Special Weather Statement, NWS Greenville-Spartanburg, SC

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
220 PM EDT THU MAY 12 2016

.SYNOPSIS...
A cold front will move into the southern Appalachians from the west
tonight and then move east across the piedmont of the Carolinas on
Friday. Drier air will spill into the region Friday afternoon into
Saturday. A reinforcing cold front arriving from the northwest
Saturday night will bring even cooler and drier high pressure to the
area Sunday into Monday. Moist southerly flow will return through
mid week along with steadily increasing shower and thunderstorm
chances.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 220 PM EDT, convection has developed mainly along the mountain
ridge and eastern escarpment of the southern Appalachians this
afternoon - as depicted well by recent HRRR runs. A secondary area
of more isolated coverage is developing in lower piedmont sections
where LAPS SBCAPE values are already 1500 to 2000 J/kg. The
convection-allowing models have the escarpment activity
moving/developing quickly east across the foothills and out over the
I-77 corridor through late afternoon. Then, the secondary line of
activity from northern GA through eastern TN will likely work over
the mountains through early evening and possibly sharpen up once
again along I-77. A third band of convection along the approaching
cold front over western TN will likely become robust across
central/eastern TN this evening as better upper support east of the
approaching 500 mb trough axis arrives. This activity should reach
the spine of the southern Appalachians between 02Z and 04Z and then
weaken and diminish in coverage as it moves east of the mountains
overnight. All of this activity will require relatively high PoPs,
certainly for mountain sections, with solid scattered coverage east
of the mountains as well. Expect mild mins overnight except for
falling western mountain temperatures in the early morning hours
post fropa.

The cold front will slowly cross the foothills and piedmont portions
of the forecast area Friday morning. Upper jet divergence and one
final shot of upper level DPVA will also cross the forecast area
Friday morning and this upper support may catch up to the
pre-frontal instability along and east of I-77 by late morning. Will
bring back thunder chances across these areas through at least Noon
or perhaps into the early afternoon. West to northwest flow and
strong deep layer drying will develop behind the front through late
Friday. Breezy conditions are likely in the mountains post fropa
Friday as a narrow window of cold advection overlaps mixing.
However, winds should remain below advisory criteria. Max temps will
be a couple of categories cooler than today.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 200 PM Thursday...This upcoming weekend looks relatively quiet
and seasonably cool, as a long wave upper trough digs across the
eastern CONUS. A reinforcing cold front will approach the area from
the NW on Saturday, with dry WLY flow ahead of it. Other than a few
upslope showers near the TN border, expect dry wx for the region.
Temps will be near normal in the mtns and a category above in the
piedmont.

Significantly lower thicknesses will spill in from the NW for
Sunday, resulting in slightly below normal temps. Breezy to windy
conditions are expected in the mtns from Saturday afternoon into
Sunday within decent 850 mb CAA.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 230 PM Thursday...the eastern CONUS upper trough will lift NE
on Monday, allowing upper ridging to begin across the Southeast. The
upper pattern remains somewhat flat thru much of next week, but with
general troughing over the west and ridging along the East Coast. At
the surface, high pressure will slide off the Mid-Atlantic coast on
Monday, while a low pressure system tries to organize over the
Southern Plains. The medium range guidance generally agrees on a
warm front, extending east of the low, activating across the Gulf
states, while a weak wedge lingers across the Carolinas. This should
set up a more unsettled wx pattern for the CWFA, with max temps
returning to near normal and min temps above normal by the middle of
next week.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
At KCLT, radar coverage remains fairly sparse around the airfield
but LAPS CAPE values of 1500 to 2000 J/kg indicate that the airmass
is primed for convection with any nearby triggering
boundaries/outflows. Will keep TEMPO TSRA timed mainly 19Z to 23Z at
this point but another round of convection could arrive later this
evening with activity developing from northern GA to eastern TN. A
third round of showers and thunderstorms may reach the Interstate 77
corridor late tonight but with a weakening trend given the more
limited nocturnal instability. Finally, upper level support may
catch up to the passing front by Noon on Friday to generate one last
round of scattered SHRA/TSRA with fropa. Anticipate mainly S to SW
winds for much of the period, but with winds toggling NW late in the
period with fropa.

