Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 020700
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
300 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 230 AM...CLEAR SKY AND LIGHT WIND ACROSS THE ENTIRE FCST AREA.
SEEING A FEW PATCHES OF FOG DEVELOPING MAINLY OVER THE WRN PIEDMONT
OF NC AND THE LITTLE TN VALLEY...AND THAT SHOULD EXPAND A BIT THRU
THE PRE-DAWN HOURS...BUT A DENSE FOG PROBLEM IS NOT ANTICIPATED.

WITH THE DEPARTURE OF THE UPPER LOW OFF THE EAST COAST THIS
MORNING...WE WILL BE LEFT WITH A NW FLOW FOR TODAY AND TONIGHT. A
WEAK SHORT WAVE DROPPING DOWN IN THE NW FLOW WILL PASS THIS
AFTERNOON AND EVENING WITH A BRIEF SHOT OF WEAK DPVA. THIS MIGHT
JUST BE ENOUGH TO FAVOR THE DEVELOPMENT OF A FEW SHOWERS OVER THE
HIGHER ELEVATIONS OF THE BALSAMS...WHICH SOME OF THE CONVECTION
ALLOWING MODELS INDICATE. WILL SLIGHTLY EXPAND THE SLIGHT CHANCE OF
SHOWERS THIS AFTERNOON...BUT MOST OF THE REGION WILL REMAIN DRY WITH
TEMPS REBOUNDING ABOUT TWO CATEGORIES RELATIVE TO YESTERDAY. SURFACE
HIGH PRESSURE WILL CONTINUE TO DRIFT SLOWLY EAST ACROSS THE REGION
THRU TONIGHT...BUT WITH THE AIR MASS MODIFYING MORE TODAY...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 /07Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...VFR CONDITIONS EXPECTED THROUGH THE
PERIOD...ALONG WITH A LIGHT N OR NW WIND. THERE IS A SMALL CHANCE OF
SOME MVFR FOG AT THE TERMINALS AROUND DAYBREAK...BUT THAT WAS NOT
INDICATED IN ANY OF THE GUIDANCE...AND SO IT WILL BE LEFT OUT OF THE
TAFS. ON SATURDAY AFTERNOON...EXPECT A FEW HIGH BASED STRATOCU TO
DEVELOP...BUT THAT SHOULD DISSIPATE WITH SUNSET. WIND WILL REMAIN
GENERALLY LIGHT FROM THE NW TO NW.

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...

            07-13Z        13-19Z        19-01Z        01-06Z
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...PM
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...PM



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