River Flood Advisory 8, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
950 PM EST THU DEC 22 2011

.SYNOPSIS...
A COLD FRONT WILL SWEEP ACROSS THE REGION TONIGHT FOLLOWED BY DRY
AIR OVERSPREADING THE AREA FRIDAY INTO SATURDAY. LOW PRESSURE WILL
SLIDE BY OFF TO OUR SOUTH CHRISTMAS DAY INTO MONDAY.

&&

.NEAR TERM /THROUGH FRIDAY/...
AT 905 PM EST...AN UPPER RIDGE WAS LOCATED OVER THE WESTERN
ATLANTIC...WHILE AN UPPER TROUGH WAS OVER THE SOUTHERN ROCKIES.
A COLD FRONT WAS ANALYZED OVER THEN NC MOUNTAINS THIS EVENING.
SHOWERS AHEAD OF THIS FRONT WERE MOVING QUICKLY EAST INTO THE
FOOTHILLS AND PIEDMONT...AND THE REMAINING UPPER SAVANNAH RIVER
COUNTIES WILL BE CLEARED FORM THE TORNADO WATCH. CATEGORICAL POPS
WILL BE CARRIED AHEAD OF THE FRONT INTO THE LATE EVENING...AFTER
WHICH VEERING WINDS WILL INTRODUCE A DOWNSLOPE FLOW COMPONENT...
ENDING PRECIPITATION. WINDS ARE EXPECTED TO BE GREAT ENOUGH TO
PREVENT FOG FROM FORMING OVER MOST OF THE AREA...BUT THE UPPER
SAVANNAH RIVER VALLEY MAY HAVE ENOUGH OF A LULL IN WINDS FOR SOME
PATCHY DENSE FOG. TEMPERATURES WILL BE WELL ABOVE NORMAL...AS COLD
ADVECTION WILL BE SLOW TO SET UP BEHIND THE FRONT.

DRY AIR WILL INCREASE IN THE WAKE OF THE COLD FRONT...YIELDING
CLEARING SKY CONDITIONS FRIDAY. A FEW NW FLOW SHRA MAY DEVELOP OVER
THE TN BORDER DURING THE MORNING...BUT FADE IN THE AFTERNOON. EXPECT
DRY WX...NW WINDS...AND HIGHS IN THE MID 50S WITHIN THE MTN VALLEYS
TO MID TO UPPER 60S EAST OF I-85.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 230 PM THU...A CONFLUENT UPPER FLOW PATTERN SHOULD EXIST
ACROSS THE E THROUGH THE WEEKEND. NRN STREAM ENERGY WILL MOVE EWD
ACROSS THE GREAT LAKES TO NEW ENGLAND...WHILE A SRN STREAM SYSTEM
DEVELOPS OVER THE SRN PLAINS AND W TX. AN UPPER JETLET SE OF THESE
FEATURES AND NW OF THE FORECAST AREA WILL LIKELY KEEP SOME HIGH
LEVEL CLOUDINESS IN THE PICTURE THROUGH THE PERIOD. AT THE
SFC...WEAK HIGH PRES WILL DEVELOP UNDER THE CONFLUENT FLOW ALOFT AND
PERSIST THROUGH SAT. SHALLOW MOISTURE AHEAD OF THE SRN STREAM SYSTEM
MAY RETURN TO THE AREA LATE SAT NIGHT INTO SUNDAY. THE NAM SHOWS
VERY LIMITED FORCING WITH LITTLE TO NO WARM ADVECTION THROUGH THE
DAY ON SUNDAY...AND THE BEST MOISTURE PASSING JUST S OF THE AREA.
THE ECMWF HAS BEEN MORE AGGRESSIVE WITH THE SUNDAY MOISTURE...BUT
THE 12Z RUN DID BACK OFF A BIT. THE GFS APPEARS TO BE A MORE MIDDLE
OF THE ROAD SOLUTION. THE CONSENSUS WILL FEATURE THE BEST SUNDAY
PRECIP CHANCES IN THE SE HALF OF THE AREA. EXPECT MAX TEMPS A COUPLE
OF CATEGORIES ABOVE NORMAL SAT...AND SLIGHTLY ABOVE NORMAL SUNDAY.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 230 PM THU...DRY RIDGING WILL DEVELOP OVER THE AREA ON MON. IN
A CONTINUED PROGRESSIVE FLOW PATTERN...ANOTHER SRN STREAM SYSTEM
OVER W TX MON MAY LIFT EWD TO THE BASE OF THE APPALACHIANS LATE TUE.
AN ASSOCIATED SFC REFLECTION SHOULD DEVELOP OVER THE ERN GULF. THE
CONSENSUS SOLUTION IS THAT THE BEST PRECIPITATION CHANCES WILL
STRIKE A GLANCING BLOW ACROSS THE SE PART OF THE AREA SUN AFTN. THE
12Z ECM HAS COME IN FEATURING A DIFFERENT SOLUTION...WITH A STRONGER
E COAST RIDGE PUSHING MOISTURE BACK INTO THE SRN APPALACHIANS TUE.
WILL NOT TREND THE FORECAST TOWARD THIS SOLUTION AT PRESENT.

