« Back
NWS Peachtree City, Ga » Text Product » GSP Area Forecast Discussion


Printer-friendly Version
Current Version              Previous Versions:   1  2  3  4  5  6  7  8  9  

Area Forecast Discussion

632
FXUS62 KGSP 311319
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
919 AM EDT TUE MAR 31 2015

.SYNOPSIS...
HIGH PRESSURE WILL PREVAIL OVER THE REGION TODAY AHEAD OF ANOTHER
WEAK COLD FRONT WHICH WILL MOVE OVER THE AREA TOMORROW NIGHT.
SURFACE RIDGING WILL QUICKLY BUILD AGAIN FOR WEDNESDAY WHILE
PRECIPIATION CHANCES INCREASE ON THURSDAY AS MOIST SOUTHERLY FLOW
RETURNS. YET ANOTHER COLD FRONT IS EXPECTED TO APPROACH THE
CAROLINAS FRIDAY EVENING WITH HIGH PRESSURE DOMINATING THE PATTERN
FOR SATURDAY AND SUNDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
OF 915 AM...I WILL UPDATE THE FORECAST TO REMOVE HEADLINE TO THE
FROST ADVISORY. IN ADDITION...I WILL ADJUST TEMPERATURES AND
DEWPOINTS TO OBSERVATIONS AND MAKE MINOR ADJUSTMENTS TO THE MORNING
SKY FORECAST. OVERALL THE FORECAST IS IN GREAT SHAPE.

AS OF 630 AM...WEAK HIGH PRESSURE MOVING OVERHEAD WILL KEEP WEATHER
QUIET THIS MORNING. NO CHANGES.

FOR THE NEXT 24 HOURS...WE WILL REMAIN UNDER A NW FLOW ALOFT BETWEEN
THE UPPER TROF OFF THE EAST COAST AND AN UPPER RIDGE MOVING FROM THE
ROCKIES TO THE PLAINS THROUGH TONIGHT. A SHORT WAVE DROPPING DOWN
INTO THE TROF WILL MOVE ACROSS THE SOUTHEAST WHILE AN INTERACTION
BETWEEN JET STREAKS IN THE NRN AND SRN STREAMS PROVIDES SOME UPPER
DIVERGENCE ACROSS MS/AL/GA THIS AFTERNOON. THIS SHOULD PROVIDE A
FAVORABLE ENVIRONMENT FOR CONVECTION TO DEVELOP ALONG AN OLD FRONTAL
BOUNDARY STRETCHING ACROSS THE DEEP SOUTH. THE ISSUE IS WHETHER OR
NOT ANY OF THE PRECIP NEAR THE FRONT DEVELOPS FAR ENOUGH TO THE NE
TO REACH NE GEORGIA AND THE UPSTATE. WILL INCLUDE A SLIGHT CHANCE IN
THE SAVANNAH RIVER BASIN IN THE LATE AFTERNOON/EARLY EVENING FOR
NOW...BUT THIS MIGHT HAVE TO BE BUMPED UP LATER DEPENDING ON
CONVECTIVE TRENDS. MEANWHILE...A WEAK REINFORCING COLD FRONT
DROPPING DOWN FROM THE NW DRIVEN BY A NRN STREAM WAVE MAY REACH THE
MTNS DURING THE LATE AFTERNOON AND EARLY EVENING. MOISTURE ALONG AND
AHEAD OF THIS BOUNDARY WILL HELP TO FUEL SOME SHOWER POTENTIAL
MAINLY ALONG THE TN BORDER. HOWEVER...THE BULK OF THE FCST AREA
SHOULD REMAIN DRY. HIGH TEMPS SHOULD BE A FEW DEGREES WARMER THAN
YESTERDAY AS THE AIR MASS CONTINUES TO MODERATE. ASSUMING THE FCST
WORKS OUT WITH NO PRECIP THRU PEAK HEATING...AND NO SIGNIFICANT
MOISTURE RETURN...WE SHOULD EXPECT DEWPOINTS TO REMAIN LOW AND
AFTERNOON MIN RH TO FALL INTO THE 25 TO 30 PERCENT RANGE MAINLY OVER
THE NC PIEDMONT/FOOTHILLS/NRN MTNS.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM EDT TUESDAY...THE SHORT TERM FCST PERIOD INITIALIZES
WEDNESDAY MORNING AMIDST RISING HEIGHTS ALOFT WHILE SURFACE HIGH
PRESSURE BUILDS ACROSS THE SOUTHERN APPS BEHIND A COLD FRONT.   SAID
HIGH PRESSURE CENTER WILL ADVECT SOUTHEAST TAKING ROOT JUST OFF THE
NC/SC COASTLINE LEADING TO COOLER/DRIER CONDITIONS ON
WEDNESDAY...AHEAD OF RETURNING MOIST SOUTHERLY FLOW INTO THURSDAY.
MEANWHILE FURTHER WEST OVER THE CENTRAL PLAINS...SURFACE
CYCLOGENESIS WILL YIELD DEVELOPMENT OF A BROAD BAROCLINIC ZONE AND
CONSEQUENT WARM SECTOR OVER THE DEEP SOUTH.  WARM FRONT ASSOCIATED
WITH WAA REGIME WILL CONTINUE ADVECTING NORTHWARD THROUGH THE DAY ON
THURSDAY WHILE THE ABOVE MENTIONED HIGH PRESSURE REMAINS ANCHORED TO
THE EAST.  MODELS CONTINUE TO INDICATE IMPROVING UPGLIDE/UPSLOPE
FORCING ALONG THE WESTERN FLANK OF THE RIDGE ON THURSDAY WITH A
RATHER SHARP INSTABILITY GRADIENT TO THE SOUTH/SOUTHWEST ALONG THE
I20 CORRIDOR...WHICH ACCORDING TO THE LATEST NAM COULD SLIDE INTO
THE REGION LATE IN THE DAY INCREASING THUNDER CHANCES.  AT THE SAME
TIME...ANOTHER MORE POTENT UPPER WAVE AND ASSOCIATED SURFACE FRONT
WILL BE SLIDING INTO THE OH VALLEY REGION SETTING UP A MORE ACTIVE
WEATHER PATTERN LATE IN THE PERIOD WITH THE PREFRONTAL PRECIPITATION
MOVING INTO THE TN VALLEY AROUND THE 12Z TIMEFRAME FRIDAY MORNING.

