Flash Flooding and Flood in South Carolina, May 1, 2016

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1042 PM EDT SAT APR 30 2016

.SYNOPSIS...
AN UPPER LOW WILL APPROACH THE AREA WITH A FRONTAL PASSAGE MONDAY
MORNING.  A SECOND MAJOR FRONT AHEAD OF A MASS OF COLD AIR FROM
CANADA IS EXPECTED BY THURSDAY.

&&

.NEAR TERM /THROUGH SUNDAY/...
AS OF 1030 PM EDT SATURDAY...WELL...THANK GOODNESS THE RAIN IS
COMING TO AN END ON THE SOUTH SIDE OF CHARLOTTE...WHERE RADAR
ESTIMATES OF STORM TOTAL PRECIPITATION ARE UPWARDS OF 7 INCHES. GSP
STP IS A LITTLE ON THE HIGH SIDE...BUT CERTAINLY LOOKS LIKE A GOOD
SWATH OF 5-6 INCHES. THESE ALL SET UP ON THE BOUNDARY BUT WERE
ENHANCED BY LOW-LEVEL SHEAR...SO EVEN WITH DECREASING INSTABILITY
THE STORMS WERE ABLE TO ANCHOR OVER THE AREA. NOT IN THE CLEAR YET
AS ANOTHER ROUND OF MODERATE RAIN IS MOVING ACROSS THE UPSTATE. HAVE
UPDATED POPS AGAIN TO ACCOUNT FOR TRENDS BUT FOCUS HAS BEEN ON
CURRENT WX SITUATION THIS EVENING.

OTHERWISE...AN INTERESTING SURFACE PATTERN PREVAILS OVER THE REGION
AS A WEDGE BOUNDARY CONTINUES TO HOLD...ACTUALLY PUSHING A BIT
FURTHER TO THE SOUTH OVER THE LAST FEW HOURS...ALL WHILE A WARM
FRONT APPROACHES FROM THE SOUTH.  ALOFT...SHORTWAVE VORT ENERGY IS
PUSHING THROUGH THE TN VALLEY AT THIS TIME AND WILL LIKELY PROMOTE
FURTHER EXPANSION OF CONVECTION OVER WESTERN NC THROUGH THE
AFTERNOON/EVENING.  CURRENTLY...CONVECTION HAS INITIATED IN THE WARM
SECTOR ACROSS NORTHEAST GA WITH PROPAGATION TAKING SAID CELLS
NORTHEAST UP THE I85 CORRIDOR OVER THE NEXT FEW HOURS.  LATEST
MESOANALYSIS PROVIDES AN ILLUSTRATION OF THE WEDGE BOUNDARY LOCATION
AS SBCAPE PLOTS INDICATE A SHARP 500+ JOULES GRADIENT ALONG/SOUTH OF
I85 WITH SURFACE WINDS REFLECTING SUCH WITH ENE FLOW DOMINATING OVER
THE NC PIEDMONT...SOUTHWEST TOWARDS GSP...WITH ESE FLOW FURTHER
SOUTH IN THE WARM SECTOR.  THE MAJORITY OF THE FCST AREA REMAINS
UNDER THE MARGINAL RISK FOR SEVERE WX THIS AFTERNOON WITH LARGE HAIL
AND DAMAGING WINDS BEING THE PRIMARY THREAT.  WITH THAT...ENHANCED
SRH IN PROXIMITY TO THE WEDGE BOUNDARY COULD YIELD A BRIEF SPIN UP
TORNADO IF CONVECTIVE BOUNDARY INTERACTION OCCURS.  WITH DEEP
UPDRAFTS AND PWATS IN EXCESS OF 1.5 INCHES LOCALIZED HEAVY RAINFALL
ADJACENT TO ANY HEAVIER CONVECTION IS ALSO A POSSIBILITY.

