Special Weather Statement, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
135 PM EDT WED APR 4 2012

.SYNOPSIS...
ANOTHER COLD FRONT WILL DROP SOUTH ACROSS THE AREA THURSDAY...AS AN
AREA OF UPPER LEVEL LOW PRESSURE APPROACHES FROM THE MISSISSIPPI
VALLEY. COOL AND DRY HIGH PRESSURE WILL BUILD INTO THE REGION FRIDAY
AND WEAKEN OVER THE WEEKEND. ANOTHER COLD FRONT IS EXPECTED TO CROSS
THE AREA EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1 PM EDT WED...CURRENT FORECAST APPEARS TO BE ON TRACK. RADAR
SHOWS SCATTERED CONVECTION DEVELOPING IN THE MOUNTAINS AS EXPECTED
WHICH WILL BECOME MORE WIDESPREAD AS THE AFTERNOON PROGRESSES.
SEVERE THREAT STILL LOOKS MARGINAL AS FORECAST SOUNDINGS INDICATE
CAPES GENERALLY STAYING BELOW 1000J AND WITH WARM TEMPS ALOFT SEVERE
HAIL DOES NOT LOOK PROMISING. WITH DRYING IN THE COLUMN...DCAPES MAY
INCREASE ENOUGH TO PRODUCE SOME ISOLATED DAMAGING WIND GUSTS WITH
BEST STORMS.

PREVIOUS DISCUSSION...
THE REGION WILL REMAIN UNDER A WEAK AND RATHER FLAT AREA OF RIDGING
TODAY AND TONIGHT BETWEEN THE UPPER LOW OVER THE WRN PLAINS AND A
STRONG NRN STREAM TROF THAT WILL DIG ACROSS THE GREAT LAKES STATES
AND NEW ENGLAND. THE RIDGE WON/T BE NEARLY HAS SHARP AS IT WAS A
COUPLE DAYS AGO AND THERE WILL BE A DEEP LAYER WESTERLY FLOW OVER
THE REGION TODAY...VEERING MORE TO NORTHWEST TONIGHT. EMBEDDED IN
THAT FLOW WILL BE SEVERAL MCV/S. HOWEVER...WITH THE WESTERLY
FLOW...THE AIRMASS SHOULD DRY OUT MORE THAN YDAY ACROSS THE
REGION...PARTICULARLY OVER THE FOOTHILLS AND PIEDMONT. THE BUFKIT
SOUNDINGS SHOW A RETURN OF THE MID LEVEL WARMING AND ENOUGH DRYING
DOWN LOW TO LIMIT CAPE VALUES. THIS MAY BE OVERDONE CONSIDERING HOW
HIGH THE DEWPOINTS ARE NOW AND HOW MOIST THE AIRMASS IS IN GENERAL.

THE WAY I THINK IT WILL WORK TODAY IS THAT SCT CONVECTION WILL
DEVELOP AGAIN OVER THE HIGH TERRAIN. IT MAY ALSO GET A BOOST FROM A
MORE ORGANIZED AREA OF CONVECTION MOVING OUT OF ERN TN. THE STORMS
WILL MOVE EAST ON FAIRLY STRONG OUTFLOW BNDRYS CONSIDERING THE 25-30
DEGREE DEWPOINT DEPRESSIONS. IN GENERAL...THE COVERAGE WILL BE
BETTER OVER THE NC ZONES THAN SC OR GA WITH LIKELY POPS OVER THE
NORTH AND MID-RANGE CHANCE POPS SOUTH. THERE WILL ALSO BE A STRONGER
MCS THAT IS LIKELY TO DROP ACROSS WV/VA AND NRN NC BY EARLY EVENING
IN A BELT OF STRONGER UNIDIRECTIONAL SHEAR. THIS FEATURE SHOULD MISS
US TO THE NE...BUT IT MAY CLIP THE NRN PIEDMONT.