AS FOR THE FCST...POPS REMAIN BELOW MENTIONABLE LEVELS THROUGH THE
DAY ON WEDNESDAY AMONGST MOSTLY SUNNY SKIES AND ABOVE NORMAL
TEMPERATURES.  ABOVE MENTIONED UPGLIDE/UPSLOPE FORCED PRECIPITATION
WARRANTS INCREASING POPS OVERNIGHT FROM THE SOUTHWEST WHERE LIKELY
POPS ARE FEATURED OVER THE UPPER SAVANNAH RIVER VALLEY BY MIDDAY
THURSDAY WITH THUNDER MENTIONED...WITH LOWER CHANCE LEVEL POPS
FURTHER EAST WHERE LESS FAVORABLE FORCING/INSTABILITY RESIDES.  POPS
WILL LOWER SOMEWHAT OVERNIGHT AS ANY INSTABILITY DEGRADES...HOWEVER
CONTINUE IN THE CHANCE RANGE THROUGH THE PERIOD AS THE NEXT FRONT
WILL BE KNOCKING ON THE DOOR.  TEMPERATURES ON THURSDAY WILL BE
AROUND OR JUST BELOW NORMAL AS ANY SKY COVER AND ASSOCIATED
PRECIPITATION LIMIT HEATING...DESPITE MODEST WAA AT THE SURFACE.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 330 AM EDT TUESDAY...THE MEDIUM RANGE FCST PERIOD INITIALIZES
FRIDAY MORNING AHEAD OF A COLD FRONT PUSHING SOUTHEAST THROUGH THE
OH VALLEY INTO THE TN VALLEY REGION.  A SURFACE WAVE DEVELOPING
ALONG THE FRONTAL AXIS WILL DEEPEN AS SOUTHERLY FLOW OVER THE
SOUTHEAST SETS UP AN IMPROVING WARM SECTOR WHERE DEWPOINTS ARE FCST
TO SURGE INTO THE UPPER 50S TO LOWER 60S WITH SURFACE TEMPERATURES
FCST IN THE 70S TO NEAR 80.  AS DIURNAL HEATING MAXIMIZES...WOULD
NOT BE SURPRISED TO SEE SCATTERED CONVECTION ON FRIDAY AHEAD OF THE
FRONT...AS DEPICTED ON BOTH THE GFS/ECMWF.  THAT SAID...MODELS FAVOR
QUITE A BIT OF MOISTURE IN THE MID/UPPER LEVELS LIMITING LAPSE
RATES...THUS DAMPENING THE POTENTIAL FOR DEEP/ORGANIZED CONVECTION
DESPITE MODEST SHEAR THROUGH THE PROFILE.  FCST FEATURES CHANCE
LEVEL POPS ACROSS THE EAST WHILE INCREASING LIKELY POPS ARE FAVORED
OVER THE MTNS WITH THUNDER MENTIONED REGIONWIDE.  THE FRONT WILL
PUSH THROUGH THE REGION DURING THE EVENING HOURS WITH AN ADDITIONAL
ROUND OF SHOWERS/THUNDERSTORMS POSSIBLE ALONG AND JUST BEHIND THE
FRONTAL AXIS.  BY THAT TIME EXPECTING INSTABILITY TO BE AT A PREMIUM
THEREFORE ONLY ISOLATED/SCATTERED THUNDERSTORMS LOOK FEASIBLE AT
THAT POINT.  HIGH PRESSURE WILL SPILL IN SHARPLY ON SATURDAY MORNING
FROM THE WEST LEADING TO A DRYING FCST FOR THE REMAINDER OF THE
WEEKEND AMONGST NEAR NORMAL TEMPERATURES AND MOSTLY SUNNY SKIES.
THE NEXT ROUND OF WEATHER IS FCST ON MONDAY AS ANOTHER WEAK
SHORTWAVE SLIDES THROUGH THE TN VALLEY INTO THE SOUTHERN APPS.

