Area Forecast Discussion
Issued by NWS Greer, SC

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FXUS62 KGSP 281739
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
139 PM EDT MON JUL 28 2014

.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TODAY. IN ITS WAKE...CANADIAN
HIGH PRESSURE WILL MOVE IN AND DOMINATE THE SURFACE PATTERN THROUGH
MIDWEEK LEADING TO WELL BELOW NORMAL TEMPERATURES AND PLEASANT
CONDITIONS. PRECIPITATION CHANCES WILL RAMP BACK UP AGAIN ON
THURSDAY AND FRIDAY AS ATLANTIC MOISTURE SPREADS OVER THE REGION AND
LOW LEVEL WINDS BECOME MORE EASTERLY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM...WITH NO ECHOES CURRENTLY ON RADAR OR UPSTREAM OF THE
MOUNTAINS HAVE DECIDED TO REMOVE MENTIONABLE POPS FOR THE AFTERNOON
IN THE TN BORDER COUNTIES. OTHERWISE...IT LOOKS LIKE THE COLD FRONT
HAS EDGED THROUGH THE AREA AS WINDS HAVE SHIFTED TO THE W/NW AND
DEWPOINTS HAVE FALLEN INTO THE MID 60S ACROSS THE PIEDMONT. CURRENT
FORECAST GRIDS HAVE THIS WELL IN HAND.

AS OF 10 AM...MADE SOME ADJUSTMENTS TO INCREASE WINDS...ESPECIALLY
OVER THE MOUNTAINS WHERE SOME GUSTS IN THE 30-40 MPH RANGE OCCURRING
ABOVE 4000 FT. LOWERED CLOUD AMOUNTS OUTSIDE THE TN BORDER COUNTIES
BASED ON LATEST SATELLITE IMAGERY. HAVE NOTED A COUPLE ISOLATED NW
FLOW SHOWERS IN THE NORTHERN MOUNTAINS SO WILL MAINTAIN THE ISOLATED
TYPE POPS THERE THROUGH THE DAY. JUST MINOR ADJUSTMENTS TO MOST
GRIDS FIELDS.

AS OF 600 AM EDT MONDAY...EARLIER PREFRONTAL SHOWER ACTIVITY HAS
DIMINISHED THEREFORE LOWERED POPS ACROSS THE ENTIRE REGION FOR THE
REMAINDER OF THE MORNING.  COLD FRONT IS CURRENTLY LOCATED ACROSS
THE CUMBERLAND PLATEAU AND IS STILL ON SCHEDULE TO ENTER THE
MOUNTAINS OVER THE NEXT FEW HOURS....AND CONTINUE PUSHING
SOUTHEAST.  POPS STILL RAMP UP TO LOW END SLIGHT CHANCE LEVELS BY
LATE AFTERNOON AND EVENING ACROSS THE HIGH TERRAIN AS UPSLOPE
SHOWER PROBABILITIES INCREASE.  TWEAKED TEMPERATURES AND DEWPOINTS
TO REFLECT LATEST OBSERVATIONS AND LEFT THE REMAINDER OF THE
FORECAST AS IS.

PREVIOUS DISCUSSION...

AS OF 330 AM EDT MONDAY...BROAD UPPER TROF CONTINUES TO DOMINATE THE
PATTERN ALOFT WHILE SURFACE CYCLONE CENTERED OVER THE EASTERN GREAT
LAKES SPREADS A COLD FRONT THROUGH THE OHIO VALLEY.  LINE OF
PREFRONTAL CONVECTION CONTINUES TO WEAKEN AND SLIDE SOUTHEAST ACROSS
THE REGION AS EXPECTED.  THE COLD FRONT IS STILL FORECAST TO
PUSH INTO THE MOUNTAINS THIS MORNING BEFORE SPILLING INTO THE
FOOTHILLS/PIEDMONT REGIONS BY EARLY AFTERNOON.  EXTREME NEAR TERM
PORTION OF THE FORECAST FEATURES EAST/WEST ORIENTED BAND OF
CATEGORICAL POPS ASSOCIATED WITH ABOVE MENTIONED CONVECTIVE LINE.
POPS WILL TAPER INTO THE LATE MORNING HOURS ACROSS THE ENTIRE REGION
AS THE FRONT SLIDES IN AND CANADIAN HIGH PRESSURE BEGINS TO BUILD.

