Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 050534
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
134 AM EDT SUN JUL 5 2015

.SYNOPSIS...
A BROAD UPPER LEVEL TROUGH WILL REMAIN OVER THE SOUTHEAST THROUGH
MONDAY...PROVIDING LIFT AND MAINTAINING ELEVATED RAIN AND
THUNDERSTORM CHANCES EACH DAY. SLIGHTLY DRIER CONDITIONS RETURN
TUESDAY AND WEDNESDAY...BEFORE A FRONT BECOMES NEARLY STATIONARY
JUST NORTH OF OUR REGION LATE IN THE WEEK.  HIGH TEMPERATURES WILL
REMAIN BELOW AVERAGE INTO MONDAY...THEN WARM TO AROUND SEASONAL
NORMALS FOR THE REST OF THE WEEK.

&&

.NEAR TERM /THROUGH TODAY/...
AS OF 130 AM EDT SUNDAY...FIRST WAVE OF PRECIP CONTINUES TO SLIDE
NORTHWARD INTO WESTERN NC AT THIS TIME.  RATES HAVENT BEEN ALL THAT
IMPRESSIVE...AND ARE NOT EXPECTED TO INCREASE AS BEST THERMO FORCING
REMAINS TO THE SOUTH WHICH IS EVIDENT ON LATEST SPC MUCAPE PLOTS.
TWEAKED POPS OVER THE WESTERN TIER OF THE FCST AREA TO ACCOUNT FOR
COVERAGE AND CAMPOP TRENDS.  OTHERWISE...PARTLY/MOSTLY CLOUDY SKIES
PREVAIL THEREFORE NO SIG CHANGES WERE MADE/NEEDED IN THE IMMEDIATE
NEAR TERM.

PREVIOUS DISCUSSION...

AS OF 215 PM EDT...NEARLY THE ENTIRE FORECAST AREA REMAINS FAIRLY
STABLE THIS AFTERNOON UNDER ABUNDANT MID CLOUDS WITH PATCHY LIGHT
SHRA FALLING INTERMITTENTLY. MOUNTAIN SHOWERS ARE STARTING TO SHOW
SOME VERTICAL DEVELOPMENT...AND A FEW BREAKS OVER THE NC FOOTHILLS
AND THE ERN FRINGE HOLD OUT SOME CHANCE FOR ISOLD TSTMS TO REDEVELOP
IN LINE WITH THE HRRR. OTHERWISE...500 MB HEIGHTS CONTINUE TO FALL
ACROSS THE MS RIVER VALLEY THIS AFTERNOON...AND HEIGHT FALLS WILL
CONTINUE EASTWARD ACROSS TN TONIGHT THROUGH SUNDAY. INTERMITTENT
SHORTWAVES WILL PIVOT EAST THROUGH THE FORECAST AREA AROUND THIS
UPPER TROUGH DURING THIS PERIOD. IN ADDITION...THE ENTRANCE REGION
OF AN UPPER JETLET WILL REMAIN PARKED JUST WEST OF THE SRN
APPALACHIANS THROUGH THE NEAR TERM...ALTHOUGH THE JETLET LOOKS A BIT
WEAKER THAN IN PREVIOUS MODEL RUNS. AT THE SURFACE...A STALLED FRONT
REMAINS DRAPED NORTH AND WEST OF THE AREA THIS AFTN...WITH A
LINGERING SFC TROUGH AXIS STRETCHED OUT WELL TO THE SOUTH IN THE
BETTER INSTABILITY. GIVEN ALL OF THESE VARIOUS FORCING
MECHANISMS...ALONG WITH CONTINUED WSW UPSLOPE INTO THE SW MTNS...AND
PRECIPITABLE WATER VALUES RUNNING 1.5 TO 1.75 INCHES OVER THE
AREA...ANTICIPATE THE PRECIPITATION COVERAGE MAKING A COMEBACK FROM
THE WEST TONIGHT THROUGH SUNDAY. OTHER THAN ANY LINGERING DIURNAL
SHRA/TSRA...A FAIRLY SHARP W TO E GRADIENT WILL BE FEATURED ON
POPS...WITH THE SW MOUNTAINS THE CLEAR FOCUS FOR ANY HIGHER END
UPSLOPE QPF. NO CHANGES ARE NEEDED AT PRESENT TO THE FFA. WILL
CONTINUE A SMALLER THAN CLIMO RANGE ON MIN/MAX TEMPS.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
AS OF 205 PM SUNDAY...RISING HEIGHTS ALOFT WILL BE THE PRIMARY STORY
OF THE SHORT TERM...AS THE UPPER LOW FILLS AND SLOWLY LIFTS INTO THE
MID-ATLANTIC...AND AN UPPER RIDGE AXIS BEGINS BUILDING OVER THE
SOUTHEAST STATES. THIS WILL RESULT IN A MARKED CHANGE TO THE
THERMODYNAMIC CHARACTER OF THE AIR MASS ACROSS THE AREA...FROM
UNSEASONABLY MOIST AND RELATIVELY COOL CONDITIONS...TO MUCH MORE
SEASONAL LEVELS OF HEAT AND HUMIDITY BY TUESDAY AFTERNOON.

