Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 291039
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
639 AM EDT SUN MAR 29 2015

.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE SOUTHEAST COAST BY LATE IN THE DAY.
A LOW PRESSURE CLIPPER SYSTEM AND ASSOCIATED COLD FRONT WILL THEN
PASS OVER THE AREA EARLY MONDAY MORNING. HIGH PRESSURE WILL RETURN
BRIEFLY AT MIDWEEK...BUT ANOTHER COLD FRONT WILL DROP DOWN INTO THE
REGION BY FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 620 AM EDT SUNDAY...TOUCHED UP WORDING IN BOTH THE CURRENT
FREEZE PRODUCTS ALONG WITH THIS AFTERNOONS FIRE DANGER STATEMENT FOR
NORTHEAST GA.  SPEAKING OF FREEZE...A FEW SITES HAVE BEEN RATHER
STUBBORN TO DECOUPLE LEADING TO SLIGHTLY LESS RADIATIONAL COOLING
THAN EXPECTED.  HOWEVER...IT NOW SEEMS ALL SITES HAVE DECOUPLED WITH
MOST IF NOT ALL LOCATIONS IN THE FCST AREA AT OR BELOW FREEZING WITH
LIGHT/CALM WINDS.  AS FOR ANY RECORDS....SEEMS GSP/CLT WOULD HAVE
THE BEST SHOT TO BREAK/TIE ANY RECORDS...HOWEVER LOOKING MORE
UNLIKELY AS ABOVE MENTIONED DELAYED DECOUPLING HAS AFFECTED MORNING
TEMPERATURES TRENDS.  CONFIDENCE IS NOT HIGH IN THAT EITHER SITE
WILL FALL THE NEEDED 3-5 DEGREES FROM CURRENT OBS BEFORE WARMING
BEGINS.  AS FOR THE FCST...TWEAKED TEMPERATURE AND DEWPOINT TRENDS
AND LEFT THE REMAINDER OF THE FCST AS IT WAS.

PREVIOUS DISCUSSION...

AS OF 315 AM EDT SUNDAY...UPPER HEIGHTS CONTINUE TO RISE ACROSS THE
SOUTHEAST THIS MORNING AS SHORT WAVE RIDGING SLIDES OVERHEAD.  AT
THE SURFACE...BROAD SURFACE HIGH PRESSURE RIDGE CONTINUES TO
MIGRATE THROUGH THE SOUTHERN/CENTRAL APPS...EVENTUALLY SETTING UP
OVER THE LOW COUNTRY THIS AFTERNOON.  MEANWHILE...ANOTHER UPPER
SHORTWAVE WILL BE RIGHT ON THE HEELS OF THE PROGRESSIVE SHORTWAVE
RIDGE AS IT DIGS OUT OF ONTARIO INTO THE UPPER MIDWEST.  A COLD
FRONT WILL EXTEND SOUTHWARD ACROSS THE MIDWEST...BEFORE SLIDING INTO
THE OHIO RIVER VALLEY LATE IN THE DAY.  ALTHOUGH WIDESPREAD FREEZING
CONDITIONS CONTINUE TO DEVELOP THIS MORNING DUE TO ABUNDANT
RADIATIONAL COOLING...EXPECTING SFC FLOW TO VEER SOUTHERLY BY LATE
MORNING AS THE HIGH CENTER MIGRATES SOUTHEAST ALLOWING FOR THE
RETURN OF WEAK WAA.  AS A RESULT...TEMPERATURES WILL GRADUALLY
MODERATE THROUGH THE DAY HOWEVER STILL TOPPING OUT NEARLY A CAT
BELOW NORMAL LEVELS.  ADDITIONALLY...AS TEMPERATURES WARM THIS
AFTERNOON EXPECTING RH VALUES TO PLUMMET INTO THE TEENS TO LOWER 20S
ACROSS THE ENTIRE FCST AREA.  WINDS WILL BE CALMER TODAY AS THE HIGH
SLIDES OVERHEAD...HOWEVER A FIRE DANGER STATEMENT REMAINS IN EFFECT
FOR PORTIONS OF NORTHEAST GA AT THE REQUEST OF LAND MANAGERS...WITH
NO OTHER PRODUCTS PLANNED FOR NC/SC.

