National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KGSP 141431
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1031 AM EDT FRI JUN 14 2013

.SYNOPSIS...
DRY HIGH PRESSURE WILL BUILD INTO THE AREA FROM THE NORTH TODAY
THROUGH TONIGHT AND SETTLE ACROSS THE REGION THROUGH THE WEEKEND.
THE NEXT COLD FRONT WILL APPROACH FROM THE NORTHWEST BY THE MIDDLE
OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 1030 AM EDT FRIDAY...DRIER AND SUNNY CONDITIONS THIS AFTERNOON
OVER THE FOOTHILLS AND PIEDMONT. OVER THE NRN MTNS A CU FIELD HAS
INCREASED WITH DAYTIME HEATING AND I/VE UPPED CLOUD COVER ACROSS
THOSE ZONES. OTHERWISE EVERYTHING IS IN GOOD SHAPE.

AS OF 645 AM EDT...THE DEPARTING SFC COLD FRONT STRETCHES FROM THE
SE COASTLINE TO THE FL PANHANDLE. SCATTERED STRATOCUMULUS HAVE
REMAINED PERSISTENT IN THE NRLY POST FROPA COLD ADVECTION FLOW
ACROSS THE MTNS...BUT WITH COVERAGE DWINDLING AS DRIER AIR MOVES IN
ALONG WITH HIGH PRESSURE FROM CANADA. ALOFT...A FEW FINAL SPOKES OF
500 MB VORTICITY WILL DIVE INTO THE DEPARTING UPPER TROUGH AXIS AND
CROSS MAINLY WRN NC THROUGH THE DAY...BUT WITH PROFILES TOO DRY FOR
ANYTHING OTHER THAN SCATTERED STRATOCUMULUS. MAX TEMPS WILL RETURN
TO NEAR OR SLIGHTLY BELOW NORMAL VALUES THROUGHOUT THIS AFTN.

