Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 310716
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
316 AM EDT MON AUG 31 2015

.SYNOPSIS...
H 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.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM EDT...REGIONAL RADARS SHOW THE BACK EDGE OF THE
PRECIPITATION GENERALLY LIFTING NORTH OF THE INTERSTATE 40 CORRIDOR
EARLY THIS MORNING AS AN UPPER VORTICITY MAXIMA CROSSES THE REGION
FROM THE SW. HOWEVER...A MOISTURE PLUME ORIENTED MORE N/S OVER THE
ERN PIEDMONT WILL LIKELY KEEP SHOWER ACTIVITY GOING LONGER EAST OF
INTERSTATE 77...PERHAPS UNTIL A LITTLE AFTER DAYBREAK.

OTHERWISE...PLENTY OF LOW LEVEL MOISTURE WILL LINGER BEHIND THE
DEPARTING UPPER SHORTWAVE...WITH RATHER PERSISTENT LOW LEVEL STRATUS
LIKELY DEVELOPING THROUGH THE MORNING HOURS. LITTLE TO NO UPPER
SUPPORT IS THEN EXPECTED FOR THE REMAINDER OF THE DAY AFTER THE
SHORTWAVE DEPARTS...LEAVING LIGHT SW FLOW OVER THE AREA BETWEEN A
TROUGH NEAR THE MS RIVER VALLEY AND AN OFFSHORE ATLANTIC RIDGE. ANY
BETTER TROPICAL MOISTURE SHOULD REMAIN SHUNTED TO THE COASTAL
REGION. IN THE ABSENCE OF ANY DEEPER LAYER FORCING...WEAK CONVECTION
WILL BE PREFERRED ALONG THE HIGHER TERRAIN FOR THE AFTN AND EVENING
HOURS...WITH A SECONDARY MAXIMA IN THE ERN PIEDMONT CLOSER TO THE
DEEPER MOISTURE. HOWEVER...PROFILES DO NOT EXHIBIT MUCH INSTABLITY
GIVEN THE EXPECTED WARM MID LEVEL TEMPERATURES. ANOTHER ROUND OF LOW
STRATUS WILL BE POSSIBLE TONIGHT...MOST LIKELY IN THE MOUNTAIN
VALLEYS. EXPECT MAXES TO REACH NEAR CLIMO THIS AFTN ONCE THE STRATUS
SCATTERS...BUT WITH MINS 1 TO 2 CATEGORIES ABOVE CLIMO TONIGHT.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 230 AM MONDAY...ON TUESDAY...THE CWA WILL REMAIN UNDER THE
WESTERN EDGE OF A DIRTY 592 DM RIDGE. FORECAST SOUNDINGS SHOWS A
LAYER OF NEARLY SATURATED AIR BETWEEN H8-H7...UNDER A WELL DEFINED
H65 INVERSION. I WILL FORECAST PARTLY TO MOSTLY CLOUDY CONDITIONS
THROUGH THE DAY. USING A BLEND OF PREFERRED MOS...HIGH
TEMPERATURES SHOULD RANGE FROM THE L80S WITHIN THE MTN VALLEYS TO
UPPER 80S EAST...VIRTUALLY NEAR NORMALS. HOWEVER...CAPES ACROSS
THE REGION SHOULD PEAK NEAR VALUES OF 1000 J/KG...WITH CIN
LINGERING WELL INTO THE AFTERNOON. PROVIDED FLOW LESS THAN 10 KTS
FROM THE SFC TO 15 KFT...STORM MOTIONS AND CONVERGENCE WILL REMAIN
LIMITED. I WILL FORECAST DIURNAL CHC POPS ACROSS THE MTNS AND
ADJACENT FOOTHILLS WITH SCHC VALUES EAST.