AS THE ABOVE MENTIONED COLD FRONT MOVES THROUGH THE OH VALLEY INTO
THE TN VALLEY...EXPECTING HIGH LEVEL CIRRUS TO ADVECT DOWNSTREAM
ACROSS THE SOUTHERN APPS.  POPS WILL BEGIN TO INCREASE AFTER
MIDNIGHT AS THE FRONT APPROACHES.  SHOWERS WILL LIKELY BE NUMEROUS
IN NATURE ACROSS THE HIGH TERRAIN AS ENTRANCE REGION OF UPPER JET
SLIDES BY ALONG WITH MODEST LLJ POSSIBLY ENHANCING MOISTURE FLUX AND
UPSLOPE POTENTIAL.  THEREFORE POPS WILL INCREASE TO CATEGORICAL
LEVELS ALONG THE SPINE WITH LIKELY/CHANCE LEVEL POPS FURTHER EAST
THROUGH PERIODS END.  QPF WILL LIKELY BE MAXIMIZED OVER THE CLIMO
FAVORED REGIONS OF THE SW NC MTNS WHERE UPWARDS OF A QUARTER INCH IS
POSSIBLE...WITH GENERALLY LESS THAN A TENTH ELSEWHERE.  TEMPERATURES
OVERNIGHT WILL COOL DIURNALLY BUT SHOULD BE MUCH CLOSER TO NORMAL
LEVELS THAN NIGHTS PAST.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
AS OF 330 AM EDT SUNDAY...THE MODELS STILL SUGGEST A RAPID FRONTAL
PASSAGE ON MONDAY MORNING AS THE SHORT WAVE PASSES OVERHEAD QUICKLY.
HAVE LIMITED THE PRECIP PROBABILITY E OF THE MTNS TO THE CHANCE
RANGE AS THE MOISTURE RETURN FROM THE GULF/ATLANTIC IS NOT GREAT AND
THE SYSTEM IS COMING IN FROM THE WNW. EITHER WAY...IT SHOULD BE OVER
AND DONE WITH BY 18Z MONDAY. THEREAFTER...NW FLOW AND DOWNSLOPE E OF
THE MTNS WILL ALLOW TEMPS TO CLIMB ROUGHLY TEN DEGREES ABOVE SUNDAYS
HIGHS IN SPITE OF THE PASSAGE OF A COLD FRONT EARLY IN THE DAY. THE
REST OF THE SHORT RANGE IS RELATIVELY QUIET. MONDAY NIGHT AND
TUESDAY WILL SEE A WEAK HIGH MOVE OVERHEAD THEN OFF THE SE COAST.
THE GFS CONTINUES TO WANT TO ACTIVATE THE OLD FRONT ACROSS THE
SOUTHEAST AS A WARM FRONT ON TUESDAY. THINK THE EWD EXTENT OF THIS
IS OVERDONE/PREMATURE TUESDAY AFTERNOON AND PREFER TO STICK CLOSER
TO THE DRIER NAM SOLUTION. TEMPS ON TUESDAY WILL BE A FEW DEGREES
WARMER THAN MONDAY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 315 AM SUNDAY...NOT SURE THAT CONFIDENCE HAS IMPROVED ALL THAT
MUCH OUT IN THE MEDIUM RANGE...AS IT SEEMS EACH NEW MODEL RUN BEARS
ONLY A VAGUE RESEMBLANCE TO THE PREVIOUS ONE. THE FIRST ISSUE IS THE
ACTIVATION OF THE OLD SURFACE BOUNDARY AS A WARM FRONT ACROSS THE SE
ON TUESDAY NIGHT AND WEDNESDAY...AHEAD OF THE DAMPENING SRN STREAM
SHORT WAVE. NOT SURE THE GFS IS NOT OVERDONE WITH THE EXTENT OF THE
PRECIP NEAR THE FRONT TO OUR S/SW...SO HAVE KEPT THE PRECIP CHANCES
LOW AND IN LINE WITH NEIGHBORS. ANY CHANCE OF PRECIP WE HAVE WILL
GRADUALLY DEVELOP A FOCUS NEAR THE S/SW UPSLOPE LOCATIONS NEAR THE
BLUE RIDGE BY WEDNESDAY MORNING. FORCING ASSOCIATED WITH THE SRN
STREAM WAVE NEVER IMPRESSES MUCH AS IT PASSES THRU WEDNESDAY NIGHT
AND THURSDAY SO THE PRECIP PROBABILITY WAS LIMITED TO THE CHANCE
RANGE...WHICH IS HOPEFULLY NOT OVERDONE. PERHAPS THE MOST IMPORTANT
PART OF THE FCST FOR THIS PART OF THE WEEK IS THE EASTERN UPPER TROF
LIFTING OUT AND THE REPLACEMENT WITH A BROAD UPPER RIDGE ALONG THE E
COAST...WHICH SHOULD SPELL A WARMUP TO ABOVE NORMAL TEMPS FOR A
CHANGE. THE NEXT PROBLEM WILL BE LATE IN THE WEEK WITH A COLD FRONT
EXPECTED TO DROP DOWN FROM THE NW AS A NRN STREAM SHORT WAVE PASSES
OVER THE GT LAKES/MIDWEST ON FRIDAY. SOME MINOR CHANGES WERE MADE TO
THE PRECIP CHANCES ON FRIDAY BASED ON THE NEW GUIDANCE...MAINLY TO
RAISE THE CHANCE EARLIER ON FRIDAY. THE GUIDANCE SUGGESTS THE
WESTERN CAROLINAS AND NE GEORGIA WILL BE IN A BROAD WARM SECTOR
AHEAD OF THE COLD FRONT...WHICH MEANS WE MIGHT SEE ENUF BUOYANCY TO
FEED SOME DEEPER CONVECTION. RIGHT NOW...THERE DOES NOT APPEAR TO BE
MUCH FAVORABLE OVERLAP BETWEEN CAPE AND SHEAR...BUT THIS WILL BE
FURTHER EVALUATED.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AT KCLT AND ELSEWHERE...VFR CONDITIONS WILL PREVAIL THROUGH THE TAF
PERIOD. LIGHT NORTHEAST WINDS WILL VEER SOUTHERLY THROUGH MORNING AS
HIGH PRESSURE SHIFTS OVERHEAD WITH MOST SITES HAVING A SOUTHERLY
COMPONENT OF FLOW NLT THAN 15Z-16Z.  STILL FCSTING SKC TO PREVAIL AT
ALL SITES THROUGH THE MIDDAY BEFORE HIGH LEVEL CIRRUS ADVECTS
DOWNSTREAM FROM FRONTAL AXIS OVER THE OHIO VALLEY REGION.  BEYOND
THIS EXPECTING HIGH LEVEL CIGS TO DEVELOP OVERNIGHT AMIDST CONTINUED
SOUTHERLY 06-08KT WINDS AHEAD OF THE APPROACHING FRONTAL INTRUSION.
AS FOR PRECIP...ADDED PROB30S TO ALL TAFS AFTER THE 09Z-10Z
TIMEFRAME MONDAY TO ACCOUNT FOR -SHRA WITH THE EXCEPTION OF AT KAVL
WHERE -SHRA WAS PREVAILED.  MODELS WERE HINTING AT FURTHER
DETERIORATION OF CONDITIONS JUST BEYOND THIS TAF CYCLE...THUS
NOTHING WAS INCLUDED THIS GO AROUND.

