Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 310547
AFDGSP

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

.SYNOPSIS...
WEAK SURFACE HIGH PRESSURE WILL LINGER OVER THE REGION FOR THE NEXT
SEVERAL DAYS. MOISTURE OF VARYING DEGREES FROM THE REMNANTS OF
TROPICAL CYCLONE ERIKA WILL CONTINUE TO SPREAD NORTH ACROSS THE
SOUTHEAST THROUGH THE END OF THE WORK WEEK...WITH INCREASING CHANCES
FOR AFTERNOON SHOWERS AND THUNDERSTORMS.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM EDT...REGIONAL RADARS SHOW THE BACK EDGE OF THE
PRECIPITATION GENERALLY LIFTING NORTHWARD THROUGH WRN NC EARLY THIS
MORNING AS AN UPPER VORTICITY MAXIMA PASSES OVER 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
REGIONS. 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 PM EDT SUNDAY...UPPER WEAKNESS OVER THE SOUTHERN PLAINS
WILL CONTINUE TO WEAKEN AS RIDGING CONTINUES TO BUILD OVER MOST OF
THE COUNTRY. A WEAKNESS WILL CROSS THE OHIO VALLEY THROUGH THE SHORT
TERM BUT ANY INFLUENCE FROM IT SHOULD STAY JUST TO OUR NORTH UNTIL
THE END OF THE PERIOD WHEN THE ASSOCIATED FORT MAX DIVES SOUTH
TOWARD THE CAROLINAS...ROTATING AROUND THE UPPER RIDGE. MEANWHILE
THE REMNANTS OF ERIKA ARE NOW PROGGED TO STAY TO OUR SOUTH AND
GRADUALLY DISSIPATE. SHOULD SEE A GRADUAL INCREASE IN PW VALUES BUT
REMAINING BELOW 2 INCHES...AND FOR THE MOST PART BELOW 1.75 INCHES.
HAVE CONTINUED TREND OF MAINLY DIURNAL POPS THROUGH THE SHORT TERM
AND SHOWING A SLIGHT WARMING TREND AS WELL...CLOSER TO SEASONAL
HIGHS...TO ACCOUNT FOR LESS AVAILABLE MOISTURE IN THIS FORECAST
CYCLE THAN PREVIOUSLY SHOWN. BETTER CHANCE FOR CONVECTION WEDNESDAY
AFTERNOON THAN TUESDAY JUST DUE TO THE APPROACHING UPPER VORT
MAX...BUT STILL ONLY CHANCES AT BEST /AND BEST CHANCES LIMITED TO
THE MOUNTAINS/.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 245 PM EDT SUNDAY...UPPER RIDGING WILL BEGIN TO WEAKEN INTO
THE EXTENDED AS A SHORTWAVE ALOFT DIVES DOWN THE NORTHWEST FLOW ON
THE EASTERN EDGE OF THE UPPER RIDGE...BRINGING A SLIGHT INCREASE IN
DIURNAL CONVECTION CHANCES AS WE MOVE INTO THE EXTENDED. STILL SOME
UNCERTAINTY AS TO WHAT THE REMNANTS OF ERIKA WILL DO BUT BOTH THE
GFS AND ECMWF HAVE THE MOISTURE SPREADING ACROSS THE DEEP SOUTH
TOWARD THE END OF THE WEEK...WITH INCREASING PW VALUES INTO THE
WEEKEND /HOVERING JUST UNDER 2 INCHES AT LEAST ON THE GFS/. 12Z
ECMWF IS MORE ROBUST WITH THE MOISTURE THAN THE GFS BUT BOTH BRING
DECENT QPF VALUES...ESPECIALLY ON SATURDAY AS THE WAVETRAIN SLIDES
EAST AND VERY VERY WEAK SOUTHWEST FLOW DEVELOPS AS THE RIDGE AXIS IS
MORE OVER THE WESTERN ATLANTIC THAN THE APPALACHIAN SPINE.
HOWEVER...CONTINUED TO KEEP POPS AT CHANCE AT BEST FOR NOW JUST
BECAUSE WE ARE LOOKING SEVERAL DAYS OUT AND QUITE A BIT COULD STILL
CHANGE BETWEEN NOW AND THEN. TEMPERATURES FAIRLY CLOSE TO SEASONAL
NORMALS.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AT KCLT...PERSISTENT SHRA IN THE SRLY FLOW OF TROPICAL MOISTURE
SHOULD WRAP UP MAINLY EAST OF THE AIRFIELD THROUGH DAYBREAK...WITH
JUST OCCASIONAL -SHRA NEAR THE AIRFIELD. 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. ANTICIPATE 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 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 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...

            05-11Z        11-17Z        17-23Z        23-00Z
KCLT       HIGH 100%     MED   65%     HIGH  87%     HIGH 100%
KGSP       HIGH  91%     LOW   29%     HIGH  94%     HIGH 100%
KAVL       MED   75%     LOW   29%     HIGH 100%     HIGH 100%
KHKY       LOW   58%     MED   62%     MED   69%     HIGH 100%
KGMU       HIGH  91%     LOW   29%     HIGH 100%     HIGH 100%
KAND       HIGH  91%     MED   69%     HIGH  94%     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...TDP
NEAR TERM...HG
SHORT TERM...TDP
LONG TERM...TDP
AVIATION...HG


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