OVERNIGHT THE CONVECTION WILL GRADUALLY WIND DOWN. HOWEVER...THIS
PROCESS COULD TAKE A WHILE...WITH AREAS THAT DON/T GET WORKED OVER
TODAY SUPPORTING WEAKLY ORGANIZED STORMS AS LATE AS MIDNIGHT. SOME
OF THE STORMS TODAY WILL PROBABLY PRODUCE ENOUGH WIND TO CAUSE
DAMAGE. THE HAIL THREAT DOESN/T LOOK AS GREAT WITH THE WARM MID
LEVELS.

LATE TONIGHT ANOTHER COLD FRONT...ASSOCIATED WITH THE STRONG NRN
STREAM TROUGH...WILL PUSH INTO THE FA FROM THE NORTH. QUITE A BIT OF
FORCING WILL COME TOGETHER OVER THE FA ON THU...BUT THE WAY IT LOOKS
NOW...THE LATTER HALF OF WED NIGHT SHOULD BE FAIRLY QUIET.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 320 AM WEDNESDAY...A COLD FRONT WILL QUICKLY BACK DOOR ITS WAY
ACROSS THE NC PIEDMONT THURSDAY MORNING...BUT THEN SLOW ITS
SOUTHWESTWARD PROGRESS DURING THE DAY AS IT ENCOUNTERS STRONG
INSOLATION ACROSS THE UPSTATE...AND LOW PRESSURE DEVELOPS IN
RESPONSE TO THE UPPER LOW KICKING OUT OVER THE TENN VALLEY. AS THIS
OCCURS...LOW LEVEL WIND FIELDS WILL RESPOND SUCH THAT GOOD
CONVERGENCE WILL DEVELOP ALONG THE FRONT...WHILE ISENTROPIC LIFT
WILL INCREASE OVER DEVELOPING COOL AIR WEDGE. MEANWHILE...DIFFLUENT
FLOW IN ADVANCE OF THE LOW AS WELL AS PRECURSOR SHORT WAVE TROUGHS
WILL PROVIDE FAVORABLE UPPER SUPPORT. THE END RESULT SHOULD BE
NUMEROUS TO WIDESPREAD SHOWERS AND STORMS ACROSS THE AREA THURSDAY.
FORECAST SOUNDINGS FOR THURSDAY ARE VERY MOIST WITH WARM MID LEVEL
TEMPS/WEAK LAPSE RATES. SHEAR WILL BE SLIGHTLY ENHANCED AS WIND
FIELDS RESPOND TO THE UPPER LOW...BUT STILL LEAVE MUCH TO BE DESIRED
FROM A SEVERE WEATHER THREAT STANDPOINT. ALTHOUGH THE SEVERE THREAT
SHOULD BE RELATIVELY LOW...COMBINATION OF DEEP FORCING...MOIST
PROFILES...AND ANTECEDENT CONDITIONS (ESP OVER THE MTNS) MAY
INCREASE THE CHANCES FOR LOCALLY EXCESSIVE RAINFALL. MAX TEMPS WILL
RANGE FROM THE LOWER/MID 60S ACROSS THE NORTHWEST NC PIEDMONT (WHERE
MAXES WILL LIKELY OCCUR AROUND 12Z...TO NEAR 80 ACROSS THE UPPER
SAVANNAH RIVER VALLEY.

LIKELY POPS OVERSPREAD THE ENTIRE AREA THURSDAY NIGHT...AS THE UPPER
LOW PASSES TO OUR SOUTH. DEFORMATION ZONE FORCING WILL BE THE
PRIMARY IMPETUS FOR ACTIVITY THURSDAY NIGHT...WITH EASTERLY UPSLOPE
FLOW POSSIBLY ADDED TO THE MIX AS WELL. AN EXCESSIVE RAINFALL THREAT
WILL PERSIST...ESPECIALLY IF A CONCENTRATED BAND OF SHOWERS
GENERATES WITHIN THE DEFORMATION ZONE.