OUTLOOK...CIG/VSBY RESTRICTIONS WILL BE POSSIBLE WITH THE NEXT FROPA
ON MONDAY AT ALL SITES...ESPECIALLY FOR MID/LATE MORNING AT KAVL.
BROAD SURFACE HIGH PRESSURE REGAINS CONTROL IN THE MIDDLE OF NEXT
WEEK...AHEAD OF AN APPROACHING WARM FRONT AND RESULTANT MOISTURE
RETURN LATER IN THE WEEK.

CONFIDENCE TABLE...

            10-16Z        16-22Z        22-04Z        04-06Z
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

&&

.FIRE WEATHER...
A DRY POLAR AIRMASS REMAINS OVER THE REGION TODAY AHEAD OF THE
RETURN OF SOUTHERLY FLOW TONIGHT.  AS TEMPERATURES WARM DIURNALLY
EXPECTING RH VALUES TO PLUMMET INTO THE TEENS TO LOWER 20S ACROSS
THE ENTIRE FCST AREA.  WINDS WILL BE RATHER LIGHT...HOWEVER...DRYING
FUELS WILL LEAD TO ENHANCED FIRE DANGER.  IN COORDINATION WITH GA
LAND MANAGERS...A FIRE DANGER STATEMENT REMAINS IN EFFECT FOR
NORTHEAST GA THIS AFTERNOON.

&&

.CLIMATE...
RECORD MINIMUM TEMPERATURES FOR MARCH 29TH...

GSP  26  1899
CLT  26  2013
AVL  19  1982

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FREEZE WARNING UNTIL 11 AM EDT THIS MORNING FOR GAZ010-017-018-
     026-028-029.
     FIRE DANGER STATEMENT FROM NOON EDT TODAY THROUGH THIS EVENING
     FOR GAZ010-017-018-026-028-029.
NC...FREEZE WARNING UNTIL 11 AM EDT THIS MORNING FOR NCZ035>037-048-
     051>053-056>059-062>065-068>072-082-502-504-506>510.
SC...FREEZE WARNING UNTIL 11 AM EDT THIS MORNING FOR SCZ001>014-019.

&&

$$
SYNOPSIS...PM
NEAR TERM...CDG
SHORT TERM...PM
LONG TERM...PM
AVIATION...CDG
FIRE WEATHER...
CLIMATE...



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