Alert archive / South Carolina / Special Weather Statements in 2011

Special Weather Statement, NWS Greenville-Spartanburg, SC

April 20, 2011Transylvania County, North Carolina; Oconee County, Pickens County, South Carolina

NWS Greenville-Spartanburg, SC issued this special weather statement at Apr 20, 2011, 9:42 AM EDT for Transylvania County, North Carolina; Oconee County, Pickens County, South Carolina. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Apr 20, 2011, 9:42 AM EDT (13:42 UTC)
Expired: Apr 20, 2011, 10:30 AM EDT
In force: 48 min
Issued by: NWS Greenville-Spartanburg, SC

Counties Transylvania County, NC, Oconee County, SC, Pickens County, SC

The radar

The Greer radar (KGSP), 73 km from the middle of the area, began a volume at 13:45 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 1.7 hours before the alert went out and 214 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1316 J/kg
Mixed-layer CIN: -128 J/kg
Mixed-layer LCL: 466 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 85 m²/s²
0-3 km storm-relative helicity: 57 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Greenville-Spartanburg, SC wrote its last area forecast discussion before this special weather statement went out at Apr 20, 7:03 AM EDT, 2 hours 39 minutes earlier.

Area forecast discussion, Apr 20, 7:03 AM EDT, 2 hours 39 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
703 AM EDT WED APR 20 2011

.SYNOPSIS...
A COLD FRONT WILL APPROACH THE REGION FROM THE WEST TODAY AND
GRADUALLY SLIDE ACROSS THE WESTERN CAROLINAS TONIGHT AND EARLY
THURSDAY. THE FRONT WILL BECOME STATIONARY AND LINGER ACROSS THE
UPPER SAVANNAH RIVER VALLEY THROUGH THURSDAY. SURFACE HIGH PRESSURE
WILL THEN BUILD TO OUR NORTHEAST AND ESTABLISH A COOL AIR WEDGING
PATTERN OVER THE CAROLINAS ON FRIDAY. WARM SOUTH TO SOUTH WESTERLY
WINDS WILL REESTABLISH THEMSELVES OVER THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
LINE OF CONVECTION MOVG ACROSS E TN EARLY THIS MRNG CONTINUES TO
WEAKEN NOT ONLY WITH COOLING BUT AS IT ENCOUTERS THE DRYER AIR OVER
THE S APPALACHIANS. TWEAKED WINDS AND TEMPS...REST OF FCST LOOKS
GOOD ATTM.

PREVIOUS DISCUSSION...LATEST MODEL RUNS HAVE COME IN WITH LESS SHEAR
AND CAPE...AND WITH QPF REDUCED AS WELL. THE 4KM WRF HARDLY SHOWS
ANY PRECIP E OF THE MTNS THIS AFTN. LOW LEVEL MOISTURE WILL STILL
INCREASE TODAY AND WITH HEATING EXPECT CAPE VALUES AROUND 1200 J/KG.
BUFKIT SOUNDINGS SHOW 0-6KM BULK SHEAR AS HIGH AS 38KT. LOOK FOR AN
INCRSNG CHC OF SHWRS/TSTMS OVER THE MTNS THIS MRNG WITH LIKELY POPS
EARLY TO MID AFTN. POPS DROP OFF E OF THE MTNS WITH SOLID CHC
ADJACENT FOOTHILLS...BUT JUST A LOW END CHC AT CLT AS THE SFC
BOUNDARY MOVES INTO THE AREA. HIGHS WILL BE WELL ABOVE AVG THIS
AFTN. CONVECTION SHOULD DIMINISH WITH COOLING THIS EVE AND THE SFC
BOUNDARY IS EXPECTED TO PUSH JUST S OF THE CWA OVERNIGHT. MRNG LOWS
WILL BE ABOVE AVG.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM WEDNESDAY...A COLD FRONT IS EXPECT TO BECOME NEARLY
STATIONARY ALONG THE I-20 CORRIDOR BY SUNRISE THURSDAY. HIGH
PRESSURE CENTERED OVER THE GREAT LAKES IS FORECAST TO INCREASINGLY
RIDGE SOUTHWARD THROUGH THE DAY. MODELS INDICATE THAT WEAK SFC BASED
INSTABILITY WILL DEVELOP AS FAR NORTH AS THE UPPER SAVANNAH RIVER
VALLEY. ELSEWHERE...CONDITIONS SHOULD REMAIN FAIRLY STABLE AND MOIST
BELOW H5. WEAK UPSLOPE AND ISENTROPIC LIFT MAY SUPPORT A FEW SHRA
ACROSS THE NC FOOTHILLS AND PIEDMONT. THE GREATEST COVERAGE WILL
REMAIN ALONG THE SC/GA LINE NEAR THE SFC BOUNDARY AND
INSTABILITY...I WILL FORECAST LIKELY POPS OVER EXTREME NE GA TO SCHC
POPS NORTH OF THE CLT METRO. HIGHS ARE FORECAST TO PEAK ONE TO TWO
DEGREE ABOVE NORMAL.

