Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1257 AM EDT Sat Aug 14 2021

.SYNOPSIS...
A stormy pattern will persist over the area through the weekend,
with scattered if not numerous showers and thunderstorms developing
each afternoon. Temperatures will remain above normal through
Saturday. Cooler but still rainier weather will arrive Sunday with a
stalling cold front and possibly impacts from the remnants of
Tropical Storm Fred in the early to middle part of next week.

&&

.NEAR TERM /THROUGH TODAY/...
100 AM Update...Strong convec is beginning to wane across the far
ern zones associated with an outflow bndry and DCAPE on the order of
1100 J/kg. Not anticipating any additional severe activity, but a few
cells could generate over the next couple hrs and produce high
rainfall rates. The flood advisory for Rowan Co will continue thru
0630z as continued runoff and perhaps new precip will affect the
areas arnd Salisbury, Town Creek, and it/s tributaries.

As of 945 pm EDT: Radar continues to depict isolated to scattered
thunderstorms developing mainly along the boundary left over by
earlier convection along the I-85 corridor from Charlotte to
Concord. Expect another hour or so of continued activity in this
area before the region finally stabilizes. Farther west across the
Upstate of SC, radar shows weak outflows working west and this
region still exhibits some late day 2000+ sbCAPE values in the
latest LAPS analysis. Will thus also feature isolated coverage there
through about midnight. Otherwise, the coverage should steadily
dwindle through the late evening and early overnight hours, although
small PoPs will be retained through the early morning hours near the
TN border as increasing moisture in advance of frontal zone
interacts with westerly low-level flow to initiate a few showers.
Patchy fog should be relegated mainly to the mountain river valleys
overnight, and any Piedmont locations that received heavy rain late
this evening.

Another day of moderate-to-strong instability is expected on
Saturday, while slight height falls are expected across the
Southeast as a major short wave trough passes across southeast
Canada and the northeast Conus. Meanwhile, the short term models
agree in depicting a lee/pre-frontal trough across the heart of the
CWA during the afternoon. Overall, forecast conditions are quite a
bit more favorable for deep convection Saturday afternoon, and
likely PoPs will be advertised across the mountains and portions of
the foothills, with 30-50% chances across the remainder of the
forecast area. There will also be an uptick in the severe weather
potential, owing largely to the higher overall coverage. Temps will
remain above normal through the period, with max heat indices
expected to range in the 99-102 range across the Piedmont again
Saturday afternoon.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY/...
As of 145 PM EDT Friday: Saturday night, the approach of a
highly-elongated upper trough should ultimately push a frontal
boundary through the area from the north/northwest, advecting dry
cP air with it.  With the Bermuda High anchored over the western
Atlantic, persistent southeasterly flow will drive a plume of higher
PWATs into the area, inducing isentropic ascent over the cold air.
Ultimately, this leads to the development of a summertime cold air
damming event, with a clear isobaric signature evident in all the
global models by daybreak Sunday.  Throughout Sunday, widespread
cloud cover and precipitation into the cold dome should further
strengthen this in situ CAD.  Consequently, temps should be easily
10 degrees cooler on Sunday than they were on Saturday.  As with
all frontal passages, some thunder is guaranteed.  Model soundings
indicate PWATs in excess of 1.8-2", warm cloud depths of 10-11 kft,
and minimal MBE vectors - making heavy rain the primary threat
from this convection.

This trend continues into Monday.  With cold air entrenched across
the Piedmont and Foothills, the wedge boundary appears to set up
near or south of the southern tier of our CWA.  A slight weakening
in flow off the Atlantic will allow moisture to relapse slightly,
and PoPs drop off a tad accordingly; nonetheless, Sunday and Monday
both entail widespread categorical PoPs across the mountains, with
chance to likely PoPs elsewhere.  Surface heating will be severely
hampered by cloud cover and rainfall, limiting instability; however,
can't rule out some embedded thunder, especially given that robust
upglide should lend itself to elevated convection.  Once again,
heavy rain will be the biggest threat here, and perhaps an uptick
in flash flood threat given that this rainfall will take place
with many areas already saturated by Sunday's rainfall.

Monday evening, moisture should ramp up again as remnants of
Tropical Depression Fred approach from the south.  The brunt of
these impacts, however, will not be felt until past the end of
the short term forecast.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 200 PM EDT Friday: Monday evening, tropical moisture will
arrive in earnest.  Although model guidance remains split on Fred's
track and intensity, these details may not matter much - with a
remnant wedge in place, a focusing boundary just barely south of
the CWA, and robust moisture in place, heavy rain is a guarantee
whether Fred is intact and over our region or falling apart and well
to our west.  Although the ECMWF's excessive totals seem overdone,
it's likely we'll see notable rainfall totals regardless.  So,
for now, keeping the QPF forecast on the high side of guidance;
most models are predicting significant rainfall totals through
Tuesday night, with the GFS being the extremely unimpressed
exception for its last several runs.  Consequently, we anticipate
at least localized hydrological threats on Tuesday, as widespread
heavy rain falls on areas already primed by days of moist weather.

