Special Weather Statement, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
222 PM EDT TUE MAR 20 2012

.SYNOPSIS...
A WARM AND MOIST AIR MASS WILL DOMINATE THE REGION THROUGH THE END
OF THE WORK WEEK. A COLD FRONT IS THEN EXPECTED TO PUSH EAST ACROSS
THE CAROLINAS AND NORTHEAST GEORGIA SATURDAY...FOLLOWED BY DRY HIGH
PRESSURE BUILDING IN SUNDAY AND REMAINING INTO EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 215 PM...A HIGHLY AMPLIFIED PATTERN REMAINS IN PLACE THIS
AFTERNOON...WITH A CUTOFF LOW PRESSURE SYSTEM MOVING INTO W TX...AND
A DEEP RIDGE OVER THE APPALACHIANS. SCATTERED AFTN CONVECTION HAS
FIRED MAINLY NEAR THE NC BLUE RIDGE AND HIGHER MTN PEAKS...WHERE LOW
LEVEL CONVERGENCE AND UPSLOPE FLOW ARE PROVIDING THE BEST
FORCING...AND WHERE LAPSE RATES ALOFT ARE THE STEEPEST. THIS
ACTIVITY COULD SPREAD ISOLD TO SCT COVERAGE INTO THE FOOTHILLS AND
PIEDMONT THROUGH THE EVENING ON THE STRENGTH OF ANY OUTFLOWS. THERE
IS LITTLE STEERING FLOW UP THE SOUNDINGS AND ANY TSTMS WILL PRODUCE
LOCALLY VERY HEAVY RAINFALL. SFC BASED CAPE VALUES OF 1000 TO 2000
J/KG ACROSS THE REGION SHOULD YIELD SOME STRONG STORMS...WITH
ISOLATED SEVERE POSSIBLE FROM ANY CELLS EXHIBITING 55 DBZ TO AROUND
22 KFT.

AFTER THE MAINLY DIURNAL CONVECTION WANES A LITTLE BY
MIDNIGHT...COVERAGE OF SHOWERS AND ISOLD TSTMS MAY INCREASE AGAIN
OVERNIGHT ACROSS NRN SECTIONS WITH A LIGHT SE UPSLOPE INTO THE NC
BLUE RIDGE...AND ALSO FROM A VORT MAX MOVING SWD JUST E OF THE UPPER
RIDGE. COVERAGE ACROSS THE INTERSTATE 77 CORRIDOR MAY THEN EXPAND
THROUGH WED AS BETTER DEEP LAYER DPVA MOVES SWD ACROSS CENTRAL NC
AND SC. MID LEVEL TEMPERATURES INCREASE A LITTLE ON WED...SO SFC
BASED CAPE VALUES WILL LIKELY BE LESS THAN TUE. HOWEVER...STORMS
WILL CONTINUE TO BE SLOW MOVERS AND POSE AN ISOLATED HYDRO THREAT.
TEMPERATURES WILL REMAIN ABOUT 15 DEGREES ABOVE NORMAL THROUGHOUT.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AT 220 PM EDT TUESDAY...ON WEDNESDAY NIGHT A HIGH AMPLITUDE UPPER
RIDGE WILL BE OVER MOST OF THE EAST...WITH AN EMBEDDED UPPER LOW
OVER THE MID ATLANTIC COAST...WHILE A CLOSED UPPER LOW WILL BE
LOCATED OVER THE SOUTHERN PLAINS. THE ATLANTIC UPPER LOW WEAKENS
AND DRIFTS SOUTH THROUGH FRIDAY...WHILE THE CLOSED LOW PROGRESSES
NORTHEAST INTO THE CENTRAL PLAINS...AND THE UPPER RIDGE NARROWS
OVER THE APPALACHIANS.

A SURFACE RIDGE WILL REMAIN CENTERED OVER THE WESTERN ATLANTIC...
RESULTING IN A WEAK SOUTHERLY UPSLOPE FLOW INTO THE SOUTHERN
APPALACHIANS ON FRIDAY. MOISTURE ASSOCIATED WITH THE COASTAL UPPER
LOW WILL LINGER ON THE COAST...AND MAY EXTEND AS FAR WEST AS THE
INTERSTATE 77 CORRIDOR ON THURSDAY. ON FRIDAY THE COASTAL MOISTURE
DEPARTS WITH ITS UPPER SYSTEM...WHILE GULF INFLOW INTO THE SOUTHERN
APPALACHIANS IMPROVES AHEAD OF A COLD FRONT. THIS FRONT REACHES THE
MOUNTAINS LATE IN THE DAY ON FRIDAY.

