Flood Watch 4, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
933 AM EST MON NOV 28 2011

.SYNOPSIS...
LOW PRESSURE SYSTEM OVER THE TENNESSEE VALLEY WILL MOVE NORTH TODAY
AND TONIGHT. A COLD FRONT WILL MOVE SLOWLY ACROSS THE AREA TUESDAY.
HIGH PRESSURE WILL THEN BUILD IN BEHIND THE FRONT. A WEAK COLD FRONT
WILL APPROACH THE NORTH CAROLINA MOUNTAINS ON FRIDAY....FOLLOWED BY
ANOTHER AREA OF CANADIAN HIGH PRESSURE FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AT 930 AM EST... SURFACE LOW IS JUST WEST OF THE WESTERN TIP OF NC.
THIS PLACES THE CWA IN THE WARM SECTOR WITH STRONG SOUTH AND
SOUTHEAST WIND FLOW SPREADING MOISTURE INTO THE CONFLUENT PREFRONTAL
REGION UNDER DIVERGENCE ALOFT. THIS LOW LEVEL WIND DIRECTION ALSO
RESULTS IN SIGNIFICANT UPSLOPE COMPONENT. BLENDED TOTAL PRECIPITABLE
WATER SATELLITE IMAGERY SHOWS AXIS OF HIGHEST VALUES EXTENDING FROM
EAST TN SOUTHWARD THRU GA TO NORTHWEST FLORIDA. PRECIPITABLE WATER
IN THE AXIS IS ROUGHLY 200 PERCENT OF NORMAL. THE BAND OF DEEP
MOISTURE WILL SHIFT EASTWARD DURING THE DAY AS UPPER LEVEL CLOSED
LOW TRAVELS FROM EAST TN TOWARD THE MIDDLE OH RIVER VALLEY.
GFS/ECMWF/NAM/RUC 500 MB HEIGHT FIELDS DISPLAY ONLY SUBTLE
DIFFERENCES DURING THE REST OF TODAY... SO ALL MODELS CONTINUE
STRONG SOUTHEAST... UPSLOPE FLOW ACROSS THE AREA. EMPHASIS IS STILL
ON EXCESSIVE RAINFALL IN THE WESTERN PORTION OF THE CWA...
ESPECIALLY VICINITY BLUE RIDGE ESCARPMENT FROM N GA ALONG NC/SC
BORDER. THE 06Z NAM FIRE WEATHER HIGH RESOLUTION RUN PLACES HEAVIEST
RAINFALL IN THAT PART OF THE CWA.

PREVIOUS DISCUSSION...MODELS REMAIN IN GOOD AGREEMENT ON
TIMING/STRENGTH OF APPROACHING LOW AND ASSOC COLD FRONT AND SHWRS
WILL CONTINUE TO SPREAD ACROSS THE AREA TODAY. ALTHO LATEST QPF FCST
IS SLIGHTLY LOWER...AS DEEP MOISTURE CONTINUES TO SURGE N OVER THE
REGION...QPF OVER THE W MTNS REMAINS QUITE HIGH AND THE CURRENT
FLOOD WATCH LOOKS WELL PLACED FOR NOW. AS THE PRES GRADIENT TIGHTENS
TODAY WINDS WILL INCREASE AND THE LAKE WIND ADVSRY OVER THE MTNS
ALSO LOOKS GOOD AND WILL NOT BE EXPANDED ATTM. WIND SHEAR INCREASES
SIGNIFICANTLY TODAY BUT CAPE AND INSTABILITY ARE EXPECTED TO BE
FAIRLY LOW. BUFKIT SOUNDINGS SHOW NAM CAPE IS HIGHER THAN THE CAPPED
GFS SO USED A BLEND AND KEPT MENTION OF SLIGHT CHC TO CHC TSTMS THIS
AFTN-EVE. THE NON-ZERO TORNADO THREAT CONTINUES AS WELL. STRONG S
FLOW WILL KEEP TEMPS ABOVE AVG TODAY AND TONIGHT BUT AFTER MIDNIGHT
TEMPS COOL ENOUGH FOR SOME SNOW TO MIX IN AT HIGHER MTN PEAKS AND
RIDGES.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 AM MONDAY...THE CLOSED UPPER LOW WILL BE LOCATED OVER TN
TUESDAY MORNING...AND WILL MOVE NORTHEAST DURING THE DAY. THE GFS
HAS THE LOW REACHING THE OH VALLEY BY TUESDAY EVENING...WHILE THE
NAM LAGS BEHIND IN EASTERN KY. BY WEDNESDAY MORNING THIS FEATURE IS
OVER THE EASTERN GREAT LAKES. A TROUGH TRAILING THE LOW CROSSES THE
SOUTHERN APPALACHIANS WEDNESDAY NIGHT.

