Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 280655
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
255 AM EDT SUN JUN 28 2015

.SYNOPSIS...
A COLD FRONT WILL PUSH OUT OF THE REGION EARLY TODAY BRINGING COOLER
AND DRIER CONDITIONS TO START THE NEW WEEK. ANOTHER FRONT WILL
APPROACH THE REGION BY MID-WEEK AND WEAKEN ACROSS THE MOUNTAINS.
THEREAFTER THE REGION WILL STAY IN A WARM AND MOIST ENVIRONMENT
WHICH WILL SUPPORT ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM
COVERAGE TYPICAL OF EARLY JULY.

&&

.NEAR TERM /THROUGH TONIGHT/...
POST-FRONTAL DEEP LAYERED DRYING WILL CONTINUE TO OVERSPREAD THE
REGION TODAY RESULTING IN A SUNNY SUNDAY. COMBINED WITH UNSEASONABLY
LOW SFC DWPTS...MAXIMUM TEMPERATURES WILL TOP OUT ABOUT A CATEGORY
BELOW CLIMO FOR THE FIRST TIME IN ABOUT TWO WEEKS. DRY AIR THROUGH A
DEEP LAYER LINGERS THROUGH TONIGHT PROVIDING CLEAR SKIES. WITH THE
LINGERING DRY AIR...MONDAY MORNING MINIMUM TEMPS WILL RADIATE DOWN
TO VALUES 6-8 DEG F BELOW NORMAL.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
AT 230 AM EDT SUNDAY...ON MONDAY AN ANOMALOUS HIGH AMPLITUDE UPPER
TROUGH WILL BE OVER EASTERN NORTH AMERICA...WHILE A RIDGE OF SIMILAR
PROPORTIONS WILL BE OVER THE WEST. A CLOSED UPPER LOW WILL BE
LIFTING OUT OF THE TROUGH OVER SOUTHERN QUEBEC...WHILE SHORTWAVE
ENERGY UPSTREAM DIVES SOUTHEAST ACROSS THE UPPER MIDWEST INTO THE
TROUGH AXIS. ON TUESDAY ANOTHER SHORTWAVE DIVES ACROSS THE GREAT
LAKES ON THE HEELS OF THE PREVIOUS SHORTWAVE. THE TRAILING EDGE OF
BOTH SHORTWAVES APPEAR TO CROSS THE SOUTHERN APPALACHIANS...ONE ON
MONDAY NIGHT...AND THE OTHER ON TUESDAY NIGHT.

AT THE SURFACE...MONDAY MORNING FEATURES DRY HIGH PRESSURE OVER THE
SOUTHERN APPALACHIANS IN THE WAKE OF A DEPARTING FRONT OF THE
CAROLINA AND GA COASTS. THE HIGH WEAKENS DURING THE DAY...FOLLOWED
BY AND INCREASE IN MOISTURE AHEAD OF THE REMAINS OF A WEAKENING COLD
FRONT. THE REMAINS OF THE FRONT CROSS THE MOUNTAINS ON TUESDAY...
MOVING INTO THE PIEDMONT ON TUESDAY NIGHT.

