Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 301032
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
632 AM EDT SUN AUG 30 2015

.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL LIFT NORTHEAST ACROSS THE REGION
TODAY. OTHERWISE...WEAK SURFACE HIGH PRESSURE WILL REMAIN IN PLACE
OVER THE AREA THROUGH THE WEEK. MOISTURE MAY SPREAD NORTHWARD FROM
THE REMNANTS OF TROPICAL SYSTEM ERIKA...BUT WITH A GREAT DEAL OF
UNCERTAINTY OVER HOW MUCH MOISTURE MAY REACH THE AREA.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 625 AM...LATEST REGIONAL RADAR INDICATES A BAND OF LIGHT
RETURNS LIFTING BRISKLY NORTH ACROSS THE COASTAL PLAIN...WITH A FEW
AREAS OF SPRINKLES ACROSS THE PIEDMONT. GIVEN THE LATEST RADAR
TRENDS...I WILL UPDATE THE POPS AND WEATHER TO INDICATE GREATER
COVERAGE STARTING MID DAY. COVERAGE SHOULD PEAK LATE TONIGHT...WITH
BOTH THE 6Z NAM AND GFS SHOWING A HEAVY BAND OF RAINFALL SLIDING
OVER THE CLT METRO AREA AFTER MIDNIGHT. THE PEAK COVERAGE SHOULD
OCCUR WITH THE PASSAGE OF MID LEVEL Q VECTOR CONVERGENCE. I WILL
UPDATE QPF TO INDICATE GREATER AMOUNTS...ESPECIALLY ACROSS THE
PIEDMONT. THE RAINFALL AND THUNDER WILL BE HIGHLIGHTED IN THE HWO.

AS OF 325 AM...A MID LEVEL LOW NEAR THE FL PANHANDLE THIS MORNING
WILL LIFT NORTHWARD TODAY. AS THE LOW TRACKS NORTH...IT WILL WEAKEN
INTO A S/W...EXPECTED TO PASS OVER THE CWA TONIGHT. AS THE MID LEVEL
FEATURE APPROACHES THE WESTERN CAROLINAS...CLOUDS ACROSS THE REGION
WILL THICKEN AND LOWER ALONG WITH THE DEVELOPMENT OF SCT SHOWERS.
LATEST RADAR IMAGES AND SFC OBSERVATIONS INDICATED A FEW PATCHES OF
SPRINKLES DRIFTING OVER THE LAKE LANDS. LATEST RUNS OF THE NAM AND 4
KM WRF SHOW SPRINKLES REMAINING ACROSS THE REGION THIS
MORNING...WITH SHOWERS THIS AFTERNOON AND EVENING. FORECAST
SOUNDINGS SHOW CAPE VALUES REMAIN QUITE LOW ACROSS THE REGION THIS
AFTERNOON...I WILL FORECAST PRIMARILY SHOWERS. THE GFS INDICATES THAT
THE PERIOD OF GREATEST SYNOPTIC SCALE FORCING WILL LIKELY OCCUR
BETWEEN 0Z TO 6Z MON. DURING THIS PERIOD...THE CLOSED LOW OR S/W
WILL SLIDE ACROSS THE REGION...RESULTING IN A BELT OF Q-VECTOR
CONVERGENCE ACROSS THE CAROLINAS. I WILL FORECAST 30 TO 50 POPS
DURING THE LATE AFTERNOON AND EVENING. THE COMBINATION OF THICK
CLOUD COVER AND SHOWERS SHOULD KEEP HIGHS ACROSS THE UPPER SAVANNAH
RIVER VALLEY LIMITED TO THE U70S...WITH MID 80S EXPECTED ACROSS THE
CLT METRO.

