Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 280723
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
323 AM EDT TUE JUL 28 2015

.SYNOPSIS...
HIGH PRESSURE WILL PERSIST OVER THE REGION THROUGH WEDNESDAY...WITH
CONTINUED WARM TEMPERATURES. A WEAK COLD FRONT WILL APPROACH THE
AREA FROM THE NORTHWEST ON THURSDAY AND SETTLE JUST SOUTH OF THE
REGION ON FRIDAY. THE FRONT WILL LIKELY REMAIN STALLED JUST SOUTH OF
THE AREA THROUGH THE WEEKEND...WITH COOLER TEMPERATURES EXPECTED.
MOISTURE SHOULD INCREASINGLY RETURN NORTHWARD OVER THE FRONT THE
LATTER HALF OF THE WEEKEND INTO EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 320 AM...RADAR INDICATED WEAK ISOLATED SHOWERS ACROSS THE NC
PIEDMONT WITH ANOTHER CLUSTER SLIDING EAST TOWARD THE NORTH FOUR NC
COUNTIES. CAMS INDICATE THAT THE CONVECTION WILL GRADUALLY DISSIPATE
ACROSS THE MTNS...WITH A FEW SHRA LINGERING ACROSS THE PIEDMONT
THROUGH SUNRISE. THIS AFTERNOON...NEAR TERM MODELS SHOW THE CENTER
OF THE H5 HIGH OVER THE CENTRAL PLAINS...WITH NW TO SE HEIGHTS
ACROSS THE WESTERN CAROLINAS. RECENT W/V IMAGES INDICATED THAT WELL
DEVELOP VORT MAX WAS MOVING OVER THE WESTERN OHIO RIVER VALLEY. 0Z
RUNS OF THE NEAR TERM MODELS DID RESOLVE THIS FEATURE VERY
WELL...BUT THE NAM APPEARS THE BEST INITIALIZED WITH THE FEATURE.
THE VORT SHOULD TRACK SE THROUGH THE DAY...REACHING THE SOUTHERN
APPALACHIANS BY EARLY THIS EVENING. FORECAST SOUNDINGS SHOW GREATER
INSTABILITY AND LOWER LFC THIS AFTERNOON COMPARED TO THE PAST
SEVERAL DAYS. GIVEN THE APPROACH OF THE MID LEVEL FEATURE AND MORE
SUPPORTIVE THERMAL PROFILES...I WILL FORECAST 40 POPS ACROSS THE
MTNS AND 30 POPS EAST. THE CENTER OF THE VORT IS EXPECTED TO PASS TO
THE SW...HOWEVER...CONVECTION ACROSS THE FA MAY REMAIN WELL INTO THE
EVENING. I WILL KEEP SCT POPS IN THE FORECAST UNTIL MIDNIGHT. HIGH
TEMPERATURES THIS AFTERNOON WILL REMAIN COMPARABLE TO THE PAST TWO
DAYS...SLIGHTLY COOLER THAN YESTERDAY.

TONIGHT...CONVECTION AFTER MIDNIGHT IS FORECAST TO REMAIN
SPARSE...BUT ENOUGH TO SUPPORT SCHC POPS. PERIODS OF DEBRIS
CLOUDS...MILD THICKNESSES...AND LIGHT SOUTH LLVL WINDS SHOULD KEEP
MIN TEMPERATURES MILD. USING A BLEND OF PREFERRED GUIDANCE...I WILL
FORECAST LOWS IN THE UPPER 60S WITHIN THE MTN VALLEYS TO LOW 70S
EAST.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 245 AM EDT TUESDAY...A BROAD UPPER RIDGE WILL STRETCH ACROSS
THE SOUTHERN TIER OF THE UNITED STATES ON WEDNESDAY. WEAK LOBES OF
VORTICITY MAY DROP SOUTHWARD THROUGH THE WESTERN CAROLINAS WEDNESDAY
AFTERNOON ALONG THE ERN PERIPHERY OF THE RIDGE. MOUNTAIN TRIGGERING
OF CONVECTION IS LIKELY EARLY WED AFTERNOON...ESPECIALLY ALONG THE
ERN SLOPES WHERE LOW LEVEL CONVERGENCE WILL BE BEST. ANY EARLY TO
MID AFTERNOON MOUNTAIN ACTIVITY MAY DEVELOP EASTWARD OFF THE HIGHER
TERRAIN INTO THE PIEDMONT THROUGH THE EVENING AND EARLY OVERNIGHT
HOURS.

