000
FXUS62 KGSP 080309
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1009 PM EST FRI MAR 7 2014

.SYNOPSIS...
DRIER AND WARMER HIGH PRESSURE WILL RETURN TO OUR REGION THIS
WEEKEND AND PERSIST THROUGH EARLY NEXT WEEK. ANOTHER LOW WILL
APPROACH THE CAROLINAS FROM THE WEST DURING THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 955 PM EDT...IT IS BECOMING INCREASINGLY APPARENT THAT THE
MODEL AND MOS FORECASTS HAVE BEEN UNDERDONE WITH THE FOG POTENTIAL
FOR OVERNIGHT GIVEN THE DEEP DRYING ABOVE A VERY MOIST SURFACE
LAYER. IN ADDITION...THE NW PIEDMONT MIN TEMP FORECAST HAS BEEN
LOWERED ANOTHER DEGREE OR TWO...RAISING THE SPECTER OF FREEZING FOG
FORMATION ACROSS THE PIEDMONT AND POSSIBLY THE FOOTHILLS. THIS
LANGUAGE HAS BEEN ADDED TO THE FORECAST AND THE SPS FOR NOW...ALONG
WITH THE PATCHY BLACK ICE MENTION...BUT A FREEZING FOG ADVISORY
COULD WELL BE NEEDED FOR NRN PARTS OF THE AREA FOR THE OVERNIGHT
HOURS.

LOW LEVEL THICKNESSES WILL INCREASE SAT IN RESPONSE TO THE DEPARTING
UPPER LOW AND SHALLOW RIDGING ALOFT...WITH A DEEP W/SW FLOW
DEVELOPING. UNDER MOSTLY SUNNY SKIES...AFTER ANY MORNING FOG OR LOW
CLOUDS DISSIPATE...MAX TEMPS ARE EXPECTED TO BE AROUND 10 DEGREES
ABOVE CLIMO...TOPPING OUT AROUND 70 ACROSS MUCH OF THE UPSTATE/NE
GA...WITH MID/UPPER 60S EXPECTED ACROSS MUCH OF WESTERN NC.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 200 PM EST FRIDAY...THE SHORT TERM PERIOD INITIALIZES SATURDAY
EVENING AMIDST WEAKENING DEEP LAYER RIDGING.  A CLIPPER TYPE SYSTEM
WILL EJECT OUT OF THE NORTHERN PLAINS INTO THE LOWER GREAT LAKES
REGION OVERNIGHT SATURDAY WITH A WEAK COLD FRONT SPREADING ACROSS
THE OHIO RIVER VALLEY BEFORE EVENTUALLY PUSHING INTO THE HIGH
TERRAIN OF WESTERN NC EARLY ON SUNDAY MORNING.  SHOWER ACTIVITY
ALONG THE FRONT DOES NOT LOOK PARTICULARLY PRONOUNCED BY THE TIME IT
REACHES THE TN BORDER.  HOWEVER...WEAK NORTHWEST UPSLOPE FLOW BEHIND
THE FRONT WILL WARRANT MENTION OF AT LEAST CHANCE LEVELS POPS
THROUGH LATE MORNING SUNDAY AS MOISTURE POOLS ALONG THE WESTWARD
FACING SLOPES.  TEMPERATURES ON SUNDAY WILL REMAIN ABOVE NORMAL
ACROSS MOST OF THE REGION DESPITE THE WEAK FROPA.  THE HIGH TERRAIN
WILL EXPERIENCE TEMPERATURES TOPPING OUT NEAR NORMAL WITH THE
FOOTHILLS/PIEDMONT REGIONS PEAKING AT 6-8 DEGREES ABOVE NORMAL DUE
TO DOWNSLOPING FLOW AND LESS DENSE SKY COVER.

ANOTHER WARM AND MOSTLY SUNNY DAY AHEAD FOR MONDAY AS WEAK SURFACE
RIDGING BUILDS ACROSS THE SOUTHEAST UNDER PERSISTENT NORTHWEST FLOW
ALOFT.  TEMPERATURES ON MONDAY WILL EXCEED NORMAL LEVELS YET AGAIN
ACROSS THE ENTIRE REGION AS DAYTIME HIGHS REACH INTO THE UPPER 50S
TO LOWER 60S ACROSS THE HIGH TERRAIN...AND UPPER 60S TO LOWER 70S
ACROSS THE PIEDMONT.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM FRIDAY...THE MEDIUM RANGE WILL START OUT WITH SPLIT
QUASI-ZONAL UPR FLOW ACRS THE CONUS...WITH A CLOSED LOW INVOF SRN TX
AND AN AMPLIFIED NRN STREAM TROF ENTERING THE NRN ROCKIES. THE
DETERMINISTIC MODELS ARE IN GENERAL AGREEMENT ON THE SRN STREAM LOW
EJECTING OUT ACRS THE NRN GULF TUESDAY-TUE NGT...THEN GETTING
SHEARED OUT AS IT ENTERS CONFLUENT FLOW BY THE TIME IT REACHES FL.
THE NRN STREAM SHORTWAVE TROF...MEANWHILE...AMPLIFIES INTO A DEEP
LONGWAVE TROF ACRS THE ERN STATES BY WED-THU. THERE IS A LOT OF
DISAGREEMENT ON THE DETAILS GIVEN THE COMPLEX FLOW REGIME AND
PATTERN CHANGE. I STUCK CLOSE TO THE 12Z WPC GUIDANCE...WHICH
FAVORED AN ENSEMBLE MEAN APPROACH TO THE FCST.