SLIGHT CHANCE TO CHANCE POPS WILL BE CARRIED ON THURSDAY...GREATEST
DURING DAYTIME HEATING AND NEAR THE SOUTH FACING BLUE RIDGE
ESCARPMENT...WHERE LIMITED INSTABILITY AND UPSLOPE FLOW COINCIDE.
AS WARM MOIST SOUTHERLY FLOW AND INSTABILITY INCREASE ON FRIDAY...
GREATER POPS WILL BE CARRIED...ESPECIALLY IN THE WEST OVER TERRAIN.
MODEL HELICITY VALUES APPEAR RATHER TAME ON FRIDAY. TEMPERATURES
WILL REMAIN WELL ABOVE NORMAL UNDER THE UPPER RIDGE.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 220 PM TUESDAY...MODEL CONSENSUS IS COMING MORE IN LINE SINCE
YESTERDAYS MORNING SOLNS. THE UPPER LEVEL LOW IS NOW WELL DEPICTED
TO BE DROPPING SW INTO THE OH VALLEY AT THE BEGINNING OF THE PERIOD
AND TO CONTINUE SWEEP ACROSS THE CAROLINAS THROUGH SUN. THE LATEST
CMC IS STILL A S/LY OUTLIER...BUT IT/S GOOD TO SEE THE TIGHTER
AGREEMENT BETWEEN THE GFS/ECMWF. OVERALL CONFIDENCE IS SOMEWHAT
ABOVE AVERAGE.

POPS WERE THUS ADJUSTED UP A BIT INTO THE LOW LIKELY CAT FOR SAT
AFTERNOON AND EVENING ACROSS THE NRN MOST ZONES. THE FRONTAL PASSAGE
WILL CONTINUE TO BE CARRIED BY HIGH END CHANCE POPS EARLY SAT. DONT
ANTICIPATE A GREAT PRECIP THREAT AS MOST OF THE MOISTURE WILL BE
ASSOCIATED SOLELY WITH THE INCOMING LOW. PROBABLY ABOUT 1/4 TO 3/4
OF AN INCH OF RAIN IN MOST PLACES THAT ACTUALLY RECEIVE RAINFALL BTW
FRI NIGHT AND SUN MORNING. HOWEVER...ISOL HIGHER AMOUNTS ARE
POSSIBLE WITH THE ADDED CONVECTIVE THREAT SAT. MID LEVEL LAPSE RATES
WILL INCREASE AND IN CONJUNCTION WITH DECENT LLVL INSTABILITY...A
FEW SHOWERS COULD BECOME FAIRLY STRONG. SFC WINDS WILL NOT SHIFT
NW/LY UNTIL THE UPPER LOW IMPINGES UPON THE REGION...SO TEMPS ON SAT
POST FROPA WILL STILL LIKELY REACH ABOUT 10-15 DEGREES F ABOVE
NORMAL. SOME SMALL MEASURE OF AN AIRMASS MIX ON SUN WILL ONLY LOWER
MAXES A FEW DEGREES AS INSOLATION BEGINS TO INCREASE WITH A
STRENGTHENING SUBSIDENCE ZONE.

MON AND TUE WILL COME UNDER THE INFLUENCE OF ANOTHER STRONG UPPER
LEVEL RIDGE AND RELATIVELY DRY ATL SFC HIPRES...SO NO POPS WILL BE
MAINTAINED THESE DAYS AND TEMPS SHOULD REBOUND TO WELL ABOVE NORMAL
TO START THE NEXT WEEK.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
AT KCLT...ANY CONVECTION THREATENING THE AIRFIELD LATE TODAY WILL
HAVE TO BE DRIVEN BY OUTFLOWS FROM MTN AND FOOTHILL STORMS...AND
CONFIDENCE IS LOW ON THAT REACHING KCLT. WILL USE CB CLOUD TYPE
AFTER 23Z...AND THEN KEEP CB GOING OVERNIGHT AS A WEAK SHORTWAVE
MOVES SWD TOWARD CENTRAL NC. WILL KEEP ANY CIGS VFR...AND ACCEPT
MVFR CONSENSUS ON FOG TOWARD DAYBREAK. THUNDER CHANCES AT KCLT MAY
BE A BIT BETTER JUST PAST THE CURRENT TAF PERIOD AS THE BEST UPPER
SUPPORT MOVES BY. EXPECT LIGHT SE WINDS THROUGHOUT.