THURSDAY NIGHT...CAD WILL DEVELOP OVER THE FORECAST AREA AS THE SFC
HIGH CENTER SETTLES OVER NEW ENGLAND AND LOW PRESSURE DEEPENS ACROSS
THE CENTRAL PLAINS. CIRCULATION AROUND THE LOW WILL RESULT IN
INCREASING UPSLOPE FLOW AND ISENTROPIC LIFT ACROSS THE CWA. I WILL
KEEP LIKELY POPS ACROSS THE MTNS AND CHC POPS EAST...FAVORING SHRA.
MIN TEMPS ARE FORECAST TO RANGE 5 TO 8 DEGREES ABOVE NORMAL.

FRIDAY...CAD IS EXPECTED TO PEAK DURING THE MORNING AND BEGIN TO
FADE DURING THE LATE AFTERNOON. SOUTHWEST H85 WINDS WILL STRENGTHEN
THROUGH THE DAY...YIELD GREATER ISENTROPIC LIFT ACROSS THE WEDGE.
FORECAST SOUNDINGS INDICATE A THICK SATURATED LAYER WITHIN THE
LOWEST 5 KFT. IN ADDITION...A SIGNIFICANT DECK OF CIRRUS LEVEL
MOISTURE SHOULD ARRIVE DURING THE MORNING AND REMAIN THROUGH THE
AFTERNOON...HELPING TO CONTINUE THE CAD. THE COMBINATION OF RICH
MOISTURE AND WEAK LIFT SHOULD PROVIDE LIKELY COVERAGE ACROSS THE
MTNS AND HIGH CHC EAST. THE NAM MOS AND 2M TEMPS SFC TEMPS INDICATE
WEDGE-LIKE VALUES AND AGREE WELL WITH THE PREVIOUS FORECAST. I WILL
CONTINUE TO INDICATE HIGH IN THE L60S ACROSS MOST THE CWA.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 315 AM WEDNESDAY...VERY LITTLE CHANGE EXPECTED IN THE PATTERN
ACROSS THE SOUTHEAST U.S. FROM THIS WEEKEND THROUGH TUESDAY. A VERY
STRONG BERMUDA HIGH IS EXPECTED TO REMAIN RIDGED ACROSS THE REGION
THROUGH THE PERIOD. FORECAST SOUNDINGS KEEP LLVL MOISTURE FAIRLY
HIGH THROUGH THE PERIOD...RESULTING IN DIURNAL INSTABILITY. I WILL
TIME CHC TO SCHC COVERAGE EACH AFTERNOON AND EARLY EVENING.
TEMPERATURES WILL REMAIN GENERALLY 5 TO 8 DEGREES ABOVE NORMAL.

&&

.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...STILL EXPECT INCRSNG WIND SHEAR THIS MRNG BUT NOT ENOUGH
FOR LLWS REMARK. AS FRONT MOVES IN FROM THE NW THIS AFTN-EVE VFR
CUMULUS WILL DEVELOP BUT CHC PRECIP OR CB CLOUDS TOO LOW TO MENTION
ATTM. SW WINDS WILL SWING N AFT 06Z.

ELSEWHERE...LOW CLOUDS COMING IN FROM THE W WILL IMPACT KAVL FIRST
WITH VFR LOW CLOUD CIGS BY 15Z. EXPECT LOW LVL WIND SHEAR AT KAVL
UNTIL 15Z. FOR OTHER TERMINALS VFR CUMULUS WILL DEVELOP BY THIS AFTN
BUT CHC PRECIP OR CB CLOUDS TOO LOW TO MENTION ATTM.