Elsewhere, thunderstorms triggering along the Blue Ridge will keep
TEMPO TSRA going at KAVL for a few hours past issuance time.
Development should hold off until around 19Z at most of the foothill
sites and TEMPOs timed 19Z to 23Z appear about right for these
locations. Another round of convection may arrive from the west
through the evening hours with yet another round of weakening
SHRA/TSRA possible overnight just ahead of the approaching cold
front. MVFR conditions will be limited mainly to the heaviest
downpours and also possible at KAVL and KHKY early Friday with
better low level moisture. Expect a drying trend with a sharp
northwesterly wind shift Friday morning. Gusts of 20 to 25 kt are
likely at KAVL Friday morning with mixing and cold advection.

Outlook: A cold front will move east of the area Friday afternoon
with drying expected through Saturday. A reinforcing cold front will
cross the region Saturday night with cooler and drier conditions
expected Sunday through Monday. Southerly flow and moisture will get
slowly reestablished through the middle of next week. Diurnal
thunderstorms will become possible again - especially over the
mountains.

Confidence Table...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       High 100%     High 100%     High 100%     High  98%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High  80%     High  97%
KHKY       High 100%     High 100%     High  94%     High  82%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High 100%     High 100%     High  90%

The percentage reflects the number of guidance members agreeing
with the schedule 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...HG
NEAR TERM...HG
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...HG

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
319 PM EDT THU MAY 12 2016

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-131930-
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-
319 PM EDT THU MAY 12 2016

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 SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
DEVELOP ACROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA THIS
AFTERNOON THROUGH THIS EVENING. THE MAIN THREATS FROM THESE
STORMS WILL BE CLOUD TO GROUND LIGHTNING...SMALL HAIL...AND GUSTY
WINDS. SOME OF THESE STORMS MAY PRODUCE LARGER HAIL AND STRONG
DOWNBURST WINDS.

.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...

SKYWARN SPOTTERS ARE REQUESTED TO FORWARD ANY REPORTS OF LARGE
HAIL...DAMAGING WINDS...TORNADOES OR FLASH FLOODING TO OUR OFFICE.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
225 PM EDT THU MAY 12 2016

SCZ001-002-121900-
OCONEE MOUNTAINS SC-PICKENS MOUNTAINS SC-
225 PM EDT THU MAY 12 2016

...A STRONG THUNDERSTORM WILL IMPACT PORTIONS OF NORTHEASTERN OCONEE
AND NORTHWESTERN PICKENS COUNTIES UNTIL 300 PM EDT...

AT 224 PM EDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 8
MILES NORTH OF WALHALLA...OR NEAR SALEM...MOVING NORTHEAST AT 20 MPH.

LOCATIONS TO BE IMPACTED INCLUDE...
WALHALLA...SALEM...LAKE KEOWEE...OCONEE STATE PARK...DEVILS FORK STATE
PARK...JOCASSEE GORGES...LAKE JOCASSEE...KEOWEE TOXAWAY STATE PARK...NINE
TIMES AND BAD CREEK.

HALF INCH HAIL AND WIND GUSTS UP TO 45 MPH WILL BE POSSIBLE IN THESE
AREAS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND TV
STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

LAKE JOCASSEE AND LAKE KEOWEE ARE IN THE PATH OF THIS STORM. CLOUD
TO GROUND LIGHTNING AND GUSTY WINDS WILL CREATE DANGEROUS BOATING
CONDITIONS. MOVE TO SHORE IMMEDIATELY.

