Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
156 PM EDT Fri Jul 9 2021

.SYNOPSIS...
A weak cold front will lay over to the north of the region tonight
through Saturday. Warm and moist high pressure will set up over the
southeast through the rest of the weekend and persist throughout
next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 10 AM Friday: We're already seeing a cluster of thunderstorms
make their way into Graham and Swain Counties from Eastern Tenn.
This activity should steadily push eastward into the aftn with
convective coverage expanding in the process. Otherwise, the fcst
appears to be in fairly good shape wrt the earlier onset of
convection.

Over the next 24 hours, the upper pattern is expected to flatten and
deamplify across the region. A weak cold front over the lower OH
Valley region should move in our direction with enough mid/upper
support to keep it moving through tonight. Ahead of the front, model
guidance suggests a favorable environment for thunderstorms to
develop over the western Carolinas and northeast Georgia. Although
the mid/upper forcing doesn't look all that great, the air mass
should sustain mixed-layer CAPE around 1500-2000 J/kg by midday and
enough shear (15-20 kt) to provide for some weak organization.
Expect a handful of strong/severe storms, altho chances are slightly
better to our east. The CAMs develop storms a bit earlier than
usual, so the main threat will be more toward the early part of the
afternoon. The coverage should decrease during the mid/late
afternoon, followed by the frontal passage in the early morning
hours on Saturday. Temps should be slightly above normal.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 130 pm EDT Friday: A deep, closed, low pressure system will
cut off from the Midwest to the southern Plains Saturday night
through Sunday. With this sytem in place to the west, and
strengthening Bermuda high pressure in place off the southeast
coast, southerly flow will continue over our region along with
elevated moisture levels. The stacked low pressure system will
slowly start to fill through Monday. The persistent, deep southerly
flow will maintain precipitable water values of 1.5 to 2 inches in
area profiles, with daily thunderstorm chances running well above
climo each afternoon and evening. Will keep the coverage best across
the NC mountains where light terrain triggering in the southerly
upslope will be best. Surface based instability and lapse rates look
fairly unimpressive and this should mute the severe thunderstorm
threat each day. Expect near climo temps on Sunday, maybe a few
degrees below on maxes with clouds on Monday.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 140 pm EDT Friday: An upper level trough axis west of the
Appalachians early in the period on Tuesday will slowly deamplify as
it moves east through the week. With a moist and unstable airmass
persisting across the region, precipitation will maintain a focus of
mainly diurnal convection each afternoon and evening, with more
isolated shower coverage at night. PoPs will be best over the
mountains where the moisture will be deeper and forcing better.
Slightly more zonal flow will develop briefly on Thursday as the
northern tier wave phases back into the westerlies, but with
cyclonic flow redeveloping upstream by Friday. Little to no airmass
change during this period means persistence on near climo temps and
above climo diurnal rainfall chances through Friday.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
At KCLT and elsewhere: A weak cold front will continue to push
thru the fcst area this aftn and early evening generating sct to
numerous showers and thunderstorms as it does. The latest CAM
guidance has the bulk of the activity south and/or east of our
fcst area by 23z or so, with the possibility of a few lingering
showers. As such, I kept a TEMPO for TSRA at all sites (except
KHKY and KAVL) for the first 4 hrs or so of the taf period. It's
looking like the thunderstorms have already moved east of KHKY
and KAVL, and they will only see showers for the rest of the
afternoon/evening. After the convection moves east, winds should
continue to favor a WSWLY direction and eventually become light
and vrb overnight. They will eventually pick back up from the S
towards the end of the taf period late tomorrow morning/early aftn.
The only exception will be KAVL, where winds will favor a NWLY
direction thru tonight and into the overnight before becoming
light and vrb tomorrow morning. In addition, we'll likely see
some fog developing over the mtn valleys and possibly the NC
Piedmont early Saturday morning.

Outlook: An unsettled pattern, with mainly diurnal convection
and morning stratus/fog, is expected to persist thru the weekend
and into early next week.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High  92%     High  97%
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...Munroe
NEAR TERM...JPT/PM
SHORT TERM...Munroe
LONG TERM...Munroe
AVIATION...JPT

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
517 AM EDT Fri Jul 9 2021

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-100930-
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-
517 AM EDT Fri Jul 9 2021

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

.DAY ONE...Today and tonight.

Thunderstorms are expected to develop across the region today ahead
of an approaching cold front. Storms will begin to develop this
morning over the mountains and will move east across the foothills
and Piedmont this afternoon. A few of the thunderstorms will be
strong to severe with damaging wind gusts and large hail possible.
Frequent lightning and heavy downpours will also accompany the
storms. The storms should push to the east of the area during the
early part of the evening.

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

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

PM

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
125 PM EDT Fri Jul 9 2021

SCZ001-004-091800-
Greater Oconee SC-Oconee Mountains SC-
125 PM EDT Fri Jul 9 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHERN OCONEE COUNTY UNTIL 200
PM EDT...

At 125 PM EDT, Doppler radar was tracking a strong thunderstorm 10
miles east of Toccoa, or 4 miles southwest of Westminster, moving
east at 30 mph.