CHANCES FOR SHOWERS AND THUNDERSTORMS SUNDAY NIGHT INTO MONDAY WILL
BE HIGHEST ACROSS NORTHERN AND FAR WESTERN ZONES...AS THE UPPER LOW
MEANDERS JUST WEST OF THE APPALACHIANS. AS THE DEEPER MOISTURE LIFTS
INTO THE MID-ATLANTIC...THE HYDRO THREAT IS EXPECTED TO WANE MONDAY
AFTERNOON...WHILE THERE MAY BE AN UPTICK IN THE LOCAL SEVERE STORM
POTENTIAL...ESPECIALLY ACROSS THE SOUTHERN HALF OF THE FORECAST
AREA...WHERE LESS CLOUD COVER IS ANTICIPATED. BY TUESDAY...A RETURN
TO A MORE TYPICAL DIURNAL DEEP CONVECTIVE CYCLE IS EXPECTED...WITH
THE POTENTIAL FOR ISOLATED STRONG-TO-SEVERE PULSE STORMS.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM INDEPENDENCE DAY...THE MEDIUM RANGE BEGINS 00Z
WEDNESDAY AS A FRONTAL BOUNDARY STEERED BY AN UPPER TROUGH OVER THE
CENTRAL PLAINS/GREAT LAKES REGION CONTINUES ITS EASTWARD PROGRESSION
TOWARDS THE FORECAST AREA. H5 HEIGHTS BEGIN TO FLATTEN LATE
WEDNESDAY...AND BY THURSDAY AN ATLANTIC UPPER HIGH WITH SURFACE
REFLECTION INTRUDES INTO THE SOUTHEAST. GLOBAL MODELS DIVERGE WITH
THE HANDLING OF THIS FEATURE AND ABOVE-MENTIONED FRONT. THE GFS IS
MORE BULLISH ON THE NORTHWARD AND WESTWARD EXTENT OF THE HIGH...AND
THEREFORE ACTS TO SOMEWHAT BLOCK  THE APPROACHING FRONT AND KEEP
MAIN IMPACTS FROM A SERIES OF WEAK SURFACE LOWS/IMPULSES FARTHER TO
THE NORTH OF THE CWFA. THE ECMWF KEEPS THE HIGH PRESSURE FEATURE
FARTHER TO THE SOUTH...SO THE TRACK REMAINS A BIT FARTHER TO THE
SOUTH THAN THE GFS. THERE IS AGREEMENT THAT SOME TYPE OF IMPULSE/LOW
WILL DEVELOP OVER THE CENTRAL PLAINS FRIDAY...THOUGH MODELS AGAIN
DIVERGE ON BOTH TIMING AND STRENGTH OF THE FEATURE. WENT WITH A
BLEND OF THE FASTER/WEAKER GFS AND SLOWER/STRONGER ECMWF AS NO
PARTICULAR SOLUTION STANDS OUT AS MORE LIKELY AT THIS POINT. POPS
WERE THEREFORE ELEVATED FRIDAY NIGHT.

