Hail in South Carolina, May 11, 2016

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1030 AM EDT WED MAY 11 2016

.SYNOPSIS...
WARM ATLANTIC HIGH PRESSURE WILL DOMINATE OUR WEATHER THROUGH
THURSDAY. A COLD FRONT WILL CROSS THE AREA FROM THE WEST EARLY
FRIDAY BRINGING DRIER AND SLIGHTLY COOLER WEATHER FOR THE WEEKEND.
UNSETTLED WEATHER WILL LIKELY RETURN EARLY NEXT WEEK AS A WARM
FRONT MOVES NORTHWARD OVER THE REGION AND STALLS.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1030 AM Wednesday...for the first time in my 25 year NWS
career I finally get to use real punctuation in my Forecast
Discussion, and I couldn't be more excited! KGSP radar shows the
remnants of earlier convection that came across the NC mountains at
daybreak now weakening rapidly over the NC foothills, while a second
batch was also weakening as it crossed the mountains. The likely
precip prob looks good for the time being in those areas, but it is
looking more and more like it will not make it to the western
Piedmont intact. Thus, have temporarily lowered the precip
probability in the I-85 corridor and south. Still expect convective
development during the middle part of the day, and a cloudy/clear
boundary across the CWA will help in that regard. So, precip chances
ramp right back up to where they were in the old forecast by 18Z. We
will keep an eye on the stronger convection moving in from middle
TN. Have no problem with the Marginal Risk and think we will
ultimately see a few strong/severe storms, but maybe the better
chances of that happening will be to the south/east of the morning
activity. The new NAM suggests that we might not recover much across
the NC mountains/foothills/NW Piedmont. Temps look ok.

Otherwise...expect convection to start bubbling as we reach
convective temperature this afternoon. Some big differences between
the near-term models on instability this afternoon...with the
typically more robust NAM indicating sbCAPE upwards of 2500-3000
J/kg especially across the southwest mountains and Upstate where low
level WAA is maximized and early morning convection has not worked
the area over /assuming that the above paragraph discussion daybreak
convection across the northern mountains comes to fruition/...whereas
the GFS keeps instability more moderate with 1500-2000 J/kg. Deep
mixed layer on soundings plus some dry air entrainment aloft will
probably keep strong to damaging wind gusts as the primary threat...
but large hail cannot be ruled out. Deep-layer shear is lacking so
it seems unlikely storms will be able to organize much...so kind of
pulsey in nature or possible evolving into multicell clusters. SPC
Day1 outlook updated to include the entire area in marginal risk.
Convection wanes late this evening.

Temperaures today will be dependent on how much in the way of high
clouds we end up with...but as the shortwave crosses westerly
downsloping flow should help to keep quite a bit of sunshine across
the Piedmont until the convection starts to bubble. Expect a little
warmer that yesterday but with high humidity keeping it moist and
uncomfortable this afternoon...and warmer overnight tonight that we
should see this morning.

IN OTHER NEWS...WE SAY SO LONG...FAREWELL...AND GOOD RIDDANCE TO THE
ERA OF ALL CAPS NWS TEXT PRODUCTS. THIS WILL BE THE LAST --FULL--
FORECAST DISCUSSION WHERE WE WILL YELL AT OUR READERS /SOME ALL-CAPS
UPDATES WILL BE ISSUED THROUGH THE EARLY MORNING HOURS/...AND WE
WILL USHER IN A KINDER GENTLER ERA WITH THE SWITCH OVER TO MIXED-
CASE TEXT THAT WILL OCCUR LATER THIS MORNING.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
As of 225 AM Wednesday...the short term FCST picks up at 12z on
Thursday with amplified upper ridging over most of the eastern conus
and an upper TROF axis just west of the Great Lakes. Over the next
couple of days the ridge will get pushed off the East Coast as the
TROF digs down over the region and multiple closed lows develop
within it.

On Thursday...SFC high pressure over New England will slide offshore
as a cold front approaches the Carolinas from the west. Warm and
moist SWLY boundary layer flow will persist over the region thru the
day with weak lee TROFFING setting up early in the day. This should
provide good chances for sct to widespread convection with ample SFC
based CAPE and moderate low to mid level shear especially over the
northern zones.

