Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
513 PM EDT Wed Jun 14 2017

.SYNOPSIS...
Subtropical high pressure centered to our east will continue to
weaken, allowing increasing moisture to spread over the forecast
area from the south. Chances for showers and thunderstorms will
increase each day through the work week and remain elevated through
the weekend. A more well-defined cold front will approach the area
early next week. Maximum and minimum temperatures will remain above
average through the entire forecast.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 5 PM EDT: sct convection has developed across the CWFA over
the past few hours, yet with little coverage over the southern and
eastern-most zones. Only one severe thunderstorm warning has been
issued thus far, but several special wx statements (ie, SPS's) have
been issued. Convective coverage will likely expand southeastward
over the next few hours and peak by the early evening. The main threats
from these thunderstorms will be cloud to ground lightning and gusty
winds. A few of these storms could produce up to 1-inch hail and
severe criteria straight-line winds of 58 mph or more.

Tonight the axis of the upper ridge continues to advance toward
the East Coast, and a backdoor cold front sags further south into
the Mid-Atlantic region at the leading edge of the associated
sfc high. Patchy fog is expected to develop over the wet soils
left behind after this afternoon's storms.  However, before that
front pushes as far south as our area, the high moves offshore
and heights begin to rise over the Appalachians and Piedmont. I
can't say this will have a tremendous effect on our sensible wx;
we will again see diurnal destabilization and scattered to numerous
tstms under a weak shear profile, like that today. Even the same
shear axis will persist across northern SC. Most models develop
slightly more QPF tomorrow, perhaps attributable to our being on
the upstream side of the ridge vs. the downstream side today. There
is the additional possibility that the shortwave moving acrs the
Tenn Valley will drive better convective organization to our west,
and that a cluster of storms could move into the NC mtns in the
evening. This is the main reason our west is included in the
marginal risk on the SPC Day 2 outlook.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
As of 100 PM EDT Wednesday: Upper-level support will a bit better
Friday and Saturday with troughiness developing over, and just west
of, the southern Appalachians with associated upper level divergence
increasing slightly atop the region. The first upper level vorticity
lobe will reach the western mountains during the nighttime hours
Thursday night, and might keep some degree of precipitation going
there through the early morning hours Friday. In addition to the
upper support, terrain forcing and low level wind field convergence
will be best over the mountains Friday and Saturday afternoons, with
a secondary axis of low level convergence out over the piedmont in a
persistent surface trough. 850 to 500 mb lapse rates will also be
best over the mountains each afternoon, with values generally 6.5
deg C/km or better. Piedmont instability should feature sbCAPE
values of 2000 to 2500 J/kg Friday afternoon, and a bit higher on
Saturday afternoon. Shear profiles will remain weak through the
short-term period. This will make slow moving cells and associated
heavy rain an increasing threat as precipitable water values remain
1.6 to 1.9 inches around the region. This will also keep the
microburst threat elevated. Temperatures will remain one to two
categories above climo through the period, but with afternoon Heat
Index values probably no higher than the lower 90s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
As of 100 PM EDT Wednesday: The diurnal convective loop is still on
through much of the weekend as deep southwesterly flow continues to
transport warm, moist air into the southeast CONUS. Numerous waves
will round the longwave trough digging into the eastern CONUS, and
upper divergence and support for large-scale lift will only increase
as heights fall across the area through early next week. Decent
instability will be present across the majority of the area each
afternoon over the weekend, so some pulse severe storms each day
cannot be ruled out. A surface cold front will approach the area
Monday and Tuesday, and shear profiles will become a little better
as far supporting possible organization of storms.

The other threat that will bear watching will be flash flood
potential with widespread convection expected each afternoon through
early next week. Specific areas are hard to nail down due to the
scattered nature of the convection, but precipitable water values
will be close to the 90th percentile or higher as compared to
climatology through the period. The main concern would be that areas
that get repeated convection over multiple days could be primed for
a quicker flash flooding response by early next week. Confidence in
any one area is low, but it will be a threat that needs to be
monitored each afternoon. There are some indications that steering
flow will improve through the period, which would be a very good
thing for areas that may become waterlogged through the next week.