Late in the week, we'll return to the typical summertime diurnal
pattern as southeasterly surface flow is reestablished and
conditions trend back to climatological temperatures.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: Showers developing on persistent outflows
will require a VCSH mention to be included at KCLT until about 03Z,
but stabilizing profiles suggest the TSRA are done there for the
night. Otherwise, convection will continue to dwindle in line with
the convection-allowing models through late evening and early
overnight. VFR conditions are expected going forward, except for
likely IFR fog/stratus in the mountain river valleys, including
KAVL, and MVFR fog possible at/near KHKY toward daybreak. Cannot
rule out some overnight fog at or near KCLT given the rainfall this
evening, but it might be able to dry out there before the vsby falls
with continued light mixing. The potential for better shower and
thunderstorm coverage looks greater Saturday afternoon and evening
as a front approaches from the north and moisture pools over the
region. Winds will generally remain light SW through the period,
with more variable directions expected at KAVL, and gusty near
thunderstorms late Saturday.

Outlook: Fairly widespread shower and thunderstorm coverage remains
in the forecast for the late weekend and the early to middle part of
next week. Fog and low stratus will be possible each morning,
especially over mountain valleys, and in areas primed by rainfall
from the previous evening. Low restrictions are also likely with any
downpours.

Confidence Table...

            05-11Z        11-17Z        17-23Z        23-00Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     Low   56%     High 100%     High 100%
KHKY       High 100%     High 100%     High 100%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High 100%     High 100%     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 are available at
the following link:

www.weather.gov/gsp/aviation

&&

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

&&

SYNOPSIS...DEO
NEAR TERM...HG/SBK
SHORT TERM...MPR
LONG TERM...MPR
AVIATION...HG

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
1024 PM EDT Fri Aug 13 2021

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-150230-
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-
1024 PM EDT Fri Aug 13 2021

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

.DAY ONE...Tonight.

Hazardous weather is not expected at this time.

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

The remnants of tropical cyclone Fred may interact with an old
front to produce heavy rainfall early next week. This could result
in a flash flooding threat, especially in areas that receive
multiple rounds of heavy rainfall.

.SPOTTER INFORMATION STATEMENT...

None.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1233 AM EDT SAT AUG 14 2021

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

1140 PM     TSTM WND DMG     5 SE CLEVELAND          35.67N 80.62W
08/13/2021                   ROWAN              NC   TRAINED SPOTTER

            TREE DOWN ON GOODNIGHT RD NEAR LILLIAN CIRCLE. VEHICLE
            RAN INTO TREE.

&&

PM

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1246 AM EDT SAT AUG 14 2021

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

1216 AM     TSTM WND DMG     2 SE SALISBURY          35.64N 80.46W
08/14/2021                   ROWAN              NC   TRAINED SPOTTER

            TREE DOWN ON A HOUSE IN 900 BLOCK OF FAITH RD.

&&

PM

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1258 AM EDT SAT AUG 14 2021

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

1211 AM     TSTM WND DMG     5 SSE SALISBURY         35.60N 80.45W
08/14/2021                   ROWAN              NC   TRAINED SPOTTER

            TREE DOWN ON POWER LINES AT BALFOUR QUARRY RD AND LEGION
            CLUB RD.

&&

PM

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
101 AM EDT SAT AUG 14 2021

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

1213 AM     TSTM WND DMG     3 SSE SALISBURY         35.62N 80.45W
08/14/2021                   ROWAN              NC   TRAINED SPOTTER

            THREE TREES DOWN NEAR THE 800 BLOCK OF N MAIN ST. IN
            GRANITE QUARRY.

&&

PM

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
102 AM EDT Sat Aug 14 2021

NCZ057-072-140530-
Rowan NC-Cabarrus NC-
102 AM EDT Sat Aug 14 2021

...A strong thunderstorm will impact portions of north central
Cabarrus and southwestern Rowan Counties through 130 AM EDT...

At 102 AM EDT, Doppler radar was tracking a strong thunderstorm 4
miles north of Kannapolis, or over Landis, moving north at 15 mph.

HAZARD...Winds in excess of 40 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...
Kannapolis, Salisbury, China Grove, Spencer, Landis, Enochville,
Granite Quarry, Faith, High Rock Lake and Piedmont Research Station.

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 3568 8033 3546 8057 3551 8070 3578 8062
      3576 8047 3573 8045 3573 8044 3572 8042
      3573 8039 3572 8038 3572 8034 3571 8033
TIME...MOT...LOC 0502Z 199DEG 11KT 3556 8060

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
113 AM EDT Sat Aug 14 2021

NCZ057-072-140545-
Rowan NC-Cabarrus NC-
113 AM EDT Sat Aug 14 2021

...A strong thunderstorm will impact portions of northeastern
Cabarrus and southeastern Rowan Counties through 145 AM EDT...

At 113 AM EDT, Doppler radar was tracking a strong thunderstorm 6
miles northeast of Downtown Concord, or 4 miles northwest of Mt
Pleasant, moving northeast at 5 mph.

HAZARD...Winds in excess of 40 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...
Kannapolis, Downtown Concord, Granite Quarry, Rockwell, Mt Pleasant,
Faith, High Rock Lake, Gold Hill and High Rock.

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 3550 8029 3536 8039 3534 8052 3550 8060
      3570 8033 3568 8033 3567 8031 3563 8029
      3562 8025 3558 8021 3555 8021 3554 8020
      3553 8020 3551 8018
TIME...MOT...LOC 0513Z 246DEG 6KT 3545 8049

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

HG