Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 222106
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
506 PM EDT FRI MAY 22 2015

.SYNOPSIS...
DRY CANADIAN HIGH PRESSURE WILL LINGER ATOP THE REGION THROUGH THE
HOLIDAY WEEKEND. A SOUTHERLY FLOW OF MOISTURE AROUND BERMUDA HIGH
PRESSURE WILL GRADUALLY RETURN NEXT WEEK.

&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 5 PM...NICE CONDITIONS ACROSS THE REGION PROVIDE LITTLE REASON
TO UPDATE THE FORECAST. RECENT SATELLITE IMAGES AND VIEW OUT THE
WINDOWS INDICATED A PATCH OF CIRRUS/WAVE CLOUDS ACROSS THE NC/SC
STATE LINE ACROSS THE FOOTHILLS AND PIEDMONT. I WILL UPDATE THE
FORECAST TO INDICATE THAT CLOUD COVER MAY REMAIN FOR A COUPLE OF
HOURS. MINOR EDITS MADE TO HOURLY TEMP AND DEWPOINTS LATE THIS
AFTERNOON.

AS OF 200 PM EDT FRIDAY...AN APPROACHING UPPER RIDGE AXIS WILL ALLOW
HEIGHTS TO CONTINUALLY RISE THROUGH THE PERIOD.  A SURFACE RIDGE
SLIDING THROUGH THE NORTHERN OHIO VALLEY REGION WILL CONTINUE TO
ADVECT EAST TONIGHT...THROUGH THE DAY ON SATURDAY ALLOWING FOR A
WEAK BACK DOOR REINFORCING FRONT TO PUSH INTO NORTHEAST GA AND THE
WESTERN CAROLINAS.  THUS...THE ENTIRE FCST REMAINS DRY WITH BELOW
NORMAL TEMPERATURES AND LIGHT GRADUALLY VEERING WINDS HIGHLIGHTING
THE PERIOD.  EXPECTING CLEAR SKIES TO PREVAIL OVERNIGHT TONIGHT
LEADING TO ABUNDANT RADIATIONAL COOLING...THEREFORE TEMPERATURES
WERE POPULATED FROM A CONSENSUS OF RAW GUIDANCE WHICH WAS 3-5
DEGREES COOLER THAN MOSGUIDE.  EXPECTING LOWS TONIGHT IN THE UPPER
40S TO LOWER 50S OVER THE LOWER TERRAIN...WHILE SOME VALUES IN THE
LOWER/MID 30S ARE EXPECTED OVER THE HIGHER ELEVATIONS.  HIGHS ON
SATURDAY WILL BE SLIGHTLY WARMER THAN TODAY...HOWEVER STILL APPROX 3-
5 DEGREES BELOW CLIMO WITH DEWPOINTS IN THE 40S SUPPORTING LOW
HUMIDITY LEVELS.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 210 PM FRIDAY...DRY WX WILL CONTINUE ON SUNDAY AS UPPER RIDGE
AXIS CONTINUES TO BUILD ATOP THE SE CONUS. LLVL FLOW AROUND BERMUDA
HIPRES WILL STEADILY ADVECT HIGHER TEMPERATURES AND DWPTS INTO THE
SOUTHERN APPALACHIANS. MAXIMUMS WILL BE A FEW DEG F WARMER
THAN SATURDAY TOPPING OUT A BIT ABOVE CLIMO. THE UPPER PATTERN
EVOLVES SLOWLY ON MONDAY WITH THE RIDGE AXIS SHARPENING. IT IS
DEBATABLE HOW JUST FAR WEST IT/S SUPPRESSIVE EFFECTS LINGER THROUGH
SUNSET BUT THE STEADY INCREASE IN LLVL MOISTURE LEADS THE MODEL
CONSENSUS TO FAVOR AT LEAST ISOLATED DIURNAL DEEP CONVECTION IN
AND/OR NEAR THE HIGH TERRAIN. TEMPERATURES ARE SLATED TO CONTINUE TO
RISE 2-3 DEG F ABOVE SUNDAY/S READINGS.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 215 PM FRI...THE MEDIUM RANGE CONTINUES TO LOOK SUMMER-LIKE
WITH AN UPPER RIDGE/ANTICYCLONE HOLDING ALONG THE SOUTHEAST COAST
AND A BERMUDA HIGH AT THE SURFACE PROVIDING A GENERALLY MOIST FLOW
FROM THE GULF/ATLANTIC AT LOW LEVELS. THIS WILL FAVOR ABOVE NORMAL
TEMPS AND MAINLY DIURNAL SHOWERS AND STORMS EACH DAY. THERE IS SOME
DISCREPANCY IN THE MODELS ON THURSDAY...FOR WHAT IT IS WORTH...IN
TERMS OF THE TIMING AND STRENGTH OF A SHORT WAVE MOVING ACROSS THE
MIDWEST/OH VALLEY. THIS FEATURE COULD PUSH A WEAK BOUNDARY INTO THE
AREA ON WEDNESDAY EVENING OR THURSDAY WHICH WOULD ENHANCE PRECIP
CHANCES MAINLY OVER THE MTNS...HENCE THE LIKELY POP OVER PARTS OF
THE MTNS BOTH DAYS. CHANCES MAY GO DOWN A BIT FOR FRIDAY IF THAT
BOUNDARY ACTUALLY MOVES THRU. THE CHANCES FOR SEVERE THUNDERSTORMS
EACH DAY LOOK MINIMAL AT THIS POINT BECAUSE OF POOR LAPSE RATES AND
RELATIVELY WEAK INSTABILITY WITH MID LEVEL WARM AIR.

&&

.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...VFR THROUGH THE PERIOD WITH WINDS BEING THE
ONLY MINOR ISSUE FOR ALL SITES.  RISING UPPER HEIGHTS AMIDST
BUILDING HIGH PRESSURE AT THE SURFACE WILL ALLOW FOR SKC...WITH
PERHAPS A FEW OCCASIONAL HIGH CIRRUS ON SATURDAY.  SAID SURFACE
RIDGE WILL SHIFT THROUGH THE OHIO VALLEY TODAY/TONIGHT...THEN EAST
OVER THE CENTRAL APPS ON SATURDAY.  IN RESPONSE...LIGHT/NORTHERLY
WINDS THIS AFTERNOON WILL CALM OVERNIGHT BEFORE VEERING
EAST/SOUTHEAST LATE IN THE PERIOD...HOWEVER GENERALLY AROUND 5KTS OR
LESS.

OUTLOOK...DEEP HIGH PRESSURE WILL SETTLE OVER THE REGION OVER THE
WEEKEND...THEN SHIFT EAST EARLY NEXT WEEK...ALLOWING MOISTURE TO
GRADUALLY RETURN OUT OF THE SOUTH. CONDITIONS SHOULD REMAIN
GENERALLY FAIR THROUGH THE PERIOD.

CONFIDENCE TABLE...

            21-03Z        03-09Z        09-15Z        15-18Z
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...CSH
NEAR TERM...NED
SHORT TERM...CSH
LONG TERM...PM
AVIATION...CDG



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