Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 011051
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
651 AM EDT TUE SEP 1 2015

.SYNOPSIS...
HIGH PRESSURE WILL LINGER ACROSS THE REGION EARLY THIS WEEK. WEAK
DISTURBANCES MAY RIPPLE ACROSS THE LOWER AND MIDDLE APPALACHIAN
REGION BY MID TO LATE WEEK. A COOL AND MOIST AREA OF HIGH PRESSURE
IS EXPECTED TO SETTLE ACROSS THE WESTERN CAROLINAS AND NORTHEAST
GEORGIA THIS WEEKEND INTO EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM EDT...IR SATELLITE IMAGERY SHOWS JUST A FEW LINGERING
PATCHES OF STRATOCUMULUS STILL TRAPPED UNDER A MID LEVEL SUBSIDENCE
INVERSION. THE IR LOW CLOUD PRODUCT SHOWS STRATUS IN THE MOUNTAIN
VALLEYS AND EAST OF INTERSTATE 77...AND PATCHY FOG WORDING WILL BE
RETAINED THROUGHOUT THIS MORNING GIVEN THE MOSTLY CLEAR SKIES AND
MOIST BOUNDARY LAYER.

OTHERWISE...UPPER HEIGHTS WILL GENERALLY BUILD OVER THE SE TODAY
BEFORE FALLING A BIT FROM THE N TONIGHT AS A WAVE GETS PICKED UP
OVER THE OH VALLEY AND CARRIED EASTWARD. SURFACE HIGH PRESSURE WILL
REMAIN CENTERED ALONG THE APPALACHIANS TO THE N OF THE FORECAST
AREA. WATER VAPOR IMAGERY CONTINUES TO SHOW PERSISTENT TROPICAL
MOISTURE EXTENDING FROM CENTRAL FL TO THE EXTREME SE COASTLINE...BUT
MOISTURE WILL BE MUCH SPARSER IN PROFILES OVER OUR FORECAST AREA.
GIVEN THE WARM TEMPS ALOFT AND WEAK INSTABILITY IN MODEL
PROFILES...EXPECT A REPEAT OF MAINLY ISOLATED TO SCATTERED WEAK
MOUNTAIN RIDGETOP CONVECTION THIS AFTERNOON AND EARLY EVENING. MAX
TEMPS SHOULD RETURN TO 90 DEGREES FOR A GOOD CHUNK OF THE
FOOTHILLS/PIEDMONT...WITH MILD MINS EXPECTED TONIGHT.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 245 AM TUESDAY...ON WEDNESDAY...THE CENTER OF A H5 RIDGE IS
FORECAST TO REMAIN OVER FL AS A S/W TROF RIPPLES SE ACROSS THE
VIRGINAS AND NC. GFS INDICATES THAT THE CENTER OF THE VORT MAX
WITHIN THE S/W WILL PASS NORTH OF THE FORECAST AREA. HOWEVER...IT
APPEARS THAT A PORTION OF THE NORTHERN NC FOOTHILLS WILL FALL UNDER
A REGION OF Q-VECTOR CONVERGENCE. FORECAST SOUNDINGS SHOW THE
GREATEST INSTABILITY WILL DEVELOP IN THE VICINITY OF THE S/W...WITH
CAPE VALUES RANGING FROM 1500-2000 J/KG. GIVEN THE WIDE FIELD OF
INSTABILITY...LATE AFTERNOON PASSAGE OF THE S/W...AND MODERATE STORM
MOTIONS...IT APPEARS TSRA COVERAGE WILL FAVOR THE NC ZONES. I WILL
FORECAST CHC POPS ACROSS THE MTNS AND ADJACENT NC FOOTHILLS...WITH
SCHC TO THE SOUTHEAST. HIGH TEMPERATURES ARE FORECAST TO RANGE FROM
THE MID 80S WITHIN THE MTN VALLEYS TO LOW 90S EAST.

ON THURSDAY...SFC HIGH PRESSURE SHOULD BUILD ACROSS THE CWA FROM THE
NORTHWEST. USING A BLEND OF PREFERRED GUIDANCE...AFTERNOON DEWPOINTS
SHOULD RANGE GENERALLY IN THE MID 60S. FORECAST SOUNDINGS INDICATE A
DEEP INVERTED-V PROFILE...WITH WEAK CAPE VALUES ACROSS THE REGION. I
WILL INDICATE SCHC POPS ALONG AND NORTH OF I-85...WITH A FEW PATCHES
OF CHC POPS ACROSS THE RIDGES. HIGH TEMPERATURES MAY RANGE 2-3
DEGREES ABOVE NORMAL.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 3 AM TUESDAY...USING A BLEND OF THE ECMWF AND GFS...A LONGWAVE
MID LEVEL RIDGE SHOULD BUILD ACROSS THE GREAT LAKES ON FRIDAY...THEN
PIVOTING ACROSS NEW ENGLAND AND STRENGTHENING TO 595 DM DURING THE
WEEKEND. A BROAD MID LEVEL LOW IS EXPECTED TO GRADUALLY FORM OVER
THE SOUTHEAST TO DEEP SOUTH OVER THE WEEKEND AND MONDAY.

