Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 281800
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
200 PM EDT SAT MAR 28 2015

.SYNOPSIS...
COLD AND DRY HIGH PRESSURE WILL SETTLE OVER THE REGION TONIGHT AND
MOVE OFF THE SOUTHEAST COAST LATE SUNDAY. A LOW PRESSURE CLIPPER
SYSTEM AND ASSOCIATED COLD FRONT WILL THEN PASS OVER THE AREA
EARLY MONDAY MORNING. HIGH PRESSURE WILL RETURN FOR MIDWEEK WITH
MOISTURE INCREASING AGAIN LATER IN THE WEEK.

&&

.NEAR TERM /THROUGH SUNDAY/...
AS OF 130 PM...UPPER LEVEL CONFLUENCE IN THE WAKE OF THE TROUGH
JUST OFF THE MID-ATLANTIC COAST WILL ALLOW DEEP HIGH PRESSURE TO
SETTLE OVER THE REGION TONIGHT. THIS HIGH IS SHOWN TO BE MORE OR
LESS CENTERED OVER THE CWFA AT 12Z SUNDAY...FOSTERING MINIMAL RH
OVER A DEEP LAYER...AND GOOD RADIATIVE CONDITIONS IN THE PRESENCE
OF AN ALREADY VERY COLD AIRMASS. PER NWS RAPID CITY RAOB
CLIMATOLOGY...850MB TEMPS TONIGHT WILL BE ON THE ORDER OF 2
STANDARD DEVIATIONS BELOW NORMAL. ON THE OTHER HAND NAM PROG
SOUNDINGS FOR TONIGHT SUGGEST DECOUPLING WILL BE SLOW TO
OCCUR...AS A MODEST PRESSURE GRADIENT STILL EXISTS MUCH OF THE
NIGHT UNTIL THE AIRMASS CENTERS OVER THE AREA. MIN TEMPS WILL
FLIRT WITH RECORDS...BUT I DID NOT FAVOR THE COLDEST GUIDANCE IN
LIGHT OF THE SLOW DECOUPLING. NONETHELESS A HARD FREEZE IS NEARLY
CERTAIN FOR MOST OF THE AREA. A FREEZE WARNING IS IN EFFECT FOR
ALL ZONES WHERE WIDESPREAD PLANT GROWTH HAS GOTTEN UNDERWAY.

