Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 281744
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
144 PM EDT TUE JUL 28 2015

.SYNOPSIS...
HIGH PRESSURE WILL PERSIST OVER THE REGION THROUGH WEDNESDAY...WITH
CONTINUED WARM TEMPERATURES. A WEAK COLD FRONT WILL APPROACH THE
AREA FROM THE NORTHWEST ON THURSDAY AND SETTLE JUST SOUTH OF THE
REGION ON FRIDAY. THE FRONT WILL LIKELY REMAIN STALLED JUST SOUTH OF
THE AREA THROUGH THE WEEKEND...WITH COOLER TEMPERATURES EXPECTED.
MOISTURE SHOULD INCREASINGLY RETURN NORTHWARD OVER THE FRONT THE
LATTER HALF OF THE WEEKEND INTO EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 145 PM...CONVECTION IS FIRING ACRS THE AREA AS EXPECTED. HAVE
UPDATED POPS BLENDING IN LATEST GUIDANCE AND CAM POP. SEVERE THREAT
STILL LOOKS LOW...BUT A NONZERO WIND THREAT WILL EXIST...GIVEN
BETTER CAPE THAN LAST FEW DAYS. THE BIGGER THREAT STILL LOOKS TO BE
HEAVY RAIN/ISOLD FLOODING...AS CURRENT STORMS ARE SHOWING VERY SLOW
MOTIONS WITH HEAVY RATES.

AS OF 1000 AM...FOG AND LOW STRATOCU IS PRETTY MUCH DISSIPATED ACRS
MOST OF THE AREA. CONDITIONS ARE CURRENTLY MUGGY...WITH DEWPTS STILL
IN THE LOW-MID 70S ACRS THE PIEDMONT...AND MID-UPR 60S IN THE MTNS.
THIS SHUD RESULT IN CONVECTIVE CU DEVELOPING/FILLING IN ACRS THE
REGION FAIRLY QUICKLY LATE THIS MORNING. THE LATEST CAMS IN DECENT
AGREEMENT ON EARLY CONVECTIVE INITIATION STARTING AROUND
MIDDAY...WITH SHOTGUN CHC COVERAGE EXPECTED DURING THE AFTN HOURS.
SHEAR IS WEAK...AND INSTBY WILL BE MODEST. THE BIGGEST THREAT LOOKS
TO BE HEAVY RAIN WITH TSTMS THIS AFTN.

NEAR TERM MODELS SHOW THE CENTER OF THE H5 HIGH OVER THE CENTRAL
PLAINS...WITH NW TO SE HEIGHTS ACROSS THE WESTERN CAROLINAS. RECENT
W/V IMAGES INDICATED THAT WELL DEVELOP VORT MAX WAS MOVING OVER THE
WESTERN OHIO RIVER VALLEY. 0Z RUNS OF THE NEAR TERM MODELS DID
RESOLVE THIS FEATURE VERY WELL...BUT THE NAM APPEARS THE BEST
INITIALIZED WITH THE FEATURE. THE VORT SHOULD TRACK SE THROUGH THE
DAY...REACHING THE SOUTHERN APPALACHIANS BY EARLY THIS EVENING.
FORECAST SOUNDINGS SHOW GREATER INSTABILITY AND LOWER LFC THIS
AFTERNOON COMPARED TO THE PAST SEVERAL DAYS. GIVEN THE APPROACH OF
THE MID LEVEL FEATURE AND MORE SUPPORTIVE THERMAL PROFILES...I WILL
FORECAST 40 POPS ACROSS THE MTNS AND 30 POPS EAST. THE CENTER OF THE
VORT IS EXPECTED TO PASS TO THE SW...HOWEVER...CONVECTION ACROSS THE
FA MAY REMAIN WELL INTO THE EVENING. I WILL KEEP SCT POPS IN THE
FORECAST UNTIL MIDNIGHT. HIGH TEMPERATURES THIS AFTERNOON WILL
REMAIN COMPARABLE TO THE PAST TWO DAYS...SLIGHTLY COOLER THAN
YESTERDAY.