SO TUESDAY LOOKS TO START OUT DRY WITH SOME INCREASE IN CLOUDS
DURING THE AFTN. LLVL FLOW STILL HAS A DOWNSLOPE COMPONENT...AND 850
MB TEMPS IN THE 10-12C RANGE SHUD ALLOW MAX TEMPS TO BE A CATEGORY
OR TWO WARMER THAN MONDAY...ABOUT 10-15 DEG ABOVE NORMAL.

TUESDAY NIGHT AND WEDNESDAY...THO THERE IS STILL MUCH DISAGREEMENT
WITH THE TIMING AND AMPLITUDE OF THE SRN STREAM LOW AMONGST THE
GUIDANCE...IT DOES LOOK MORE LIKELY WE WILL SEE A PRECIP SHIELD ACRS
THE AREA AT SOME POINT. WPC POPS ARE IN THE HIGH-END CHC TO LOW
LIKELY RANGE...HIGHEST IN THE MTNS. THICKNESSES SHUD BE WELL WITHIN
THE ALL-LIQUID RANGE...AS NO CAD WEDGE IS EXPECTED. TEMPS WILL BE
WELL ABOVE NORMAL OVERNIGHT THEN REMAIN IN THE 50S AND 60S
WEDNESDAY. QPF DOES NOT LOOK TOO HEAVY AT THIS TIME. HOWEVER...IF
THE SYSTEM CAN BECOME MORE PHASED...MAY SEE DECENT QPF AMOUNTS.

WEDNESDAY NIGHT INTO THURSDAY...MOST OF THE MODEL SOLNS DO SHOW COLD
AIR FILTERING IN BEHIND THE DEPARTING LOW WITH LINGERING NW FLOW
MOISTURE FOR RAIN CHANGING OVER TO SNOW SHWRS. THE LOW IS PROGGED TO
LIFT OUT AWAY FROM THE COAST FAIRLY QUICKLY...SO NOT EXPECTING
SIGNIFICANT SNOW ACCUMS. THE DEEPENING UPR TROF WILL ALLOW A RETURN
TO NORMAL OR BELOW NORMAL TEMPS BY THE END OF THE MEDIUM RANGE.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...CONFIDENCE IS INCREASING FOR FOG FORMATION OVERNIGHT AS
SKIES HAVE CLEARED AND ABUNDANT LOW LEVEL MOISTURE REMAINS. THE
LATEST LAMP GUIDANCE STILL HAS NOT TRENDED APPRECIABLY FOGGIER...BUT
HYDROLAPSES IN ALL MODEL SOUNDINGS APPEAR QUITE FAVORABLE. IN
ADDITION TO IFR TO LIFR FOG...THERE IS SOME POSSIBILITY OF FREEZING
FOG DEVELOPING TOWARD DAYBREAK...THROUGH MIN TEMP FORECASTS REMAIN
JUST ABOVE FREEZING. THIS WILL NEED TO BE MONITORED CLOSELY FOR
POSSIBLE DEICING OPS. OTHERWISE...EXPECT LIGHT FLOW WITH WINDS
BECOMING WSW AT 7 KT OR LESS THROUGH SAT...WITH MAINLY PASSING HIGH
CLOUDS ONCE ANY MORNING LOW CLOUDS/FOG DISSIPATE.

ELSEWHERE...EXPECT MAINLY PASSING THIN HIGH CLOUDS THROUGH THE EARLY
OVERNIGHT. LOW CLOUDS AND FOG MAY WELL FORM FIRST IN THE MTN VALLEYS
AND THE NRN TIER NEAR KHKY...THEN LATER IN THE UPSTATE. IFR
CONDITIONS ARE NOW EXPECTED KAVL TO KHKY...AND LOW CIGS COULD
PERSIST WELL INTO THE MORNING. SOME FREEZING FOG CANNOT BE RULED OUT
AT THE NC SITES AS WELL. EXPECT STEADY IMPROVEMENT THROUGH LATE
MORNING...WITH GENERALLY WSW WINDS LESS THAN 8 KT AT ALL SITES
THROUGH THE DAY...EXCEPT NW AT KAVL...WITH MAINLY HIGH CLOUDS.

OUTLOOK...A MOSTLY DRY COLD FRONT WILL CROSS THE AREA EARLY SUNDAY.
DRY HIGH PRES WILL RETURN THROUGH THE EARLY WEEK. RAIN AND
ASSOCIATED RESTRICTIONS MAY SPREAD BACK INTO THE AREA BY WED.

CONFIDENCE TABLE...

            03-09Z        09-15Z        15-21Z        21-03Z
KCLT       HIGH  81%     LOW   58%     HIGH 100%     HIGH 100%
KGSP       HIGH  87%     MED   78%     HIGH 100%     HIGH 100%
KAVL       MED   70%     LOW   43%     HIGH 100%     HIGH 100%
KHKY       HIGH  83%     MED   74%     HIGH 100%     HIGH 100%
KGMU       HIGH  95%     MED   78%     HIGH 100%     HIGH 100%
KAND       HIGH  91%     HIGH  80%     HIGH 100%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

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

&&

$$
SYNOPSIS...CSH
NEAR TERM...HG/JDL
SHORT TERM...CDG
LONG TERM...ARK
AVIATION...HG/JDL