Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 301357
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
957 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 950 AM EDT SUNDAY...INCREASING COVERAGE DUE TO ENHANCED MOIST
UPGLIDE ALONG THE MID ATLANTIC RIDGE PERIPHERY PROMPTS A QUICK
UPDATE TO ADJUST POPS UP ACROSS THE LAKELANDS...EAST ALONG AND SOUTH
OF INTERSTATE 85 WHERE PRECIPITATION CONTINUES TO SPREAD IN FROM
THE SOUTH.  LATEST 12Z NAM COMING IN RIGHT NOW...AND IS ALREADY
INDICATING CONTINUED PRECIPITATION THROUGH THE AFTERNOON ALONG
THE INTERSTATE 85/77 CORRIDORS AS UPGLIDE CONTINUES...THUS ALSO
ADJUSTED POPS OVER THESE REGIONS.  OTHERWISE...TWEAKED TEMPERATURES
AND DEWPOINTS AND LEFT THE REMAINDER OF THE FCST AS IT WAS.

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 /14Z 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...

            14-20Z        20-02Z        02-08Z        08-12Z
KCLT       HIGH 100%     HIGH 100%     HIGH  92%     MED   75%
KGSP       HIGH 100%     HIGH 100%     HIGH  83%     MED   79%
KAVL       HIGH 100%     HIGH 100%     HIGH  89%     HIGH  89%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  87%
KGMU       HIGH 100%     HIGH 100%     HIGH  84%     HIGH  81%
KAND       HIGH 100%     HIGH 100%     HIGH  90%     MED   73%

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



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