ELSEWHERE...THUNDER CHANCES APPEAR THE BEST FROM KAVL TO KHKY LATE
THIS AFTN THROUGH THIS EVENING. CANNOT RULE OUT TSTMS AT THE UPSTATE
SITES...BUT THIS WILL RELY ON WELL TRAVELED OUTFLOWS TO TRIGGER
ANYTHING. MOST LOCATIONS WILL SEE SCT TO BKN VFR CLOUDS AT 5 KFT OR
LESS...WITH MVFR FOG TOWARD DAYBREAK. THE FOG COULD BE WORSE AT
LOCATIONS RECEIVING RAINFALL THIS EVENING. UPSLOPE TRIGGERING AND A
WEAK SHORTWAVE ARRIVING IN NRLY FLOW ALOFT COULD INCREASE SHRA/TSRA
COVERAGE EARLY WED...BUT UNCERTAINTY IS TOO HIGH TO FEATURE ANY
PRECIPITATION ACROSS WRN NC AT PRESENT. OTHERWISE...EXPECT LIGHT SE
FLOW.

OUTLOOK...A WARM AND UNSTABLE AIRMASS WILL REMAIN IN PLACE THE REST
OF THE WEEK UNTIL A COLD FRONT ARRIVES FROM THE WEST LATE FRI INTO
SAT. EXPECT MAINLY DIURNAL TSTM CHANCES...WITH FOG OR STRATUS
POSSIBLE AROUND DAYBREAK EACH MORNING...ESPECIALLY IN LOCATIONS THAT
SEE RAINFALL THE NIGHT BEFORE.

AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...

WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

SYNOPSIS...SBK
NEAR TERM...HG
SHORT TERM...JAT
LONG TERM...SBK
AVIATION...HG

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
306 PM EDT TUE MAR 20 2012

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-211915-
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 NC-
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-UNION SC-CHESTER-GREENWOOD-
306 PM EDT TUE MAR 20 2012

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP
ACROSS THE REGION THROUGH THE EVENING HOURS. COVERAGE OF THE
THUNDERSTORMS WILL BE GREATEST OVER WESTERN NORTH CAROLINA...WHERE
SOME THUNDERSTORMS MAY LINGER OVERNIGHT. THE MAIN THREAT FROM
THUNDERSTORMS WILL BE LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND
LIGHTNING...BUT A FEW COULD PRODUCE HAIL AS LARGE AS QUARTERS...OR
ISOLATED DAMAGING WIND GUSTS.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

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

GERAPETRITIS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
246 PM EDT TUE MAR 20 2012

NCZ504-201930-
GREATER BURKE-
246 PM EDT TUE MAR 20 2012

...A STRONG THUNDERSTORM WILL AFFECT SOUTHERN BURKE COUNTY THROUGH
330 PM EDT...

AT 246 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR MORGANTON...MOVING SOUTHEAST AT 5 MPH.

* OTHER LOCATIONS AFFECTED INCLUDE BUT ARE NOT LIMITED TO VALDESE...
  PLEASANT GROVE...MORGANTON...GLEN ALPINE AND DREXEL.

SMALL HAIL...WIND GUSTS UP TO 40 MPH AND TORRENTIAL RAIN ARE EXPECTED
WITH THIS STORM.

LAT...LON 3568 8144 3556 8159 3557 8160 3556 8165
      3558 8171 3561 8172 3560 8173 3561 8175
      3571 8184 3584 8169

07

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SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
518 PM EDT TUE MAR 20 2012

NCZ069-070-202200-
GASTON-LINCOLN-
518 PM EDT TUE MAR 20 2012

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL LINCOLN AND NORTHERN
GASTON COUNTIES THROUGH 600 PM EDT...

AT 517 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR BOGER CITY...OR NEAR LINCOLNTON...MOVING
SOUTHEAST AT 5 MPH.

THIS STORM WILL BE NEAR...
  IRON STATION...

SMALL HAIL...WIND GUSTS UP TO 40 MPH AND TORRENTIAL RAIN ARE EXPECTED
WITH THIS STORM.

FREQUENT LIGHTNING IS ALSO OCCURRING WITH THIS STORM. IF
OUTDOORS...STAY AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE
INDOORS IF POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS
AND AVOID USING TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG
UNNECESSARY ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES.

LAT...LON 3531 8117 3543 8137 3556 8126 3556 8118
      3546 8101

JPT