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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KGSP 200127
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
927 PM EDT WED JUN 19 2013

.SYNOPSIS...
COOLER HIGH PRESSURE CENTERED NEAR NEW YORK STATE WILL RIDGE
SOUTHWARD TONIGHT AND THURSDAY. THIS HIGH WILL DRIFT TO NEAR BERMUDA
AND INTO NEXT WEEK AS AN UPPER RIDGE BUILDS IN FROM THE WEST AS
TEMPERATURES SLOWLY RISE.

&&

.NEAR TERM /THROUGH THURSDAY/...
-- Changed Discussion --
AT 930 PM EDT WEDNESDAY...AN UPPER TROUGH WAS LOCATED ALONG THE
EAST COAST...WHILE AND UPPER RIDGE WAS LOCATED OVER THE PLAINS. A
SHORTWAVE WAS MOVING THROUGH THE BASED OF THIS TROUGH. SURFACE
ANALYSIS PLACE A STATIONARY FRONT FROM THE GA COAST WEST ACROSS THE
GULF STATES...AND A WEAKENING COLD FRONT FROM SOUTHERN VA TO THE MID
MS RIVER VALLEY. RADAR HOWS ACTIVITY ALONG THE NC BLUE RIDGE...AND
IN THE MOUNTAINS OF N GA. MODEL SOUNDINGS SHOW THE ATMOSPHERE
STABILIZING THIS EVENING...AND POPS WILL BE ALLOWED TO DECREASE.
MINIMUM TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL...AS UNDER THE
ANOMALOUS UPPER TROUGH...AND WITH A RELATIVELY DRY AIR MASS.

MODEL TIME HEIGHTS SHOW LOW LEVEL MOISTURE INCREASING TOWARD SUNRISE
AS MOISTURE FROM ATLANTIC ADVECTS INTO THE AREA. THEREFORE...EXPECT
A PERIOD OF LOW CLOUDINESS EARLY THU...ESPECIALLY EAST OF I-26. ON
THU...HIGH PRESSURE LOCATED OFF THE NEW ENGLAND COAST WILL REMAIN
RIDGED INTO THE AREA PRODUCING AN EASTERLY WIND FLOW IN THE SOUTHERN
APPALACHIANS. THE UPSLOPE FLOW IN THE MOUNTAINS SHOULD PRODUCE
SCATTERED SHOWERS AND THUNDERSTORMS DURING THE AFTERNOON HOURS.
USING A BLEND OF MODELS PRODUCES MAX TEMPS ABOUT A CATEGORY BELOW
AVERAGE ON THU.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 210 PM EDT WED...SHORT RANGE MODELS AGREE THAT THE REGION WILL
REMAIN UNDER A WEAK MID LEVEL TROUGH...WITH RIDGING ACROSS THE
SOUTHERN PLAINS AND ATLANTIC. AT THE SFC...A STATIONARY FRONT AND
POSSIBLE FRONTAL WAVE WILL REMAIN ACROSS THE COASTAL PLAIN OF THE
CAROLINAS. WEAK SFC RIDGING MAY REMAIN ACROSS THE SOUTHERN
APPALACHIAN REGION. GIVEN THE SFC PATTERN...I WILL INDICATE
PERSISTENT NE WINDS ACROSS THE FOOTHILLS AND PIEDMONT FOR FRIDAY AND
SATURDAY. A BLEND OF MODEL GUIDANCE INDICATES THAT SKY COVER WILL
REMAIN PARTLY TO MOSTLY CLOUDY THROUGH THE PERIOD. THE COMBINATION
OF NE WINDS AND CLOUD COVER SHOULD YIELD TEMPERATURES 3 TO 5 DEGREES
BELOW NORMAL. OVERALL...THE CHCS OF SHRA AND TSRA APPEARS
UNFAVORABLE WITHIN THE CORRIDOR OF DEEP NE FLOW. IN FACT...MODEL
CAPE FIELDS INDICATE LITTLE TO NO VALUES FOR SFC BASED PARCELS
BETWEEN THE EAST FACING MTN SLOPES TO THE WESTERN PIEDMONT. I WILL
INDICATE SCHC POPS FOR TS ACROSS THE EXTREME WESTERN NC MTNS ON FRI
AND SAT. BY SAT...LLVL WINDS MAY VEER NE...POSSIBLY ALLOWING WEAK
INSTABILITY ACROSS NE GA AND THE EASTERN PIEDMONT DURING THE LATE
AFTERNOON.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 240 PM EDT WED...A 591 DM H5 RIDGE WILL REMAIN DOMINANT OVER
THE SE THROUGH THE MEDIUM RANGE PERIOD. ANTICIPATE A MAINLY DIURNAL
TREND OF ISOLD TO SCATTERED AFTERNOON POPS THROUGH THE PERIOD...WITH
THE MTNS BEING THE PRIMARY FOCUS. THE GFS IS THE MOST AGGRESSIVE IN
BRINGING AN INVERTED COASTAL TROUGH BACK INLAND ALONG THE SAVANNAH
ON SATURDAY...BUT THE OTHER OPERATIONAL AND ENSEMBLE MEAN SOLUTIONS
KEEP THE SYSTEM ALONG THE IMMEDIATE COAST WITH THE RIDGE PERSISTING
OVER THE WRN CAROLINAS. THE DIURNAL PATTERN OF ISOLD TO SCT SHOWERS
AND THUNDERSTORMS SHOULD THUS CONTINUE SUN THROUGH TUE...WITH
TEMPERATURES STEADILY WARMING UNDER THE UPPER RIDGE. EXPECT MAXES TO
REACH CLIMATE NORMALS BY SUNDAY AND THEN EXCEED THEM MON AND TUE.
THE UPPER RIDGE WILL BREAK DOWN IN MID WEEK AS A UPPER TROUGH FORMS
OVER THE EAST COAST FOR THE SECOND HALF OF NEXT WEEK. THE GFS IS A
BIT MORE PROGRESSIVE IN BRINGING THE TROUGH IN SOONER BY LATE WED OR
WED NIGHT AS OPPOSED TO THUR OR FRI ON THE ECMWF. TEMPS ARE EXPECTED
TO COOL SOME AS THIS TROUGH SETS UP WITH MORE CLOUDS AND HIGHER POPS.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
AT KCLT...CONVECTION DOES NOT APPEAR LIKELY THIS EVENING AS ACTIVITY
IS FOCUSED CLOSER TO A BOUNDARY IN THE MOUNTAINS...AND HEATING WILL
ABATE. A BLEND OF GUIDANCE FAVORS A VERY LOW LOW MVFR CIG BY
DAYBREAK...BUT NO VSBY RESTRICTION. CONVECTION ON THURSDAY IS
EXPECTED TO BE LIMITED TO MOUNTAINOUS TERRAIN WELL TO OFF TO THE
NORTHWEST. WINDS WILL BE LIGHT NE OVERNIGHT...APPROACHING 10 KNOTS
ON THURSDAY.