The debate continues whether or not the frontal passage on Tuesday
will be clean or not, with multiple global models suggesting the
front could stall near coastal SC/NC and provide a focus for
continued diurnal convection, especially in the southern upstate SC
zones. Max and min temperatures will decrease slightly from current
levels over the weekend and early next week as heights fall across
the eastern CONUS, though they will remain near 5 degrees above
average.

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
At KCLT and elsewhere: Modest chances for TSRA exist at all the
terminals, warranting a TEMPO. Winds will be somewhat variable this
aftn but mainly NW in the mountains and WSW elsewhere. Once again
moderately dry and weakly sheared profiles will allow storms to
produce gusty outflows. Overnight the main impacts will be from
patches of fog and low stratus forming over soils saturated by
rainfall this aftn. With the support of vsby guidance, confidence
is good enough at KAVL/KHKY seeing rainfall that restrictions for
fog are included with this issuance, but at other sites confidence
is too low.

Outlook: Chances for shra/tsra remain elevated through the
weekend, possibly resulting in afternoon restrictions. Chances
for morning visibility restrictions increase as well, mainly in
the mountain valleys, but also possible outside of the mtns where
any precipitation has recently occurred.

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 100%     High 100%
KAVL       High 100%     High 100%     High  88%     High 100%
KHKY       High 100%     High 100%     High  94%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High 100%     High  94%     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...Carroll
NEAR TERM...JPT
SHORT TERM...HG
LONG TERM...Carroll
AVIATION...JPT/Wimberley

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
253 PM EDT Wed Jun 14 2017

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-151900-
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-
253 PM EDT Wed Jun 14 2017

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

.DAY ONE...This Afternoon and Tonight.

Scattered to numerous thunderstorms will continue to develop across
the region late this afternoon through early this evening. A few of
the storms will likely produce brief severe weather in the form of
damaging wind gusts and hail as large as quarters. In addition, the
slow movement of the thunderstorms may result in locally excessive
rainfall and isolated flash flooding, especially in locations that
received heavy rain on Tuesday. Otherwise, dangerous cloud to ground
lightning will occur with any thunderstorm.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

..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.
..Sunday...No hazardous weather is expected at this time.
..Monday...No hazardous weather is expected at this time.
..Tuesday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotters are asked to relay any reports of hail, damaging winds, or
flooding to the National Weather Service.

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
500 PM EDT WED JUN 14 2017

NCZ502-504-142145-
Greater Burke NC-Greater Caldwell NC-
500 PM EDT WED JUN 14 2017

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN CALDWELL AND
SOUTHEASTERN BURKE COUNTIES UNTIL 545 PM EDT...

At 500 PM EDT, Doppler radar was tracking a strong thunderstorm 7
miles south of Lenoir, or near Lake Rhodhiss, moving south at 10 mph.

Locations to be impacted include...
Lenoir, Morganton, Sawmills, Valdese, Gamewell, Hudson, Icard,
Cajah's Mountain, Drexel and Hildebran.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 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. Do not drive across
flooded roads.

&&

LAT...LON 3595 8151 3572 8140 3560 8151 3557 8168
      3558 8168 3589 8171
TIME...MOT...LOC 2100Z 348DEG 9KT 3581 8158

TDP

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
533 PM EDT WED JUN 14 2017

NCZ051-058-142200-
Graham NC-Swain NC-
533 PM EDT WED JUN 14 2017

...A STRONG THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT SOUTH
CENTRAL SWAIN AND EASTERN GRAHAM COUNTIES UNTIL 600 PM EDT...

At 533 PM EDT, Doppler radar was tracking a strong thunderstorm with
intense lightning 5 miles northeast of Robbinsville, or 4 miles south
of Fontana Lake. This storm was nearly stationary.

Locations to be impacted include...
Robbinsville, Fontana Lake, Lake Santeetlah, Smoky Mountains-Fontana
Area, Wesser, Stecoah, Almond, Nantahala and Cheoah.