&&

LAT...LON 3494 8313 3493 8311 3495 8311 3503 8300
      3506 8287 3487 8278 3469 8320 3488 8321
TIME...MOT...LOC 1824Z 245DEG 19KT 3490 8301

MOORE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
239 PM EDT THU MAY 12 2016

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

0235 PM     HAIL             5 WNW SALEM             34.91N 83.06W
05/12/2016  E0.75 INCH       OCONEE             SC   AMATEUR RADIO

            DIME SIZE HAIL NORTH LITTLE RIVER ROAD AT HIGHWAY 30.

&&

HG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
247 PM EDT THU MAY 12 2016

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

0220 PM     HAIL             5 ESE MARSHALL          35.77N 82.60W
05/12/2016  E0.75 INCH       BUNCOMBE           NC   PUBLIC

            THREE QUARTER INCH HAIL ALONG ELLER FORD ROAD.

&&

HG

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
248 PM EDT THU MAY 12 2016

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

0235 PM     HAIL             5 WNW SALEM             34.91N 83.06W
05/12/2016  E1.00 INCH       OCONEE             SC   AMATEUR RADIO

            DIME SIZE HAIL ALONG NORTH LITTLE RIVER ROAD AT HIGHWAY
            30...WITH SOME LARGER STONES AS BIG AS QUARTERS.

&&

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
253 PM EDT THU MAY 12 2016

NCZ048-049-121930-
YANCEY NC-MADISON NC-
253 PM EDT THU MAY 12 2016

...A STRONG THUNDERSTORM WILL IMPACT PORTIONS OF EAST CENTRAL MADISON
AND WEST CENTRAL YANCEY COUNTIES UNTIL 330 PM EDT...

AT 253 PM EDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 9
MILES EAST OF MARSHALL...OR NEAR MARS HILL...MOVING NORTHEAST AT 15
MPH.

LOCATIONS TO BE IMPACTED INCLUDE...
MARS HILL...WOLF RIDGE...SWISS AND FAUST.

HALF INCH HAIL AND WIND GUSTS UP TO 40 MPH 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 3592 8235 3581 8242 3581 8246 3580 8247
      3580 8253 3581 8261 3597 8253 3599 8249
TIME...MOT...LOC 1853Z 212DEG 14KT 3585 8252

08

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
321 PM EDT THU MAY 12 2016

NCZ052-059-063-064-121945-
HAYWOOD NC-NORTHERN JACKSON NC-TRANSYLVANIA NC-SOUTHERN JACKSON NC-
321 PM EDT THU MAY 12 2016

...A STRONG THUNDERSTORM WILL IMPACT PORTIONS OF EAST CENTRAL
JACKSON...CENTRAL TRANSYLVANIA AND SOUTHEASTERN HAYWOOD COUNTIES
UNTIL 345 PM EDT...

AT 320 PM EDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 10
MILES SOUTH OF WAYNESVILLE...OR NEAR THE BLUE RIDGE PARKWAY
BETWEEN BLACK BALSAM AND MOUNT PISGAH...MOVING EAST AT 20 MPH.

LOCATIONS TO BE IMPACTED INCLUDE...
B.R. PARKWAY-BLACK BALSAM TO MOUNT PISGAH...BLACK BALSAM AREA...
GRAVEYARD FIELDS...B.R. PARKWAY-BALSAM GAP TO BLACK BALSAM AREA...
SUNBURST AND BALSAM GROVE.

DIME SIZE HAIL AND WIND GUSTS UP TO 50 MPH 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.

DIME TO NICKEL SIZE HAIL CAN CAUSE CONSIDERABLE DAMAGE TO VEHICLES.
CONSIDER MOVING VEHICLES TO A COVERED STORAGE AREA BEFORE THE STORM
ARRIVES.

&&

LAT...LON 3539 8311 3545 8283 3522 8281 3524 8291
      3525 8297 3526 8302 3528 8311
TIME...MOT...LOC 1920Z 267DEG 15KT 3534 8303

08