Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1056 PM EDT Sun Aug 13 2017

.SYNOPSIS...
A stationary front will slowly move north over the region on
Monday and Tuesday with abundant moisture remaining in place
over the area. Slightly drier high pressure will arrive during
the middle part of the week. Increased moisture is expected
to return again ahead of the next cold front that approaches
from the northwest on Thursday.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 1035 PM: Showers and storms have just continued to expand in
coverage and intensity this evening, mainly along and near the Blue
Ridge. This is aided at least in part by increasing, albeit weak
upper support, lingering sbCAPE in the 1000-2000 J/kg (owing largely
to surface dewpoints in the mid/upper 70s), PWATs near 2", and a
E/SE upslope flow in the lowest 5kft. Strongly veering low-to-mid
level flow is also resulting in slow cell movement. That being the
case, am concerned about the potential for flash flooding overnight,
particularly in the NC foothills. The main limiting factor is that I
just don't have a good feel for how much longer convection will
linger in these areas. The current activity in the NC foothills is
generally trending downward, and later redevelopment is uncertain at
this time. A mention of the flash flooding potential has been
included in the HWO for the overnight. Convection will be less
concentrated in other areas, but localized heavy rain will be
possible just about anywhere overnight.

Monday looks like a near carbon copy of today (Sunday), with more
channeled vorticity streaming thru west-southwesterly upper flow,
while the sfc front remains across the Midlands. The models have
perhaps a slightly stronger sfc wave develop near Augusta, and all
have widespread QPF response across the area during the AFTN. It's
difficult to say how unstable we will get with all the cloud cover,
but models show 1000-2000 J/kg of SBCAPE again. So I won't change
the solid CHC to likely PoPs that I inherited. Heavy rain and
isolated flood threat will continue. Temps will be near to slightly
below normal under mostly cloudy skies.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 230 PM EDT Sunday: I would say the forecast continues to
look like a record that is stuck, but then I would wonder how
many people younger than about 30 years old would know what I was
talking about. At least the latest model runs have stepped away
from the flash flood potential for Monday night with less of an
upslope SE low level flow, instead expect a slow decline through
late evening. Tuesday certainly looks like a continuation of the
recent pattern with a broad upper trof axis to the west and yet
another weak wave moving through, acting on plentiful and deep
moisture to produce scattered/numerous showers and thunderstorms. We
continue to be more worried about the flood potential with high PW
and slow moving storms, rather than the severe weather risk. Expect
the diurnal tendency to remain Tuesday night, so precip chances
gradually taper off to a chance only over the mtns. Wednesday is a
bit more uncertain because of subtle differences in the guidance. It
might be not as active if the GFS is correct with showing a short
wave ridge moving through, or it might be just as active with
another short wave moving across as in the NAM. Prefer continuity
at this point, as we will probably not see an air mass change,
so the fcst will keep a chance across the whole fcst area. High
temps will remain near normal and low temps will stay on the warm
side of normal with relatively high dewpoints. Looking ahead,
one can only hope the pattern changes before a week from tomorrow.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 215 PM EDT Sunday: the extended fcst picks up at 00z on
Thursday with fairly weak upper ridging moving over the region
from the west. By late Thurs/early Fri, the ridge is expected
to flatten as another upper trof begins to dig down over the
Western Great Lakes. The long-range models move the trof axis
to our north by early Sunday as upper ridging persists to our
west. At the sfc, more wet and unsettled weather is expected
to continue thru most of the period with the Bermuda High keeping
moist SLY low-lvl flow over the fcst area. A low develops over
the Great Lakes on Thursday and moves its associated cold front
towards the fcst area. The current run of the ECMWF is quite
a bit more progressive than the GFS or Canadian and moves the
front into the CWFA by late Thursday, whereas the other models
are about 24 hrs slower. It still appears that the front will
stall out just to our SE by late Friday/early Saturday, however
the models are now showing a greater degree of drying as
reinforcing high pressure slides to our north over the weekend.
As for the sensible fcst, no significant changes were made,
save for lower dewpoints and PoPs over the weekend. Otherwise,
still expecting scattered diurnal convection each day, with
the higher PoPs on Thurs and Fri as the front moves into the
fcst area. Temps will likely start out just above normal and
cool a bit towards the end of the period.

&&

.AVIATION /03Z MONDAY THROUGH FRIDAY/...
At KCLT and Elsewhere: Showers continue to gradually expand in
coverage and slowly move southeast along the Blue Ridge this
evening. The most likely areas to see convection this evening will
be KAVL (over the first couple of hours of the forecast period), and
KHKY (after 02Z or so). Tempos for SHRA w/ restrictions are carried
at those two sites. The convective potential is much more uncertain
at the other terminals, but opted to continue inclusion of a VCSH at
those sites from 02-03Z into the overnight hours. Otherwise, low
stratus (w/ mtn valley fog) is expected to expand over the area
toward daybreak, with IFR/LIFR conditions anticipated at the western
NC terminals, and mostly MVFR at the Upstate SC sites. Winds will
generally remain light NE overnight, gradually turning toward the SE
on Monday. Additional convection is anticipated Monday afternoon,
with PROB30s warranted at all sites.