MOVING ALONG INTO THE OVERNIGHT...EXPECTING THE OVERALL INTENSITY
AND COVERAGE OF CONVECTION TO DEPLETE AS HEATING IS LOST AND THE
WARM FRONT PUSHES NORTH OF THE AREA THEREBY REMOVING ANY SFC
FOCUSING MECHANISMS.  HOWEVER...GUIDANCE CONTINUES TO FAVOR SHRA AND
PERHAPS TSRA OVER THE MTNS WHERE UPSLOPING WILL ENHANCE UPDRAFTS.
GIVEN THE RAINFALL...ONCE THE CONVECTION WAINS WOULD NOT BE
SURPRISED IF PATCHY/WIDESPREAD FOG CONSUMES MUCH OF THE FCST AREA BY
MORNING.  SUNDAY LOOKS FAIRLY SIMILAR TO TODAY ASIDE FOR THE ENTIRE
FCST AREA BEING FIRMLY IN THE WARM SECTOR.  SHEAR LOOKS A BIT BETTER
AS A PREFRONTAL TROF MOVES INTO THE REGION...WHILE ANOTHER PIECE OF
H5 SHORTWAVE ENERGY DOES THE SAME.  STRONG/SEVERE CONVECTION IS
POSSIBLE ON SUNDAY WITH LARGE HAIL AND DAMAGING WINDS BEING THE
PRIMARY CONCERN AS SFC FLOW WILL BE VEERED THUS RESULTING IN LESS
FAVORABLE TORNADO CONDITIONS.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 1205 PM EDT SATURDAY...UPPER HEIGHTS ATOP THE SE CONUS WILL
BEGIN TO FALL ON MONDAY AS SOUTHERN PLAINS ENERGY TRANSLATES
EASTWARD. THE RECENTLY POSTED OP RUNS OF THE 30/12 UTC NAM/GFS
SUPPORT THE 30/00 UTC ECMWF TREND OF THE MAIN LLVL BAROCLINIC
ZONE LINGERING NEAR OR NW OF THE CWFA. HENCE...IN CONJUNCTION WITH
THE DEVELOPING FAVORABLE UPPER LEVEL DYNAMICS...CHANCES FOR
DIURNALLY ENHANCED DEEP CONVECTION WILL BE INCREASING. INITIAL
THOUGHTS WILL BE FOR ON AN UPWARD BUMP IN TSTM PROBABILITIES MONDAY
AFTERNOON. CONTINUED UNSETTLED BUT LESS WARM WX CONDITIONS ARE
EXPECTED ON TUESDAY GIVEN THE PROGGED SLOW EVOLUTION OF THE MEAN
PATTERN FEATURING BROAD/DEEP SW FLOW AND THE SLOW SE SAGGING OF
ATTENDANT FRONTAL SYSTEM. WILL PLAN AND KEEPING SOLID MID-CHANCE
POP IF NOT AN UPWARD NUDGE TO LIKELY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 130 PM SATURDAY...THE EXT RANGE WILL FEATURE A DEVELOPING
UNSEASONAL AND BROAD ERN CONUS ULVL TROF. THIS TROF WILL INTERACT
WITH A STATIONARY FRONT TRAPPED IN A DEEP MEAN SW/LY FLOW. THERE ARE
SIGFNT MODELED DIFFERENCES AS TO THE AMOUNT OF S/W ENERGY TRAVERSING
THE TROF...THE DEGREE OF ATL CYCLOGENESIS...THE AMOUNT OF LLVL COLD
AIR MAKING IT TO THE CAROLINAS...TILT OF THE ULVL TROF...AND
AVAILABLE MOISTURE. WITH THIS SAID...WILL MAINTAIN GRIDS CLOSE TO
THE PREVIOUS FCST. SINCE THE SYSTEM IS OUTSIDE THE NORMS FOR THIS
TIME OF YEAR WILL ALSO SIDE MORE WITH THE DYNAMICAL SOLNS AS OPPOSED
TO MOS GUIDANCE.

