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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KGSP 100551
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1251 AM EST WED FEB 10 2010

.SYNOPSIS...
-- Changed Discussion --
AS STRONG LOW PRESSURE MOVES FARTHER OFF THE COAST...THE
PRESSURE GRADIENT BETWEEN THE LOW AND THE HIGH OVER THE MISSISSIPPI
VALLEY WILL CREATE VERY WINDY CONDITIONS TODAY.  LOW PRESSURE OVER
THE GULF EARLY FRIDAY WILL BE WELL OFF THE CAROLINA COAST EARLY
SATURDAY.  AN UPPER LEVEL SYSTEM WILL QUICKLY CROSS FROM THE
NORTHWEST EARLY SUNDAY.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TODAY/...
WILL BE MAKING SOME SIGNIFICANT CHANGES TO THE HAZARDS THIS EVENING.
FIRST WILL EXPAND WINTER STORM WARNING TO INCLUDE GRAHAM COUNTY. WE
HAVE WARNING LEVEL SNOWS ALREADY IN THE FCST. ALTHOUGH THE GRAHAM
VALLEYS WILL NOT SEE THE HIGHEST WINDS...THE HIGHER ELEVATIONS SHUD
SEE WARNING GUSTS. OF COURSE...EVEN LOWER WIND SPEEDS WILL CAUSE
TREES AND POWER LINES TO FALL WITH THE WET GROUND.

SECOND...WILL EXPAND THE HIGH WIND WARNING TO INCLUDE THE REST OF
THE NC COUNTIES. 18Z MDL RUNS SHOW STRONG LOW LEVEL WINDS ACROSS
THIS AREA WITH DEEP ENUF MIXING TO BRING DOWN WARNING LEVEL GUSTS.
AGAIN...EVEN IF GUSTS DO NOT QUITE REACH WARNING LEVEL...PUBLIC
IMPACT OF TREES AND POWER LINES DOWN SHOULD BE SIGNIFICANT. WILL
LEAVE HIGH WIND WATCH IN PLACE ACROSS SC/GA WHERE 18Z GUIDANCE SHOWS
LOWER WIND SPEEDS. MID SHIFT CAN MAKE THE FINAL CALL FOR WARNING...
BUT EXPECT AT LEAST AN ADVISORY OVER THESE AREAS.

THIRD...WILL GO AHEAD AND ISSUE A WIND ADV FOR THE SRN STRIPE OF THE
CWFA. NO BENEFIT IN HOLDING OFF UNTIL LATER AS THIS AREA SHOULD SEE
ADV LEVEL WINDS AND AT LEAST SCT TREES AND POWER LINES DOWN.

ADDED BLOWING SNOW TO THE WSW AREA GIVEN THE WIND SPEEDS AND SNOW
SHOWERS. ALTHOUGH BLIZZARD-LIKE CONDITIONS MAY BE SEEN IN A FEW
LOCATIONS FROM TIME TO TIME...THEY WILL BE BRIEF AND WILL NOT REACH
THE DURATION CRITERION FOR A BLIZZARD WARNING. WILL INCLUDE A
MENTION OF WIND CHILL IN THE WSW AREAS...ALTHOUGH ADV READINGS WILL
BE LIMITED TO THE HIGHER ELEVATIONS. ALSO...EXPECT ADV LEVEL SNOWS
ACROSS THE SRN NC MTNS. FOLLOWING REGIONAL POLICY...THE HIGH WIND
WARNING TRUMPS THE ADV LEVEL SNOW...SO WILL JUST MENTION THAT IN THE
NPW. HAVE MADE MINOR CHANGES TO LOWS BASED ON LATEST GUIDANCE...AND
POPS BASED ON CURRENT RADAR.

