National Weather Service Weather Forecast Office

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

000
FXUS62 KGSP 140659
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
259 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/...
AS OF 215 AM EDT...ISOLD SHOWERS IN THE MOIST NRLY POST FROPA FLOW
ACROSS THE NC MTNS AND FOOTHILLS CONTINUE TO DWINDLE EARLY THIS
MORNING. OTHERWISE...SFC HIGH PRES SPILLING SWD FROM CANADA WILL
PUSH DRIER 50S DEWPOINT AIR INTO THE REGION THROUGH THE NEAR TERM.
ALOFT...A FEW FINAL ROUNDS 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.

&&

.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 /07Z FRIDAY THROUGH TUESDAY/...
AT KCLT...HIGH CLOUD CIGS MOVED EAST OF THE AIRFIELD AT ISSUANCE
TIME AND PATCHY STRATOCUMULUS IN THE COLD ADVECTION FLOW IS DRYING
UP OVER THE NC FOOTHILLS EARLY THIS MORNING. EXPECT MAINLY FEW TO
SCT VFR LEVEL STRATOCUMULUS 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 CEILINGS 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 WILL
PROVIDE TEMPO CIGS FROM KAVL TO KHKY...WITH MAINLY FEW TO SKC
CONDITIONS AT THE SC TAF SITES. CLOUDS WILL DISSIPATE THROUGH THE
DAY AS DRIER HIGH PRES ARRIVES FROM THE N...BUT WITH SLIGHTLY BETTER
STRATOCUMULUS COVERAGE 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...

            07-13Z        13-19Z        19-01Z        01-07Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH  88%     HIGH 100%     HIGH 100%     HIGH 100%
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...HG
NEAR TERM...HG
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...HG