On Friday...the models have been trending slower with the front's
arrival and have it reaching the CWFA by early Friday and moving
thru the area during the day/evening. I still expect peak coverage
of convection to occur during the mid to late morning hours with the
high likelihood of organized showers and TSTMS. Based on the timing
of the fropa...sfc-based CAPE should be kept to a minimum...however
elevated CAPE will linger thru Thurs night/Fri morning. Convection
should push east of the CWFA during the afternoon...with falling
pops from west to east thru the evening. High temps on Friday should
be about 4 to 8 degrees cooler than Thursday.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
As of 245 AM Wednesday...the medium range FCST picks up at 12z on
Saturday with very broad upper TROFFING in place over the eastern
half of the conus and ridging over the west. The TROF is expected to
flatten over the next 24 to 48 hours as the TROF axis gradually
slides eastward. By late in the weekend...the upper pattern will be
mostly flat over the SE region as most of the PVA has lifted to our
north. As we move into early next week...the long range guidance
suggests that heights will start to rise again as weak ridging tries
to build back over the Gulf of Mexico.

At the sfc...another cold front is expected to approach the forecast
area from the NW at the start of the period Sat morning. This front
should be weaker and drier than the previous front the day before
with a fairly quick passage overall. Behind the front...cooler and
drier high pressure spreads back over the region. as we move into
early next...the high slides SE and off the SE coast thus allowing
more moist SLY flow to return to the FCST area. The weekend should
be mostly dry with chances for sct to widespread showers and ts
increasing on Mon and Tues. Temps should remain near normal for most
of the period with cooler values possible towards the middle of next
week.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT AND UPSTATE TAFS...VFR CONDITIONS WILL CONTINUE THIS MORNING
WITH LIGHT SW WINDS THAT WILL PICK UP TO BETWEEN 5-10KT DURING THE
DAY...SUBSIDING AGAIN THIS EVENING. GUIDANCE INDICATES A SHIFT TO NW
WINDS NEAR THE VERY END OF THE PERIOD AND HAVE INTRODUCED THIS AT
KCLT. ONLY CONCERN THIS MORNING IS WITH SOME IFR CIGS THAT HAVE
DEVELOPED ACROSS CENTRAL NC NOT TOO FAR FROM KCLT...PLUS SOME LOW VFR
CIGS ACROSS THE UPPER SAVANNAH VALLEY. FOR NOW... THINKING THAT
SUNRISE WILL BURN THESE OFF BEFORE IMPACTING THE TAFS BUT WILL HAVE
TO BE MONITORED CLOSELY. EXPECT -TSRA TO DEVELOP IN THE AFTERNOON
AND HAVE INTRODUCED TEMPO TSRA STARTING 18-19Z. EXPECT IMPROVING
CONDITIONS AFTER 00Z.

AT KAVL/KHKY...REMNANTS OF CONVECTION ACROSS EASTERN TN ARE RIGHT AT
THE TN/NC STATE LINE AT TAF TIME AND HAVE CONTINUED VCSH FOR
KAVL...TRANSITIONING TO VCTS AT 14-15Z WITH TEMPO TSRA STARTING 16Z
GIVEN THE BETTER CONVECTION CHANCES ACROSS THE NORTHERN TIER.
OTHERWISE A VERY SIMILAR TREND TO OTHER TAFS. DEPENDING ON WHERE
TSRA DEVELOPS...MAY HAVE TO CONSIDER INTRODUCING MVFR FOG FOR
WEDNESDAY MORNING WITH THE NEXT SET OF TAFS.

OUTLOOK...SCATTERED SHOWERS AND THUNDERSTORMS AND ASSOCIATED FLIGHT
RESTRICTIONS ARE POSSIBLE THURSDAY AND FRIDAY...AS A COLD FRONT
PUSHES ACROSS THE AREA. DRIER WEATHER SHOULD RETURN FOR THE WEEKEND.

Confidence Table...

