Special Weather Statement, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
522 PM EDT FRI AUG 5 2011

.SYNOPSIS...
A WEAK SURFACE FRONT WILL REMAIN STATIONARY ACROSS NORTH GEORGIA AND
THE CAROLINAS INTO THE WEEKEND.  EXPECT THE WEATHER TO BE UNSETTLED
THROUGH EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 515 PM...WIDESPREAD CONVECTION HAS PROPAGATED SOUTH OF THE
CWFA...CLOSER TO REGION OF LOW LEVEL CONVERGENCE ALONG WEAK IN SITU
CAD BOUNDARY. LIGHT STRATIFORM RAIN LINGERS ACROSS THE EASTERN
UPSTATE...WHILE ISOLATED TO WIDELY SCATTERED CONVECTION IS FIRING IN
THE MORE UNSTABLE AIR MASS ACROSS THE HIGHER TERRAIN AND THE UPPER
SAVANNAH RIVER VALLEY. MEANWHILE...THERE IS A SHARP GRADIENT IN
MOISTURE VALUES/PWATS ORIENTED FROM NORTHWEST TO SOUTHEAST ACROSS
THE CWFA. WITH THIS IN MIND...POPS HAVE BEEN ADJUSTED TO FEATURE
LIKELY ACROSS THE EASTERN PIEDMONT AREAS...WITH SOLID CHANCES ACROSS
WESTERN AREAS...AND SLIGHT CHANCES ACROSS THE NORTHERN MTNS AND
NORTHERN FOOTHILLS FOR THE REMAINDER OF THE AFTERNOON/EARLY
EVENING.

OVERNIGHT...GUIDANCE IN AGREEMENT ON OUTFLOW BOUNDARIES CONTINUING
TO KICK OFF CONVECTION...AS FCST SNDGS SHOW ELEVATED INSTBY THRU
NIGHT. MCS ACTIVITY UPSTREAM ACRS MISSOURI AND THE TN VLY WILL REACH
THE SRN APPALACHIANS BY DAYBREAK SATURDAY. STORM MOTIONS WILL REMAIN
VERY SLOW...SO A SLGT HEAVY RAIN THREAT WILL CONTINUE...BUT NOT HIGH
ENUF TO WARRANT A FLOOD WATCH. DEBRIS CLOUDINESS FROM THIS
CONVECTION WILL START STREAMING IN OVERNIGHT...BUT PROBABLY NOT IN
TIME TO PREVENT WIDESPREAD STRATUS DEVELOPMENT IN WEAK SELY LLVL
FLOW. TEMPS WILL BE MAINLY IN THE 70S OVERNIGHT UNDER CLOUD COVER
(UPPER 60S HIGH TERRAIN).

SATURDAY...AS WEAK SHORTWAVE TRACKS ACRS THE CWFA...NUMEROUS SHWRS
AND TSTMS WILL DEVELOP WITH VERY MOIST BL IN PLACE. SHEAR REMAIN
WEAK...AND SLOW STORM MOTIONS WILL RESULT IN A HEAVY RAIN THREAT.
HOWEVER...WITH SUCH WARM AND MOIST MID LVLS...SEVERE THREAT WILL BE
LOW. VERY MOIST CONDITIONS...EARLY CONVECTIVE INITIATION AND PLENTY
OF CLOUD COVER WILL KEEP TEMPS DOWN SLIGHTLY...BUT STILL NEAR OR
SLIGHTLY ABOVE NORMAL.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 230 PM FRIDAY...GENERAL TROUGHINESS WILL PERSIST ALONG THE E
COAST THROUGH THE PERIOD. UPSTREAM CONVECTION DEVELOPING OVER THE OH
VALLEY SAT NIGHT AHEAD OF A WEAK COLD FRONT COULD MAKE A RUN TOWARD
OR INTO THE FORECAST AREA ON SUNDAY. WILL MAINTAIN HIGHER CHC POPS
WEST TO LOWER CHC EAST THROUGH SUNDAY. PIEDMONT TEMPS SHOULD WARM
INTO THE MID TO UPPER 90S ON IMPROVING DOWNSLOPE FLOW.