DO BELIEVE IT WILL BE A FAIRLY ACTIVE PERIOD WITH THE FRONTAL ZONE
BISECTING THE CWFA PROVIDING A FOCUSING MECHANISM FOR -SHRA AND
PERHAPS A COUPLE GENERAL TSTMS WED/THU AFTERNOONS. SOME DRIER AIR
LOOKS TO WORK IN AHEAD OF DEVELOPING OMEGA RIDGE FRI/SAT WHILE THE
SFC LOW PULLS NE OF THE AREA. THIS WILL CONFINE THE BETTER MOISTURE
ACROSS THE NC MTNS AND PERHAPS PRODUCE NON/ACCUM -SNSH THU NIGHT
ACROSS THE HIGHEST ELEVATIONS AS H85 TEMPS DROP TO -2 C ACCORDING TO
THE ECMWF...YET ONLY DOWN TO ARND ZERO GOING BY THE GFS. THU NIGHT
WILL BE THE COLDEST AT THE SFC AS WELL WITH HIGH ELEV TEMPS
DROPPING TO JUST ABOVE FREEZING. THIS SCENARIO WILL BE WATCHED FOR
POSSIBLE FROST/FREEZE CONCERNS. WITH CLOUD COVER LIKELY REMAINING
MCLDY/CLDY AND COOLER CP AIR MIXING BEGINNING THU...MAX TEMPS WILL
REMAIN NEAR NORMAL WED...WITH A DECREASE BY A COUPLE CATS THU/FRI
THEN A RETURN TO NORMAL LEVELS SAT AS SFC RIDGING ENGULFS THE SE
STATES.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
AT KCLT AND ELSEWHERE...ONLY CHANGES TO KCLT 03Z TAF AMD ARE TO
DELAY IFR CIGS ANOTHER HOUR WHILE HOLDING ONTO TEMPO TSRA THROUGH
04Z. OTHERWISE...WIDESPREAD CONVECTION AROUND THIS EVENING WITH TSRA
MOVING INTO THE KHKY/KCLT AREAS...WITH A BIT OF A BRIEF LULL
ELSEWHERE. HAVE TRIED TO INCORPORATE THIS INTO THE TAFS. IFR CIGS AT
KHKY SHOULD EXPAND WEST AND SOUTHWEST WITH IFR EXPECTED OVERNIGHT
EVERYWHERE EXCEPT POSSIBLY KAND. SHOULD SEE SOME IMPROVEMENT TO MVFR
AND THEN VFR SUNDAY AFTERNOON FOR ALL BUT KHKY...CURRENTLY EXPECTED
TO REMAIN MVFR. ENE TO NE WINDS THIS EVENING WILL VEER SE OVERNIGHT
AND TO SW TOMORROW...THOUGH WITH STANDARD DOWN-VALLEY COMPONENT AT
KAVL. OTHER CONCERN IS TSRA. CAPES CONTINUE TO DROP OFF OVERNIGHT
BUT ENOUGH THAT WE COULD SEE EMBEDDED TS AT ANY TIME...BUT FOR THE
MOST PART KEPT JUST -SHRA BUT TRENDED TOWARD PROB30 TSRA SUNDAY
MID-MORNING...THEN VCTS BY SUNDAY AFTERNOON. WILL HAVE TO MONITOR
FORECAST TRENDS TO UPDATE IN REAL TIME.

OUTLOOK...UNSETTLED WEATHER/OCCASIONAL CONVECTION/RESTRICTIONS ARE
EXPECTED TO CONTINUE INTO EARLY NEXT WEEK...AS A FRONT BECOMES
STALLED NEAR THE AREA. DEFINITIVE DRYING DOES NOT APPEAR LIKELY
UNTIL AT LEAST MID-WEEK.

CONFIDENCE TABLE...

            02-08Z        08-14Z        14-20Z        20-00Z
KCLT       MED   79%     MED   70%     HIGH  87%     HIGH 100%
KGSP       MED   69%     HIGH  82%     HIGH  82%     HIGH 100%
KAVL       HIGH  85%     HIGH  96%     HIGH  85%     HIGH 100%
KHKY       HIGH  83%     HIGH  90%     HIGH  86%     HIGH  85%
KGMU       HIGH  87%     MED   78%     HIGH  80%     HIGH 100%
KAND       HIGH  89%     HIGH  89%     HIGH  86%     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...SBK/WJM
NEAR TERM...CDG/TDP
SHORT TERM...CSH
LONG TERM...SBK
AVIATION...TDP

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
658 PM EDT SAT APR 30 2016

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-012300-
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-
658 PM EDT SAT APR 30 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST GEORGIA...PIEDMONT
NORTH CAROLINA...WESTERN NORTH CAROLINA AND UPSTATE SOUTH CAROLINA.

.DAY ONE...TONIGHT.

