Area Forecast Discussion
Issued by NWS Greer, SC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KGSP 311605
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1105 AM EST SAT JAN 31 2015

.SYNOPSIS...
DRY HIGH PRESSURE WILL PERSIST OVER THE WESTERN CAROLINAS AND
NORTHEAST GEORGIA THROUGH MOST OF THE WEEKEND. MOISTURE WILL RETURN
SUNDAY AFTERNOON THROUGH SUNDAY NIGHT AHEAD OF A LOW PRESSURE SYSTEM
AND ASSOCIATED COLD FRONT. THE COLD FRONT WILL CROSS THE REGION
EARLY MONDAY...WITH BREEZY TO WINDY CONDITIONS SETTING UP THROUGH
THE DAY. DRY HIGH PRESSURE WILL RETURN TUESDAY INTO WEDNESDAY...WITH
THE LATTER HALF OF THE WEEK POSSIBLY MORE UNSETTLED.

&&

.NEAR TERM /THROUGH TONIGHT/...
1050 AM UPDATE...LATEST SATELLITE IMAGERY SHOWS CONSIDERABLE
MID/HIGH CLOUDS OVERSPREADING OUR WESTERN HALF OF THE CWA AS OF LATE
MORNING HOURS. HENCE...HAVE INCREASED THE CLOUD COVER TO ACCOUNT FOR
THE TREND. OTHERWISE...CURRENT FORECAST IS ON TRACK.

620 AM UPDATE...FCST MORE OR LESS ON TRACK. TOUCHED UP TEMP TRENDS
SLIGHTLY THRU THE MRNG PER LATEST OBS...AND REVISED SKY GRIDS THRU
AFTN TO BETTER LINE UP WITH THE CIRRUS ENTERING FROM THE TENN VALLEY.

AS OF 230 AM...CANADIAN HIGH PRESSURE OVER THE SOUTHEAST WILL SHIFT
OFFSHORE BY THIS EVENING AS A LOW AMPLITUDE RIDGE MOVES OVERHEAD.
THE AIRMASS IS QUITE DRY AND NO SIGNIFICANT FORCING MECHANISM WILL
BE PRESENT. THUS A PRETTY QUIET AND INITIALLY SUNNY DAY IS IN STORE
FOR THE CWFA TODAY. LIGHTER WINDS AND SUNSHINE...COMBINED WITH
INCREASING THICKNESSES...WILL ALLOW TEMPS TO RETURN TO NEAR NORMAL.
HOWEVER DEWPOINTS WILL REMAIN LOW AND MANY AREAS WILL SEE RH DROP TO
NEAR CRITICAL LEVELS. LIGHT WINDS WILL PRECLUDE FIRE DANGER
HEADLINES THOUGH. MOISTURE DOES INCREASE APPRECIABLY IN THE UPPER
LEVELS FROM WEST TO EAST BY THE END OF THE DAY...CONTINUING
OVERNIGHT AHEAD OF AN EXPANSIVE LOW PRESSURE SYSTEM MOVING INTO THE
MISSISSIPPI VALLEY. CLOUDS WILL INCREASE AND THICKEN ACCORDINGLY
WITH TIME. MIN TEMPS WILL ALSO BE ABOUT NORMAL.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 AM SATURDAY...AN AMPLIFYING NRN STREAM WAVE OVER THE NRN
PLAINS AROUND DAYBREAK ON SUNDAY WILL REACH THE APPALACHIAN MOUNTAIN
CHAIN EARLY MONDAY. UPGLIDE MOISTURE WILL GRADUALLY RETURN FROM THE
WEST AHEAD OF THIS SYSTEM THROUGH THE DAY ON SUNDAY. HOWEVER...THE
DEEPEST MOISTURE AND FORCING STILL APPEAR FOCUSED IN THE 00Z TO 06Z
PERIOD SUNDAY NIGHT. WITH THE SFC LOW EXPECTED TO PASS FROM KY
THROUGH THE NRN VIRGINIAS...PROFILES SHOULD BE WARM ENOUGH FOR RAIN
ONLY DURING THE PERIOD OF PEAK QPF AHEAD OF THE UPPER WAVE SUNDAY
EVENING. SNOW LEVELS WILL THEN FALL QUICKLY ACROSS THE HIGHER
TERRAIN 06Z TO 12Z MONDAY...WITH 850 MB TEMPS LIKELY FALLING TO
MINUS 10 C ALONG THE SPINE OF THE SRN APPALACHIANS BY DAYBREAK
MONDAY. POST FROPA QPF UNDER THE PASSING UPPER VORT MAX...ALONG WITH
DEVELOPING NW FLOW MOISTURE...COULD PERMIT SOME LOW END ADVISORY
LEVEL ACCUMULATIONS MONDAY MORNING IN THE WESTERN MTNS. ANY RESIDUAL
NW FLOW UPSLOPE SNOWFALL WILL GRADUALLY DIMINISH THROUGH MONDAY AFTN.