DRY SFC HIGH PRESSURE WILL BECOME MORE SQUARELY SETTLED OVER THE
APPALACHIANS TONIGHT. HOWEVER...THERE MAY BE A PESKY LAYER OF
MOISTURE TRAPPED UNDER A MID LEVEL CAPPING INVERSION THAT COULD
PRODUCE SOME STRATOCUMULUS THROUGH THE OVERNIGHT HOURS INTO SAT
MORNING. WILL NOT HIT THIS TOO HARD AT PRESENT...BUT IT COULD IMPACT
THE FORECAST OF SEASONABLY COOL TEMPERATURES FOR TONIGHT.
-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY THROUGH TUESDAY NIGHT/...
AT 230 AM EDT FRIDAY...AS UPPER TROF CONTINUES TO MOVE FURTHER
OUT TO SEA...UPPER LEVEL AND SURFACE HIGH PRESSURE WILL SETTLE IN
ACROSS THE SOUTHEAST.  MODELS ARE IN GOOD AGREEMENT WITH REGARDS TO
THE FIRST HALF OF THE WEEKEND AS NEAR NORMAL TEMPERATURES AND MOSTLY
SUNNY SKIES WILL PREVAIL THROUGH SUNDAY MORNING.  BY THAT
TIME...MODEL DISCONTINUITY IS EVIDENT AS GFS GUIDANCE BREAKS DOWN
THE RIDGE WHILE THE ECMWF KEEPS IT INTACT THROUGH THE DAY.  WENT
WITH A BLEND OF THE TWO WHICH WILL INTRODUCE LOW END CHANCE POPS FOR
THE HIGHER TERRAINS AND SLIGHT CHANCE POPS ELSEWHERE FOR SUNDAY
AFTERNOON.  BY MONDAY...BOTH SOLUTIONS HAVE THE SURFACE HIGH
POSITIONED OFF THE EAST COAST ALLOWING FOR WARM MOIST SOUTHERLY FLOW
TO RETURN.  THIS INCREASING MOISTURE COMBINED WITH A SERIES OF UPPER
LEVEL IMPULSES WILL INCREASE INSTABILITY PROMPTING CHANCE POPS
ACROSS THE AREA ON MONDAY. MEANWHILE...AN UPPER LEVEL TROF EJECTING
OUT OF THE UPPER MIDWEST WILL SPREAD A COLD FRONT ACROSS THE OHIO
VALLEY.  ONCE AGAIN...THERE IS SOME DISAGREEMENT WITH REGARDS TO THE
TIMING OF THE APPROACHING COLD FRONT.  THE GFS SLOWS THE FRONT THUS
BRINGING IT INTO WESTERN NORTH CAROLINA BY NO EARLIER THAN 00Z
WEDNESDAY WHILE THE ECMWF IS MUCH FASTER BRINGING THE FRONT THROUGH
BY LATE MORNING TUESDAY.  IF THE ECMWF WERE TO VERIFY...THIS WOULD
PRODUCE THE GREATEST POTENTIAL FOR ANY STRONG THUNDERSTORM
DEVELOPMENT AS CONVERGENCE AHEAD OF AND ALONG THE FRONT WOULD BE
ABLE TO TAP INTO A MORE HEATED AIRMASS.  WENT WITH A BLEND OF THE
TWO AT THIS TIME BLANKETING THE ENTIRE REGION WITH SOLID CHANCE POPS
THROUGH THE AFTERNOON AND EARLY EVENING HOURS ON TUESDAY.  EITHER
WAY...THE FRONT SHOULD MOVE SOUTH OF THE I85 CORRIDOR AND INTO THE
MIDLANDS/LOW COUNTRY BY SUNRISE WEDNESDAY.  EXPECT TEMPERATURES TO
BE NEAR OR SLIGHTLY BELOW NORMAL THROUGH THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AT 300 AM EDT FRIDAY...AS COLD FRONT PUSHES INTO THE LOW COUNTRY ON
WEDNESDAY MORNING HIGH PRESSURE WILL BUILD TO THE NORTH TEMPORARILY
ADVECTING IN A SLIGHTLY COOLER/DRIER AIRMASS.  HOWEVER...BY
WEDNESDAY EVENING THIS RIDGE WILL MOVE OVER THE ATLANTIC THUS
RETURNING THE REGION TO DOMINANT SOUTHERLY FLOW.  AS MOISTURE
INCREASES YET AGAIN ON THURSDAY AND INTO FRIDAY...ANY PRECIPITATION
CHANCES WILL RESIDE DURING THE AFTERNOON HOURS AS DIURNAL CONVECTION
SHOULD BE THE MAIN THREAT.  TEMPERATURES DURING THIS PERIOD WILL
REMAIN AT OR SLIGHTLY BELOW NORMAL.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
AT KCLT...PATCHY STRATOCUMULUS IN THE COLD ADVECTION FLOW CONTINUES
TO DRY UP OVER THE NC MTNS AROUND DAYBREAK THIS MORNING...LEAVING
THE KCLT AREA MAINLY CLEAR. EXPECT MAINLY FEW TO SCT VFR LEVEL
STRATOCUMULUS TO DEVELOP THROUGH THE PERIOD AS WEAK SPOKES OF
VORTICITY CROSS THE REGION BEHIND THE DEPARTING UPPER TROUGH AXIS.
NRLY FLOW WILL INCREASE AS HIGH PRES PUSHES IN FROM THE N
TODAY...WITH SOME LOW END GUSTS LIKELY WITH MIXING. THE HIGH BASED
STRATOCUMULUS COULD BECOME A CEILING TONIGHT WITH A MID LEVEL
INVERSION IN PLACE...BUT WILL KEEP SKY CONDITIONS SCT FOR NOW.

ELSEWHERE...STRATOCUMULUS IN THE POST COLD FROPA NRLY FLOW CONTINUES
TO DISSIPATE ACROSS THE MTNS EARLY THIS MORNING...WITH MAINLY FEW TO
SCT CLOUDS AROUND KAVL AND CLEAR ACROSS THE FOOTHILLS. SLIGHTLY
BETTER STRATOCUMULUS COVERAGE IS POSSIBLE AT KHKY THROUGH THE DAY
WITH PASSING WEAK UPPER WAVES. THERE IS SOME POTENTIAL FOR MOISTURE
TO BECOME TRAPPED UNDER A MID LEVEL INVERSION TONIGHT AND PRODUCE
CIGS AT THE FOOTHILL TAF SITES...BUT WILL KEEP CONDITIONS SCT FOR
NOW. VALLEY FOG SHOULD BE CONFINED MAINLY TO THE LITTLE TN VALLEY
THIS MORNING. EXPECT NRLY FLOW THROUGH THE DAY WITH OCNL LOW END
GUSTS EVERYWHERE BUT KAND WHERE WINDS WILL BE LIGHTEST.

OUTLOOK...HIGH PRESSURE WILL PRODUCE GENERALLY QUIET WEATHER AND VFR
CONDITIONS THROUGH THE WEEKEND. TSTM CHANCES WILL INCREASE AGAIN
EARLY NEXT WEEK.

CONFIDENCE TABLE...

            14-20Z        20-02Z        02-08Z        08-14Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  87%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  87%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  87%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  87%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  87%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  87%

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
-- End Changed Discussion --

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...HG
NEAR TERM...HG/MCAVOY
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...HG