ON WEDNESDAY...SHORT RANGE MODELS INDICATE THAT THE CWA WILL FALL
WITHIN A WEAKNESS WITHIN THE MID LEVEL RIDGE. IN FACT...A S/W IS
EXPECTED TO RIPPLE ACROSS THE MID APPALACHIANS DURING THE
AFTERNOON....POSSIBLY BRUSHING THE REGION WITH MID LEVEL FORCING.
NAM FORECAST SOUNDINGS INDICATE THE CAPE VALUES WILL INCREASE TO
1500-2000 J/KG BY THE HEAT OF THE AFTERNOON. IN ADDITION...HIGH
TEMPERATURES ARE FORECAST TO RISE AROUND 2 DEGREE ABOVE VALUES
EXPECTED FOR TUESDAY. GIVEN THE LARGE FIELD OF INSTABILITY AND
PASSING DISTURBANCE ACROSS THE MID APPALACHIANS...A BROKEN BAND OF
TSRA MAY DEVELOP OVER THE VA/WV DURING THE AFTERNOON...SPREADING SE
DURING THE LATE AFTERNOON AND EVENING. I WILL FORECAST CHC POPS
ACROSS THE MTNS AND NC FOOTHILLS...WITH SCHC EAST OF I-85.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 310 AM MONDAY...MID LEVEL HEIGHTS ARE FORECAST TO DECREASE
ACROSS THE CWA DURING THE EXTENDED PERIOD. BY THE END OF THE
WEEK...THE CENTER OF A 595 DM RIDGE WILL SETTLE OVER THE NORTHEAST
CONUS...WITH A BROAD WEAKNESS OVER THE SOUTHEAST. THIS PATTERN
SHIFT WILL PROVIDE NEAR NORMAL TEMPERATURES DURING THE
WEEKDAYS...WITH A COOLING TREND DURING THE WEEKEND. I WILL
FORECAST SCHC TO CHC DIURNAL POPS WEDNESDAY THROUGH FRIDAY FOR
SHOWERS/THUNDERSTORMS...COVERAGE FAVORING THE MTNS. HOWEVER...THE
SFC PATTERN BY SAT NIGHT...ESPECIALLY ON THE 0Z GFS...APPEARS TO
SHOW A DEVELOPING AREA OF CAD. THE GFS INDICATES THAT BROAD AND
WEAK ISENTROPIC LIFT AND UPSLOPE FLOW WILL BE POSSIBLE ACROSS THE
REGION ON SUNDAY. I DID NOT WANT TO SINK HIGH TEMPS TO CAD
LEVELS...BUT DID ADJUST A LITTLE COOLER. IN ADDITION...I HAVE
MOSTLY CLOUDY CONDITIONS THROUGH MOST OF THE WEEKEND. POPS WILL
REMAIN IN THE CHC RANGE EACH DAY THIS WEEKEND.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...
AT KCLT...PERSISTENT SHRA IN THE SRLY FLOW OF TROPICAL MOISTURE
SHOULD WRAP UP MAINLY EAST OF THE AIRFIELD THROUGH DAYBREAK.
ANTICIPATE LOWER STRATUS FILLING IN IN THE MOIST BOUNDARY LAYER
ALONG WITH DRYING ALOFT FROM THE PASSING SHORTWAVE BY DAYBREAK. THE
RESULTING MVFR TO IFR CLOUDS COULD BE QUITE PERSISTENT THROUGH THE
MORNING HOURS BEFORE SCATTERING EARLY THIS AFTERNOON. EXPECT LIGHT
NE SURFACE WINDS THROUGH THE PERIOD WITH WEAK SURFACE HIGH PRESSURE
TO THE NORTH.

ELSEWHERE...ANY LINGERING EARLY MORNING SHOWERS WILL IMPACT MAINLY
KAVL TO KHKY THROUGH 09Z BEFORE PULLING NORTH. MID AND UPPER LEVEL
DRYING BEHIND THE PASSING UPPER WAVE WILL PROMOTE LOW STRATUS
DEVELOPMENT IN THE MOIST BOUNDARY LAYER THROUGH DAYBREAK. THE
STRATUS MAY BE QUITE PERSISTENT THROUGH THE MORNING HOURS...WITH
LITTLE SCATTERING BEFORE NOON. ANY ISOLD TO SCT RIDGE TOP WEAK
CONVECTION THIS AFTN WILL BE TOO SPARSE TO MENTION AT ANY OF THE TAF
SITES YET. EXPECT MAINLY LIGHT NE FLOW AT THE FOOTHILL SITES...WITH
WINDS BECOMING SE AT KAVL THROUGH THE AFTERNOON.

OUTLOOK...A PLUME OF GULF AND ATLANTIC MOISTURE WILL CONTINUE TO
WRAP UP ALONG THE SE COAST...GENERALLY JUST SOUTHEAST OF THE
TERMINAL FORECAST AREA...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...

            07-13Z        13-19Z        19-01Z        01-06Z
KCLT       HIGH  94%     HIGH  81%     HIGH 100%     HIGH 100%
KGSP       MED   66%     HIGH  81%     HIGH 100%     HIGH 100%
KAVL       HIGH  80%     HIGH  88%     HIGH 100%     HIGH 100%
KHKY       MED   76%     MED   79%     HIGH 100%     HIGH 100%
KGMU       MED   70%     MED   71%     HIGH 100%     HIGH 100%
KAND       MED   70%     MED   70%     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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