TONIGHT...CONVECTION AFTER MIDNIGHT IS FORECAST TO REMAIN
SPARSE...BUT ENOUGH TO SUPPORT SCHC POPS. PERIODS OF DEBRIS
CLOUDS...MILD THICKNESSES...AND LIGHT SOUTH LLVL WINDS SHOULD KEEP
MIN TEMPERATURES MILD. USING A BLEND OF PREFERRED GUIDANCE...I WILL
FORECAST LOWS IN THE UPPER 60S WITHIN THE MTN VALLEYS TO LOW 70S
EAST.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 245 AM EDT TUESDAY...A BROAD UPPER RIDGE WILL STRETCH ACROSS
THE SOUTHERN TIER OF THE UNITED STATES ON WEDNESDAY. WEAK LOBES OF
VORTICITY MAY DROP SOUTHWARD THROUGH THE WESTERN CAROLINAS WEDNESDAY
AFTERNOON ALONG THE ERN PERIPHERY OF THE RIDGE. MOUNTAIN TRIGGERING
OF CONVECTION IS LIKELY EARLY WED AFTERNOON...ESPECIALLY ALONG THE
ERN SLOPES WHERE LOW LEVEL CONVERGENCE WILL BE BEST. ANY EARLY TO
MID AFTERNOON MOUNTAIN ACTIVITY MAY DEVELOP EASTWARD OFF THE HIGHER
TERRAIN INTO THE PIEDMONT THROUGH THE EVENING AND EARLY OVERNIGHT
HOURS.

GRADUAL HEIGHT FALLS ARE THEN EXPECTED THROUGH THURSDAY...BUT WITH
THE BEST SHORTWAVE ENERGY ASSOCIATED WITH A VIGOROUS NRN STREAM WAVE
PASSING N OF THE AREA FROM THE OH VALLEY TO THE MID ATLANTIC THROUGH
THU NIGHT. THE DEVELOPING TROUGH WILL ALLOW A COLD FRONT TO ARRIVE
IN THE SOUTHERN APPALACHIANS FROM THE NORTHWEST THU AFTERNOON...BUT
IT WILL LIKELY STALL OVER THE LOWER PIEDMONT THROUGH EARLY FRIDAY
MORNING. ABOVE CLIMO TEMPERATURES WILL PERSIST THROUGH THE PERIOD.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 245 AM EDT TUESDAY...MORE PROMINENT HEIGHT FALLS ARE EXPECTED
ON FRIDAY...WITH AN EASTERN CONUS TROUGH DEVELOPING AND LINGERING
OVER THE REGION THROUGH THE WEEKEND INTO EARLY NEXT WEEK. THE
STALLED BOUNDARY ALONG THE SRN PERIPHERY OF THE AREA WILL ALLOW
DEEPER MOISTURE TO REMAIN CLOSE BY...BUT WITH SOME MEASURE OF DRYING
ARRIVING FROM THE NORTH FRIDAY INTO SATURDAY. A DECENT N TO S
GRADIENT OF SLIGHT CHANCE TO SOLID CHANCE POPS WILL BE WARRANTED
BOTH AFTERNOONS. MAX TEMPS WILL FALL TO OR BELOW CLIMO VALUES.