TONIGHT...THE MID LEVEL TROF WILL TRACK NE...FOLLOWED BE WEAK HEIGHT
RISES DURING THE LATE NIGHT HOURS. I WILL TREND POPS LOWER AFTER
MIDNIGHT...BUT REMAINING IN THE SCHC TO LCHC RANGE. LOW TEMPERATURES
ARE FORECAST TO RANGE FROM THE L60S ACROSS THE MTNS TO THE UPPER 60S
EAST.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 245 AM EDT SUNDAY...A WEAK UPPER LEVEL CLOSED LOW/TROUGH WILL
REMAIN ORPHANED OVER E TX THROUGH THE SHORT TERM PERIOD...WHILE A
BROADER UPPER RIDGE BUILDS OVER THE ERN CONUS THROUGH TUESDAY. UNDER
THIS UPPER RIDGE...WEAK SURFACE HIGH PRESSURE WILL LINGER ALONG THE
APPALACHIANS. THERE APPEARS TO BE IMPROVING CONSENSUS IN THE
NUMERICAL MODELS ON KEEPING THE DEEPER TROPICAL MOISTURE ASSOCIATED
WITH THE ERIKA REMNANTS SHUNTED SOUTH OF THIS SURFACE RIDGE...WITH
THE GREATEST MOISTURE CONFINED MAINLY FROM FL TO THE COASTAL
CAROLINAS MON THROUGH TUE. FOR OUR REGION...THIS MEANS CONTINUED
WEAK INSTABILITY IN VERTICAL PROFILES UNDER THE RIDGE...BUT WITH
PRECIPITABLE WATER VALUES GRADUALLY INCREASING. WILL CONTINUE TO
FEATURE MAINLY DIURNAL SCATTERED CONVECTION WITH MAX TEMPS SLOWLY
REBOUNDING TO NEAR CLIMO DESPITE THE CLOUD COVER.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 245 AM EDT SUNDAY...A VERY WEAK UPPER LEVEL FLOW PATTERN WILL
EXIST WED THROUGH SAT AS THE PERSISTENT GULF COAST TROUGH SLOWLY
MIGRATES EAST UNDER THE BROAD FLAT ERN RIDGE. ANY REMNANT ERIKA
CIRCULATION APPEARS TO MAKE LITTLE NWD PROGRESS THROUGH THE MEDIUM
RANGE...WITH THE ECM/NAM CAMP KEEPING THE REMNANT LOW CENTER NEAR
COASTAL GA/NE FL WHILE THE GFS CAMP IS FARTHER SW NEAR THE FL
PANHANDLE. THIS WILL MAKE FOR HIGHLY UNCERTAIN MOISTURE PROFILES
OVER THE REGION...WITH A SHARP GRADIENT IN PRECIPITABLE WATER LIKELY
FROM THE DRIER NRN MOUNTAINS TO THE MORE MOIST LOWER SE PIEDMONT.
ANY PREDECESSOR RAIN EVENT POTENTIAL FOR EARLY IN THE PERIOD NOW
APPEARS QUITE NEBULOUS GIVEN THE CURRENT WEAK STATE OF THE ERIKA
REMNANTS AND POSSIBILITY OF SOME DRIER AIR REINFORCING FROM NORTH
MID TO LATE WEEK IN THE SURFACE RIDGE. WILL CONTINUE THE CURRENT
FORECAST THINKING OF SLIGHTLY ABOVE CLIMO/MAINLY DIURNAL POPS WED
THROUGH SAT...WITH GRADUALLY CLIMBING TEMPERATURES IN THE ABSENCE OF
ANY STRONG SIGNAL FOR HEAVY RAINFALL.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AT KCLT...A MID LEVEL LOW NEAR THE FL PANHANDLE THIS MORNING WILL
LIFT NORTHWARD TODAY. AS THE LOW TRACKS NORTH...IT WILL WEAKEN INTO
A S/W...EXPECTED TO PASS OVER THE CWA TONIGHT. AS THE MID LEVEL
FEATURE APPROACHES THE WESTERN CAROLINAS...CLOUDS ACROSS THE REGION
WILL THICKEN AND LOWER ALONG WITH THE DEVELOPMENT OF SCT SHOWERS.
SKY SHOULD REMAIN BKN TO OVC WITH MID LEVEL CLOUDS THROUGH THE
DAYLIGHT HOURS. BASED ON RAPID NORTHWARD MOTION OF MORNING RA OVER
THE COASTAL PLAIN...I WILL START VCSH BY 17Z. FORECAST SOUNDINGS
INDICATE MVFR CEILINGS DEVELOPING ONE TO TWO HOURS AFTER
SUNSET...LOWER OVERNIGHT TO PRE DAWN IFR. I WILL HIGHLIGHT THE 4Z TO
8Z WINDOW FOR THE GREATEST RAINFALL RATES...LOWERING VIS TO TEMPO
IFR. WINDS BE CHALLENGING TODAY...I WILL START THE TAF WITH ENE
WINDS...VEERING TO SE LATE THIS AFTERNOON AND EVENING....THEN BACK
TO NE DURING THE PRE DAWN HOURS.

ELSEWHERE...CONDITIONS WILL REMAIN VFR THROUGH THE DAYLIGHT HOURS
TODAY. HOWEVER...AN APPROACHING MID LEVEL FEATURE WILL RESULT IN
WIDESPREAD RESTRICTIVE CEILINGS AROUND SUNSET...ALONG WITH SCATTERED
SHOWERS. I WILL INCLUDE AT LEAST A VCSH MENTION FOR EACH TERMINAL
LATE THIS AFTERNOON. THE GREATEST POTENTIAL FOR MEASURABLE RAINFALL
WILL OCCUR THIS EVENING. LIGHT WINDS...FAVORING THE SOUTHEAST
TODAY...WITH BACKING TO NE TONIGHT.

OUTLOOK...THE SOUTHEAST REGION IS FORECAST TO REMAIN UNDER A PLUME
OF GULF AND ATLANTIC MOISTURE THROUGH THE MIDDLE OF NEXT WEEK. IN
ADDITION...MOISTURE ASSOCIATED WITH THE REMNANTS OF ERIKA COULD
REACH THE SOUTHERN APPALACHIANS DURING THE MID WEEK. RESTRICTIONS
ARE POSSIBLE DURING PERIODS OF RAIN AND WITH THE MTN VALLEY FOG
AROUND DAWN.

CONFIDENCE TABLE...

            10-16Z        16-22Z        22-04Z        04-06Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     MED   75%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  80%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  80%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  80%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  80%
KAND       HIGH 100%     HIGH 100%     HIGH  85%     HIGH  90%

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


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