WINDY CONDITIONS WILL BE THE OTHER MAIN STORY LATE SUNDAY NIGHT
THROUGH MONDAY. MOST MODEL PROFILES HAVE 40 TO 50 KT OF WIND ATOP A
SHALLOW MIXED LAYER OVER THE MTNS MONDAY. BREEZY TO WINDY CONDITIONS
WILL OCCUR THROUGHOUT THE AREA...AND NPW PRODUCTS COULD BE NEEDED
FOR THE HIGHER TERRAIN. WILL CONTINUE THE HWO MENTION OF BOTH WIND
AND SNOW ON MONDAY. DOWNSLOPE WARMING EAST OF THE MTNS WILL PERMIT
MAXES TO RISE TO WITHIN ABOUT ONE CATEGORY OF CLIMO HIGHS DESPITE
THE COLD ADVECTION.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 245 AM SATURDAY...FAIRLY ZONAL FLOW SHOULD SET UP ALOFT TUE
INTO WED...AS A CUTOFF LOW OVER WRN MEXICO STARTS TO PHASE BACK INTO
THE WESTERLIES OVER S TX. A WEAK SFC HIGH WILL SHUTTLE EASTWARD
ACROSS OUR REGION...WITH LITTLE MORE THAN PASSING MID/HIGH CLOUDS
EXPECTED. TEMPERATURES NEARLY 10 DEGREES BELOW CLIMO ON TUE WILL
REBOUND TO JUST SLIGHTLY BELOW NORMAL FOR WED.

DIFFERENCES DEVELOP IN THE NUMERICAL MODEL HANDLING OF THE UPPER
FLOW PATTERN FROM MID TO LATE NEXT WEEK. THERE IS THE GENERAL
APPEARANCE OF A ONE/TWO PUNCH OVER THE SOUTHEAST FROM THE PHASING
SRN TIER WAVE FOLLOWED BY SOME MEASURE OF A DIGGING NRN TIER WAVE
EMERGING FROM THE PLAINS. THE ECWMF SUPPRESSES ALL OF THE DEEP
MOISTURE S OF OUR AREA...WHILE THE GFS PERMITS MOISTURE TO STREAM N
OF THE GULF COAST SFC WAVE AND MERGE WITH A COLD FRONT ARRIVING FROM
THE NW ON THU. IT IS ALSO MUCH MORE AMPLIFIED WITH THE DIGGING WAVE
MERGING FROM THE PLAINS ON THU. THE ENSEMBLE MEAN SOLUTIONS ARE
SOMEWHERE IN BETWEEN AND THESE WILL BE FOLLOWED. THAT MEANS
GENERALLY LOW END CHC OR SLIGHT CHC POPS FOR MAINLY THE WED NIGHT TO
THU NIGHT PERIODS...WITH PRIMARILY RAIN OR A RAIN/SNOW MIX ACROSS
THE NRN HALF. DRYING SHOULD RETURN BEHIND ANY DEPARTING LOW/WAVE ON
FRIDAY.

&&

.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT AND ELSEWHERE...VFR THRU THE PERIOD UNDER HIGH
PRESSURE...BUT WITH CIRRUS SLOWLY INCREASING AHEAD OF LOW PRESSURE
MOVING THRU THE CENTRAL CONUS. WINDS WILL REMAIN LIGHT BUT
DIRECTIONS A LITTLE TRICKY THIS AM. LARGE SCALE FLOW WOULD SUGGEST A
PREVAILING NW BREEZE THIS MRNG...BUT WITH LEE TROUGHING THEY MAY TRY
TO FLIP TO SW EARLIER THAN ANTICIPATED. THE FLOW WILL LIKELY BACK
INTO THE SW QUAD BY MIDDAY ANYWAY...BUT KAVL WILL INSTEAD SEE SOME
VARIABILITY AND EVENTUALLY PREVAIL NW.

OUTLOOK...MOISTURE BEGINS TO RETURN SUNDAY AHEAD OF ANOTHER LOW
PRESSURE SYSTEM...WHICH IS LIKELY TO BRING PRECIP AND RESTRICTIONS.
DRYING IS EXPECTED BY LATE MONDAY AFTER THE LOW PASSES. ANOTHER
MOIST LOW PRES SYSTEM MAY AFFECT THE REGION LATE NEXT WEEK.

CONFIDENCE TABLE...

            16-22Z        22-04Z        04-10Z        10-12Z
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...HG
NEAR TERM...JOH/WIMBERLEY
SHORT TERM...HG
LONG TERM...HG
AVIATION...WIMBERLEY


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.