            14-20Z        20-02Z        02-08Z        08-12Z
KCLT       High 100%     High 100%     High 100%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High 100%     High 100%     Med   75%
KHKY       High 100%     High 100%     High 100%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High  98%     High 100%     High 100%     High 100%

The percentage reflects the number of guidance members agreeing
with the schedule TAF issuance flight rule category.  Complet 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...PM/TDP
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...TDP

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
626 AM EDT WED MAY 11 2016

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-121030-
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-
626 AM EDT WED MAY 11 2016

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 SHOWERS AND THUNDERSTORMS ARE POSSIBLE
OVER THE WESTERN CAROLINAS AND NORTHEAST GEORGIA TODAY AND
TONIGHT. THE MAIN THREATS 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...THURSDAY THROUGH TUESDAY.

..THURSDAY...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE POSSIBLE
AHEAD OF AN APPROACHING COLD FRONT LATE IN THE DAY. SOME OF THESE
STORMS MAY PRODUCE DAMAGING WIND AND HAIL.
..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...

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

JPT

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
905 AM EDT WED MAY 11 2016

NCZ048-051>053-111345-
HAYWOOD NC-BUNCOMBE NC-SWAIN NC-MADISON NC-
905 AM EDT WED MAY 11 2016

...A LINE OF THUNDERSTORMS WILL IMPACT PORTIONS OF MADISON...
NORTHEASTERN SWAIN...NORTHWESTERN BUNCOMBE AND HAYWOOD COUNTIES
UNTIL 945 AM EDT...

AT 905 AM EDT...DOPPLER RADAR INDICATED THE LEADING EDGE OF A LINE
OF THUNDERSTORMS ALONG A LINE EXTENDING FROM 13 MILES SOUTH OF
GREENEVILLE TO 12 MILES SOUTH OF SEVIERVILLE...AND MOVING EAST AT 25
MPH.

LOCATIONS TO BE IMPACTED INCLUDE...
MARSHALL...LAKE JUNALUSKA...WEAVERVILLE...MARS HILL...MAGGIE VALLEY...HOT
SPRINGS...LEICESTER...SMOKY MOUNTAINS-CATALOOCHEE...SMOKY MOUNTAINS-BIG
CREEK AND SMOKY MOUNTAINS-BALSAM MOUNTAIN.

WIND GUSTS UP TO 40 MPH 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 3603 8259 3597 8261 3598 8251 3582 8241
      3580 8234 3575 8234 3546 8311 3551 8316
      3551 8326 3559 8347 3566 8330 3576 8316
      3579 8308 3578 8299 3588 8290 3593 8292
      3595 8287 3593 8281 3600 8278 3606 8264
TIME...MOT...LOC 1305Z 288DEG 24KT 3597 8282 3571 8359

08

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
120 PM EDT WED MAY 11 2016

SCZ001-004-111745-
GREATER OCONEE SC-OCONEE MOUNTAINS SC-
120 PM EDT WED MAY 11 2016

...A STRONG THUNDERSTORM WILL IMPACT PORTIONS OF SOUTHERN OCONEE
COUNTY UNTIL 145 PM EDT...

AT 120 PM EDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 9
MILES SOUTHWEST OF WALHALLA...OR 4 MILES WEST OF WESTMINSTER...MOVING
SOUTHEAST AT 20 MPH.

LOCATIONS TO BE IMPACTED INCLUDE...
SENECA...WESTMINSTER...OAKWAY...FAIR PLAY AND TOWNVILLE.

PEA SIZE HAIL AND WIND GUSTS UP TO 40 MPH WILL BE POSSIBLE IN THESE
AREAS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PLEASE REPORT DAMAGING WINDS...HAIL...OR FLOODING TO THE NATIONAL
WEATHER SERVICE GREENVILLE-SPARTANBURG BY CALLING TOLL FREE...1...800...
2 6 7...8 1 0 1...OR BY POSTING ON OUR FACEBOOK PAGE...OR TWEET IT USING
HASHTAG NWSGSP. YOUR MESSAGE SHOULD DESCRIBE THE EVENT AND THE
SPECIFIC LOCATION WHERE IT OCCURRED.

&&

LAT...LON 3452 8309 3453 8308 3453 8310 3459 8317
      3461 8316 3461 8323 3465 8328 3474 8322
      3466 8284 3464 8283 3463 8285 3463 8284
      3462 8284 3462 8286 3461 8286 3447 8300
      3447 8301
TIME...MOT...LOC 1720Z 294DEG 16KT 3467 8317

08