Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 291050
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
650 AM EDT FRI APR 29 2016

.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE REGION TODAY INTO SATURDAY. A
LOW PRESSURE SYSTEM WILL APPROACH FROM THE WEST LATE SATURDAY
THROUGH SUNDAY NIGHT BRINGING A CHANCE OF THUNDERSTORMS TO THE AREA.
THE LOW WILL LIFT NORTHEAST ALONG THE COAST EARLY NEXT WEEK...BUT
LEAVE A TRAILING COLD FRONT NEAR THE CAROLINA COAST.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM EDT...AN AREA OF LOW STRATUS HAS MOVED DOWN ACROSS THE
CLT METRO AREA. CLOUD COVER SHALL BE INCREASED ACROSS THOSE AREAS.
IT IS NOT KNOWN IF THE DELAY IN HEATING WILL AFFECT THE MAXT...BUT
THOSE AREAS WERE KEPT SLIGHTLY COOLER ANYWAY.

THE NEXT 24 HOURS SHOULD BE FAIRLY QUIET...BUT QUITE WARM. AN UPPER
LEVEL RIDGE WILL MOVE OVERHEAD TODAY...WITH DRIER AIR AT THE SURFACE
AND A WARM LAYER ALOFT THAT ACTS AS AN EFFECTIVE CAP TO KEEP A LID
ON THE DEEP CONVECTION. THE WESTERLY FLOW ALOFT WILL ALSO HELP TO
RAISE TEMPS E OF THE MTNS AND DRY OUT THE BOUNDARY LAYER. THUS...WE
MAY FLIRT WITH RECORD HIGHS...ALTHO THE FCST AS CONSTRUCTED WOULD
HAVE US FALLING SHORT BY A FEW DEGREES. THE MODEL GUIDANCE SUGGESTS
THAT A SHORT WAVE WILL MOVE IN FROM THE WEST LATE TONIGHT. THINK
THIS WILL BRING LITTLE MORE THAN AN INCREASE IN MID/UPPER LEVEL
CONVECTIVE DEBRIS CLOUDINESS. ANY PRECIP ASSOCIATED WITH THE NEXT
SYSTEM TO THE WEST WILL MOST LIKELY NOT REACH THE MTNS BEFORE
DAYBREAK ON SATURDAY. THE INCREASING CLOUDS LATE TONIGHT SHOULD KEEP
TEMPS SEASONALLY MILD WITH LOW TEMPS NEARLY TEN DEGREES ABOVE NORMAL.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300AM EDT FRIDAY MORNING...NEXT CHANCE FOR PRECIP APPEARS TO
BE SATURDAY AFTERNOON AS UPPER SYSTEM MAKES ITS WAY INTO THE CENTRAL
PLAINS WITH A GOOD FETCH OF GULF MOISTURE AHEAD OF IT IN MUCH OF THE
SE CONUS. HEAVIEST PRECIP IS EXPECTED ON SUNDAY AS QG-FORCING WITH
THE UPPER WAVE REACHES THE APPALACHIANS...CONTINUING INTO MONDAY.
COLD FRONT MONDAY MORNING ENDS SIGNIFICANT RAIN FOR TUESDAY...BUT
PASSAGE OF A SMALLER UPPER IMPULSE COULD CREATE SOME SHOWERS ON
WEDNESDAY...THOUGH WITH MUCH LESS BL MOISTURE TO WORK WITH.  TOTAL
PRECIP EXPECTED FOR SATURDAY THROUGH MONDAY IS AROUND AN INCH.

WITH GOOD DEEP BL MOISTURE ADVECTION WITH THE SATURDAY-MONDAY
SYSTEM...CONVECTIVE INSTABILITY WILL BE RISING AS WELL, REACHING AN
LI OF AROUND -4 SATURDAY AFTERNOON AND -5 SUNDAY AFTERNOON. BULK
SHEAR IS NOT PARTICULARLY IMPRESSIVE AT AROUND 30KTS SATURDAY AND
35KTS ON SUNDAY.  NONETHELESS...THE DOMINANT FORM OF PRECIP. SATURDAY
AND SUNDAY AFTERNOON WILL BE THUNDERSTORMS...WITH SOME LOW-END
SEVERE HAIL AND MICRO/MACRO BURSTS POSSIBLE.