THUNDERSTORMS WILL CONTINUE TO DEVELOP ACROSS THE REGION THIS
EVENING. A FEW STRONG THUNDERSTORMS WILL BE POSSIBLE...PRODUCING
SMALL HAIL AND/OR GUSTY WIND...BUT THE BIGGEST THREAT WILL COME
FROM LOCALIZED VERY HEAVY RAINFALL.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

..SUNDAY...THUNDERSTORMS ARE EXPECTED...SOME POSSIBLY PRODUCING
SEVERE HAIL OR WIND GUSTS.
..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.

.SPOTTER INFORMATION STATEMENT...

NONE.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1009 PM EDT SAT APR 30 2016

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

0959 PM     FLASH FLOOD      3 W PINEVILLE           35.09N 80.93W
04/30/2016                   YORK               SC   AMATEUR RADIO

            3-4 INCHES OF WATER AT CAROWINDS BLVD AND I-77.

&&

TPALMER

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1019 PM EDT SAT APR 30 2016

NCZ071-082-010245-
UNION NC-MECKLENBURG NC-
1019 PM EDT SAT APR 30 2016

...A THUNDERSTORM WITH TORRENTIAL RAINFALL WILL IMPACT PORTIONS OF
SOUTHEASTERN MECKLENBURG AND CENTRAL UNION COUNTIES UNTIL 1045 PM
EDT...

AT 1018 PM EDT...DOPPLER RADAR WAS TRACKING A THUNDERSTORM WITH
TORRENTIAL RAINFALL 9 MILES WEST OF MONROE...OR NEAR WESLEY CHAPEL...
MOVING NORTHEAST AT 35 MPH.

LOCATIONS TO BE IMPACTED INCLUDE...
MONROE...INDIAN TRAIL...WEDDINGTON...STALLINGS...UNIONVILLE...WESLEY
CHAPEL...WINGATE...WAXHAW...LAKE PARK AND MINERAL SPRINGS.

PEA SIZE HAIL AND WIND GUSTS UP TO 40 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.

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 3501 8030 3488 8077 3491 8079 3494 8078
      3501 8085 3502 8084 3520 8056
TIME...MOT...LOC 0218Z 244DEG 29KT 3497 8072

07

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1026 PM EDT SAT APR 30 2016

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

1025 PM     FLASH FLOOD      ROCK HILL               34.94N 81.03W
04/30/2016                   YORK               SC   LAW ENFORCEMENT

            WATER RESCUE AT KING DRIVE AND DOBY DRIVE.

&&

TPALMER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1111 PM EDT SAT APR 30 2016

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

0950 PM     FLASH FLOOD      5 SSW ROCK HILL         34.87N 81.06W
04/30/2016                   YORK               SC   LAW ENFORCEMENT

            A REPORT OF ROADWAY FLOODING ON RAMBO ROAD.

0950 PM     FLASH FLOOD      3 SE FORT MILL          34.97N 80.90W
04/30/2016                   YORK               SC   LAW ENFORCEMENT

            A REPORT OF ROADWAY FLOODING AT THE INTERSECTION OF
            HOLBROOK ROAD AND BRIARWOOD CIRCLE.

1050 PM     HEAVY RAIN       3 W ROCK HILL           34.94N 81.08W
04/30/2016  M3.50 INCH       YORK               SC   COCORAHS

            3.50 INCHES OF RAIN IN THE LAST 4.5 HOURS.

&&

OUTLAW

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1123 PM EDT SAT APR 30 2016

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

0940 PM     FLASH FLOOD      2 E STALLINGS           35.09N 80.65W
04/30/2016                   UNION              NC   AMATEUR RADIO

            WOODHAVEN LANE IN THE HEMBY BRIDGE AREA OF INDIAN TRAIL
            REPORTS OF AREA ROADS COVERED IN WATER WITH ALL THE
            DITCHES FULL.

&&

OUTLAW

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1137 PM EDT SAT APR 30 2016

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

1045 PM     FLASH FLOOD      4 SW ROCK HILL          34.89N 81.07W
04/30/2016                   YORK               SC   OFFICIAL NWS OBS

            THE STREAMGAGE AT WILDCAT CREEK AT ROBERTSON RD ROSE
            ABOVE THE FLOOD STAGE OF 9FT AT 1045 PM.

&&

TPALMER