OUTLOOK...A COLD FRONT WILL STALL NEAR S CWA TONIGHT AND THU.
UNSETTLED CONDITIONS WILL ACCOMPANY THE FRONT. LOW CLOUDS AND
SHOWERS EXPECTED THU NIGHT AND FRI AS COLD AIR DAMMING DEVELOPS
OVER THE REGION. CONDITIONS SHOULD GRADUALLY IMPROVE THROUGH THE
WEEKEND.

&&

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

&&

SYNOPSIS...NED
NEAR TERM...RB
SHORT TERM...NED
LONG TERM...NED
AVIATION...RB

Hazardous weather outlook, Apr 20, 8:02 AM EDT, 1 hour 40 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
802 AM EDT WED APR 20 2011

GAZ010-017-018-026-028-029-NCZ059-062>065-SCZ001>006-010-011-211215-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-HART-ELBERT-NORTHERN JACKSON-MACON-
SOUTHERN JACKSON-TRANSYLVANIA-HENDERSON-OCONEE MOUNTAINS-
PICKENS MOUNTAINS-GREENVILLE MOUNTAINS-GREATER OCONEE-
GREATER PICKENS-GREATER GREENVILLE-ANDERSON-ABBEVILLE-
802 AM EDT WED APR 20 2011

...SEVERE THUNDERSTORM WATCH 167 IN EFFECT UNTIL NOON EDT TODAY...

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

.DAY ONE...TODAY AND TONIGHT.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   SEVERE THUNDERSTORM WATCH.

THIS AFTERNOON THROUGH EARLY EVENING...SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP OVER THE WESTERN CAROLINAS AND
NORTHEAST GEORGIA. ONE OR TWO OF THESE STORMS MAY BECOME STRONG TO
SEVERE.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH 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.

NCZ033-035>037-048>053-056>058-068>072-082-501>510-SCZ007>009-
012>014-019-211215-
AVERY-ALEXANDER-IREDELL-DAVIE-MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-
BUNCOMBE-CATAWBA-ROWAN-GRAHAM-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-
SPARTANBURG-CHEROKEE-YORK-LAURENS-UNION SC-CHESTER-GREENWOOD-
802 AM EDT WED APR 20 2011

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

.DAY ONE...TODAY AND TONIGHT.

THIS AFTERNOON THROUGH EARLY EVENING...SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP OVER THE WESTERN CAROLINAS AND
NORTHEAST GEORGIA. ONE OR TWO OF THESE STORMS MAY BECOME STRONG TO
SEVERE.

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

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.

In the hours before

Special weather statement, Apr 20, 7:35 AM EDT, 2 hours 7 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
735 AM EDT WED APR 20 2011

NCZ058-201200-
GRAHAM-
735 AM EDT WED APR 20 2011

...A STRONG THUNDERSTORM WILL AFFECT GRAHAM COUNTY THROUGH 800 AM
EDT...

AT 728 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 8 MILES NORTHWEST OF MARBLE...OR 12 MILES NORTH
OF MURPHY...MOVING NORTHEAST AT 55 MPH.

THIS STORM WILL BE NEAR...
  SANTEETLAH LAKE AND ROBBINSVILLE...
  FONTANA VILLAGE...
  STECOAH...

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

LAT...LON 3545 8387 3544 8368 3542 8365 3544 8364
      3543 8359 3539 8360 3533 8364 3532 8369
      3529 8369 3525 8371 3524 8377 3525 8384
      3521 8396 3523 8401 3536 8404

MCAVOY

Special weather statement, Apr 20, 8:39 AM EDT, 1 hour 3 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
839 AM EDT WED APR 20 2011

NCZ064-065-509-SCZ001>006-201400-
TRANSYLVANIA-HENDERSON-POLK MOUNTAINS-OCONEE MOUNTAINS-
PICKENS MOUNTAINS-GREENVILLE MOUNTAINS-GREATER OCONEE-
GREATER PICKENS-GREATER GREENVILLE-
INCLUDING THE CITIES OF...BREVARD...HENDERSONVILLE...GREENVILLE
839 AM EDT WED APR 20 2011

...A BRIEF PERIOD OF VERY WINDY CONDITIONS THIS MORNING...

