook: A typical, diurnal summertime convective pattern is
expected to prevail into early next week, with coverage scattered at
best. Mtn valley low stratus and fog will be possible each morning.

Confidence Table...

            12-18Z        18-24Z        00-06Z        06-12Z
KCLT       High 100%     High 100%     High 100%     High  89%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High  92%     High 100%     High  84%
KHKY       High 100%     High 100%     High  95%     Med   76%
KGMU       High 100%     High 100%     High 100%     High  95%
KAND       High 100%     High 100%     High 100%     High  95%

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

&&

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

&&

SYNOPSIS...AP
NEAR TERM...WJM
SHORT TERM...AP
LONG TERM...AP
AVIATION...WJM

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
554 PM EDT Thu Aug 19 2021

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-202200-
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 NC-
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-Union SC-Chester-Greenwood-
554 PM EDT Thu Aug 19 2021

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 to move east across the
Upstate, foothills, and Piedmont this afternoon and early this
evening. Some storms will become strong to severe, producing frequent
cloud- to- ground lightning, damaging wind gusts, and hail. Locally
heavy rainfall is also possible. The storms should end by mid-evening
near or just east of the Charlotte metro area.

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

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
600 PM EDT Thu Aug 19 2021

NCZ068-070-SCZ008-009-192230-
Gaston NC-Cleveland NC-York SC-Cherokee SC-
600 PM EDT Thu Aug 19 2021

...Strong thunderstorms will impact portions of southeastern
Cleveland, Gaston, central York and northeastern Cherokee Counties
through 630 PM EDT...

At 559 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from 9 miles west of Gastonia to 4 miles west of
York. Movement was northeast at 20 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Gastonia, York, Rock Hill, Kings Mountain, Mt Holly, Belmont,
Bessemer City, South Gastonia, Tega Cay and Clover.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3498 8095 3488 8144 3524 8145 3541 8117
      3540 8100 3532 8099 3527 8102 3517 8100
      3515 8101 3515 8104 3514 8105 3511 8103
      3509 8106 3506 8106 3504 8104 3509 8096
TIME...MOT...LOC 2159Z 242DEG 20KT 3523 8133 3498 8130

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
612 PM EDT Thu Aug 19 2021

SCZ012>014-192245-
Laurens SC-Union SC-Chester SC-
612 PM EDT Thu Aug 19 2021

...A strong thunderstorm will impact portions of east central
Laurens, western Chester and southern Union Counties through 645 PM
EDT...

At 612 PM EDT, Doppler radar was tracking a strong thunderstorm 12
miles south of Union, or near Whitmire, moving east at 15 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Union, Monarch Mill, Lockhart, Carlisle, Rose Hill State Park, Leeds,
Sedalia, Tuckertown and Santuc.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3448 8156 3453 8162 3453 8164 3452 8165
      3446 8170 3458 8181 3482 8144 3482 8140
      3457 8137 3457 8142 3450 8142 3450 8144
      3449 8144 3449 8149 3445 8154
TIME...MOT...LOC 2212Z 260DEG 12KT 3455 8162

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
620 PM EDT Thu Aug 19 2021

NCZ071-082-192245-
Union NC-Mecklenburg NC-
620 PM EDT Thu Aug 19 2021

...A strong thunderstorm will impact portions of southeastern
Mecklenburg and western Union Counties through 645 PM EDT...

At 620 PM EDT, Doppler radar was tracking a strong thunderstorm 6
miles east of Indian Land, or near Weddington, moving east at 15 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Monroe, Indian Trail, Weddington, Stallings, Wesley Chapel, Waxhaw,
Lake Park, Mineral Springs, Hemby Bridge and Marvin.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3488 8079 3494 8078 3503 8086 3506 8087
      3515 8056 3488 8050
TIME...MOT...LOC 2220Z 259DEG 13KT 3499 8075

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
629 PM EDT Thu Aug 19 2021

NCZ069>071-082-SCZ009-013-014-192300-
Gaston NC-Union NC-Lincoln NC-Mecklenburg NC-York SC-Union SC-
Chester SC-
629 PM EDT Thu Aug 19 2021

...Strong thunderstorms will impact portions of southeastern Lincoln,
Mecklenburg, eastern Gaston, southwestern Union, northern Chester,
York and east central Union Counties through 700 PM EDT...

At 629 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from 11 miles southeast of Lincolnton to 8 miles
northeast of Chester to 13 miles east of Union. Movement was
northeast at 25 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Gastonia, Rock Hill, Uptown Charlotte, Huntersville, York, Chester,
Central Charlotte, South Charlotte, Northeast Charlotte and Southwest
Charlotte.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3482 8072 3482 8080 3494 8078 3508 8091
      3501 8091 3492 8086 3484 8087 3483 8090
      3471 8087 3462 8154 3545 8113 3554 8095
      3550 8096 3549 8094 3551 8091 3551 8079
      3542 8075 3540 8077 3535 8071
TIME...MOT...LOC 2229Z 246DEG 20KT 3541 8107 3481 8113 3469 8139

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
655 PM EDT Thu Aug 19 2021

NCZ071-072-082-SCZ009-014-192330-
Union NC-Cabarrus NC-Mecklenburg NC-York SC-Chester SC-
655 PM EDT Thu Aug 19 2021

...Strong thunderstorms will impact portions of Cabarrus,
Mecklenburg, Union, northern Chester and eastern York Counties
through 730 PM EDT...

At 655 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Huntersville to 6 miles northwest of
Monroe to 4 miles southeast of Chester. Movement was east at 35 mph.

HAZARD...Wind gusts of 50 to 55 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Rock Hill, Uptown Charlotte, Huntersville, Kannapolis, Downtown
Concord, Monroe, Chester, Central Charlotte, South Charlotte and
Northeast Charlotte.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3481 8032 3482 8080 3494 8078 3508 8091
      3492 8086 3482 8090 3470 8086 3465 8089
      3468 8136 3516 8100 3535 8096 3536 8092
      3537 8096 3541 8095 3551 8075 3550 8042
      3540 8036 3519 8051 3516 8044 3519 8028
TIME...MOT...LOC 2255Z 247DEG 30KT 3537 8084 3506 8061 3468 8115

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...55 MPH

RWH

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
734 PM EDT Thu Aug 19 2021

NCZ071-072-082-200000-
Union NC-Cabarrus NC-Mecklenburg NC-
734 PM EDT Thu Aug 19 2021

...A strong thunderstorm will impact portions of south central
Cabarrus, southeastern Mecklenburg and northern Union Counties
through 800 PM EDT...

At 734 PM EDT, Doppler radar was tracking a strong thunderstorm 13
miles northeast of Monroe, or 8 miles north of Marshville, moving
east at 25 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Monroe, Indian Trail, Stallings, Unionville, Wesley Chapel, Lake
Park, Hemby Bridge, Midland, Fairview In Union County and Wingate.

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.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3501 8030 3495 8077 3523 8061 3527 8045
      3519 8051 3518 8050 3518 8048 3517 8047
      3516 8044 3517 8042 3516 8041 3518 8037
      3517 8036 3518 8031 3519 8030 3519 8028
TIME...MOT...LOC 2334Z 253DEG 20KT 3511 8036

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

RWH