ON WED...A TROUGH AXIS IS EXPECTED TO CARVE OUT OVER THE MID SECTION
OF THE COUNTRY AND THEN SWING EWD ACROSS THE REGION ON THURSDAY.
THIS SYSTEM WILL TRANSLATE EWD SO QUICKLY THAT LITTLE TO NO GULF
MOISTURE TAP APPEARS POSSIBLE...AND LITTLE DEEP MOISTURE WILL
ACCOMPANY THE WAVE. WILL THUS KEEP THE FORECAST ON THE LOW SIDE OF
GUIDANCE POPS FOR THU.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
AT KCLT...MVFR WILL CONTINUE FOR SEVERAL HOURS BEHIND DEPARTING
PRECIPITATION...UNTIL VEERING WINDS INTRODUCE ENOUGH OF A DOWNSLOPE
COMPONENT TO RETURN VFR BEFORE DAWN.

ELSEWHERE...MVFR WILL PERSIST BEHIND DEPARTING SHOWERS UNTIL WINDS
VEER AND BRING DOWNSLOPE FLOW AND VFR TOWARD DAYBREAK. IT NOW
APPEARS THERE WILL BE ENOUGH WINDS TO PREVENT MORNING FOG FROM
RESTRICTING VSBY...EVEN AT KAND.

OUTLOOK...VFR UNTIL MOISTURE RETURNS AHEAD OF A GULF COAST SYSTEM
SAT NIGHT INTO SUN. RESTRICTIONS SUNDAY WOULD APPEAR TO BE MINIMAL
THIS FAR NORTH OF THE SURFACE SYSTEM. VFR AGAIN ON MONDAY.

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...CSH
NEAR TERM...JAT/NED
SHORT TERM...HG
LONG TERM...HG
AVIATION...JAT

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
919 PM EST THU DEC 22 2011

GAZ010-017-018-026-028-NCZ033-048>053-058-059-062>065-501-503-505-
507-509-SCZ001>006-010-240230-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-HART-AVERY-MADISON-YANCEY-MITCHELL-
SWAIN-HAYWOOD-BUNCOMBE-GRAHAM-NORTHERN JACKSON-MACON-
SOUTHERN JACKSON-TRANSYLVANIA-HENDERSON-CALDWELL MOUNTAINS-
BURKE MOUNTAINS-MCDOWELL MOUNTAINS-RUTHERFORD MOUNTAINS-
POLK MOUNTAINS-OCONEE MOUNTAINS-PICKENS MOUNTAINS-
GREENVILLE MOUNTAINS-GREATER OCONEE-GREATER PICKENS-
GREATER GREENVILLE-ANDERSON-
919 PM EST THU DEC 22 2011

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

.DAY ONE...TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.

GAZ029-NCZ035>037-056-057-068>072-082-502-504-506-508-510-SCZ007>009-
011>014-019-240230-
ELBERT-ALEXANDER-IREDELL-DAVIE-CATAWBA-ROWAN-CLEVELAND-LINCOLN-
GASTON-MECKLENBURG-CABARRUS-UNION NC-GREATER CALDWELL-GREATER BURKE-
EASTERN MCDOWELL-GREATER RUTHERFORD-EASTERN POLK-SPARTANBURG-
CHEROKEE-YORK-ABBEVILLE-LAURENS-UNION SC-CHESTER-GREENWOOD-
919 PM EST THU DEC 22 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 ARE POSSIBLE LATE THIS EVENING
IN THE FOOTHILLS AND PIEDMONT. CLOUDS TO GROUND LIGHTNING WILL BE
THE MAIN HAZARD WITH THESE STORMS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.