OVERALL...SOUTHWESTERLY FLOW DRIVEN BY THE BERMUDA HIGH WILL LEND
ITSELF TO MORE OF A GULF FETCH...KEEPING DEEP LAYER MOISTURE
ABUNDANT THROUGH MOST OF THE PERIOD. A LACK OF GOOD UPPER FORCING
COMBINED WITH SOMEWHAT UNIMPRESSIVE INSTABILITY FOR MID-SUMMER WILL
LEND ITSELF TO MAINLY DIURNAL POPS NEAR CLIMO FOR MOST OF THE
PERIOD...THOUGH THE PREVIOUSLY MENTIONED LOW/FRONTAL BOUNDARY WILL
ENHANCE THE DIURNAL POPS LATER IN THE WEEK. BOTH MAX AND MIN TEMPS
WILL REMAIN NEAR TO JUST ABOVE CLIMO THROUGH THE ENTIRE MEDIUM
RANGE.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH THE TAF CYCLE WITH THE
POSSIBLE EXCEPTION OF MVFR RESTRICTIONS ASSOCIATED WITH MID MORNING
SHRA...AND POSSIBLE AFTERNOON TSRA.  INITIALIZED TAF WITH LIGHT SW
WINDS UNDER SCT MID TO BKN HIGH CLOUDS.  A 3HR TEMPO WAS ADDED FROM
11Z-14Z AS LATEST HRRR INDICATES BAND OF SHRA RIDING UP THE I85
CORRIDOR AROUND OR JUST AFTER DAYBREAK.  OTHERWISE...GUSTY SW WINDS
TODAY WITH SCT LOW VFR CLOUDS UNDER BKN HIGH LEVEL CIRROSTRATUS.
PROB30 CARRIES OVER FROM PREVIOUS TAF CYCLE TO ACCOUNT FOR ANY
ADDITIONAL CONVECTIVE DEVELOPMENT THIS AFTERNOON.  WINDS WILL
SUBSIDE AFTER SUNSET AS THE MIXED LAYER ERODES ALONG WITH RISING
MID/HIGH LEVEL CIGS.

ELSEWHERE...HIGHER PRECIP CHANCES THAN THAT OF KCLT ABOVE...HOWEVER
TRENDS ARE FAIRLY SIMILAR WITH SLIGHT TIMING ADJUSTMENTS.
INITIALIZED ALL TAFS VFR WITH SOME DETERIORATION FCST AT KAVL AS
CURRENT PRECIP SLIDES NORTHEAST OVER THE AIRFIELD WITHIN AN HOUR OR
SO.  OTHERWISE...TRIED TO TIME PRECIP THROUGH THE MORNING PER LATEST
CAMS AT ALL AIRFIELDS...HOWEVER WITH LOW CONFIDENCE.  FOR THE
AFTERNOON/EVENING POPS ARE HIGHEST OVER WESTERN NC ADJACENT TO
APPROACHING UPPER LOW...THUS KAVL/KHKY HAVE PREVAILING SHRA WITH
VCTS WHILE THE REMAINING SITES FEATURE VCSH WITH PROB30S FOR TSRA.

OUTLOOK...THE PATTERN WILL FINALLY RETURN TO MORE OF A DIURNAL
NATURE ON MONDAY AS THE UPPER LOW EJECTS NORTHEAST.  THIS DIURNAL
PRECIPITATION TREND WILL PERSIST THROUGH MOST OF THE WORK WEEK.
RESTRICTIONS WILL REMAIN A POSSIBILITY EACH AFTERNOON DUE TO
SHRA/TSRA...AND ALSO EACH MORNING WHERE PREVIOUS RAINS HAVE OCCURRED.

CONFIDENCE TABLE...

            05-11Z        11-17Z        17-23Z        23-00Z
KCLT       HIGH 100%     HIGH  94%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       LOW   57%     MED   78%     HIGH  85%     HIGH 100%
KHKY       HIGH 100%     MED   66%     HIGH  95%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH  95%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     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_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH THROUGH THIS EVENING FOR GAZ010-017-018-026-
     028-029.
NC...FLASH FLOOD WATCH THROUGH THIS EVENING FOR NCZ048-051-052-058-
     059-062-063.
SC...FLASH FLOOD WATCH THROUGH THIS EVENING FOR SCZ001-004.

&&

$$
SYNOPSIS...LEV
NEAR TERM...CDG/CSH/HG
SHORT TERM...JDL
LONG TERM...LEV
AVIATION...CDG



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