Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
208 PM EDT Thu Jun 15 2017

.SYNOPSIS...
A deep ridge over the Atlantic will continue to transport warm,
moist air into the area through the weekend and into early next
week, keeping chances of afternoon showers and thunderstorms in the
forecast. A cold front approaching the area will increase chances
for storms on Monday, with some rain chances hanging around next
week as the front stalls near our area.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 200 PM: Convection is now well underway over the mountains,
but so far what cumulus exist over the Piedmont look stunted on
GOES-16. Meso model runs have come into consensus that the mountain
activity will slowly propagate into the foothills, and that an
apparent convergence zone in our far southeast will drive a second
round of development across the lower Piedmont in the last couple
hours of the day. Indeed cu are most widespread in that area. The
arrival of the shortwave trough now over KY/TN may also play a
role in this activity. Given the appreciable sfc-midlevel theta-E
lapse (delta values exceeding 20 K) it is within reason to expect
the stronger cells will be capable of severe downbursts. And one
cannot forget the mature MCS plowing thru the Tenn Valley, which
is stronger and further south than depicted on the HRRR. It is
moving toward more buoyant air, but as it moves into the weaker
flow over the Deep South it might begin to fizzle. It certainly
could at least brush the SW NC mtns, but the HRRR suggests the
bowing gust front would miss us.

From a synoptic standpoint, things look appreciably more favorable
for convective development over our area tomorrow. The shortwave
will be passing over the area during peak heating; no significant
DPVA is suggested by the NAM or GFS, but its presence leads
to steeper lapse rates than we've seen most of this week so
far. Furthermore some degree of low level convergence is resolved
with the prefrontal (and/or lee) trough. Likely PoPs are fcst over
most of the CWFA.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 130 PM EDT Thursday: Slightly better upper level forcing will
be over the region on Saturday with a weak trough axis and
associated vorticity maximum arriving from the west. This could lead
to more non-diurnal scattered coverage early in the period Friday
night through Saturday morning. However, peak heating should still
yield the best convective coverage Saturday afternoon as sbCAPE
values surge to 2000 to 2500 J/kg around the region. Westerly flow
will increase a bit on Sunday as the digging northern stream trough
amplifies toward the Ohio River Valley - with a lingering vorticity
lobe in the weakness atop our region. The initiation of the
strongest convection should once again occur along and east of the
Blue Ridge on Sunday afternoon and sbCAPEs may be a touch higher
Sunday compared to Saturday. Meanwhile, south to southwest low level
flow will continue to pump moisture into the region and precipitable
water values and the associated localized flooding threat will
remain elevated all weekend. Expect well above climo PoPs both days
this weekend with min temps well above climo and maxes around climo.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 130 PM EDT Thursday: Uncertainty in the medium range is
increasing due to a number of factors, though overall it appears we
will remain in a wet pattern. A surface cold front will approach
the area Monday night as an upper level longwave trough digs into
the east coast, suggesting that we may not see a diurnal lull in
pops Monday night into Tuesday morning. Frontal passage will occur
some time during the day on Tuesday, and most solutions agree this
will not be clean. There is disagreement as to exactly where the
front may get hung up, but at least the southern half of our
forecast area will hold on to pops through Tuesday. The upper and
surface ridges over the Atlantic will retreat a bit by Wednesday, so
an Atlantic moisture fetch will set up over the Carolinas. With the
surface boundary washing out somewhere close to our area, high-end
chances for diurnal convection will remain through the end of the
week.

The other wildcard at the moment is the erratic behavior of the
trough/tropical wave feature somewhere in the Gulf at the end of the
period. Direct impacts for our area appear unlikely, but the remnant
moisture from the system could serve to either increase or decrease
QPF towards the end of the period depending on its track and where
moisture transport is best. The system will be watched, but
regardless of its track, the medium range will remain muggy and
rather wet. Minimum temperatures will run roughly 5 degrees above
average, with maximum temperatures near average.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
At KCLT and elsewhere: Winds will be rather variable this aftn
with a weak pressure pattern across the region, plus the possible
influence of a shortwave approaching from the west. By evening
SW-ly winds are expected to prevail. Diurnally driven TSRA are the
initial impact weather expected during the period. Said storms
will spread generally from the mountains into the foothills and
Piedmont over the course of the aftn, with profiles favorable
for strong to severe winds to develop in some. A second wave of
activity could develop in a convergence zone over the Upstate in
the late afternoon or early evening, aided by the shortwave, and
per several meso model runs and sfc analysis. Hence VCSH/VCTS are
kept into the evening as needed. Dry air above the sfc should once
again limit fog mainly to areas where soils are wet from antecedent
rainfall. KAVL/KHKY saw restrictions this morning and are expected
to see them again; guidance hints that KCLT may also be affected.