THE PERSISTENT NW FLOW WILL CONTINUE SUN NIGHT THROUGH MONDAY. UPPER
FORCING MAY IMPROVE ON MONDAY AS AN 80 KT JET PUSHES SE INTO THE OH
VALLEY AND INCREASES UPPER DIVERGENCE ACROSS THE SE. DOWNSLOPE
WARMING SHOULD YIELD PLENTY OF UPPER 90S TEMPS E OF THE MTNS MON
AFTN.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 225 PM FRIDAY...THE BROAD TROFINESS CONTINUES IN THE MEDIUM
RANGE BRINGING TEMPERATURES THAT WILL BE CLOSER TO NORMAL. A WEAK
SURFACE FRONT WILL DRIFT DOWN FROM THE NORTH IN MID WEEK WITH A
CHANCE OF SHRA/TSRA OVER THE MOUNTAINS LATE TUESDAY AND MOUNTAINS
AND FOOTHILLS LATE WEDNESDAY.  700MB WIND SPEEDS WILL BE IN THE 20
TO 30 KT RANGE IN THE PREFRONTAL ENVIRONMENT WHICH WILL NOT BE
MARGINAL FOR CONVECTIVE ENHANCEMENT. THE FRONT WILL SHIFT SOUTH OF
THE AREA BY LATE WEDNESDAY NIGHT AND DRIER AIR WILL MOVE IN FROM THE
NORTH.  TEMPERATURES WILL BE ABOUT TWO CATEGORIES ABOVE NORMAL TUES
AND WED AND DROP TO NEAR OR JUST ABOVE FOR THUR AND FRI BEING NORTH
OF THE FRONT.

&&

.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...A CLUSTER OF TSTMS CONTINUES TO VERY SLOWLY WORK EASTWARD
ACRS THE SRN NC PIEDMONT...WITH HEAVY RAIN AT THE TERMINAL AT TIME
OF ISSUANCE. LINGERING TS WILL CONTINUE TO ABOUT 19Z...THEN
SCATTERED TO NUMEROUS STORMS IN THE AREA WILL WARRANT CB MENTION
INTO THE EVENING. OVERNIGHT...VERY MOIST CONDITIONS WILL RESULT IN A
FAIRLY HIGH CHANCE OF VSBY AND CIG RESTRICTIONS THRU DAYBREAK
SATURDAY. GUIDANCE IS NOT IN AGREEMENT ON DETAILS...BUT GIVEN THE
WIDESPREAD HEAVY RAIN...LEANING TOWARD IFR SATURDAY MORNING. AN
UPPER DISTURBANCE WILL CROSS THE REGION SATURDAY AFTN...WITH
NUMEROUS SHWRS AND TSTMS DEVELOPING AGAIN...BUT WILL KEEP CB OUT FOR
NOW.

ELSEWHERE...WIDESPREAD CONVECTION ACRS THE PIEDMONT WILL CONTINUE
INTO THE EVENING HOURS. FOR NOW...NO IMMINENT IMPACTS...SO JUST CB
ATTM. WITH WIDESPREAD RAINFALL THIS AFTN/EVE...EXPECT FOG AND
STRATUS TO DEVELOP OVERNIGHT AT ALL SITES. IT IS NOT A SLAM
DUNK...HOWEVER AS DEBRIS CLOUDINESS FROM CONVECTION APPROACHING FROM
THE WEST MAY LIMIT COOLING TO REALLY SOCK THE AREA IN...BUT STILL
EXPECT AT LEAST SOME RESTRICTIONS THRU DAYBREAK SATURDAY. GUIDANCE
NOT IN AGREEMENT ON DETAILS...SO ADJUSTMENTS WILL BE MADE WITH NEW
GUIDANCE AND THE MONITORING OF TRENDS. AN UPPER DISTURBANCE WILL
CROSS THE REGION SATURDAY AFTN...WITH NUMEROUS SHWRS AND TSTMS
DEVELOPING AGAIN...BUT WILL KEEP CB OUT FOR NOW.

OUTLOOK...MOISTURE ON EASTERLY FLOW WILL INCREASE THRU THE WEEKEND.
RESTRICTIONS COULD LINGER INTO THE WEEKEND IN THE MOIST UPSLOPE
FLOW. EXPECT SCATTERED TO NUMEROUS SHWRS/TSTMS SATURDAY AFTN. MORE
TYPICAL DIURNAL TSTMS EXPECTED FROM SUNDAY INTO NEXT WEEK.

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...DEO
NEAR TERM...ARK/JDL
SHORT TERM...HG
LONG TERM...DEO
AVIATION...ARK

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
533 PM EDT FRI AUG 5 2011

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-062145-
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-
533 PM EDT FRI AUG 5 2011

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

.DAY ONE...TONIGHT.

ISOLATED TO SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP
THROUGH THE EVENING HOURS...WITH ISOLATED STORMS CONTINUING
OVERNIGHT. THE AIR MASS OVER THE REGION IS EXTREMELY MOIST WHILE
WINDS ALOFT ARE VERY WEAK. THIS WILL RESULT IN SLOW MOVING STORMS
PRODUCING VERY HEAVY RAINFALL. LOCALIZED FLASH FLOODING WILL BE
POSSIBLE...ESPECIALLY IN URBAN AREAS.

IN ADDITION TO THE FLOODING THREAT...AN ISOLATED THUNDERSTORM OR
TWO WILL BE CAPABLE OF PRODUCING BRIEF PERIODS OF DAMAGING WINDS
THIS EVENING.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

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

LANE