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Area Forecast Discussion

006
FXUS62 KGSP 240240
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1040 PM EDT WED JUL 23 2014

.SYNOPSIS...
WEAK HIGH PRESSURE ATOP THE REGION WILL GIVE WAY TO A SURFACE FRONT
APPROACHING FROM THE NORTHWEST TONIGHT. THE FRONT IS EXPECTED TO
MOVE ACROSS THE CAROLINAS AND NORTH GEORGIA THURSDAY AFTERNOON AND
EVENING. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT FOR FRIDAY AND
THE WEEKEND. ANOTHER FRONT IS EXPECTED TO PASS ON MONDAY.

&&

.NEAR TERM /THROUGH THURSDAY/...
AS OF 1030 PM EDT...THE PRIMARY LATE EVENING TSTM COVERAGE HAS BEEN
IN SRN UPSTATE SECTIONS WHERE THE COMBINATION OF LINGERING
INSTABILITY IN AREAS THAT AVOIDED AFTN CONVECTION AND PASSING WEAK
UPPER VORT LOBE ENERGY WILL GENERATE ISOLD TO SCT TSTMS. COVERAGE
SHOULD BE FAIRLY SPARSE IN MOST OTHER SECTIONS FOR THE REMAINDER OF
THE OVERNIGHT...WITH ANY UPSTREAM PRE/FRONTAL CONVECTION LIKELY
WEAKENING OVER TN...OR WITH JUST ISOLD TO SCT COVERAGE REDEVELOPING
IN WESTERLY UPSLOPE NEAR THE TN BORDER TOWARD DAYBREAK. ANTICIPATE
PATCHY LOW CLOUDS AND FOG THROUGH THE EARLY MORNING HOURS WHERE
HEAVY RAIN FELL TODAY...AND PERHAPS MORE WIDESPREAD FOG THROUGHOUT
THE MTN VALLEYS.

PRE/FRONTAL SHRA/TSRA COULD REACH THE SRN APPALACHIANS DURING THE
MORNING HOURS...WITH COVERAGE LIKELY INCREASING ACROSS THE MTNS
LATER IN THE MORNING...AND THEN THROUGHOUT THE REGION THU AFTN. THE
FRONTAL ZONE FORCING...A DIGGING UPPER TROUGH...AND SBCAPE VALUES
POOLING TO BETWEEN 1000-2000 J/KG DURING THE AFTERNOON WILL WARRANT
LIKELY POPS THROUGHOUT. SPC IS HIGHLIGHTING THE INTERSTATE 77
CORRIDOR EWD WITH A 5 PERCENT SEVERE THREAT THU. WITH SLIGHTLY
IMPROVING SHEAR...WOULD NOT BE SURPRISED TO SEE A FEW SEVERE STORMS
THURSDAY AFTERNOON. MAX TEMPS ON THU WILL BE TEMPERED BY CLOUDS AND
CONVECTION SO THEY SHOULD BE A COUPLE DEGREES LOWER THAN TODAY.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
AS OF 200 PM WED...COLD FRONT WILL CONTINUE TO PUSH THRU THE PIEDMONT
THURSDAY EVENING...WITH AXIS OF DEEP UPPER TROUGH MOVING THRU EARLY
FRI. POPS WILL DECLINE EAST OF THE MTNS FOLLOWING THE END OF
HEATING...WITH LLVL CONVERGENCE UNLIKELY TO OVERCOME THE INHIBITION
RESULTING FROM POOR LAPSE RATES ABOVE THE PBL. PROFILES FROM THE
HIGHER TERRAIN HOWEVER DO SHOW THE EFFECTS OF MIDLEVEL CAA FOLLOWING
THE FRONT...THUS A SCHC POP IS KEPT INTO EARLY FRI MRNG. GOING
FORWARD HOWEVER...HIGH PRESSURE EXPANDS OUT OF THE MIDWEST WHICH
SHOULD PROVIDE AT LEAST A WEAK SUBSIDENCE INVERSION TO CAP OFF MOST
DEEP CONVECTION FRI AND SAT. THE NAM AND A PORTION OF THE SREF
MEMBERS DO NOT SHOW THE INVERSION BEING STRONG ENOUGH TO KEEP THE
ENTIRE CWFA DRY DURING THIS TIME. WILL ADVERTISE SCHC POPS OVER THE
BLUE RIDGE FRI AS WELL AS IN THE LOWER PIEDMONT...WELL SE OF
I-85...WHERE THE HIGH WILL HAVE THE LEAST INFLUENCE. THERE IS BETTER
CONSENSUS FOR A DRY FCST SATURDAY...THOUGH BY THAT TIME THE HIGH HAS
BECOME INDISTINCT DUE TO THE UPPER FLOW BECOMING NEARLY ZONAL. POPS
THUS COULD BE EASILY REINTRODUCED FOR SAT IN SUBSEQUENT FCST
PACKAGES. TEMPS DURING THE SHORT RANGE WILL RETURN TO NEAR NORMAL AS
THICKNESS VALUES INCREASE.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 1215 PM WEDNESDAY...DURING THE LATTER HALF OF THE UPCOMING
WEEKEND...DIURNALLY ENHANCED TSTM ACTIVITY HAS THE OPPORTUNITY TO
BECOME CONSIDERABLE ON SUNDAY WITHIN DEVELOPING LLVL RETURN FLOW
REGIME UNDERNEATH PROGRESSIVELY LOWERING UPPER HEIGHTS. L/WV TROUGH
AXIS IS PROGGED TO CONTINUE TO DIG INTO THE SE CONUS THROUGH
MONDAY...EVENTUALLY FORCING A COLD FRONT ACRS THE REGION BY MONDAY
NIGHT. WITH PRONOUNCED UPPER LEVEL TROUGH ACRS THE ERN CONUS AND
A CONTINENTAL AIRMASS OVERSPREADING THE REGION...A NOTABLY DRY AND
COOLER FCST IS ON TAP FOR TUESDAY AND WEDNESDAY.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
AT KCLT...SFC WINDS HAVE LARGELY RESOLVED TO LIGHT SW LATE THIS
EVENING. ISOLD UPSTREAM SHRA COULD MAKE A RUN TOWARD THE KCLT AREA
THROUGH THE EARLY MORNING HOURS...BUT CONFIDENCE IS TOO LOW TO
MENTION ANYTHING OVERNIGHT. MAINLY SCT TO BKN VFR LEVEL CLOUDS ARE
EXPECTED OVERNIGHT WELL AHEAD OF THE COLD FRONT APPROACHING FROM THE
WEST. MOISTURE AND FORCING WILL RAMP BACK UP THROUGH THU...WITH VCSH
WARRANTED AFTER 15Z AND THEN MORE WIDESPREAD SHRA WITH SCT TSTMS
THROUGH THE AFTN HOURS. RESTRICTIONS WILL BE POSSIBLE UNDER ANY TSRA
THROUGH THU AFTN.