FORECAST WILL REINTRODUCE SLIGHT CHANCE POPS BY LATE AFTERNOON
THROUGH THE OVERNIGHT ALONG PORTIONS OF THE NC MOUNTAINS AS MOISTURE
ADVECTS IN AMONGST NW FLOW ALOFT AND LIFTS MECHANICALLY.  TIGHTENING
PRESSURE GRADIENT ALONG AND BEHIND THE FRONT WILL YIELD GUSTY WINDS
ACROSS THE REGION WITH SOME OF THE HIGHER PEAKS AND RIDGETOPS
EXPERIENCING GUSTS IN EXCESS OF 30MPH...WHILE 15-20MPH GUSTS ARE
EXPECTED ACROSS THE LOWER ELEVATIONS.  TEMPERATURES THIS AFTERNOON
WILL NOT SUFFER MUCH BEHIND THE FRONT AS HIGHS WILL REACH NEAR
NORMAL LEVELS.  AS NORTHERLY FLOW CONTINUES THROUGH THE
PERIOD...EXPECTING TEMPERATURES TO COOL BY TUESDAY MORNING WHERE
LOWS WILL FALL TO BELOW NORMAL LEVELS.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 AM...DEEP ERN CONUS TROF REMAINS IN PLACE THRU THE
PERIOD...ALTHOUGH IT DOES FLATTEN SLIGHTLY BY THE END. A SERIES OF
WEAK SHORT WAVES ROTATE THRU THE TROF AND ACROSS THE AREA DURING
THIS TIME. HIGH PRESSURE SLOWLY SLIDES ACROSS THE AREA THRU THE
PERIOD KEEPING A WEAK ELY FLOW OVER THE AREA. THIS COMBINED WITH
LINGERING LOW LEVEL MOISTURE MAY LEAD TO ISOLATED UPSLOPE DIURNAL
SHRA ACROSS PORTIONS OF THE BLUE RIDGE EACH AFTERNOON. HOWEVER...
ANY QPF WILL BE VERY LIGHT. THICKNESSES DROP DRAMATICALLY IN THE
COOLER AIR MASS LEADING TO HIGHS AROUND 10 DEGREES BELOW NORMAL EACH
DAY AND LOWS 5 TO 10 DEGREES BELOW NORMAL EACH NITE.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 330 AM...DECENT AGREEMENT IN THE MEDIUM RANGE. THE DEEP ERN
CONUS TROF REMAINS IN PLACE THU...THEN TROF AXIS RETROGRADES THRU
THE WEEKEND RIDGING OVER THE ATLANTIC RETROGRADES TOWARD THE EAST
COAST. AT THE SFC...HIGH PRESSURE REMAINS RIDGED OVER THE AREA THRU
THE PERIOD AS A FRONTAL SYSTEM MOVES NE TO THE ATLANTIC COAST BY THE
END OF THE PERIOD. A SERIES OF LOW PRESSURE CENTERS WILL RIDE UP THE
FRONT AS WELL. A MOIST LOW LEVEL S TO SELY FLOW DEVELOPS IN RESPONSE
TO THESE SYSTEMS BRINGING AN INCREASING CHC OF SHOWERS AND
THUNDERSTORMS THRU THE PERIOD. HIGHS WILL BOUNCE AROUND THRU THE
PERIOD REMAINING ABOUT 10 DEGREES BELOW NORMAL. LOWS FOLLOW A
SIMILAR PATTERN REMAINING ABOUT 5 DEGREES BELOW NORMAL.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AT KCLT AND ELSEWHERE...VFR CONDITIONS WILL PREVAIL THROUGH THE TAF
PERIOD AT ALL SITES AS COLD FRONT MOVES AWAY FROM THE AREA AND
BREEZY DONWSLOPE WINDS PREVAIL. WINDS WILL BE NW AND GUSTY THROUGH
THE AFTERNOON HOURS...BUT DIMINISH AFTER SUNSET. WINDS WILL
GRADUALLY NEER TO THE N-NE LATE TONIGHT.

OUTLOOK...DRY HIGH PRESSURE WILL PREVAIL THROUGH MIDWEEK. THE ONLY
POSSIBLE RESTRICTIONS WILL BE EARLY MORNING FOG IN THE MOUNTAIN
VALLEYS. MOISTURE WILL INCREASE BY LATE WEEK AS EASTERLY FLOW
RETURNS LEADING TO INCREASING PRECIPITATION/FOG/STRATUS CHANCES.

CONFIDENCE TABLE...

            17-23Z        23-05Z        05-11Z        11-17Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     MED   79%     MED   77%
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...RWH
NEAR TERM...LG
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...LG






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