Outlook: Chances for SHRA/TSRA will remain elevated
through the weekend, possibly resulting in afternoon/evening
restrictions. Chances for morning vsby restrictions increase as
well, mainly over the mtn valleys, but also possible outside of
the mtns where any precipitation has fallen.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High 100%     High 100%     High 100%     High  94%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     Med   78%     High  91%
KHKY       High 100%     High 100%     High 100%     High  94%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High 100%     High 100%     High  94%

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...Wimberley
SHORT TERM...HG
LONG TERM...Carroll
AVIATION...Wimberley

Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
517 AM EDT Thu Jun 15 2017

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-160930-
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-
517 AM EDT Thu Jun 15 2017

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

.DAY ONE...Today and Tonight.

Scattered to numerous thunderstorms are expected to develop once
again across the area this afternoon into the evening. A few of the
storms should produce brief severe weather in the form of damaging
wind gusts and hail to the size of quarters. In addition, slow
movement of the storms could result in locally excessive rainfall and
flash flooding, especially in locations that have received heavy
rainfall since Tuesday. Otherwise, dangerous cloud to ground
lightning can occur with any thunderstorm.

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

..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.
..Wednesday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

LANE

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
132 PM EDT THU JUN 15 2017

NCZ053-064-065-151800-
Buncombe NC-Transylvania NC-Henderson NC-
132 PM EDT THU JUN 15 2017

...A STRONG THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT
NORTHEASTERN TRANSYLVANIA...NORTHWESTERN HENDERSON AND SOUTHWESTERN
BUNCOMBE COUNTIES UNTIL 200 PM EDT...

At 132 PM EDT, Doppler radar was tracking a strong thunderstorm with
intense lightning 13 miles north of Brevard, or near B.R.
Parkway-Mount Pisgah To The Nc Arboretum. This storm was nearly
stationary.

Locations to be impacted include...
Arden, Mills River, Bent Creek, B.R. Parkway-Mount Pisgah To The Nc
Arboretum, Asheville Airport, Mount Pisgah, Skyland, Etowah, Fletcher
and B.R. Parkway-Nc Arboretum To East Asheville.

In addition to intense lightning, wind gusts up to 40 mph, half inch
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.

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 8249 3532 8261 3537 8279 3541 8275
      3542 8275 3544 8278 3547 8280 3550 8278
      3553 8278 3554 8277 3556 8278 3556 8277
TIME...MOT...LOC 1732Z 199DEG 1KT 3542 8269

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
137 PM EDT THU JUN 15 2017

NCZ064-065-151800-
Transylvania NC-Henderson NC-
137 PM EDT THU JUN 15 2017

...A STRONG THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT
SOUTHEASTERN TRANSYLVANIA AND SOUTH CENTRAL HENDERSON COUNTIES UNTIL
200 PM EDT...

At 137 PM EDT, Doppler radar was tracking a strong thunderstorm with
intense lightning 8 miles southeast of Brevard, or near Dupont State
Forest. This storm was nearly stationary.

Locations to be impacted include...
Dupont State Forest, Cedar Mountain, Connestee, Little River In
Transylvania County and Crab Creek.

In addition to intense lightning, wind gusts up to 40 mph, half inch
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.

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 3517 8243 3516 8245 3517 8246 3518 8246
      3517 8249 3516 8253 3516 8255 3515 8257
      3514 8261 3513 8263 3513 8264 3512 8266
      3513 8268 3511 8270 3510 8269 3509 8271
      3517 8275 3527 8257
TIME...MOT...LOC 1737Z 323DEG 3KT 3517 8261

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
146 PM EDT THU JUN 15 2017

GAZ010-NCZ062>064-SCZ001-151815-
Rabun GA-Transylvania NC-Southern Jackson NC-Macon NC-
Oconee Mountains SC-
146 PM EDT THU JUN 15 2017

...STRONG THUNDERSTORMS WITH INTENSE LIGHTNING WILL IMPACT
NORTHEASTERN RABUN...SOUTHEASTERN MACON...SOUTHWESTERN
TRANSYLVANIA...SOUTHEASTERN JACKSON AND NORTHWESTERN OCONEE COUNTIES
UNTIL 215 PM EDT...

