Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 190242
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
942 PM EST TUE NOV 18 2014

.SYNOPSIS...
COLD HIGH PRESSURE WILL LINGER THROUGH WEDNESDAY. A RELATIVELY DRY
COLD FRONT WILL APPROACH FROM THE NORTHWEST EARLY THURSDAY WITH HIGH
PRESSURE MOVING BACK OVER THE REGION ON FRIDAY. DEEPER MOISTURE WILL
SPREAD OVER THE AREA ON SUNDAY AND MONDAY.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 930 PM TUE...BROAD UPPER TROF CONTINUES TO PREVAIL ACROSS THE
EAST/CENTRAL CONUS...REINFORCING CAA ACRS THE SRN APPALACHIANS. DRY
HIGH PRESSURE OVER THE SOUTHERN STATES WILL KEEP SKIES CLEAR TONIGHT
AND WINDS GENERALLY LIGHT NORTHERLY OR CALM. VERY COLD TEMPERATURES
ARE IN STORE TONIGHT WITH PRIME RADIATIVE CONDITIONS IN CONJUNCTION
WITH THE EXCEPTIONALLY COLD AIRMASS. RECORD LOWS WILL BE CLOSELY
APPROACHED IF NOT BROKEN. FOR MIN TEMP VALUES WE FAVORED A BLEND OF
GUIDANCE ON THE COLDER END OF THE SPECTRUM. TRENDS OVERNIGHT HAVE
BEEN UPDATED PER LATEST OBS AND THE HRLY SHORT TERM GUIDANCE. FCST
MINS ARE WITHIN A DEGREE OF RECORDS AT GSP AND AVL...AND TYING THE
RECORD AT CLT. IT WOULD NOT BE SURPRISING IF BRIEF DIPS A COUPLE
DEGREES LOWER OCCURRED DURING CALM PERIODS AROUND DAYBREAK...SO I
WOULD NOT BE SURPRISED IF ALL THREE WERE BROKEN.

MEANWHILE FURTHER WEST...ANOTHER UPPER SHORTWAVE AND ASSOCIATED
SURFACE TROF/FRONT WILL BE SLIDING THROUGH THE NORTHERN PLAINS AND
INTO THE UPPER MIDWEST. CLOSER TO HOME EXPECTING HIGH PRESSURE TO
SLIDE BY TO THE SOUTHEAST THEREBY ALLOWING FOR SOUTHWESTERLY BACKING
FLOW AND INCREASING LOW LEVEL THICKNESS VALUES. FCST FOR WEDNESDAY
REMAINS DRY WITH IMPROVING HIGH LEVEL CLOUDINESS THROUGHOUT THE DAY.
TEMPERATURES ON WEDNESDAY WILL BENEFIT FROM ABOVE MENTIONED
THICKNESS RISES WITH HIGHS 8-10 DEGREES ABOVE THAT OF
TODAY...ESPECIALLY IN THE MOUNTAINS.  MIN RH VALUES WILL FALL INTO
THE UPPER TEENS TO LOWER 20S ACROSS MUCH...IF NOT ALL OF THE CWFA.
HOWEVER LATEST FM PLOTS PROMPT LITTLE FIRE WX CONCERN.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 145 PM TUESDAY...A WEAK CLIPPER-TYPE COLD FRONT CROSSES THE
AREA WED NITE. LOW LEVEL MOISTURE BEHIND THIS FRONT WILL LEAD TO
CLOUDS AND ISOLATED SNOW SHOWERS ACROSS THE NRN MTNS THRU THU MORN.
WHILE THERE SHOULD BE QUITE A BIT OF CLOUDINESS ACROSS THE TN BORDER
COUNTIES...VERY LITTLE IN THE WAY OF SNOWFALL IS EXPECTED. THE
MOISTURE IS NOT VERY DEEP...THE CAA IS WEAK AND NOT VERY COLD...AND
THE LOW LEVEL FLOW HAS A SIGNIFICANT WLY COMPONENT INSTEAD OF A MORE
FAVORABLE NWLY DIRECTION. BREEZY TO WINDY CONDITIONS CAN BE EXPECTED
THOUGH WED NITE AND THU. OUTSIDE OF THE MTNS...THERE MAY BE SOME
CIRRUS WED EVENING...BUT SKIES CLEAR OFF THRU THU. BREEZY CONDITIONS
WILL DEVELOP THU AS WELL. HIGHS AND LOWS WILL BE AROUND 10 DEGREES
BELOW NORMAL ALL AREAS.