PREVIOUS DISCUSSION...H5 LOW DIGS TOWARD THE MID ATLANTIC REGION
LATE AFTN-EARLY EVE WITH SHORTWAVE TROF SWINGING THRU CWA WITH
BETTER FORCING. MOISTURE NOT AS GOOD AS EARLIER MODEL RUNS
ADVERTISED BUT STILL EXPECT CAT POPS INTO THIS EVE...JUST WITH LOWER
AMTS. TEMP/THKNS SEVERAL DEG WARMER THAN FCST SO THE ADVSRY WILL BE
DROPPED. MID LEVEL DRY SLOT STILL EXPECTED TO WRAP INTO THE AREA
FROM THE SW THIS EVE...ALONG WITH  COLD FROPA...TO SHUT PRECIP OFF
MOST AREAS. WITH LOW LVL MOISTURE WRAPPING BACK UP TO THE GREAT
LAKES...NW FLOW SNOW WILL INCREASE OVERNIGHT THRU WED NEAR THE TN
BORDER WITH 2-4 INCHES ACCUM BY LATE WED AFTN. VERY WINDY CONDITIONS
WILL ALSO DEVELOP AS THE PRES GRADIENT TIGHTENS...ESP OVER THE MTNS.
MRNG LOWS WILL FALL INTO THE 20S WITH A FEW TEENS IN THE MTNS SO
EXPECT VERY COLD WINDS CHILLS... BUT NOT TO ADVSRY LEVELS. WILL
UPGRADE HIGH WIND WATCH TO A WARNING FROM THE NC FOOTHILS ADJACENT
THE MTNS...DOWN TO THE NC S MTNS AND THE SC-GA MTNS. THE N AND CNTRL
MTNS WILL BE COVERED IN THE WSW...ALONG WITH THE NW FLOW SNOW...AND
THE REST OF THE HIGH WIND WATCH WILL BE KEPT IN PLACE WHERE LATER
SHIFTS CAN DECIDE WHETHER A WARNING OR ADVSRY WILL BE NEEDED. STRONG
GUSTY NW WINDS WED WILL CREATE GOOD DOWNSLOPE FLOW AT ELEVS SE OF
THE MTNS AND TEMPS ARE EXPECTED TO WARM INTO THE MID 40S OVER NE GA
AND UPSTATE SC... U30-L40S IN THE NC PIEDMONT...BUT REMAIN IN THE
M20S-L30S OVER THE NC MTNS.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...
AS OF 230 PM TUESDAY...THE UPPER LOW WILL MOVE AWAY FROM THE EAST
COAST ON WEDNESDAY NIGHT...WHILE A FLAT UPPER RIDGE OVER THE PLAINS
DEAMPLIFIES. THE GFS FILLS AN UPPER LOW OVER THE SOUTHWEST ON
THURSDAY...THEN MOVES THE REMAINING TROUGH ACROSS THE NORTHERN GULF
OF MEXICO ON FRIDAY.

A TIGHT PRESSURE GRADIENT WILL REMAIN OVER THE NC MOUNTAINS ON
WEDNESDAY NIGHT...WITH NORTHWEST FLOW SNOWS AND WARNING CRITERIA
WINDS CONTINUING. BY THURSDAY MORNING SNOWFALL ENDS AND WINDS
DECREASE BELOW WARNING CRITERIA ON ALL BUT THE HIGHEST PEAKS. DRY
HIGH PRESSURE MOVES EAST INTO THE AREA ON THURSDAY. MID AND HIGH
LEVEL MOISTURE WILL OVERSPREAD THE SOUTHERN PERIPHERY OF THE SURFACE
RIDGE LATE THURSDAY NIGHT...AND WILL COVER THE SOUTHERN HALF OF OUR
AREA ON FRIDAY. MODEL TIME HEIGHTS AND 850 MB RELATIVE HUMIDITY IN
THE UPPER SAVANNAH RIVER VALLEY SUPPORT NO LOW CLOUDS FRIDAY...SO
THE SLIGHT CHANCE POPS HAVE BEEN REMOVED FROM THE FORECAST.

TEMPERATURES WILL REMAIN BELOW NORMAL...BUT WITH A WARMING TREND
THROUGH THURSDAY NIGHT AS HEIGHTS RISE ALOFT IN THE WAKE OF THE
UPPER LOW. MAXIMUM TEMPERATURES WILL FALL SLIGHTLY ON FRIDAY UNDER
INCREASING MID AND HIGH LEVEL CLOUDS COVER.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 150 PM TUESDAY...WEAK SFC RIDGING TO BUILD INTO THE SOUTHERN
APPALACHIANS SATURDAY AND UNDER MODERATE WNW FLOW ALOFT...STILL
EXPECTING A FAIR WX DAY...BUT CHILLY...AS MAX TEMPERATURES ARE
FCST TO BE SVRL CATEGORIES BELOW CLIMO. RATHER VIGOROUS LOOKING
CLIPPER TO AFFECT THE REGION ON SUNDAY WHICH HAS THE POTENTIAL TO
TRIGGER A PERIOD OF SNOW SHOWERS...EVEN INTO THE PIEDMONT. CONTINUED
CHILLY AS WELL...WITH MAX TEMPS STILL SVRL CATEGORIES BELOW NORMAL.