Locations to be impacted include...
Seneca, Westminster, Fair Play and Oakway.

Wind gusts up to 40 mph and pea size hail will be possible in these
areas.

LAT...LON 3453 8308 3454 8311 3456 8313 3456 8314
      3457 8314 3458 8316 3459 8316 3459 8317
      3461 8316 3460 8320 3462 8324 3470 8323
      3464 8287 3453 8294 3447 8300
TIME...MOT...LOC 1725Z 291DEG 25KT 3464 8316

LANE

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
133 PM EDT Fri Jul 9 2021

NCZ037-057-091800-
Rowan NC-Davie NC-
133 PM EDT Fri Jul 9 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL DAVIE AND
NORTHWESTERN ROWAN COUNTIES UNTIL 200 PM EDT...

At 133 PM EDT, Doppler radar was tracking a strong thunderstorm 8
miles southwest of Mocksville, or 4 miles southwest of Cooleemee,
moving east at 20 mph.

Locations to be impacted include...
Cooleemee, Cleveland and Woodleaf.

Wind gusts up to 40 mph and pea size hail will be possible in these
areas.

LAT...LON 3571 8070 3583 8072 3587 8047 3583 8046
      3584 8047 3583 8049 3582 8047 3580 8047
      3579 8048 3577 8045 3574 8046 3573 8044
      3571 8044
TIME...MOT...LOC 1733Z 262DEG 16KT 3578 8062

LANE

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
134 PM EDT Fri Jul 9 2021

NCZ069-070-091800-
Gaston NC-Lincoln NC-
134 PM EDT Fri Jul 9 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTH CENTRAL LINCOLN AND NORTH
CENTRAL GASTON COUNTIES UNTIL 200 PM EDT...

At 134 PM EDT, Doppler radar was tracking a strong thunderstorm near
Lincolnton, or near High Shoals, moving east at 20 mph.

Locations to be impacted include...
Lincolnton, High Shoals, Iron Station, Boger City and Crouse.

Wind gusts up to 45 mph and pea size hail will be possible in these
areas.

LAT...LON 3538 8131 3546 8132 3549 8108 3537 8108
TIME...MOT...LOC 1734Z 262DEG 16KT 3542 8124

LANE

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
138 PM EDT Fri Jul 9 2021

SCZ008-091815-
Cherokee SC-
138 PM EDT Fri Jul 9 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN CHEROKEE COUNTY
UNTIL 215 PM EDT...

At 138 PM EDT, Doppler radar was tracking a strong thunderstorm 6
miles south of Gaffney, or 5 miles northeast of Pacolet Mills, moving
east at 20 mph.

Locations to be impacted include...
Thicketty and Saratt.

Wind gusts up to 45 mph and half inch hail will be possible in these
areas.

LAT...LON 3487 8148 3488 8152 3487 8153 3488 8153
      3487 8154 3487 8156 3494 8175 3503 8173
      3501 8148 3497 8148 3497 8149 3494 8149
      3494 8148
TIME...MOT...LOC 1738Z 283DEG 18KT 3497 8167

LANE

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
155 PM EDT Fri Jul 9 2021

NCZ068-070-091830-
Gaston NC-Cleveland NC-
155 PM EDT Fri Jul 9 2021

...A STRONG THUNDERSTORM WILL IMPACT EAST CENTRAL CLEVELAND AND
NORTHWESTERN GASTON COUNTIES UNTIL 230 PM EDT...

At 154 PM EDT, Doppler radar was tracking a strong thunderstorm 9
miles southwest of Lincolnton, or near Cherryville, moving southeast
at 15 mph.

Locations to be impacted include...
Cherryville, Waco and Bessemer City.

Wind gusts up to 45 mph, pea size hail and very heavy rainfall rates
up to 2 inches per hour will be possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Very heavy 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 3525 8131 3539 8147 3542 8143 3542 8137
      3538 8122
TIME...MOT...LOC 1754Z 301DEG 13KT 3540 8139

LANE

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
213 PM EDT Fri Jul 9 2021

NCZ070-071-091845-
Gaston NC-Mecklenburg NC-
213 PM EDT Fri Jul 9 2021

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN MECKLENBURG AND
SOUTHEASTERN GASTON COUNTIES UNTIL 245 PM EDT...

At 213 PM EDT, Doppler radar was tracking a strong thunderstorm 7
miles southeast of Gastonia, or 4 miles south of Cramerton, moving
east at 20 mph.

Locations to be impacted include...
Charlotte Douglas Airport, Steele Creek, Southwest Charlotte, Belmont
and Lake Wylie.

Wind gusts up to 50 mph and dime size hail will be possible in these
areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Gusty winds can blow down trees that are dead, or that have weakened
root systems. Outdoor furniture and similar items can be tossed
around if not anchored. Seek shelter indoors.

&&

LAT...LON 3514 8105 3515 8105 3515 8111 3516 8114
      3520 8114 3523 8092 3512 8091
TIME...MOT...LOC 1813Z 270DEG 17KT 3517 8109

LANE