PRECIPITATION ACCOMPANYING THE LOW AND ITS ASSOCIATED COLD POOL IS
EXPECTED TO START OUT TUESDAY MORNING AS RAIN AT ALL BUT THE HIGHEST
ELEVATIONS...AS SUPPORTED BY BLENDED MODEL THICKNESS NOMOGRAMS...AND
A TOP DOWN APPROACH USING BLENDED MODEL WET BULBS. AN EXAMINATION
OF MODEL SOUNDINGS INDICATES THAT IF SURFACE WET BULBS WERE JUST A
BIT COOLER TUESDAY MORNING...AS THEY WILL BE TO THE SOUTHWEST OF OUR
AREA...SNOW LEVELS COULD BE LOWER.

SNOW LEVELS LOWER TO THE MOUNTAIN VALLEY FLOORS TUESDAY NIGHT...BUT
JUST AS POPS AND QPF DECREASE WITH THE DEPARTURE OF THE LOW...
LIMITING ACCUMULATIONS TO AT MOST TWO INCHES ON THE HIGHEST RIDGE
TOPS. A WARM NOSE ALOFT IS NOTED IN MODEL SOUNDINGS LATE TUESDAY
NIGHT...WHEN SLEET BECOMES POSSIBLE IN THE NC MOUNTAINS. EARLY
WEDNESDAY NORTHWEST FLOW SETS UP ALONG THE TN BORDER...BUT MOISTURE
RAPIDLY DECREASES...AND THE EVENT ENDS QUIETLY AS DAYTIME WARMING
ALLOWS A CHANGEOVER TO RAIN IN THE MOUNTAIN VALLEYS.

MAXIMUM TEMPERATURES WILL BELOW WINTERTIME NORMALS ON TUESDAY UNDER
THE UPPER LOW...INCREASING TO JUST ABOVE MID WINTER VALUES ON
WEDNESDAY. MINIMUM TEMPERATURES WILL BE JUST ABOVE MID WINTER VALUES
BOTH TUESDAY NIGHT AND WEDNESDAY NIGHT.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 245 AM MONDAY...THE UPPER LEVEL TROF AXIS WILL BE OFF TO THE
EAST BEGINNING 12Z THU AS S/W RIDGE BEGINS WORKING INTO THE REGION.
THESE GENERAL SYNOPTICS HAVE NOT CHANGED MUCH SINCE THE PREVIOUS
FCST...SO LITTLE CHANGES WERE MADE TO THE EXT PERIOD. STILL EXPECT A
LARGE THETA/E TROF TO ENCOMPASS THE SE REGION THU TO KEEP MAX TEMPS
A COUPLE DEGREES BELOW NORMAL...AND VERY GOOD INSOLATION MODIFYING
THE AIR MASS PRODUCING AROUND NORMAL MAXES BY FRI. A CLIPPER SYSTEM
LOOSELY AGREED UPON BY THE OP MODELS WILL HAVE LITTLE MOISTURE TO
WORK WITH FRI...SO DONT ANTICIPATE MUCH MORE THAN SOME LOW END
-RASNSH ACROSS THE NRN MTN SPINE THROUGH 12Z SAT. A FAIRLY
STRONG...1032 MB...POLAR HIGH WILL BUILD IN QUICKLY ACROSS THE OH
VALLEY BEHIND THE S/W PASSAGE SAT AND GENERATE SOME MEASURE OF A
LOWER AIR MASS MIX WHILE THE SFC FLOW VEERS E/LY TO S/LY THROUGH
SUN. MODERATE MLVL SUBSIDENCE WILL KEEP THE ATMOS DRY THROUGH THE
LOWER LEVELS...WHILE SCT/BKN CI/ACU MOVES IN AHEAD OF A DEEPENING
SYSTEM WEST OF THE CWFA. SO...THINK CLOUD COVER AND AIR MASS MIX
WILL COMBINE TO KEEP MAX TEMPS A CAT OR SO BELOW NORMAL EVEN WITH
DEEP SW/LY FLOW SETTING UP SUN.

&&

.AVIATION /15Z MONDAY THROUGH FRIDAY/...
AT KCLT...MAIN CONCERN WILL BE LOWERING CIG AS FRONT APPROACHES FROM
THE W TODAY. EXPECT SCT SHWRS WITH VFR OCNL MVFR CIG...LOWERING TO
IFR LATE THIS AFTN IN MDT RAIN. CHC TSTMS TOO LOW TO MENTION IN TAF.
SE WINDS WILL SLOWLY INCREASE THRU THE DAY WITH GUSTS OVER 20KT THIS
AFTN-EVE. GUIDANCE IN AGREEMENT CIG/VSBY WILL STAY IFR OVERNIGHT.