ELSEWHERE...EVENING CONVECTION IS EXPECTED TO BE LIMITED MAINLY TO
THE MOUNTAINS NEAR A WEAK FRONT. A CONSENSUS OF MODEL GUIDANCE
FAVORS LOW MVFR COGS TOWARD DAYBREAK...EXCEPT AT KAND WHERE CLOUD
COVER IS EXPECTED TO BE MORE LIMITED. BLENDED MODEL DATA SUPPORTS
DAYBREAK MVFR VSBY RESTRICTIONS IN THE NC MOUNTAINS...INCLUDING
KAVL...AND A LOW VFR RESTRICTION AT KAND. LIGHT NE WINDS WILL
PERSIST OVERNIGHT IN THE FOOTHILLS...WITH LIGHT AND VARIABLE
EXPECTED AT KAVL. NE WINDS WILL APPROACH 10 KNOTS IN THE FOOTHILLS
THURSDAY...WHILE SE WINDS APPROACH 10 KNOTS AT KAVL.

OUTLOOK...AFTERNOON AND EVENING CONVECTION IS EXPECTED...WITH THE
BEST COVERAGE OVER THE MOUNTAINS. EARLY MORNING STRATUS IS POSSIBLE
EACH DAY...ACCOMPANIED BY VALLEY FOG IN THE MOUNTAINS.

CONFIDENCE TABLE...

            01-07Z        07-13Z        13-19Z        19-01Z
KCLT       HIGH 100%     HIGH  92%     HIGH  95%     HIGH 100%
KGSP       HIGH 100%     MED   79%     HIGH  87%     HIGH 100%
KAVL       HIGH  94%     HIGH  90%     HIGH  92%     HIGH 100%
KHKY       HIGH  97%     HIGH  85%     HIGH  95%     HIGH 100%
KGMU       HIGH 100%     MED   74%     HIGH  92%     HIGH 100%
KAND       HIGH 100%     HIGH  92%     HIGH  92%     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
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...DEO
NEAR TERM...JAT/LG
SHORT TERM...NED
LONG TERM...DEO
AVIATION...JAT