MODEL FORECAST SOUNDINGS SHOW INSTABILITY TO BE QUITE WEAK ON
MONDAY...AND MAINLY LIMITED TO THE MOUNTAINS...WITH MOISTURE
CONFINED TO BETWEEN 7000 AND 650 MB. BY TUESDAY MOISTURE AND
INSTABILITY WILL HAVE IMPROVED AHEAD OF THE APPROACHING SURFACE
BOUNDARY...SUPPORTING DAYTIME AND EVENING CONVECTION. SOME SHEAR WILL
BE AVAILABLE FOR ORGANIZATION...BUT LOW LEVEL WINDS WILL FAVOR THE
WEST...LIMITING UPSLOPE FLOW ENHANCEMENT OF PRECIPITATION TO THE
WEST SLOPES OF THE APPALACHIANS. TEMPERATURES WILL RISE FROM
SLIGHTLY BELOW NORMAL TO NEAR NORMAL AS THE AIR MASS MODIFIES AND
DOWNSLOPE FLOW ENSUES.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AT 230 AM EDT SUNDAY...ON WEDNESDAY A HIGH AMPLITUDE ANOMALOUS UPPER
TROUGH WILL EXTEND FROM THE CANADIAN ARCTIC TO SOUTHERN GA...WHILE A
SOMEWHAT FLAT UPPER RIDGE RESIDES OVER THE SW USA. THE UPPER RIDGE
RETROGRESSES SLIGHTLY BY THURSDAY...INCREASING THE WAVELENGTH AND
DECREASING THE AMPLITUDE OF THE UPPER PATTERN. ON FRIDAY SHORTWAVE
ENERGY DROPPING INTO THE TROUGH RESULTS IN SLIGHT RETROGRESSION AND
AN INCREASE IN AMPLITUDE. DEAMPLIFICATION IS SEEN AGAIN ON SATURDAY
AS THE SOUTHERN AND NORTHERN STREAM GO OUT OF PHASE...PARTICULARLY
IN WESTERN CANADA.

AT THE SURFACE...WEDNESDAY FEATURES WEAK SURFACE RIDGING OVER THE
SOUTHERN APPALACHIANS...WITH A LEE TROUGH...APPARENTLY THE REMAINS
OF PASSING FRONT...IS DOWNSTREAM OVER THE PIEDMONT. A COLD FRONT
MOVING INTO THE OH RIVER VALLEY ON WEDNESDAY STALLS ON THURSDAY FROM
THE DELMARVA REGION TO THE MID MS RIVER VALLEY. THIS FRONT STARTS TO
MOVE N ON FRIDAY...WHILE A COLD FRONT MOVES ACROSS THE CENTRAL
PLAINS AND MID MS RIVER VALLEY. THIS FRONT WEAKENS AS IT CROSSES THE
SOUTHERN APPALACHIANS BY SATURDAY.

SUFFICIENT INSTABILITY SHOULD BE PRESENT MOST DAYS TO SUPPORT DIURNALLY
MODULATED CONVECTION...WITH PASSING FRONTS POSSIBLY EXTENDING
CONVECTION KEEPING CONVECTION ALIVE INTO THE OVERNIGHT HOURS. MODEL
FORECAST SOUNDINGS SHOW SOME AMOUNT OF LOW LEVEL SHEAR PRESENT...
LENDING LIMITED SUPPORT FOR ORGANIZED CONVECTION. WITH LOW LEVEL
FLOW FAVORING THE WEST...UPSLOPE ENHANCED PRECIPITATION WOULD BE
CONFINED TO THE WEST SLOPES OF THE APPALACHIANS. TEMPERATURES WILL
RUN NEAR NORMAL.

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
AT KCLT...DRYING AND SCOURING EARLY THIS MORNING WILL LESSEN THE
POSSIBILITY OF STRATUS CIGS DEVELOPING...ESPECIALLY HEADING TOWARD
DAYBREAK. FOR THE DAYLIGHT HOURS...MOSTLY CLEAR CONDITIONS ARE ON TAP
WITH NW WINDS THIS MORNING BACKING TO WSW THIS AFTERNOON.

ELSEWHERE...AREAS OF PIEDMONT STRATUS SHOULD DISSIPATE AS THE
PRE-DAWN HOURS WEAR ON...OTHERWISE VFR THROUGH THE PERIOD.

OUTLOOK...A DRY AIRMASS WILL PERSIST OVER THE REGION THROUGH
EARLY WEEK...BRINGING MOSTLY VFR CONDITIONS. AN ACTIVE PATTERN WILL
RETURN BY MID-WEEK...WITH PERIODIC SHRA/TSRA POSSIBLY BRINGING
RESTRICTIONS.

CONFIDENCE TABLE...

            07-13Z        13-19Z        19-01Z        01-06Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       MED   64%     HIGH  91%     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...JAT
NEAR TERM...CSH
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...CSH



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