SHOWER CHANCES WILL BEGIN TO TAPER OFF EARLY FRIDAY...AS THE UPPER
LOW EXITS THE SOUTHEAST COAST. COOL CANADIAN HIGH PRESSURE RIDGING
DOWN THE EASTERN SEABOARD WILL GRADUALLY DEEPEN WITH TIME...ALLOWING
SKIES TO CLEAR FROM NORTH TO SOUTH...AS DEEP NE FLOW BECOMES
ESTABLISHED. MAX TEMPS FRIDAY AND FRI NIGHT WILL BE BELOW NORMAL
OWING TO EARLY CLOUD COVER AND A COOL NORTHEAST BREEZE.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 1215 PM WEDNESDAY...FOR THE LATTER HALF OF THE UPCOMING
WEEKEND...THE MEDIUM RANGE MODELS ARE DEPICTING THE FLOW ALOFT TO
EVOLVE INTO A NON-DESCRIPT NW FLOW ATOP THE SE CONUS. A WEAKENING
PLAINS COLD FRONT SHOULD BE ABLE TO SWEEP QUICKLY SE WITH LITTLE
ASSOCIATED WX. AHEAD OF THE FRONT...MAXES ARE PROGGED TO RISE TO
A FEW CATEGORIES ABOVE CLIMO.

EXPECT A PATTERN CHANGE STARTING EARLY NEXT WEEK AS GLOBAL MODELS
CONTINUE TO ADVERTISE DEVELOPING EASTERN CONUS L/WV TROUGH. WITHIN
THE INITIAL POST-FRONTAL AIRMASS PERIOD THOUGH...MONDAY/S MAX
TEMPERATURES SHOULD STILL BE A FEW DEG F ABOVE NORMAL. WITHIN THE
CONTINUED FALLING UPPER HEIGHT REGIME...MAX TEMPS WILL DIP TO AROUND
CLIMO ON TUESDAY...AND AS ENERGY ROTATES THROUGH...THERE WILL EXIST
THE POSSIBILITY OF A FEW SHOWERS BEING WRUNG OUT...ESPECIALLY ACRS
THE MOUNTAINS. AT THIS POINT...NOT SURE HOW SOON EASTERN L/WV TROUGH
WILL LIFT/FILL...BUT WILL PLAN ON CONTINUING THE TREND...SLIPPING
TEMPS A CATEGORY BELOW NORMAL FOR TUESDAY NIGHT AND WEDNESDAY.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AT KCLT...BIGGEST QUESTION IN THE NEAR TERM IS WHETHER CONVECTION
WILL AFFECT THE AIR FIELD LATE THIS AFTERNOON/EVENING. LATEST HRRR
INDICATES THAT SOME SHOWERS/STORMS WILL MOVE BY OR ACROSS THE
AIRFIELD AROUND 22Z. HENCE...WILL RETAIN CONTINUITY AND MENTION
-SHRA/VCTS FROM 22Z-00Z. OTHERWISE EXPECT VFR CONDITIONS. A BACKDOOR
COLD FRONT WIL MOVE THROUGH LATE TONIGHT WHICH WILL CAUSE WINDS TO
SHIOFT TO THE NE.

ELSEWHERE...EXPECT SCATTERED TO NUMEROUS -SHRA/-TSRA TO DEVELOP AND
MOVE BY OR NEAR THE AIRFIELDS. HENCE...WILL CARRY A COUPLE HOURS OF
-SHRA/VCTS DURING THE LATE AFTERNOON HOURS. AREAS OF LIFR CONDITIONS
MAY DEVELOP AGAIN IN THE MOIST AIRMASS EARLY THU MORNING...SO HAVE
MAINTAINED CONTINUITY WITH THIS MORNING AT KAVL/KAND/KHKY AND
INDICATED A COUPLE HOURS OF LIFR AROUND SUNRISE. OTHERWISE...EXPECT
VFR CONDITONS.