THE SFC HIGH SETS UP OVER THE SOUTHEAST COAST DURING THE DAY SUNDAY
AS A SHORTWAVE RIDGE MOVES OVERHEAD. THIS USHERS IN SWLY WARM
ADVECTION ALOFT...THOUGH THE ASSOCIATED MOISTURE WILL REMAIN OFF TO
OUR WEST. THUS A DRY AND SUNNY DAY IS ANTICIPATED PERHAPS WITH A FEW
ELEVATED CLOUDS FILTERING IN BY LATE AFTN. HOWEVER TEMPS WILL REMAIN
CHILLY...MAXES BEING 10 OR MORE DEGREES BELOW CLIMO.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 215 AM SATURDAY...NOT MUCH CHANGE IN THINKING FOR THE SHORT
RANGE. A SHORT WAVE DIGGING ACROSS THE GT LAKES SUNDAY NIGHT WILL
PUSH A COLD FRONT DOWN FROM THE NW. A TRAILING WAVE WILL HELP TO
PUSH THAT BOUNDARY ACROSS THE FCST AREA ON MONDAY MORNING. PRECIP
CHANCES RAMP UP SUNDAY EVENING ALONG THE TN BORDER AND THEN SPREAD
ACROSS THE REST OF THE MTNS/FOOTHILLS LATE SUNDAY
NIGHT...EVENTUALLY SPILLING E OF THE MTNS MONDAY MORNING.
FORTUNATELY...PARTIAL THICKNESS/FCST SOUNDINGS SUGGEST THAT PRECIP
WILL BE ALL LIQUID. MIN TEMPS EARLY MONDAY MORNING SHOULD REMAIN
ABOVE FREEZING...AND THE MODEL TREND ON THIS WAS UP A DEGREE FROM
THE PREVIOUS FCST. THE FORCING/DEEPER MOISTURE WILL BE A FAIRLY
QUICK SHOT THOUGH...AND BY MIDDAY MONDAY THE FRONT SHOULD ALREADY
BE S OF THE FCST AREA. THAT WILL ALLOW PRECIP CHANCES TO END BY
LATE MONDAY AFTERNOON...AND FOR TEMPS TO REBOUND BY TEN TO FIFTEEN
DEGREES FOR HIGHS. THINK THE NEXT SYSTEM WILL REMAIN FAR ENOUGH TO
THE WEST TO NOT BE A PROBLEM UNTIL THE MEDIUM RANGE.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 315 AM SATURDAY...THE MODEL GUIDANCE REMAINS CONSISTENT WITH
ITS DEPICTION OF A SRN STREAM SHORT WAVE UNDERCUTTING THE NRN STREAM
RIDGE ON TUESDAY NIGHT AND WEDNESDAY. MOISTURE RETURN AHEAD OF THE
WAVE WILL SUPPORT A SMALL CHANCE OF SHOWERS STEADILY INCREASING FROM
THE WEST ON WEDNESDAY AS A WEAK WARM FRONTAL FEATURE LIFTS NWD. THE
NEW GUIDANCE IS FAIRLY CONSISTENT WITH DROPPING A SFC COLD FRONT
DOWN FROM THE NW LATER IN THE WEEK...WITH THE TIMING OF THE FRONTAL
PASSAGE BEING THURSDAY NIGHT. DID NOT MAKE MANY CHANGES TO THE
MEDIUM RANGE...OTHER THAN TO RAISE THE POP INTO THE CHANCE RANGE
EVERYWHERE THURSDAY NIGHT. TEMPS SHOULD BE BACK ABOVE NORMAL.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AT KCLT AND ELSEWHERE...VFR THRU THE PERIOD WITH DRY CONTINENTAL
HIGH PRESSURE BUILDING INTO THE REGION. THIS WILL KEEP CLOUDS SPARSE
AND VSBY UNRESTRICTED. NWLY WINDS THIS AFTN WILL BE GUSTY AT
TIMES...BUT NOT LIKELY TO BRING MUCH ATTENTION OUTSIDE THE HIGHER
ELEVATIONS OF THE MTNS. THE HIGH WILL CENTER OVERHEAD NEAR DAYBREAK
SUNDAY...WHICH SHOULD ALLOW FOR A PERIOD OF CALM WINDS BEFORE IT
MOVES OFF TO THE SE LATER IN THE DAY. SOME VARIABILITY MAY BE NOTED
BEFORE THE WINDS SET UP IN THE SW QUADRANT. LEE TROUGHING MAY BACK
WINDS A BIT CLOSER TO S AT KCLT.

OUTLOOK...ANOTHER FRONT APPROACHES FOR MONDAY. CIG/VISB
RESTRICTIONS WILL BE POSSIBLE WITH THIS 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...

            18-24Z        00-06Z        06-12Z        12-18Z
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

&&

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

GSP  26  1899
CLT  26  2013
AVL  19  1982

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FREEZE WARNING FROM MIDNIGHT TONIGHT TO 11 AM EDT SUNDAY FOR
     GAZ010-017-018-026-028-029.
NC...FREEZE WARNING FROM MIDNIGHT TONIGHT TO 11 AM EDT SUNDAY FOR
     NCZ035>037-048-051>053-056>059-062>065-068>072-082-502-
     504-506>510.
SC...FREEZE WARNING FROM MIDNIGHT TONIGHT TO 11 AM EDT SUNDAY FOR
     SCZ001>014-019.

&&

$$
SYNOPSIS...JPT
NEAR TERM...WIMBERLEY
SHORT TERM...PM
LONG TERM...PM
AVIATION...WIMBERLEY
CLIMATE...WIMBERLEY


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