HIGH PRESSURE BUILDS BACK INTO THE AREA FRI...BUT SHUD SEE ANOTHER
ROUND OF CLOUDS ACROSS THE MTNS WITH LINGERING LOW LEVEL
MOISTURE...BUT NO PRECIP. CIRRUS AGAIN MOVES ACROSS THE AREA THU
NITE THEN CLEARS DURING THE DAY FRI. BREEZY CONDITIONS ALSO LINGER
ACROSS THE HIGHER ELEVATIONS THU NITE...WITH LIGHTER WINDS ALL AREAS
FRI. LOWS RISE A COUPLE OF DEGREES THU NITE...WITH HIGHS RISING
SEVERAL DEGREES ACROSS THE MTNS...BUT REMAIN NEARLY STEADY
ELSEWHERE.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 215 PM EST TUESDAY...MEDIUM RANGE MODELS IN AGREEMENT THAT
HEIGHTS WILL RISE OVER THE EASTERN U.S. EARLY IN THE WEEKEND AS A
SOUTHERN STREAM SHORT WAVE MOVES INTO TEXAS ON SAT...AND THEN LIFTS
NE INTO THE GREAT LAKES SUNDAY NIGHT AS IT MINORS OUT. THE BONE OF
CONTENTION IS HOW THE MODELS THEN HANDLE SHORT WAVES MOVING THROUGH
THE MEAN LONG WAVE TROUGH WHICH IS FORECAST TO REMAIN WEST OF THE
AREA THORUGH TUE. THE EC IS FASTER WITH A WAVE MOVING BY TO THE NW
ON MONDAY WHICH PUSHES THE SURFACE COLD FRONT THROUGH THE AREA EARLY
MONDAY. THE SLOWER GFS DOES NOT BRING THE FRONT THROUGH UNTIL LATE
MONDAY AFTERNOON AND NIGHT. WPC FAVORED THE SLOWER GFS FOR THE
FRONTAL PASSAGE AND ALSO DEPICTED AN ENSUING FRONTAL WAVE OVER
CENTRAL SC AT 12Z TUE. HOWEVER...THE 12Z GFS SUGGESTS THAT THE
FRONTAL WAVE DEVELOPMENT ON TUE WILL BE WELL EAST OF THE WESTERN
CAROLINAS AND NE GA SIMIAR TO THE 00Z EC.

