Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 021435
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1035 AM EDT SAT MAY 2 2015

.SYNOPSIS...
EXPECTING DEEP LAYER RIDGING TO CONTINUE THROUGH THE WEEK WITH AN
OCCASIONAL SHOWER OR THUNDERSTORM POSSIBLE DURING PEAK HEATING EACH
DAY...MAINLY ACROSS THE MOUNTAINS AND FOOTHILLS OF WESTERN NORTH
CAROLINA. TEMPERATURES WILL MODERATE TO ABOVE NORMAL LEVELS WITH
HIGHS TOPPING OUT IN THE LOWER TO MID 80S NEAR PERIODS END.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM EDT...TEMPERATURES ARE RISING A TOUCH MORE QUICKLY
THAN GUIDANCE THIS MORNING...AND THICKNESSES WILL SUPPORT A ONE
DEGREE OR SO UPWARD BUMP IN MAXES FOR THIS AFTN. OTHERWISE...LITTLE
MORE THAN A FEW HIGH CLOUDS WITH THE UPPER WAVE ARRIVING FROM THE NW
ARE EXPECTED...ALONG WITH FEW TO SCT STRATOCUMULUS WITH THE DAY/S
HEATING. THE UPPER SHORTWAVE AND LOCAL LEVEL CONVERGENCE WILL BE
MAXIMIZED IN THE EXTREME SRN MTNS LATE DAY...BUT NOTHING MORE THAN
ISOLD SHRA COVERAGE APPEARS POSSIBLE THER GIVEN THE PALTRY MOISTURE
AND INSTABILITY IN SOUNDINGS.

OTHERWISE...SURFACE HIGH PRESSURE WILL CONTINUE TO DRIFT SLOWLY EAST
ACROSS THE REGION THRU TONIGHT...BUT WITH THE AIR MASS
MODIFYING...LOW TEMPS TONIGHT WILL BE A FEW DEGREES WARMER.
THUS...NO CONCERNS FOR FROST/FREEZE IN SPITE OF ANOTHER MOSTLY CLEAR
AND CALM NIGHT.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 230 AM EDT SATURDAY...SOME MINOR DISCREPANCIES IN THE LATEST
GUIDANCE AS IT PERTAINS TO POSSIBLE CONVECTION THROUGH THE SHORT
TERM.  THE PERIOD INITIALIZES SUNDAY MORNING WITH A BROAD FLAT UPPER
RIDGE CENTERED OVER THE SOUTHEASTERN UNITED STATES...WHILE AT THE
SURFACE A HIGH PRESSURE CENTER WILL BE ANCHORED OFF THE CAROLINA
COAST.  MODELS CONVERGE ON THE EVOLUTION OF A WEAK UPSTREAM H5 WAVE
THAT IS FCST TO SLIDE THOUGH THE OH VALLEY INTO THE SOUTHERN APPS
LATE DAY SUNDAY.  HOWEVER...THE NAM SEEMS A TAD BIT STRONGER WITH
THE WAVE THAN THE GFS/ECMWF WHICH EFFECTIVELY USHERS COOLER MID
LEVEL AIR OVERHEAD ON SUNDAY AFTERNOON.  THIS WOULD ALLOW FOR STEEPER
LAPSE RATES THUS LEADING TO ENHANCED INSTABILITY.  AS FOR THE
FCST...THINK THE NAM MIGHT BE A TAD OVERDONE HOWEVER OPTED FOR
SLIGHT CHANCE POPS OVER THE MTNS WHILE THE LOWER TERRAIN REMAINS DRY
WHERE ANY DEEP LAYER SUBSIDENCE IS EXPECTED TO HOLD.