Outlook: Chances for restrictions will remain elevated through late
week as a moist pattern persists.  Therefore rounds of
afternoon/evening shra and tsra are favored each day, with morning
visb/cig restrictions possible as well for locales that experience
recent rainfall, as well as in the mtn valleys to affect KAVL.

Confidence Table...

            03-09Z        09-15Z        15-21Z        21-00Z
KCLT       High  95%     Med   77%     High  85%     High 100%
KGSP       High 100%     Low   56%     High  86%     High 100%
KAVL       Low   51%     High  90%     High  81%     High 100%
KHKY       High  86%     Med   78%     High  88%     High  98%
KGMU       High 100%     Med   79%     High  88%     High 100%
KAND       High 100%     Med   71%     High  91%     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 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...JPT
NEAR TERM...ARK/JDL
SHORT TERM...PM
LONG TERM...JPT
AVIATION...JDL

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
1028 PM EDT Sun Aug 13 2017

GAZ010-017-018-026-028-029-NCZ033-036-037-048>053-057>059-062>065-
069>072-082-SCZ001>014-019-150230-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Avery-Iredell-Davie-
Madison-Yancey-Mitchell-Swain-Haywood-Buncombe-Rowan-Graham-
Northern Jackson-Macon-Southern Jackson-Transylvania-Henderson-
Lincoln-Gaston-Mecklenburg-Cabarrus-Union-Oconee Mountains-
Pickens Mountains-Greenville Mountains-Greater Oconee-
Greater Pickens-Greater Greenville-Spartanburg-Cherokee-York-
Anderson-Abbeville-Laurens-Chester-Greenwood-
1028 PM EDT Sun Aug 13 2017

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

.DAY ONE...Tonight.

Scattered rain showers and isolated thunderstorms will remain
possible across the area through the overnight. The main threats will
be from locally heavy rainfall and occasional cloud to ground
lightning.

.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.

NCZ035-056-068-501>510-150230-
Alexander-Catawba-Cleveland-Caldwell Mountains-Greater Caldwell-
Burke Mountains-Greater Burke-McDowell Mountains-Eastern McDowell-
Rutherford Mountains-Greater Rutherford-Polk Mountains-Eastern Polk-
1028 PM EDT Sun Aug 13 2017

This Hazardous Weather Outlook is for piedmont North Carolina and
western North Carolina.

.DAY ONE...Tonight.

Scattered to numerous rain showers and isolated thunderstorms will
continue overnight across the North Carolina foothills. Due to slow
movement, and the potential for multiple heavy showers and storms to
move over the same areas, localized excessive rainfall and flash
flooding will be possible. Occasional cloud to ground lightning can
occur with any thunderstorm.

.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.

LANE

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
930 PM EDT SUN AUG 13 2017

NCZ503>506-140200-
McDowell Mountains NC-Burke Mountains NC-Greater Burke NC-
Eastern McDowell NC-
930 PM EDT SUN AUG 13 2017

...HEAVY RAIN SHOWERS WILL IMPACT EASTERN MCDOWELL AND SOUTHWESTERN
BURKE COUNTIES UNTIL 1000 PM EDT...

At 927 PM EDT, Doppler radar was tracking an area heavy rain showers
from 4 miles southeast of Marion to near Table Rock.  The showers
were generally stationary.

Locations to be impacted include...
Marion, Glen Alpine, Lake James State Park, Table Rock, Lake James,
Nebo, Glenwood, Ashford, Fero and Oak Hill.

Torrential rainfall rates up to 3 inches per hour will be possible in
these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3555 8190 3559 8205 3589 8197 3581 8171
TIME...MOT...LOC 0127Z 197DEG 15KT 3564 8195

JMP

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
934 PM EDT SUN AUG 13 2017

NCZ507-508-140200-
Greater Rutherford NC-Rutherford Mountains NC-
934 PM EDT SUN AUG 13 2017

...A HEAVY RAIN SHOWER WILL IMPACT NORTHWESTERN RUTHERFORD COUNTY
UNTIL 1000 PM EDT...

At 934 PM EDT, Doppler radar was tracking a heavy rain shower 12
miles northwest of Rutherfordton, or 6 miles east of Chimney Rock
State Park, moving west at 10 mph.

Locations to be impacted include...
Chimney Rock State Park, Shingle Hollow, Green Hill and Thermal City.