ELSEWHERE...THE TERMINAL FORECAST AREA IS MOSTLY QUIET LATE THIS
EVENING...BUT WITH ISOLD TO SCT SHRA/TSRA JUST SE OF KAND IN AREAS
UNWORKED OVER BY THE AFTN CONVECTION...AND AHEAD OF A WEAK MID LEVEL
SHORTWAVE. WILL KEEP THIS ACTIVITY S/E OF ALL TAF SITES
OVERNIGHT...WITH JUST MAINLY SCT TO BKN VFR CIGS. HOWEVER...LIFR TO
IFR CIGS AND PERHAPS VSBY REMAIN POSSIBLE AT KAVL AFTER 09Z.
PRECIPITATION COVERAGE WILL THEN RAMP UP FROM THE WEST WITH THE
ARRIVING FRONT THROUGH THU...WITH COVERAGE FEATURED MAINLY DURING
THE AFTN HOURS. ANTICIPATE SW WINDS BECOMING MORE WESTERLY WITH
TIME...EXCEPT PERSISTENT NW FLOW AT KAVL.

OUTLOOK... SHOWERS AND THUNDERSTORMS WILL END THU EVENING AS A COLD
FRONT MOVES SOUTHEAST OF THE AREA. FRI AND SAT SHOULD BE QUIET AND
VFR...EXCEPT FOR THE MTN VALLEYS WHERE EARLY MORNING FOG MAY OCCUR.
THUNDERSTORMS WILL RETURN TO THE FORECAST FOR SUNDAY AFTERNOON
THROUGH MON AS ANOTHER COLD FRONT APPROACHES AND THEN MOVES THROUGH
THE AREA ON MON.

CONFIDENCE TABLE...

            02-08Z        08-14Z        14-20Z        20-02Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     MED   67%     HIGH  90%     MED   74%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     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...CSH
NEAR TERM...HG
SHORT TERM...WIMBERLEY
LONG TERM...CSH
AVIATION...HG






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