In addition to intense lightning, wind gusts up to 40 mph, pea size
hail and very heavy rainfall rates up to 2 inches per hour will be
possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3548 8368 3534 8350 3529 8358 3528 8367
      3527 8369 3525 8370 3526 8372 3525 8373
      3524 8376 3526 8379 3526 8380 3536 8386
TIME...MOT...LOC 2133Z 323DEG 3KT 3537 8373

TDP

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
534 PM EDT WED JUN 14 2017

GAZ028-029-SCZ010-142200-
Elbert GA-Hart GA-Anderson SC-
534 PM EDT WED JUN 14 2017

...A STRONG THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT NORTH
CENTRAL ELBERT...CENTRAL HART AND SOUTHWESTERN ANDERSON COUNTIES
UNTIL 600 PM EDT...

At 534 PM EDT, Doppler radar was tracking a strong thunderstorm with
intense lightning near Hartwell, or near Reed Creek, moving southeast
at 15 mph.

Locations to be impacted include...
Hartwell, Reed Creek, Iva, Starr, Lake Hartwell, Rock Branch, Nuberg
and Sadlers Creek State Park.

In addition to intense lightning, wind gusts up to 40 mph, pea size
hail and very heavy rainfall rates up to 2 inches per hour will be
possible in these areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

Lake Hartwell is in the path of this storm. Cloud to ground
lightning and gusty winds will create dangerous boating conditions.
Move to shore immediately.

&&

LAT...LON 3438 8303 3451 8287 3434 8261 3416 8284
TIME...MOT...LOC 2134Z 317DEG 12KT 3440 8289

TDP

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
550 PM EDT WED JUN 14 2017

SCZ010-142230-
Anderson SC-
550 PM EDT WED JUN 14 2017

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN ANDERSON COUNTY
UNTIL 630 PM EDT...

At 550 PM EDT, Doppler radar was tracking a strong thunderstorm near
Anderson, or near Biltmore Park, moving southeast at 10 mph.

Locations to be impacted include...
Anderson, Homeland Park, Belton, Honea Path, Anderson Airport and
Broadway Lake.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 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. Do not drive across
flooded roads.

&&

LAT...LON 3452 8272 3463 8255 3447 8233 3431 8258
TIME...MOT...LOC 2150Z 321DEG 8KT 3453 8258

TDP

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
552 PM EDT WED JUN 14 2017

GAZ028-029-142230-
Elbert GA-Hart GA-
552 PM EDT WED JUN 14 2017

...A STRONG THUNDERSTORM WILL IMPACT CENTRAL ELBERT AND SOUTHERN HART
COUNTIES UNTIL 630 PM EDT...

At 552 PM EDT, Doppler radar was tracking a strong thunderstorm 5
miles south of Hartwell, moving southeast at 10 mph.

Locations to be impacted include...
Elberton, Hartwell, Bowman, Russell State Park, Lake Russell, Dewy
Rose, Rock Branch, Nuberg, Sweet City and Ruckersville.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 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. Do not drive across
flooded roads.

&&

LAT...LON 3404 8297 3405 8299 3429 8308 3438 8289
      3420 8274 3416 8272 3415 8272 3414 8271
      3404 8296
TIME...MOT...LOC 2152Z 333DEG 9KT 3428 8295

TDP

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
621 PM EDT WED JUN 14 2017

GAZ026-142245-
Franklin GA-
621 PM EDT WED JUN 14 2017

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN FRANKLIN COUNTY
UNTIL 645 PM EDT...

At 621 PM EDT, Doppler radar was tracking a strong thunderstorm 6
miles southwest of Carnesville, moving southeast at 10 mph.

Locations to be impacted include...
Carnesville, Franklin Springs, Victoria Bryant State Park and
Royston.

Wind gusts up to 40 mph, pea size hail and very heavy rainfall rates
up to 2 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. Do not drive across
flooded roads.

&&

LAT...LON 3423 8335 3425 8334 3426 8334 3432 8339
      3440 8327 3428 8311 3424 8317 3425 8320
      3424 8321 3425 8324 3424 8325 3426 8330
TIME...MOT...LOC 2221Z 322DEG 9KT 3429 8330

TDP