Torrential rainfall rates up to 3 inches per hour will be possible in
these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3553 8197 3552 8197 3538 8201 3539 8212
      3541 8216 3540 8218 3540 8227 3547 8225
      3550 8222 3551 8223 3552 8223 3553 8217
      3552 8214 3554 8207
TIME...MOT...LOC 0134Z 098DEG 10KT 3547 8213

JMP

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1001 PM EDT SUN AUG 13 2017

SCZ005-010-140230-
Greater Pickens SC-Anderson SC-
1001 PM EDT SUN AUG 13 2017

...A THUNDERSTORM WITH TORRENTIAL RAINFALL WILL IMPACT NORTH CENTRAL
ANDERSON AND SOUTHEASTERN PICKENS COUNTIES UNTIL 1030 PM EDT...

At 1001 PM EDT, Doppler radar was tracking a thunderstorm with
torrential rainfall 7 miles east of Clemson, or 5 miles east of
Pendleton, moving north at 5 mph.

Locations to be impacted include...
Clemson, Central, Pendleton, Norris, Liberty and Sandy Springs.

Torrential rainfall rates up to 3 inches per hour will be possible in
these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3459 8257 3461 8281 3480 8281 3478 8252
TIME...MOT...LOC 0201Z 184DEG 5KT 3465 8269

JMP

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1007 PM EDT SUN AUG 13 2017

NCZ507>510-140230-
Greater Rutherford NC-Polk Mountains NC-Rutherford Mountains NC-
Eastern Polk NC-
1007 PM EDT SUN AUG 13 2017

...A THUNDERSTORM WITH INTENSE LIGHTNING AND TORRENTIAL RAINFALL WILL
IMPACT NORTHWESTERN RUTHERFORD AND NORTHEASTERN POLK COUNTIES UNTIL
1030 PM EDT...

At 1006 PM EDT, Doppler radar was tracking a thunderstorm with
intense lightning and torrential rainfall 9 miles northwest of
Rutherfordton, or 8 miles east of Chimney Rock State Park. This storm
was nearly stationary.

Locations to be impacted include...
Chimney Rock State Park, Bat Cave, Shingle Hollow, Green Hill,
Thermal City, Lake Adger and Union Mills.

Torrential rainfall rates up to 3 inches per hour will be possible in
these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

Frequent lightning is occurring with this storm. If outdoors, try to
get indoors or into a hard topped vehicle. Otherwise, stay away from
open areas and isolated high objects such as trees. When indoors,
stay away from windows and doors and avoid using wired electronic
devices. Do not take a shower or bath. Try to unplug unnecessary
appliances before the storm approaches.

&&

LAT...LON 3552 8197 3552 8188 3526 8206 3538 8227
      3539 8226 3545 8228 3547 8226 3546 8225
      3547 8224 3550 8222 3552 8223 3553 8218
      3552 8214 3554 8204
TIME...MOT...LOC 0206Z 036DEG 4KT 3544 8210

JMP

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1032 PM EDT SUN AUG 13 2017

SCZ005-010-140300-
Greater Pickens SC-Anderson SC-
1032 PM EDT SUN AUG 13 2017

...A THUNDERSTORM WITH TORRENTIAL RAINFALL WILL IMPACT NORTH CENTRAL
ANDERSON AND SOUTHEASTERN PICKENS COUNTIES UNTIL 1100 PM EDT...

At 1032 PM EDT, Doppler radar was tracking a thunderstorm with
torrential rainfall 6 miles south of Easley, moving northeast at
15 mph.

Locations to be impacted include...
Easley, Powdersville, Liberty, Welcome and Piedmont.

Torrential rainfall rates up to 3 inches per hour will be possible in
these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3467 8276 3488 8262 3481 8247 3479 8246
      3478 8246 3478 8245 3476 8246 3474 8246
      3460 8263
TIME...MOT...LOC 0232Z 217DEG 21KT 3474 8261

KRENTZ

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
1121 PM EDT SUN AUG 13 2017

NCZ509-510-140415-
Polk Mountains NC-Eastern Polk NC-
1121 PM EDT SUN AUG 13 2017

...A CLUSTER OF THUNDERSTORMS WILL IMPACT POLK COUNTY UNTIL 1215 AM
EDT...

At 1120 PM EDT, Doppler radar indicated the leading edge of a cluster
of thunderstorms along a line extending from 7 miles west of
Rutherfordton to 5 miles southwest of Columbus, and moving east at 10
mph.

Locations to be impacted include...
Columbus, Tryon, Saluda, Mill Spring and Lake Adger.

Torrential rainfall rates up to 3 inches per hour will be possible in
these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3538 8211 3537 8211 3535 8208 3534 8207
      3533 8205 3532 8205 3519 8215 3520 8235
      3523 8236 3540 8221 3540 8218 3541 8217
      3541 8216
TIME...MOT...LOC 0320Z 276DEG 10KT 3538 8210 3521 8229

JMP