Area Forecast Discussion
Issued by NWS Greer, SC

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427
FXUS62 KGSP 071746
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1246 PM EST SUN FEB 7 2016

.SYNOPSIS...
STRONG LOW PRESSURE WILL REMAIN OF THE CAROLINA COAST THROUGH
TONIGHT...BUT MOST OF THE ASSOCIATED CLOUDS AND PRECIPITATION
WILL REMAIN OVER THE CENTRAL AND EASTERN CAROLINAS. A COLD FRONT
WILL PUSH THROUGH THE REGION MONDAY...USHERING IN BELOW NORMAL
TEMPERATURES WHICH WILL LAST THROUGH THE WEEK. MOIST WESTERLY FLOW
INTO THE MOUNTAINS BEHIND THE FRONT WILL BRING PERIODS OF SNOWFALL
TO THAT AREA FROM MONDAY THROUGH WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM...SATELLITE IMAGERY SHOWS WHAT A DIFFERENCE YOUR
LOCATION MAKES IN TERMS OF WHAT YOUR IMPRESSION OF THE KIND OF
DAY IT IS. THE WRN EDGE OF THE CLOUD SHIELD ASSOCIATED WITH THE
OFFSHORE LOW HAD MOVED A BIT FARTHER EAST...BUT STILL WAS WEST OF
METRO CHARLOTTE. SO... IT IS A BRIGHT SUNNY DAY OVER MOST OF THE NC
MTNS/FOOTHILLS...UPSTATE SC...AND NE GEORGIA...WITH TEMPS WARM
NICELY AS EXPECTED. MEANWHILE...THE CHARLOTTE METRO AREA AND I-77
CORRIDOR ARE STUCK UNDER ANOTHER MID-LEVEL CLOUD DECK AGAIN. STILL
EXPECT THE CLOUD SHIELD TO THIN AND MOVE OUT TO THE EAST IN THE
EARLY AFTERNOON...WHICH WILL HOPEFULLY SAVE THE HIGH TEMP OVER IN
THE WRN PIEDMONT.

TONIGHT...A SHORT WAVE ROTATING AROUND AN UPPER LOW DIVING INTO THE
MIDWEST WILL APPROACH THE AREA BY THE END OF THE PERIOD. THE COLD
FRONT ASSOCIATED WITH THIS SYSTEM WILL APPROACH THE AREA FROM THE
WEST AS WELL. INCREASING MOISTURE AHEAD OF THIS SYSTEM WILL MOVE
INTO THE MTNS...ALONG WITH INCREASING FORCING. SNOW SHOWERS WILL
MOVE INTO THE TN BORDER COUNTIES TOWARD MORNING...WITH ONLY MINOR
ACCUMS AT BEST BEFORE DAYBREAK. LOWS WILL BE NEAR NORMAL.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 245 AM SUNDAY...AT THE START OF THE PERIOD MONDAY
MORNING...THE LEADING EDGE OF A DEEP UPPER TROUGH WILL REACH THE
SOUTHERN APPALACHIANS. A COLD CANADIAN AIRMASS WILL PUSH INTO THE
REGION AS THE TROUGH EXPANDS SOUTH AND EAST FROM THERE...BRINGING
A COOLING TREND INTO MIDWEEK. EDDIES ROTATING AROUND THE CLOSED
CIRCULATION WITHIN THE TROUGH WILL PROVIDE PERIODS OF DYNAMIC LIFT
ACROSS THE WHOLE CWFA. IN THE MOUNTAINS...THE ALREADY WESTERLY
FLOW VEERS TO NW WITH THE PASSAGE OF THE FIRST EDDY AND CONTINUES
SOMEWHAT STEADILY THRU AT LEAST WED MORNING...ALONG WITH PLENTY
OF LOW LEVEL MOISTURE. SNOW SHOWERS ARE EXPECTED THROUGHOUT THE
PERIOD...WITH SOME VARIATION IN FREQUENCY/INTENSITY AS THE UPPER
DISTURBANCES PASS...RESULTING IN VARYING DEGREES OF LIFT AS WELL AS
WIND SPEED. THE BEST COMBINATION OF THE INGREDIENTS APPEARS LIKELY
TO COME TOGETHER MONDAY EVENING. HOWEVER...AT THIS TIME THE FAVORED
QPF AND SNOW RATIO GUIDANCE DO NOT SUPPORT ACCUMS MEETING WATCH
CRITERIA. AN ADVISORY IS LIKELY TO BE ISSUED AT SOME POINT...BUT
CAN/T SAY FOR CERTAIN THAT WARNING CRITERIA WOULD BE MET AT ANY
POINT DURING THE PERIOD. I WILL BEEF UP THE EXISTING HWO MENTION
FOR THE NW FLOW AREAS TO BETTER HIGHLIGHT THE CONDITIONS.

EAST OF THE BLUE RIDGE...QG FORCING AND DEEP MOISTURE OVERLAP MONDAY
AFTN...AND THERE CONTINUES TO BE SOME SMALL SBCAPE FORECAST BY THE
MAJOR MODELS DURING PEAK HEATING. SHOWERS NOW LOOK LIKELY OVER THE
NC PIEDMONT AT THIS TIME...HOWEVER GFS/NAM WET-BULB PROFILES ARE TOO
WARM FOR SNOW AT THE SURFACE DURING THE PEAK POPS. LINGERING SHOWERS
MON EVENING MAY TURN PARTIALLY TO SNOW BEFORE ENDING...BUT NO ACCUM
IS EXPECTED. ANOTHER SHOT OF UPPER LIFT IS STILL PROGGED FOR TUESDAY
WHEN TEMPS WILL HAVE COOLED ENOUGH TO SUPPORT SNOW...BUT BY THEN
THE PRESENCE OF ENOUGH MOISTURE IS QUESTIONABLE DOWNSTREAM OF THE
MOUNTAINS. POPS TUE REMAIN SLIGHT CHANCE OUTSIDE THE FOOTHILLS.