At 145 PM EDT, Doppler radar indicated strong thunderstorms with
intense lightning along a line extending from 17 miles east of
Franklin to 9 miles east of Clayton, and moving southeast at 5 mph.

Locations to be impacted include...
Highlands, Cashiers, Lake Toxaway, Oconee State Park, Gorges State
Park, Lake Glenville, Mountain Rest, Sapphire, Bad Creek and Pine
Mountain.

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...

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.

Frequent lightning is occurring with these storms. 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 storms approach.

&&

LAT...LON 3514 8290 3475 8316 3485 8335 3519 8312
TIME...MOT...LOC 1745Z 297DEG 4KT 3510 8309 3488 8324

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
203 PM EDT THU JUN 15 2017

NCZ064-065-SCZ002-003-151830-
Transylvania NC-Henderson NC-Pickens Mountains SC-
Greenville Mountains SC-
203 PM EDT THU JUN 15 2017

...A STRONG THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT
SOUTHEASTERN TRANSYLVANIA...SOUTH CENTRAL HENDERSON...NORTHWESTERN
GREENVILLE AND NORTH CENTRAL PICKENS COUNTIES UNTIL 230 PM EDT...

At 202 PM EDT, Doppler radar was tracking a strong thunderstorm with
intense lightning 6 miles southeast of Brevard, or near Caesars Head
State Park, moving southeast at 10 mph.

Locations to be impacted include...
Pleasant Ridge State Park, Caesars Head State Park, Jones Gap State
Park, Dupont State Forest, Table Rock State Park, Pumpkintown, Little
River In Transylvania County, Cleveland, Cedar Mountain and
Connestee.

In addition to intense lightning, wind gusts up to 40 mph, half inch
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.

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 3511 8279 3526 8267 3517 8239 3497 8262
TIME...MOT...LOC 1802Z 302DEG 9KT 3515 8266

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
217 PM EDT THU JUN 15 2017

NCZ033-501-502-151845-
Caldwell Mountains NC-Greater Caldwell NC-Avery NC-
217 PM EDT THU JUN 15 2017

...A STRONG THUNDERSTORM WITH INTENSE LIGHTNING WILL IMPACT
NORTHWESTERN CALDWELL AND SOUTHEASTERN AVERY COUNTIES UNTIL 245 PM
EDT...

At 217 PM EDT, Doppler radar was tracking a strong thunderstorm with
intense lightning 6 miles southwest of Blowing Rock, or 5 miles
southeast of Grandfather Mountain State Park, moving east at 15 mph.

Locations to be impacted include...
Lenoir, Blowing Rock In Caldwell County, Grandfather Mountain State
Park, B.R. Parkway-Linville Falls To Grandfather, Edgemont, Globe,
Patterson, Upton and Collettsville.

In addition to intense lightning, wind gusts up to 40 mph and half
inch hail 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.

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 3611 8181 3612 8169 3612 8155 3610 8152
      3610 8149 3591 8149 3595 8180 3597 8182
      3597 8184 3614 8184 3614 8182
TIME...MOT...LOC 1817Z 270DEG 14KT 3605 8175

HG

Special Weather Statement
National Weather Service Greenville-Spartanburg SC
221 PM EDT THU JUN 15 2017

GAZ010-151845-
Rabun GA-
221 PM EDT THU JUN 15 2017

...THUNDERSTORMS WITH TORRENTIAL RAINFALL WILL IMPACT NORTHEASTERN
RABUN COUNTY UNTIL 245 PM EDT...

At 220 PM EDT, Doppler radar indicated thunderstorms with torrential
rainfall along a line extending from 16 miles north of Walhalla to 7
miles east of Clayton, and moving southeast at 5 mph.

Locations to be impacted include...
Pine Mountain.

Very heavy rainfall rates up to 2 inches per hour will be possible
in these areas. Isolated flooding of low lying and poor drainage
areas may develop quickly.

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 3500 8324 3500 8310 3496 8312 3495 8311
      3495 8313 3494 8311 3494 8313 3493 8314
      3493 8316 3492 8316 3489 8320 3488 8321
      3488 8324 3485 8325 3485 8327 3482 8327
      3483 8329 3482 8331 3480 8330 3484 8336
TIME...MOT...LOC 1820Z 303DEG 5KT 3500 8317 3488 8326

HG