ON FRIDAY...THE CENTER OF A SFC HIGH WILL DEVELOP OVER NEW
ENGLAND...WITH A INCREASE OF RIDGING ARRIVING OVER THE CWA DURING
THE AFTERNOON. I WILL FORECAST INCREASING CLOUD COVER THROUGH THE
DAYLIGHT HOURS FRIDAY. MODEL CAPES INDICATE THAT WEAK TO MODERATE
INSTABILITY WILL DEVELOP WITH HIGH TEMPS REACHING AROUND 2 DEGREES
ABOVE NORMAL. POPS SHOULD VERIFY WELL WITH CHC POPS ACROSS THE CWA.
SFC WINDS SHOULD VEER FROM THE NE DURING THE LATE AFTERNOON.

THE MEDIUM RANGE MODELS INDICATE THAT THE COLD AIR DAMMING PATTERN
WILL PEAK DURING THIS WEEKEND. IN FACT...THE GFS INDICATES THAT
PIEDMONT WINDS WILL STRENGTHEN TO MARGINALLY GUSTY NE WINDS AFTER
SUNRISE. THE NE WINDS...BKN TO OVC SKY COVER...SCT
SHRA/TSRA...SHOULD PROVIDE COOLER TEMPERATURES ON SATURDAY. THE 2M
TEMPS FROM THE ECMWF AND GFS HAVE HIGH TEMPERATURES IN THE MID TO
UPPER 70S ON SAT. I WILL COOL HIGH FOR SAT...BUT WILL SHOULD TEMPS
GENERALLY 5 DEGREE WARMER THAN THE RAW MODEL VALUES. ON SUNDAY...NE
WINDS APPEAR AS STRONG AS SAT...BUT CLOUD COVER APPEARS A DEGREE
THINNER. HIGH TEMPS WILL REMAIN BELOW NORMAL...BUT LIKELY 2 TO 3
DEGREES WARMER THAN SAT. ON MONDAY...THE SFC HIGH CENTER SHIFTS OVER
THE WESTERN ATLANTIC...RESULTING IN WEAKER WINDS ACROSS THE REGION.
I WILL LIMIT CHC POPS TO THE MTNS AND FOOTHILLS. HIGHS TEMPS MAY
RANGE WITHIN A COUPLE OF DEGREES OF NORMAL ON MON.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AT KCLT...PATCHY VLIFR/LIFR STRATUS EAST OF THE AIRFIELD...ALONG
WITH DEVELOPING PATCHY FOG...REMAIN THE PRIMARY CONCERNS THIS
MORNING. THE LAMP MOS CONTINUES TO BE QUITE RESERVED ON MORNING
RESTRICTIONS SO WILL ONLY MENTION SOME TEMPO MVFR FOG FOR A COUPLE
OF HOURS PAST DAYBREAK. VFR CUMULUS WILL REDEVELOP WITH HEATING
THROUGH THE DAY. LIGHT WINDS WILL BE MOSTLY FROM THE NE GIVEN THE
SFC HIGH PRESSURE TO THE NORTH.

ELSEWHERE...THE BEST CHANCE OF LINGERING MORNING LOW STRATUS AND FOG
WILL BE IN THE MOUNTAIN RIVER VALLEYS...AFFECTING KAVL. VFR CUMULUS
SHOULD DEVELOP WITH HEATING TODAY. PROFILES DO NOT EXHIBIT MUCH
INSTABILITY...BUT INSTABILITY AND COVERAGE WILL BE BEST NEAR KAVL
WHERE A VCTS WILL BE ADVERTISED. EXPECT LIGHT WINDS
THROUGHOUT...WITH MORE N TO NE FLOW EARLY...BECOMING MORE SRLY AT
THE UPSTATE TAF SITES THROUGH THE PERIOD.

OUTLOOK...A PLUME OF GULF AND ATLANTIC MOISTURE WILL CONTINUE TO
WRAP UP ALONG THE SE COAST THROUGH THE WEEK. RESTRICTIONS ARE
POSSIBLE DURING PERIODS OF ANY SCATTERED SHOWERS OR THUNDERSTORMS.
IN ADDITION...LOW CLOUDS AND FOG MAY DEVELOP EACH NIGHT...ESPECIALLY
IN THE MOUNTAIN VALLEYS.

CONFIDENCE TABLE...

            11-17Z        17-23Z        23-05Z        05-06Z
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

&&

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

&&

$$
SYNOPSIS...NED
NEAR TERM...HG
SHORT TERM...NED
LONG TERM...NED
AVIATION...HG



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