MONDAY LOOKS A LITTLE BETTER AS FAR AS PRECIP CHANCES ARE CONCERNED
AS SOUTHERLY MOIST WAA REGIME PREVAILS ALLOWING FOR INCREASING
MOISTURE THROUGH THE LOW/MID LEVELS.   THUS MODELS FAVOR A BETTER
CONSENSUS FOR POPS ON MONDAY WHERE PEAK HEATING AND DEWPOINTS IN THE
50S COMBINE TO YIELD UPWARDS OF 800-1000J/KG SBCAPE ALONG THE BLUE
RIDGE.  SOUTHERLY UPSLOPING FLOW COULD AID CONVECTION AS IT PERTAINS
TO OVERCOMING ANY CIN...THUS POPS ARE INCREASED SPATIALLY AND IN
MAGNITUDE ON MONDAY WITH MID LEVEL CHANCE POPS FEATURED OVER THE
MTNS WHILE SLIGHT CHANCE POPS ARE INCLUDED FOR THE NORTHERN NC
FOOTHILLS/PIEDMONT.  THE REMAINDER OF THE FCST AREA SHOULD CONTINUE
TO REMAIN DRY AMIDST DEEP LAYER RIDGING.  TEMPERATURES WILL MODERATE
THROUGH THE PERIOD ALL THE WHILE EXCEEDING NORMAL LEVELS.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 245 AM EDT SATURDAY...THE MEDIUM RANGE FCST PERIOD INITIALIZES
TUESDAY MORNING AMIDST CONTINUED UPPER RIDGING...WITH A SURFACE HIGH
CENTERED OFF THE CAROLINA COAST ON THE MOVE OUT TO SEA.  GUIDANCE
CONTINUES TO HINT AT SOME SORT OF HYBRID LOW PRESSURE SYSTEM SLIDING
NORTH OUT OF THE CARRIBEAN...EVENTUALLY EJECTING NORTHEAST WELL OUT
TO SEA.  DEWPOINTS IN THE UPPER 50S TO LOWER 60S WILL ALLOW FOR
MODEST DESTABILIZATION ACROSS THE REGION ON TUESDAY DURING PEAK
HEATING.  ABOVE MENTIONED EASTWARD MIGRATING SURFACE RIDGE WILL
PERHAPS PROVIDE ENOUGH LOW LEVEL SUBSIDENCE TO MITIGATE ANY
SHRA/TSRA OUTSIDE OF THE MOUNTAINS ON TUESDAY...THUS THE FCST
REMAINS DRY FOR THESE LOCATIONS WHILE THE HIGH TERRAIN HAS CHANCE
LEVEL POPS FEATURED.  THIS PATTERN WILL LIKELY PERSIST THROUGH THE
REMAINDER OF THE PERIOD WITH A BIT OF A LULL IN ACTIVITY EXPECTED ON
WEDNESDAY AS THE PRIMARY UPPER RIDGE AXIS SHIFTS OVERHEAD.  MODELS
FAVOR CONTINUED UPPER RIDING THURSDAY AND FRIDAY...HOWEVER WITH
WEAKER SFC SUBSIDENCE YIELDING GRADUALLY EXPANDING REGIONS OF
MENTIONABLE POPS AS DIURNAL AIRMASS TYPE SHRA/TSRA IS
EXPECTED...PRIMARILY OVER THE MOUNTAINS/FOOTHILLS OF WESTERN NC.
BY THIS TIME GUIDANCE INDICATES THE ABOVE MENTIONED HYBRID LOW OFF
THE CAROLINA COAST...ALLOWING FOR NORTHERLY BACKED SURFACE FLOW.
WITH HIGH PRESSURE LIKELY RESIDING OVER THE NORTHEAST...THIS PATTERN
COULD USHER A WEAK WEDGE FRONT INTO THE REGION FOR THE START OF THE
WEEKEND.  HOWEVER AT THIS RANGE UNCERTAINTY IS HIGH.    TEMPERATURES
THROUGH THE MEDIUM RANGE WILL REMAIN ABOVE NORMAL LEVELS.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...VFR CONDITIONS EXPECTED THROUGH THE
PERIOD...ALONG WITH A LIGHT N OR NW WIND AT LESS THAN 10 KT. SOME
HIGH BASED STRATOCU WILL DEVELOP THRU THE DAY...BUT IF A CEILING
FORMS...IT SHOULD BE ABOVE 050 AND MAINLY OVER THE SW MTNS. THERE
COULD BE AN ISOLATED SHOWER OVER THE BALSAM MTNS AND UPPER FRENCH
BROAD VALLEY TO THE SW OF KAVL...BUT THIS SHOULD NOT AFFECT ANY
TERMINALS. THE CLOUDS SHOULD DISSIPATE WITH SUNSET. EXPECT MAINLY
CLEAR SKY AND LIGHT/VARIABLE WIND TONIGHT.

OUTLOOK...MAINLY DRY CONDITIONS WILL PERSIST THROUGH THE PERIOD...
BUT WITH RETURN FLOW MOISTURE VERY SLOWLY REDEVELOPING OVER THE MTNS
THROUGH EARLY NEXT WEEK.

CONFIDENCE TABLE...

            14-20Z        20-02Z        02-08Z        08-12Z
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

&&

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

&&

$$
SYNOPSIS...CDG
NEAR TERM...HG/PM
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...HG/PM



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