IN THE WAKE OF AFOREMENTIONED CLIPPER...A PERIOD OF NC MTN NW FLOW
SNOW SHOWERS IS POSSIBLE...OTHERWISE GENERALLY FAIR...BUT BLUSTERY
AND COOL CONDITIONS ARE ON TAP TO ROUND OUT THE HOLIDAY WEEKEND.
THE MEAN PATTERN CHANGES LITTLE BY THE END OF THE PERIOD...AS
EASTERN CONUS L/WV TROUGH LINGERS. SENSIBLE WX FOR THE REGION
LOOKS TO BE MINIMAL...STILL FAIR AND COOL.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
AT KCLT...IFR CONDITIONS WILL CLEAR UP VERY QUICKLY AFTER 06Z AS THE
COLD FRONT MOVES THROUGH THE TERMINAL AREA AND SCOURS OUT THE LOW
LEVEL MOISTURE. WESTERLY WINDS WILL INCREASE...WITH GUSTS OF 25 KT
OR BETTER BY DAYBREAK. FLOW WILL TURN SLIGHTLY MORE NORTHWEST
THROUGH THE DAY...WITH GUSTS OF 35 KT OR BETTER DEVELOPING WITH
DEEPER MIXING. SOME GUSTS OF 40 TO 50 KT WILL BE POSSIBLE LATER THIS
AFTERNOON...BUT CONFIDENCE IS TOO LOW TO PUT GUSTS THIS STRONG IN
THE TAF FOR NOW. TOWER PERSONNEL SHOULD CLOSELY MONITOR WINDS TODAY
IN CASE TOWER EVACUATIONS BECOME NECESSARY DUE TO HIGH WINDS.

AT KAVL...RETURNING NW FLOW MOISTURE BEHIND THE FRONT WILL YIELD
MAINLY VFR CIGS THROUGH THE DAY...ALTHOUGH BRIEF MVFR CIGS AND A
SNOW SHOWER CANNOT BE RULED OUT. WINDS WILL BE THE MAIN ISSUE...AS
GUSTS ABOVE 35 KT ARE EXPECTED BY DAYBREAK...WITH GUSTS ABOVE 45 KT
LIKELY WITH MIXING BY MIDDAY. TOWER PERSONNEL SHOULD CLOSELY MONITOR
THE WIND SPEEDS TODAY AS A SAFETY PRECAUTION.

ELSEWHERE...SCATTERED STRATOCUMULUS ARE EXPECTED THROUGHOUT THE DAY
IN STRENGTHENING NW FLOW COLD ADVECTION. WIND GUSTS CLOSE TO 30 KT
ARE ANTICIPATED BY DAYBREAK...WITH GUSTS ABOVE 35 KT WITH DEEPER
MIXING BY MIDDAY. GUSTS OF 40 TO 50 KT LATE THIS AFTERNOON CANNOT BE
RULED OUT...ESPECIALLY AT KHKY. TOWER PERSONNEL SHOULD CLOSELY
MONITOR THE WIND SPEEDS TODAY AS A SAFETY PRECAUTION.

OUTLOOK...WIND SPEEDS WILL SLOWLY DIMINISH LATE TONIGHT THROUGH
THURSDAY AS DRIER HIGH PRES BUILDS IN FROM THE WEST. VFR CONDITIONS
SHOULD THEN CONTINUE THROUGH THE REST OF THE OUTLOOK PERIOD.
-- End Changed Discussion --

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
GA...HIGH WIND WARNING FROM 6 AM THIS MORNING TO 6 AM EST THURSDAY
     FOR GAZ010.
     HIGH WIND WATCH FROM 6 AM EST THIS MORNING THROUGH LATE
     TONIGHT FOR GAZ017-018-026-028.
     WIND ADVISORY FROM 6 AM THIS MORNING TO 6 AM EST THURSDAY FOR
     GAZ029.
NC...WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR NCZ033-
     048>053-058-059-501-503-505.
     HIGH WIND WARNING FROM 6 AM THIS MORNING TO 6 AM EST THURSDAY
     FOR NCZ035>037-056-057-062>065-068>072-082-502-504-
     506>510.
SC...HIGH WIND WARNING FROM 6 AM THIS MORNING TO 6 AM EST THURSDAY
     FOR SCZ001>003.
     HIGH WIND WATCH FROM 6 AM EST THIS MORNING THROUGH LATE
     TONIGHT FOR SCZ004>010.
     WIND ADVISORY FROM 6 AM THIS MORNING TO 6 AM EST THURSDAY FOR
     SCZ011>014-019.
-- End Changed Discussion --

&&

$$
SYNOPSIS...SBK
NEAR TERM...RB/RWH
SHORT TERM...JAT
LONG TERM...CSH
AVIATION...HG