HIGH TEMPERATURES WILL DROP 10 DEGREES FROM THE LOW 80S SATURDAY
THROUGH MONDAY DOWN TO THE LOW 70S TUESDAY THROUGH FRIDAY BEHIND THE
FROPA MONDAY AFTERNOON.  EC MODEL IS SLOWER WITH FROPA MONDAY THAN
THE GFS MODEL...THOUGH OTHER FEATURES ARE SIMILAR THROUGH MONDAY
MORNING.  EC AND GFS DIFFER CONSIDERABLE FOR TUESDAY AND BEYOND IN
THE DETAILS OF HOW A DEEP SYSTEM DEVELOPS OVER THE EASTERN CONUS.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300AM FRIDAY...RAIN CHANCES DECLINE WITH MAJOR COLD FROPA
MONDAY.  TEMPERATURES ALSO DECLINE BY 10 DEGREES FOR TUESDAY-THURSDAY
BEHIND THE FRONT.  TUESDAY IS EXPECTED TO BE DRY IN THE GFS MODEL ON
TUESDAY WITH A CHANCE OF RAIN RETURNING ON WEDNESDAY AS A SMALL
UPPER SYSTEM CROSSES SOUTHERN STATES.  PRECIP AMOUNTS WITH ACTIVITY
WEDNESDAY WILL BE LIGHT DUE TO SCOURING OF MOISTURE BY COLD FRONT.
THERE IS CONSIDERABLE EC-GFS DISAGREEMENT FOR TUESDAY THROUGH FRIDAY
WITH THE EC MODEL ACTUALLY HAVING PRECIP ON TUESDAY.  BOTH MODELS
TEND TO SHOW THE DEVELOPMENT OF A DEEP UPPER LONG WAVE TROUGH OVER
THE EASTERN CONUS...BUT DIFFER IN MAJOR WAYS IN DETAILS OF TIMING
AND PLACEMENT OF SURFACE FEATURES AND PRECIP.  CURRENT FORECAST IS A
BLEND OF THE POSSIBILITIES...WITH SOME CHANCE FOR RAIN MOST DAYS.
THOUGH THE EC MODEL IS WETTER THROUGH THE PERIOD...NEITHER IT NOR
THE GFS MODEL HAVE MORE THAN A HALF INCH FOR TUESDAY THROUGH FRIDAY
DUE TO A LACK OF GOOD MOISTURE ADVECTION INTO THE REGION.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AT KCLT AND KHKY...AN IFR/LIFR STRATUS DECK COULD NOT BE CONTAINED TO
THE NW PIEDMONT...AND IT HAS OOZED SOUTHWARD TO COVER ALMOST THE
ENTIRE METRO AREA. CONDITIONAL CLIMO SUGGESTS THIS WILL BEGIN TO
LIFT AND SCATTER OUT AROUND 13Z. THERE COULD BE A BRIEF MVFR CEILING
ONCE THIS HAPPENS. ENOUGH HEATING SHOULD TAKE PLACE TO LIFT ANY
CLOUD BASE TO VFR LEVELS BY LATE MONRNING. EXPECT ONCE THE HEATING
OCCURS...THE WIND DIRECTION WILL COME AROUND TO LIGHT SW. WIND WILL
GO VERY LIGHT AGAIN FRIDAY NIGHT. EXPECT INCREASING MID/HIGH CLOUDS
BY 12Z SATURDAY.

ELSEWHERE...VFR THROUGH THE PERIOD.

OUTLOOK...VFR CONDITIONS SHOULD PERSIST INTO SATURDAY MORNING.
UNSETTLED WEATHER/POSSIBLE RESTRICTIONS/CONVECTION RETURN FROM THE
WEST BY SUNDAY.

CONFIDENCE TABLE...

            11-17Z        17-23Z        23-05Z        05-06Z
KCLT       LOW   56%     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       LOW   56%     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

&&

.CLIMATE...
RECORDS FOR 04-29

               MAX TEMPERATURE         MIN TEMPERATURE
  STATION      HIGH        LOW         HIGH        LOW
  -------  ----------  ----------  ----------  ----------
   KAVL      89 1970     46 1999     63 1956     28 1967
   KCLT      91 1888     48 1999     65 1994     33 1973
                                        1991
                                        1914
   KGSP      91 1917     47 1999     67 1975     32 1992

&&

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

&&

$$
SYNOPSIS...PM/WJM
NEAR TERM...PM
SHORT TERM...WJM
LONG TERM...WJM
AVIATION...PM
CLIMATE...


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