Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 250747
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
347 AM EDT WED MAR 25 2015

.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE EAST COAST TODAY...ALLOWING A WARM
FRONT TO LIFT NORTH ACROSS THE REGION TONIGHT. A COLD FRONT WILL
CROSS THE AREA THURSDAY NIGHT. A STRONG UPPER LEVEL DISTURBANCE WILL
MOVE OVER THE APPALACHIANS FRIDAY THROUGH FRIDAY NIGHT...WITH COOL
HIGH PRESSURE SETTLING IN OVER THE WEEKEND. A LOW PRESSURE CLIPPER
SYSTEM WILL CROSS THE AREA FROM THE NORTHWEST EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM...RECENT SATELLITE IMAGES INDICATE A VARIETY OF MID
AND HIGH CLOUDS ACROSS THE CWA. TO THE EAST...A FIELD OF LOW CLOUDS
HAS DEVELOPED ACROSS THE SOUTHERN SAVANNAH RIVER VALLEY. THE AREA OF
LOWER CLOUD COVER APPEARED ASSOCIATED WITH AN EXPANDING AREA OF 295K
ISENTROPIC LIFT. BETWEEN 9Z TO 12Z...LLVL SOUTHEAST WINDS WILL
STRRENGHTEN AND ISENTROPIC LIFT AND UPSLOPE LIFTING ARE FORECAST TO
BECOME WIDESPREAD....RESULTING IN THICK AND LOW CLOUD COVER. THE NAM
INDICATES THAT OMEGA WILL ARRIVE AROUND SUNRISE. ROUNDS OF LIGHT
RAIN AND DRIZZLE SHOULD DEVELOP WITH THE ARRIVAL OF THE LOW LEVEL
LIFT. POPS THIS AFTERNOON ARE FORECAST TO RANGE FROM CHC POPS TO NEAR
50 ACROSS THE EAST FACING SLOPES. WEAK SFC RIDGING COMBINED WITH
STEADY NORTHEAST WINDS MAY RESULT IN A HYBRID OR IN-SITU CAD THROUGH
THE REST OF THE DAY. BASED ON MOS CONSENSUS...I WILL FORECAST HIGHS
IN THE U50S ACROSS THE MTNS TO LOW TO MID 60S EAST OF I-85.

TONIGHT...THE CENTER OF HIGH PRESSURE WILL SHIFT OVER THE WESTERN
ATLANTIC AS A COLD FRONT APPROACHES FROM THE WEST. MODELS CONTINUE
TO INDICATE PERIODS OF ISENTROPIC LIFT ACROSS THE
REGION...HOWEVER...WINDS DO REMAIN FROM THE SOUTHWEST. I WILL KEEP
POPS LIMITED TO THE 30 TO 40% RANGE. LOW TEMPERATURES ARE FORECAST
TO RANGE FROM THE LOW 50S ACROSS THE MTNS TO MID/UPPER 50S EAST. IN
ADDITION...FOG WILL LIKLY DEVELOP EAST OF THE MTNS LATE TONIGHT.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 315 AM WEDNESDAY...THE UPPER RIDGE WILL BEGIN TO EXIT OFF THE
EAST COAST ON THURSDAY...AS A DIGGING TROF ENTERS THE MS VALLEY.
BOTH THE NAM AND GFS HAVE COME IN MUCH MORE CAPPED DURING THE DAY ON
THURSDAY ACRS THE CWFA. THE CWFA SHUD BE WELL WITHIN A STOUT WARM
SECTOR OF A LOW PRES SYSTEM TRACKING NE INTO THE GREAT LAKES. GIVEN
LITTLE IN THE WAY OF A TRIGGER FOR CONVECTION...AND EXPECTED MID LVL
CAP (SEEN ON FCST SNDGS)...I HAVE CUT BACK POP FOR THURSDAY. TEMPS
WILL BE ABOUT 10-15 DEG ABOVE NORMAL...DESPITE A FAIR AMOUNT OF
CLOUDS.

THURSDAY NIGHT...A COLD FRONT WILL PUSH THRU THE AREA...BRINGING
WITH IT A BAND OF CONVECTION. SHEAR WILL INCREASE ALONG THE
FRONT...BUT INSTBY WILL WANE...SUCH THAT SEVERE THREAT LOOKS RATHER
SMALL. THE NEW DAY 2 CONVECTIVE OUTLOOK IS LITTLE CHANGED FROM THE
PREVIOUS DAY 3...WITH JUST A LARGE AREA OF GENERAL THUNDER RISK
ASSOCIATED WITH THE FRONT. TEMPS WERE BUMPED UP A CATEGORY OR
TWO...GIVEN THE SLOWER PASSAGE OF THE FRONT. QPF AMOUNTS WILL BE
LIGHT.