ELSEWHERE...SIMILAR TO KCLT BUT CONDITIONS LOWERING EARLIER.

OUTLOOK...COLD FRONT WILL MOVE E OF THE AREA TUE AND SHOWERS
DIMINISH BEHIND THE FRONT...BUT UNSETTLED WEATHER WILL LINGER THRU
THE DAY. A ROUND OF SNOW SHOWERS PSBL AT KAVL TUE WITH PASSAGE OF
UPPER LOW. CONDITIONS WILL IMPROVE WED ON.

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...FLOOD WATCH THROUGH LATE TONIGHT FOR GAZ010-017-018.
     LAKE WIND ADVISORY UNTIL 6 PM EST TUESDAY FOR GAZ010.
NC...FLOOD WATCH THROUGH LATE TONIGHT FOR NCZ048-051>053-058-059-
     062>065.
     LAKE WIND ADVISORY UNTIL 6 PM EST TUESDAY FOR NCZ033-048>053-
     058-059-062>065-501-503-505-507-509.
SC...FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ001>006.

&&

SYNOPSIS...LGL
NEAR TERM...LGL/RB
SHORT TERM...JAT
LONG TERM...SBK
AVIATION...LGL/RB

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
625 AM EST MON NOV 28 2011

GAZ026-028-029-NCZ035>037-056-057-068>072-082-502-504-506-508-510-
SCZ007>014-019-291130-
FRANKLIN-HART-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-ANDERSON-ABBEVILLE-LAURENS-UNION SC-
CHESTER-GREENWOOD-
625 AM EST MON NOV 28 2011

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

.DAY ONE...TODAY AND TONIGHT.

THUNDERSTORMS ARE IN THE FORECAST TODAY AND THIS EVENING. IN
ADDITION TO CLOUD TO GROUND LIGHTNING...THESE THUNDERSTORMS MAY
PRODUCE DAMAGING WINDS OR AN ISOLATED TORNADO.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.

GAZ017-018-SCZ001>006-291130-
HABERSHAM-STEPHENS-OCONEE MOUNTAINS-PICKENS MOUNTAINS-
GREENVILLE MOUNTAINS-GREATER OCONEE-GREATER PICKENS-
GREATER GREENVILLE-
625 AM EST MON NOV 28 2011

...FLOOD WATCH IN EFFECT THROUGH LATE TONIGHT...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST GEORGIA 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.

   FLOOD WATCH.

THUNDERSTORMS ARE IN THE FORECAST TODAY AND THIS EVENING. IN
ADDITION TO CLOUD TO GROUND LIGHTNING...THESE THUNDERSTORMS MAY
PRODUCE DAMAGING WINDS OR AN ISOLATED TORNADO.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.

GAZ010-NCZ048-051>053-058-059-062>065-291130-
RABUN-MADISON-SWAIN-HAYWOOD-BUNCOMBE-GRAHAM-NORTHERN JACKSON-MACON-
SOUTHERN JACKSON-TRANSYLVANIA-HENDERSON-
625 AM EST MON NOV 28 2011

...LAKE WIND ADVISORY IN EFFECT UNTIL 6 PM EST TUESDAY...
...FLOOD WATCH IN EFFECT THROUGH LATE TONIGHT...

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

   LAKE WIND ADVISORY.
   FLOOD WATCH.

THUNDERSTORMS ARE IN THE FORECAST TODAY AND THIS EVENING. IN
ADDITION TO CLOUD TO GROUND LIGHTNING...THESE THUNDERSTORMS MAY
PRODUCE DAMAGING WINDS OR AN ISOLATED TORNADO.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

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

   LAKE WIND ADVISORY.

.SPOTTER INFORMATION STATEMENT...

NONE.

NCZ033-049-050-501-503-505-507-509-291130-
AVERY-YANCEY-MITCHELL-CALDWELL MOUNTAINS-BURKE MOUNTAINS-
MCDOWELL MOUNTAINS-RUTHERFORD MOUNTAINS-POLK MOUNTAINS-
625 AM EST MON NOV 28 2011

...LAKE WIND ADVISORY IN EFFECT UNTIL 6 PM EST TUESDAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN NORTH 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.

   LAKE WIND ADVISORY.

THUNDERSTORMS ARE IN THE FORECAST TODAY AND THIS EVENING. IN
ADDITION TO CLOUD TO GROUND LIGHTNING...THESE THUNDERSTORMS MAY
PRODUCE DAMAGING WINDS OR AN ISOLATED TORNADO.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

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

   LAKE WIND ADVISORY.

.SPOTTER INFORMATION STATEMENT...

NONE.

07