MAX/MIN TEMPS WILL ALREADY BE 5-8 DEGREES BELOW CLIMO MONDAY AND
MONDAY NIGHT...TRENDING DOWN ANOTHER 5-10 DEGREES TUE AND TUE NIGHT.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF EARLY SUNDAY MORNING...TROUGH AXIS PASSES OVER THE AREA
WED...AND THOUGH HEIGHTS DO RISE FROM THEN INTO FRI...FAST CYCLONIC
FLOW WILL CONTINUE OVERHEAD. UPSLOPE WINDS CONTINUE INTO THE SRN
APPALACHIANS THROUGH EARLY THU BUT THE MOISTURE FINALLY DIMINISHES
TO THE POINT THAT POPS CAN BE ALLOWED TO TAPER OFF. A LITTLE MORE
ACCUMULATING SNOW MAY OCCUR WED BUT THE PEAK OF THE EVENT MOST
LIKELY WILL HAVE PASSED BY THEN. BEHIND THE TROUGH...A CANADIAN
SFC HIGH WILL SHIFT OVER THE SOUTHEAST...KEEPING TEMPS BELOW NORMAL
THRU THE REMAINDER OF THE PERIOD EVEN AS CLEARER SKIES RETURN. THE
NEXT WEATHER-MAKER FOR OUR AREA IS A SHALLOW CLIPPER SHORTWAVE
DIVING SOUTH ACRS THE CENTRAL CONUS FRIDAY ON THE UPSTREAM SIDE
OF THE TROUGH. A WEAK WARM FRONT DEVELOPS AHEAD OF THIS FEATURE
ON BOTH THE GFS AND EC...THOUGH THE TIMING DIFFERS. HOWEVER THE
MODELS RESPOND MORE TO THE UPSLOPE FLOW INTO THE APPALACHIANS THAN
THE SHALLOW MOIST LIFT OVER THE FRONT...SO OUR ONLY POPS ARE OVER
THE MTNS/FOOTHILLS LATE FRI.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AT KCLT....THE MID-LEVEL CLOUD DECK REMAINS OVERHEAD AT ISSUANCE
TIME...BUT THIS IS EXPECTED TO FINALLY MOVE OFF TO THE EAST BY MID-
AFTERNOON. THIS SHOULD ALLOW GUSTY NNE WIND TO CONTINUE UNTIL LATE
AFTERNOON WHEN THE PRESSURE GRADIENT RELAXES AND THE BOUNDARY LAYER
STARTS TO DECOUPLE. EXPECT CLEAR SKY OVERNIGHT WITH LIGHT MOSTLY NW
WIND EVENTUALLY SHIFTING AROUND TO LIGHT SW OR S BEFORE DAYBREAK AS
THE NEXT UPPER SYSTEM APPROACHES. AT THIS TIME...IT DOES NOT APPEAR
THIS SYSTEM WILL REACH CHARLOTTE BEFORE THE VERY END OF THE TAF
PERIOD.

ELSEWHERE OUTSIDE THE MTNS...VFR CONDITIONS WILL CONTINUE THROUGH
THE PERIOD. EXPECT INCREASING HIGH CLOUDS TOWARD DAYBREAK. THINK ANY
LOW CLOUDS THAT MOVE IN AS THE NEXT SYSTEM CROSSES THE MTNS WILL
REMAIN VFR. RELATIVELY LOW CHANCE THAT ANY PRECIP WILL BREAK OUT
PAST THE MTNS BY THE END OF THE TAF PERIOD...EXCEPT FOR MAYBE KHKY.

AT KAVL...WITH LOW VFR MAY DEVELOP AROUND DAYBREAK. MOST OF THE
PRECIP ASSOCIATED WITH THE PASSAGE OF THE UPPER SYSTEM WILL STAY
CLOSER TO THE TN BORDER...BUT LIGHT PRECIP CANNOT BE RULED OUT IN
THE MORNING. EVENTUALLY...THE IMPROVING NW FLOW WILL BLOW LOW CLOUDS
AND SNOW SHOWERS UP THE FR. BROAD VALLEY...THUS THE MVFR CEILING
TOWARD THE END OF THE PERIOD.

OUTLOOK...SEVERAL ROUNDS OF STRONG UPPER LEVEL DISTURBANCES...
MOISTURE...AND REINFORCING COLDER AIR ARRIVE FROM THE NORTHWEST
MONDAY NIGHT THROUGH WEDNESDAY. RESTRICTIONS WILL BE POSSIBLE...
ESPECIALLY IN THE MOUNTAINS...WHERE SNOW SHOWERS ARE MOST LIKELY.

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 SCHEDULE TAF ISSUANCE FLIGHT RULE CATEGORY.  COMPLET HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK:

WWW.WEATHER.GOV/GSP/AVIATION

&&

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

&&

$$
SYNOPSIS...WIMBERLEY
NEAR TERM...PM/RWH
SHORT TERM...WIMBERLEY
LONG TERM...WIMBERLEY
AVIATION...PM



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