AN OUTFLOW BOUNDARY FROM A DISSIPATED LINE OF THUNDERSTORMS WILL
MOVE QUICKLY SOUTHEAST...ACROSS THE SOUTHERN MOUNTAINS OF NORTH
CAROLINA AND INTO UPSTATE SOUTH CAROLINA THROUGH 10 AM. WIND GUSTS
OF 40 TO 50 MPH WILL ACCOMPANY THE LINE. THIS MAY BLOW DOWN A FEW
TREES AND CAUSE SCATTERED POWER OUTAGES. THE STRONGEST WINDS WILL
AFFECT AREAS FROM ROSMAN TO BREVARD AND HENDERSONVILLE IN NORTH
CAROLINA...AND JAKE JOCASSEE TO PICKENS AND TRAVELERS REST IN
SOUTH CAROLINA.

MCAVOY

Special weather statement, Apr 20, 8:44 AM EDT, 58 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
844 AM EDT WED APR 20 2011

GAZ010-017-018-NCZ062-201330-
HABERSHAM-MACON-RABUN-STEPHENS-
844 AM EDT WED APR 20 2011

...STRONG THUNDERSTORMS WILL AFFECT HABERSHAM...MACON...RABUN AND
STEPHENS COUNTIES THROUGH 930 AM EDT...

AT 839 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 4 MILES NORTHWEST OF
NOTTELY DAM TO 3 MILES NORTHWEST OF AURARIA...MOVING EAST AT 50 MPH.

THESE STORMS WILL BE NEAR...
  NANTAHALA LAKE...
  LAKE BURTON...
  NACOOHE LAKE...
  LAKE RABUN...
  CLAYTON...
  TOCCOA...

SMALL HAIL...AND WIND GUSTS OF 40 TO 50 MPH ARE EXPECTED WITH THESE
STORMS.

LAT...LON 3522 8371 3531 8333 3499 8314 3475 8336
      3468 8334 3452 8313 3449 8366 3451 8367
      3454 8362 3465 8367 3476 8363 3481 8368
      3489 8366 3494 8360 3495 8356 3502 8353
      3515 8366 3516 8374

LGL

Special weather statement, Apr 20, 9:42 AM EDT, 0 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
942 AM EDT WED APR 20 2011

NCZ063>065-SCZ001>006-010-201430-
ANDERSON-GREATER GREENVILLE-GREATER OCONEE-GREATER PICKENS-GREENVILLE
MOUNTAINS-HENDERSON-OCONEE MOUNTAINS-PICKENS MOUNTAINS-SOUTHERN
JACKSON-TRANSYLVANIA-
942 AM EDT WED APR 20 2011

...AN AREA OF STRONG THUNDERSTORMS WILL AFFECT EASTERN
OCONEE...NORTHERN ANDERSON...PICKENS...SOUTHEASTERN
JACKSON...SOUTHERN HENDERSON...TRANSYLVANIA AND WESTERN GREENVILLE
COUNTIES THROUGH 1030 AM EDT...

AT 931 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORMS NEAR MOUNTAIN REST...OR 8 MILES NORTHWEST OF
WALHALLA...MOVING NORTHEAST AT 45 MPH.

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

LAT...LON 3450 8307 3453 8308 3458 8314 3488 8307
      3498 8311 3499 8310 3502 8313 3508 8316
      3509 8315 3510 8316 3523 8322 3530 8243
      3459 8235 3449 8304

LG

The office that day

Everything else NWS Greenville-Spartanburg, SC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 20, 7:35 AM EDT	Special Weather Statement	GSP	Graham	25 min
Apr 20, 8:44 AM EDT	Special Weather Statement	GSP	Macon	46 min
Apr 20, 8:57 AM EDT	Severe Thunderstorm Warning	GSP	Macon	50 min
Apr 20, 10:20 AM EDT	Special Weather Statement	GSP	Cleveland, Polk	25 min

Nearby

Special Weather Statements in South Carolina, 2011 Special Weather Statements in North Carolina, 2011 Every special weather statement in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.