FRIDAY THRU FRIDAY NIGHT...MODELS AGREE ON A WEAK WAVE DEVELOPING
ALONG THE FRONT AS IT REACHES THE ATLANTIC COAST...HELPING KEEP A
CHC FOR LINGERING SHWRS...ESP ALONG AND EAST OF I-85 THRU PERHAPS
EARLY AFTN. MEANWHILE...INCREASING MOISTURE AND NWLY UPSLOPE FLOW
WILL KEEP A CHC FOR SHWRS ALONG THE TN/NC BORDER. TEMPS WILL BE BACK
TO A COUPLE CATEGORIES BELOW NORMAL BEHIND THE FRONT. PRECIP SHUD
WANE EAST OF THE MTNS BY FRIDAY EVENING...BUT LINGER ALONG THE TN
BORDER. A FEW SNOW SHWRS WILL BE POSSIBLE THERE WITH VERY LIGHT
ACCUMS. TEMPS WILL FALL BACK INTO THE 20S IN THE MTNS AND 30S ACRS
THE PIEDMONT.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 325 AM WEDNESDAY...CANADIAN HIGH PRES WILL SLIDE INTO THE
SOUTHEAST STATES SATURDAY THRU SUNDAY...USHERING IN WELL BELOW
NORMAL TEMPS. GUIDANCE CONTINUES TO TREND DRIER WITH THE PASSAGE OF
THE STRONGLY FORCED UPPER LEVEL SHORTWAVE SATURDAY. BUT THERE MAY BE
SOME LINGERING NW FLOW SHOWERS...AT LEAST THRU MIDDAY. THE REST OF
THE AREA SHUD BE DRY WITH HIGHS ABOUT 15 DEG OR SO BELOW NORMAL. AS
THE HIGH SETTLES IN SATURDAY NIGHT...THE COOLEST TEMPS WE/VE SEEN
THIS THE FIRST WEEKEND IN MARCH CAN BE EXPECTED. LOWS IN THE TEENS
TO MID 20S IN THE MTNS AND MAINLY UPR 20S TO LWR 30S ACRS THE
PIEDMONT SUNDAY MORNING.

FROM SUNDAY ONWARD...THE DEEP UPPER TROF WILL SWING EAST...ALLOWING
FOR A NICE REBOUND IN TEMPS STARTING SUNDAY NIGHT. MONDAY/S HIGHS
ARE EXPECTED TO BE BACK TO NORMAL OR EVEN A CATEGORY OR TWO ABOVE
NORMAL WITH DRY WX CONTINUING. ANOTHER SHORTWAVE DIGS IN ACRS THE
GREAT LAKES LATE MONDAY THRU TUESDAY...WHICH WILL ALLOW ANOTHER COLD
FRONT TO DROP SOUTH INTO THE AREA. THE GFS IS FASTER AND DRIER WITH
THE FRONT...WHILE THE ECMWF HAS SOME QPF RESPONSE ACRS THE ENTIRE
AREA FOR MONDAY. GOING WITH THE SUPERBLEND TEMPS/POPS WHICH RESULTS
IN A DRY FCST AND SIMILAR TEMPS FOR TUESDAY.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...MESOSCALE MODELS INDICATE THAT THE REGION WILL BE
DOMINATED BY NE TO SW PIEDMONT AND FOOTHILL SFC RIDGING THROUGH THE
6Z TAF PERIOD. LOW LEVEL SOUTHEAST WINDS ARE EXPECTED TO INCREASE
THROUGH THIS AFTERNOON...THEN BEGIN TO WEAKEN. THE LLVL WINDS RIDING
OVER THE SFC RIDGE AND EAST FACING MTN SLOPES SHOULD RESULT IN
WIDESPREAD LIFT ACROSS THE TERMINAL. THE COMBINATION OF INCREASING
MOISTURE AND LIFT SHOULD SUPPORT STRATUS WITH PERIODS OF LIGHT
RAIN/DRIZZLE TODAY. BASED ON THE 0Z NAM FORECAST SOUNDING...MVFR
CLOUDS WILL DEVELOP AROUND 10Z WITH A STEADY NE WIND. CLOUD BASES
ARE FORECAST TO LOWER THROUGH THIS AFTERNOON...REACHING IFR DURING
THE EARLY EVENING. RAIN WILL REMAIN LIGHT...ESPECIALLY THIS MORNING.
RAINFALL RATES SHOULD INCREASE SLIGHTLY LATE THIS AFTERNOON AND
EVENING...I WILL MENTION -RADZ IN THE TAF BY 0Z.

ELSEWHERE...OVERALL...CONDITIONS SHOULD FOLLOW THE CLT DESCRIPTION.
LATEST SATELLITE AND OBS INDICATE VFR CONDITIONS ACROSS THE WESTERN
CAROLINAS. HOWEVER...MOS GUIDANCE AND FORECAST SOUNDINGS INDICATE
THAT MVFR CEILINGS WILL RAPIDLY DEVELOP DURING THE PRE DAWN HOURS.
RESTRICTIVE CEILINGS SHOULD LINGER THROUGH THE DAYLIGHT
HOURS...SUPPORTED BY LOW LEVEL LIFT AND UPSLOPE FLOW. AFTER
21Z...CLOUD BASES ARE FORECAST TO LOWER...RANGING IN THE 004-007
RANGE. RAINFALL AND DRIZZLE MAY RESTRICT VIS AT TIMES...BUT VIS
SHOULD FAVOR VALUES AROUND 6 SM. WINDS WILL REMAIN FROM THE
NORTHEAST...KAVL SHOULD SEE LIGHT SE WINDS OR CALM.

OUTLOOK...LOW LEVEL MOISTURE REMAINS ACROSS THE REGION FOR THE
BETTER PART OF THIS WEEK...WHICH COULD RESULT IN PERIODIC FLIGHT
RESTRICTIONS. A COLD FRONT WILL KEEP CHANCES OF PRECIPITATION ACROSS
THE AREA THU...POSSIBLY LINGERING INTO FRI.

CONFIDENCE TABLE...

            07-13Z        13-19Z        19-01Z        01-06Z
KCLT       HIGH  90%     HIGH  96%     HIGH 100%     MED   67%
KGSP       HIGH  87%     MED   73%     HIGH  90%     MED   64%
KAVL       HIGH  95%     HIGH  82%     HIGH  96%     HIGH  80%
KHKY       HIGH  92%     MED   76%     LOW   57%     MED   65%
KGMU       HIGH  90%     HIGH  93%     HIGH  90%     LOW   57%
KAND       HIGH  90%     HIGH 100%     HIGH  88%     MED   73%

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...ARK
NEAR TERM...NED
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...NED



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