IN REGARD TO SENSIBLE WEATHER...THE SRN STREAM SYSTEM ON SUNDAY WILL
BECOME NEGATIVELY TILTED AS IT LIFTS NE THROUGH THE OH VALLEY AND
INTO THE GREAT LAKES ON SUNDAY. A DEEP AND MOIST WARM CONVEYOR BELT
WELL AHEAD OF THE SYSTEM WILL LIFT THROUGH THE DEEP S AND TRAVERSE
THE WRN CAROLINAS AND NE GA ON SUNDAY. MODELS SUGGEST THAT IN SITU
CAD WILL INITIALLY SET UP EARLY SUNDAY MORNING AS PRECIPITATION
SPREADS IN...BUT THE OFFSHORE HIGH CENTER WILL NOT BE FAVORABLE FOR
AN ENTRENCED CAD REGIME. ANY BRIEF MIXED PTYPES WITH THE RETURNING
MOISTURE WOULD LIKELY ONLY AFFECT THE NRN NC MTNS FOR A VERY SHORT
TIME AT ONSET. OTHERWISE...PROFILES AND THICKNESSES SUPPORT ALL
LIQUID PTYPES FOR THE SUNDAY PRECIPITATION. THE WARM CONVEYOR BELT
FORCING WILL BE ROBUST BUT FAIRLY BRIEF AND SHOULD QUICKLY TRANSLATE
THROUGH THE REGION BY LATE SUNDAY AFTERNOON. CAN`T RULE OUT A
CONVECTIVE HIGH SHEAR/LOW CAPE THREAT DURING SUNDAY AS THE UNSTABLE
WARM SECTOR AIR WILL GET UNCOVERED BY SUNDAY AFTERNOON PROBABLY OVER
THE EASTERN UPSTATE THROUGH THE CLT METRO AREA. WILL MAINTAIN HIGH
POPS FOR SUNDAY.

THE FORECAST BECOMES MORE PROBLEMATIC AFTER SUNDAY DUE TO THE BEFORE
MENTIONED TIMING DIFFERENCES WITH THE COLD FRONT. THERE VERY WELL
COULD BE A SIGNIFICANT LULL IN ANY PRECIP SUNDAY NIGHT INTO
MONDAY...UNTIL THE FRONT ARRIVES. HOWEVER....WILL MAINTAIN THE
CURRENT CHANCE POPS SUN NIGHT THROUGH MONDAY. ON TUE...WILL TREND
DRYER THAN WPC AS BOTH THE EC AND GFS NOW SUGGEST A DRY PATTERN. MAX
TEMPS WILL BE TRICKY ON SUNDAY DUE TO IN-SITU CAD AND HOW FAST IT
ERODES. MODELS HAVE BEEN TRENDING WARMER AS CAD MAY GET SCOURED OUT
MOST EVERYWHERE SUNDAY AFTERNOON...SO WILL STAY CLOSE TO A MODEL
CONSENSUS.

&&

.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT AND ELSEWHERE...VFR THIS PERIOD WITH A COLD AND DRY AIRMASS
FIRMLY ENTRENCHED ACROSS ALL THE TERMINALS. FROST IS GENERALLY NOT A
CONCERN GIVEN THE LOW SFC RH. AS AN UPPER SHORTWAVE MOVES OFF THE
EAST COAST TONIGHT...HIGH PRESSURE WILL SLIDE ACROSS THE SOUTHEAST
AND SET UP OVER THE COAST WED. VERY LIGHT NWLY WINDS WILL CONTINUE
TONIGHT WHERE THEY DON/T GO CALM...BUT THE HIGH WILL BE POSITIONED
TO ALLOW SW FLOW TO PREVAIL THRU THE DAY TOMORROW. OCNL LOW END
GUSTS ARE POSSIBLE BUT LIKELY TOO INFREQUENT TO HAVE AN IMPACT.

OUTLOOK...ANOTHER COLD FRONT WILL ARRIVE ON THURSDAY WITH LIMITED
MOISTURE...FOLLOWED BY DRY HIGH PRESSURE FRIDAY AND SATURDAY.

CONFIDENCE TABLE...

            02-08Z        08-14Z        14-20Z        20-00Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     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

&&

.CLIMATE...
RECORD LOWEST MAXIMUM TEMPERATURES FOR TUESDAY...NOVEMBER 18TH...

GSP  42 2008
CLT  35 1891
AVL  31 1951

RECORD MINIMUM TEMPERATURES FOR WEDNESDAY...NOVEMBER 19TH...

GSP  18 1903
CLT  18 2008
AVL  13 1903

&&

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

&&

$$
SYNOPSIS...JPT
NEAR TERM...CDG/WIMBERLEY
SHORT TERM...RWH
LONG TERM...LG
AVIATION...WIMBERLEY
CLIMATE...RWH


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