Area Forecast Discussion
Issued by NWS Greer, SC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KGSP 311438
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1038 AM EDT MON AUG 31 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.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM EDT...CLOUDS HAVE BEEN CLEARING OUT THIS MORNING...AS
DRY AIR FILTERS IN FROM THE NORTH. THERE IS STILL ENUF LLVL MOISTURE
TO SUPPORT A DECENT FAIR WX CU DECK TODAY. BASED ON THE CURRENT
TRENDS AND LATEST GUIDANCE...THE FCST IS ON TRACK. THE BIGGEST
CHANGE WAS TO DECREASE SKY COVER...WHICH MAY CHANGE WORDING TO
MOSTLY SUNNY TO PARTLY SUNNY TODAY. AS FOR CONVECTION CHANCES THIS
AFTN...THE GUIDANCE AND CONVECTION ALLOWING MODELS AGREE ON IT BEING
CONFINED TO THE HIGH TERRAIN...AND MAINLY JUST ISOLD TO WIDELY
SCATTERED SHWRS. CANNOT RULE OUT A FEW SHWRS OUTSIDE THE MTNS...AS
THE 12Z FFC SOUNDING SHOWS A MID LVL INVERSION AROUND 550 MB...WHICH
MAY ALLOW FOR SHALLOW CONVECTION.

AS OF 700 AM EDT...REGIONAL RADARS SHOW ALL THE PRECIPITATION
ASSOCIATED WITH THE DEPARTING VORT LOBE NORTH AND EAST OF THE AREA.
HOWEVER...PLENTY OF LOW LEVEL MOISTURE IS LINGERING...WITH RATHER
PERSISTENT STRATUS EXPECTED OVER THE PIEDMONT AND PARTS OF THE
FOOTHILLS AND THE MOUNTAINS VALLEYS THROUGH THE MORNING HOURS.
LITTLE TO NO FORCING IS EXPECTED TODAY WITH MAINLY LIGHT SW FLOW
ALOFT BETWEEN A TROUGH NEAR THE MS RIVER VALLEY AND AN OFFSHORE
ATLANTIC RIDGE. ANY BETTER TROPICAL MOISTURE SHOULD ALSO REMAIN
SHUNTED TO THE COASTAL REGION. ANY ISOLD TO SCATTERED WEAK
CONVECTION TODAY SHOULD BE CONFINED MOSTLY TO THE HIGHER TERRAIN FOR
THE AFTN AND EVENING HOURS...WITH A SLIGHT SECONDARY MAXIMA POSSIBLE
IN THE ERN PIEDMONT CLOSER TO THE DEEPER COASTAL MOISTURE. PROFILES
DO NOT EXHIBIT MUCH INSTABILITY 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 /15Z MONDAY THROUGH FRIDAY/...
AT KCLT...LOWER STRATUS HAS FILLED IN AT MAINLY MVFR LEVELS...BUT
IFR CIGS ARE NOT FAR TO THE SOUTH AND EAST. WILL FEATURE MVFR WITH
TEMPO IFR FOR A COUPLE OF HOURS...WITH ONLY SLOW LIFTING AND
SCATTERING OF THE RESTRICTIONS THROUGH NOON. EXPECT LIGHT NE SURFACE
WINDS THROUGH THE PERIOD WITH WEAK SURFACE HIGH PRESSURE TO THE
NORTH.

ELSEWHERE...MORNING STRATUS IS CONFINED MAINLY TO THE MOUNTAIN
VALLEYS AND THE LOWER PIEDMONT...BUT CANNOT BE RULED OUT ACROSS THE
FOOTHILLS GIVEN THE MOIST BOUNDARY LAYER WITH DRYING ALOFT THIS
MORNING. THE STRATUS MAY BE QUITE PERSISTENT THROUGH NOON IN AREAS
WHERE IT BECOMES ENTRENCHED. 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. A RETURN OF LOW
CLOUDS IS POSSIBLE OVERNIGHT...ESPECIALLY NEAR KAVL.

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...

            14-20Z        20-02Z        02-08Z        08-12Z
KCLT       HIGH  89%     HIGH 100%     HIGH 100%     HIGH  91%
KGSP       HIGH  92%     HIGH 100%     HIGH 100%     HIGH  95%
KAVL       HIGH  92%     HIGH 100%     HIGH  95%     HIGH  87%
KHKY       HIGH  86%     HIGH 100%     HIGH  95%     HIGH 100%
KGMU       HIGH  96%     HIGH 100%     HIGH 100%     HIGH  91%
KAND       HIGH  82%     HIGH 100%     HIGH 100%     HIGH  95%

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...ARK/HG
SHORT TERM...NED
LONG TERM...NED
AVIATION...HG


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.