OUTLOOK...AN UPPER LOW WILL CROSS SOUTH OF THE REGION ON THU NIGHT
AND EARLY FTRIDAY. WIDESPREAD RAIN AND THUNDERSTORMS ARE EXPECTED
THURSDAY AFTERNOON INTO EARLY FRIDAY. COLD AIR DAMMING SHOULD ALSO
BRING WIDESPREAD LOW CIGS/VSBYS DURING THIS TIME AS WELL. A DRY HIGH
PRESSURE SYSTEM WILL BUILD IN BY FRIDAY AFTERNOON AND DOMINATE THE
WEATHER THROUGH THE WEEKEND.

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...JDL
NEAR TERM...LG
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...LG

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
626 AM EDT WED APR 4 2012

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-051030-
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-
626 AM EDT WED APR 4 2012

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

.DAY ONE...TODAY AND TONIGHT.

NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP OVER
THE MOUNTAINS THIS AFTERNOON. THE STORMS SHOULD THEN MOVE
EAST...ACROSS THE FOOTHILLS AND PIEDMONT DURING THE LATE AFTERNOON
AND EVENING HOURS. SOME OF THESE THUNDERSTORMS MAY BECOME
SEVERE...PRODUCING AREAS OF DAMAGING STRAIGHT-LINE WINDS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY WILL AFFECT THE REGION
THURSDAY AND THURSDAY NIGHT. LOCALLY HEAVY RAIN IS EXPECTED...AND
LOCALIZED FLOODING MAY DEVELOP. A FEW OF THE THUNDERSTORMS MAY
ALSO BECOME SEVERE. LARGE HAIL...DAMAGING WINDS AND LIGHTNING WILL
BE THE MAIN THREATS.

.SPOTTER INFORMATION STATEMENT...

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

MCAVOY

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
905 AM EDT WED APR 04 2012

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

0224 PM     HAIL             TUCKASEGEE              35.27N 83.12W
04/03/2012  E1.00 INCH       JACKSON            NC   PUBLIC

            HAIL TURNED GROUND WHITE. TIME DETERMINED WITH RADAR
            DATA.

&&

NED

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
914 AM EDT WED APR 04 2012

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

0655 PM     TSTM WND DMG     1 ENE BELTON            34.53N 82.47W
04/03/2012                   ANDERSON           SC   NWS EMPLOYEE

            TWO TREES DOWN ALONG ONEAL STREET.

&&

NED

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
925 AM EDT WED APR 04 2012

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

0450 PM     HAIL             5 ENE TOCCOA            34.60N 83.24W
04/03/2012  E0.50 INCH       STEPHENS           GA   PUBLIC

&&

PTANNER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
941 AM EDT WED APR 04 2012

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

1115 PM     TSTM WND DMG     2 SW MONROE             34.97N 80.57W
04/03/2012                   UNION              NC   911 CALL CENTER

            SEVERAL TREES DOWN ALONG WAXHAW HIGHWAY...ESPECIALLY NEAR
            THE INTERSECTION WITH SOUTH ROCKY RIVER ROAD.

&&

NED

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
943 AM EDT WED APR 04 2012

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

0240 PM     HAIL             5 NNW CLAYTON           34.93N 83.45W
04/03/2012  E0.75 INCH       RABUN              GA   PUBLIC

            OBSERVED OFF OF WOLFFORK RD.

&&

CSH

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
221 PM EDT WED APR 4 2012

NCZ036-037-041900-
DAVIE-IREDELL-
221 PM EDT WED APR 4 2012

...A STRONG THUNDERSTORM WILL AFFECT NORTHERN IREDELL AND
NORTHWESTERN DAVIE COUNTIES THROUGH 300 PM EDT...

AT 216 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR UNION GROVE...OR 14 MILES SOUTH OF RONDA...
MOVING EAST AT 15 MPH.

* OTHER LOCATIONS AFFECTED INCLUDE BUT ARE NOT LIMITED TO UNION
  GROVE...SHEFFIELD...MOCKSVILLE...HARMONY AND FARMINGTON.

SMALL HAIL...AND WIND GUSTS OF 30 TO 40 MPH ARE EXPECTED WITH THIS
STORM.

LAT...LON 3606 8094 3605 8050 3605 8049 3589 8049
      3593 8097 3607 8097

07