Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 251739
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1239 PM EST THU DEC 25 2014

.SYNOPSIS...
HIGH PRESSURE WILL BE CENTERED OVER OUR AREA ON FRIDAY
PROVIDING PLEASANT WEATHER WITH SLIGHTLY ABOVE NORMAL TEMPERATURES.
EXPECT THE NEXT COLD FRONT TO APPROACH FROM THE WEST THIS WEEKEND
WITH LOW PRESSURES RIDING UP ALONG THE FRONT. THE FRONT CROSSES ON
MONDAY WITH COOLER HIGH PRESSURE BUILDING IN FROM THE WEST THROUGH
MID WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM...THE FCST LOOKS LIKE IT IS ON TRACK...WITH MOST OF
THE CLOUD COVER NOW MOVING OFF THE COAST. STILL A BIT OF UPSLOPE
CLOUDINESS ON THE TN BORDER...ESPECIALLY OVER THE NRN MTNS...BUT
EVEN THAT SHOULD MELT AWAY LATE THIS AFTERNOON AND EARLY THIS
EVENING. THE REST OF THE DAY SHOULD BE DRY. TEMP TRENDS LOOK GOOD.
NO CHANGES.

REMAINDER OF PREVIOUS DISCUSSION...

ANTICIPATE FLAT UPPER RIDGING THROUGH THE DAY AS THE DEAMPLIFYING
TROUGH PASSES TO THE EAST. A SFC LEE TROUGH SHOULD DEVELOP AND KEEP
WINDS SW THROUGH THE DAY...AT LEAST ACROSS THE SRN TIER OF THE
FORECAST AREA. THE COMBINATION OF GOOD INSOLATION FROM MID MORNING
ONWARD...A LIGHT DOWNSLOPING WESTERLY 850 MB FLOW...AND THE LEE
TROUGHING WILL CONTRIBUTE TO MAXES ONE TO TWO CATEGORIES ABOVE
NORMAL IN MOST LOCATIONS EAST OF THE MTNS. THE SFC HIGH PRESSURE
CENTER WILL THEN BUILD OVERHEAD TONIGHT...WITH SEASONABLE MINS IN
THE 20S MTNS TO 30S EAST.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
AT 230 AM EST THURSDAY...ON FRIDAY MORNING AN UPPER RIDGE WILL BE
OVER THE EASTERN USA....WHILE A TROUGH WILL BE OVER THE WEST WITH A
CLOSED LOW OVER THE CENTRAL ROCKIES. BY SATURDAY THE LOW OPENS UP
AND FILLS...AND THE WESTERN TROUGH TAKES ON A POSITIVE TILTS FROM
THE NORTHERN PLAINS TO THE SOUTHERN ROCKIES...WHILE THE EASTERN RIDGE
AXIS MOVES OFF THE COAST. THE RESULT IS A LONGER WAVELENGTH AND
DECREASING AMPLITUDE INTO SATURDAY NIGHT.

A DRY SURFACE RIDGE WILL BE CENTERED OVER THE CAROLINAS ON FRIDAY
MORNING. THE RIDGE CENTER MOVES OFF THE NC COAST BY FRIDAY
EVENING...WHILE GULF MOISTURE STARTS MOVING NORTH UP THE MS RIVER
VALLEY IN ADVANCE OF A FRONT IN THE SOUTHERN PLAINS. BY SATURDAY
MORNING GULF MOISTURE OVERSPREADS THE GULF STATES...AND BY LATE IN
THE DAY IT REACHES THE UPPER SAVANNAH RIVER VALLEY AND SOUTHERN
APPALACHIANS. ISENTROPIC UPGLIDE OVER A GULF WARM FRONT WILL RESULT
IN WIDESPREAD MOISTURE ACROSS OUR AREA...THOUGH LIFT AND RESULTANT
PRECIPITATION WILL BE RATHER LIMITED.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AT 230 AM EST THURSDAY...ON SUNDAY MORNING AN UPPER HIGH CENTERED
OVER THE CARIBBEAN WILL EXTEND NORTH OFF THE EAST COAST...WHILE A
HIGH AMPLITUDE TROUGH WILL BE OVER THE PLAINS. BY MONDAY...THE RIDGE
PROGRESSES SLIGHTLY...WHILE THE TROUGH UPSTREAM RETROGRESSES
SLIGHTLY AS UPPER LEVEL ENERGY DIVES SOUTH OVER THE ROCKIES...
RESULTING IN A LOWER AMPLITUDE PATTERN THAT PERSISTS INTO TUESDAY.
AN UPPER LOW CLOSES OFF INT THE SOUTHWEST BY WEDNESDAY...WHILE
NEARLY ZONAL FLOW EXTENDS DOWNSTREAM TO THE EAST COAST.

A COLD FRONT WILL SLOWLY CROSS THE WESTERN CAROLINAS AND NE GA FROM
THE WEST ON SUNDAY AND SUNDAY NIGHT. GULF INFLOW AHEAD OF THIS
BOUNDARY WILL BE LIMITED...BUT MODEST UPSLOPE FLOW AND ISENTROPIC
UPGLIDE WILL SUPPORT WIDESPREAD...GENERALLY LIGHT PRECIPITATION. BY
MONDAY MORNING THE FRONT WILL BE EXITING OUR AREA TO THE EAST...
WHILE ANOTHER COLD FRONT APPROACHES FROM THE NW. THE SECOND FRONT
MOVES THROUGH DURING THE DAY...FOLLOWED BY SOME MOIST NW UPSLOPE
FLOW INTO THE MOUNTAINS THAT WILL LAST INTO WEDNESDAY. ALTHOUGH
COLD ADVECTION WILL SET UP...IT APPEARS THAT CRITICAL THICKNESS
VALUES MAY BE LACKING EARLY ON...AND RAIN SHOWERS WILL BE THE
PREDOMINANT PRECIPITATION TYPE UNTIL EARLY WEDNESDAY. TEMPERATURES
WILL RUN ABOVE NORMAL AHEAD OF THE FRONT...FALLING TO NEAR NORMAL
BEHIND THE FRONTS AT MIDWEEK.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...VFR THROUGH THE PERIOD. EXPECT WIND TO REMAIN NW THROUGH
THE AFTERNOON ALTHO A BRIEF W CROSSWIND CANNOT BE RULED OUT. WIND
SHOULD GO LIGHT AND VARIABLE THIS EVENING WITH SUNSET AS HIGH
PRESSURE BUILDS IN. THE HIGH IS EXPECTED TO BE JUST TO THE EAST ON
FRIDAY MORNING WHICH COULD ALLOW THE WIND TO RETURN WITH A SOUTHERLY
COMPONENT. SKY SHOULD REMAIN ESSENTIALLY CLEAR.

ELSEWHERE...SIMILAR TO KCLT WITH VFR CONDITIONS THRU THE PERIOD.
WIND SHOULD STAY NW AT KAVL. GUSTS THIS AFTERNOON SHOULD ABATE BY
21Z-22Z.

OUTLOOK...VFR THROUGH LATE SATURDAY. MOISTURE WILL RETURN AHEAD OF
THE NEXT COLD FRONT SATURDAY NIGHT...WHICH COULD BRING RESTRICTIONS
BACK BY EARLY SUNDAY MORNING. FLIGHT RESTRICTIONS COULD CONTINUE
THROUGH WEDNESDAY AS A FRONT MOVES SLOWLY ACROSS THE REGION.

CONFIDENCE TABLE...

            17-23Z        23-05Z        05-11Z        11-12Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     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...JAT
NEAR TERM...HG/PM
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...PM



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