GRADUAL HEIGHT FALLS ARE THEN EXPECTED THROUGH THURSDAY...BUT WITH
THE BEST SHORTWAVE ENERGY ASSOCIATED WITH A VIGOROUS NRN STREAM WAVE
PASSING N OF THE AREA FROM THE OH VALLEY TO THE MID ATLANTIC THROUGH
THU NIGHT. THE DEVELOPING TROUGH WILL ALLOW A COLD FRONT TO ARRIVE
IN THE SOUTHERN APPALACHIANS FROM THE NORTHWEST THU AFTERNOON...BUT
IT WILL LIKELY STALL OVER THE LOWER PIEDMONT THROUGH EARLY FRIDAY
MORNING. ABOVE CLIMO TEMPERATURES WILL PERSIST THROUGH THE PERIOD.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 245 AM EDT TUESDAY...MORE PROMINENT HEIGHT FALLS ARE EXPECTED
ON FRIDAY...WITH AN EASTERN CONUS TROUGH DEVELOPING AND LINGERING
OVER THE REGION THROUGH THE WEEKEND INTO EARLY NEXT WEEK. THE
STALLED BOUNDARY ALONG THE SRN PERIPHERY OF THE AREA WILL ALLOW
DEEPER MOISTURE TO REMAIN CLOSE BY...BUT WITH SOME MEASURE OF DRYING
ARRIVING FROM THE NORTH FRIDAY INTO SATURDAY. A DECENT N TO S
GRADIENT OF SLIGHT CHANCE TO SOLID CHANCE POPS WILL BE WARRANTED
BOTH AFTERNOONS. MAX TEMPS WILL FALL TO OR BELOW CLIMO VALUES.

THERE IS SOME POTENTIAL FOR A WEAK DISTURBANCE IN THE NE GULF OF
MEXICO TO GET ENTRAINED INTO THE TROUGH AND FEED EVEN BETTER
MOISTURE NWD THROUGH THE PIEDMONT OF THE CAROLINAS SUNDAY THROUGH
MONDAY. WILL KEEP ASSOCIATED POPS FAIRLY CONSERVATIVE IN THE CHANCE
CATEGORY GIVEN THE UNCERTAINTY...BUT CONTINUED COOLER MAX TEMPS
LOOKS MORE LIKELY WITH NO 90S EXPECTED ANYWHERE IN THE CWA SUNDAY TO
MONDAY.

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
AT KCLT...RECENT SATELLITE IMAGES AND OBSERVATIONS INDICATED
WIDESPREAD MID LEVEL CLOUDS ACROSS THE I-77 CORRIDOR. THE THICK MID
LEVEL CLOUD COVER SHOULD GRADUALLY DISSIPATE THROUGH SUNRISE.
FORECAST SOUNDINGS AND SEVERAL MOS MEMBER INDICATE THAT MVFR
CEILINGS MAY DEVELOP ONE TO TWO HOURS AFTER SUNRISE...REMAINING
THROUGH MOST OF THE MORNING. I WILL USE A TEMPO DURING THE 12Z TO
15Z FORMATION PERIOD...FOLLOWED BY A FM GROUND FOR BKN030 AT 15Z.
CAMS AND PERSISTENCE SUPPORT A PROB30 BETWEEN 19Z TO 23Z FOR TSRA.
WINDS SHOULD REMAIN BETWEEN 140-170 DEGREES AROUND 5 KTS THROUGH THE
PERIOD.

ELSEWHERE...MOSTLY CLEAR SKY...CALM WINDS...AND 2 DEGREE DEWPOINT
DEPRESSIONS MAY YIELD IFR FOG AT KAVL BY SUNRISE. I WILL INCLUDE A
TEMPO IN THE KAVL TAF FROM 10Z TO 13Z FOR IFR FOG AND MVFR CEILINGS.
KHKY MAY ALSO SEE IFR CONDITIONS AROUND SUNRISE. OTHERWISE...I WILL
MONITOR TRENDS THIS MORNING...BUT WILL SIDE WITH VFR AT THIS TIME.
THE AFTERNOON APPROACH OF A WEAK MID LEVEL DISTURBANCE SHOULD YIELD
A ROUND OF SHRA/TSRA LATE THIS AFTERNOON AND EVENING. I WILL INCLUDE
A PROB30 IN EACH TAF...GENERALLY BETWEEN 20Z TO 24Z.

OUTLOOK...A MID LEVEL RIDGE WILL REMAIN ACROSS THE WESTERN CAROLINAS
THROUGH MID WEEK. A LONGWAVE TROUGH WILL AMPLIFY ACROSS THE ATLANTIC
STATE LATE IN THE WEEK...WITH THE LIKELY PASSAGE OF A COLD FRONT ON
FRIDAY. THE POTENTIAL FOR CONVECTION WILL INCREASE EACH DAY THIS
WEEK.

CONFIDENCE TABLE...

            07-13Z        13-19Z        19-01Z        01-06Z
KCLT       HIGH 100%     MED   68%     HIGH 100%     HIGH 100%
KGSP       HIGH  93%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH  82%     HIGH  91%     HIGH 100%     HIGH 100%
KHKY       HIGH  83%     MED   78%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH  93%     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...HG
NEAR TERM...NED
SHORT TERM...HG
LONG TERM...HG
AVIATION...NED


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