THERE IS SOME POTENTIAL FOR A WEAK DISTURBANCE IN THE NE GULF OF
MEXICO TO GET ENTRAINED INTO THE TROUGH AND FEED EVEN BETTER
MOISTURE NWD THROUGH THE PIEDMONT OF THE CAROLINAS SUNDAY THROUGH
MONDAY. WILL KEEP ASSOCIATED POPS FAIRLY CONSERVATIVE IN THE CHANCE
CATEGORY GIVEN THE UNCERTAINTY...BUT CONTINUED COOLER MAX TEMPS
LOOKS MORE LIKELY WITH NO 90S EXPECTED ANYWHERE IN THE CWA SUNDAY TO
MONDAY.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AT KCLT...CONVECTION IS DEVELOPING QUICKLY EARLY THIS AFTN ACRS THE
AREA...WITH SEVERAL SLOW-MOVING SHRA JUST EAST OF THE TERMINAL AT
TIME OF 18Z TAF ISSUANCE. SO WILL START OUT WITH A VCSH AND TEMPO
FOR TS FROM 18-21Z. FROM THERE...THE HIGH-RES MODELS KEEP ISOLATED
TO SCATTERED CONVECTION LINGERING AROUND THE AREA WELL PAST SUNSET.
FOR SIMPLICITY...WILL KEEP OUT MENTION BEYOND 23Z.
OTHERWISE...TONIGHT WILL BE SIMILAR TO LAST NIGHT...WITH PLENTY OF
MID AND HIGH CLOUDS AND LIGHT SE WIND. GUIDANCE IS MIXED ON MVFR
STRATUS POTENTIAL. WILL MENTION SCT015 FOR NOW TO SHOW THE TREND.

ELSEWHERE...THE BLUE RIDGE HAS REALLY LIT UP ON RADAR OVER THE LAST
HOUR...WITH CONVECTION DRIFTING TO THE SOUTH. KGSP AND KGMU LOOK TO
HAVE THE BEST SHOT OF DIRECT HIT BY TSRA IN THE NEXT COUPLE HOURS.
ALL SITES WILL HAVE CONVECTION AROUND...SO WILL GO WITH VCTS AND
TEMPO FOR THE 18-21Z TIME FRAME. AS WITH KCLT ABOVE...GUIDANCE KEEPS
LINGERING CONVECTION BEYOND SUNSET. HOWEVER...OVERALL COVERAGE SHUD
CONTINUE TO DECREASE THRU THE NIGHT. PLENTY OF MOISTURE IN
PLACE...SO POTENTIAL FOR PATCHY FOG AND MVFR OR LOWER STRATUS.
CONFIDENCE ON EXACT IMPACTS IS LOW...BUT WILL GO WITH SIMILAR
TIMELINE AS WHAT OCCURRED LAST NIGHT.

KAVL AND KHKY MAY SEE VLIFR TO LIFR CONDITIONS THROUGH
MID MORNING. ELSEWHERE...MVFR CEILINGS MAY LINGER AT KGSP AND
DEVELOP AT KGMU DURING THE EARLY DAYLIGHT HOURS. THE AFTERNOON
APPROACH OF A WEAK MID LEVEL DISTURBANCE SHOULD YIELD A ROUND OF
SHRA/TSRA LATE THIS AFTERNOON AND EVENING. I WILL INCLUDE A PROB30
OR TEMPO IN EACH TAF...GENERALLY BETWEEN 20Z TO 24Z. MTN MVFR
CEILINGS MAY REDEVELOP LATE TONIGHT...ESPECIALLY OVER AREAS THAT SEE
RAIN THIS AFTERNOON AND EVENING.

OUTLOOK...A MID LEVEL RIDGE WILL REMAIN ACROSS THE WESTERN CAROLINAS
THROUGH MID WEEK. A LONGWAVE TROUGH WILL AMPLIFY ACROSS THE ATLANTIC
STATE LATE IN THE WEEK...WITH THE LIKELY PASSAGE OF A COLD FRONT ON
FRIDAY. THE POTENTIAL FOR CONVECTION WILL INCREASE EACH DAY THIS
WEEK.

CONFIDENCE TABLE...

            17-23Z        23-05Z        05-11Z        11-12Z
KCLT       LOW   57%     HIGH 100%     HIGH 100%     LOW   58%
KGSP       LOW   57%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     MED   67%
KHKY       LOW   57%     HIGH 100%     HIGH 100%     HIGH  83%
KGMU       LOW   57%     HIGH 100%     HIGH 100%     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...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...HG
NEAR TERM...ARK/NED
SHORT TERM...HG
LONG TERM...HG
AVIATION...ARK



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