&&

.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
AT KCLT AND ELSEWHERE...VFR THROUGH THE PERIOD...WITH ONLY SOME HIGH
CLOUDINESS THROUGH THE MORNING HOURS. CALM OR L/V WIND WILL BECOME
S/SW BY 13Z OR SO AS WEAK HIGH PRESSURE MOVES OFF TO THE EAST. A
SURFACE FRONT TO THE SOUTH AND SOUTHWEST MAY ACTIVATE AS A WARM
FRONT THIS AFTERNOON...BUT AT THIS POINT IT DOES NOT APPEAR THAT ANY
SHOWER ACTIVITY WILL REACH ANY OF THE TAF SITES...BUT KAND WOULD BE
THE CLOSEST. DEEPER BOUNDARY LAYER MIXING THIS AFTERNOON WILL ALLOW
FOR OCCASIONAL GUSTS UP TO AROUND 20 KT AT ALL TERMINALS. KAVL COULD
HAVE A PERIOD WITH AN UNUSUAL W CROSSWIND AS A WESTERLY WIND AT 850
MB STRENGTHENS A BIT THIS AFTERNOON. THE WIND SHOULD COME AROUND TO
NW AT KAVL BY MID EVENING. EXPECT A FEW TO SCT CLOUDS WITH BASES
AROUND 060 THIS AFTERNOON AND EVENING. WIND GUSTS SHOULD DIMINISH
WITH SUNSET. A WEAK REINFORCING COLD FRONT WILL REACH THE MTNS LATE
TONIGHT BUT ANY SHOWER ACTIVITY WILL PROBABLY REMAIN HUNG UP ON THE
W SLOPES. THE BOUNDARY WILL DROP DOWN INTO THE NC FOOTHILLS/PIEDMONT
BEFORE DAYBREAK ON WEDNESDAY WITH A WIND SHIFT TO N.

OUTLOOK...VFR ON WEDNESDAY. AN APPROACHING WARM FRONT AND RESULTANT
MOISTURE RETURN WILL BRING BETTER CHANCES FOR PRECIP/RESTRICTIONS
ACROSS THE AREA LATER IN THE WEEK...PERHAPS STARTING THURSDAY
MORNING. A COLD FRONT WILL AFFECT THE AREA FRIDAY INTO EARLY
SATURDAY...BRINGING ANOTHER ROUND OF RAIN/POSSIBLE THUNDERSTORMS AND
RESTRICTIONS. VFR WILL RETURN FOR THE REST OF THE WEEKEND.

CONFIDENCE TABLE...

            13-19Z        19-01Z        01-07Z        07-12Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH  92%     MED   78%
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...FIRE DANGER STATEMENT UNTIL 6 PM EDT THIS EVENING FOR NCZ033-
     035>037-048>050-053-056-057-065-068>072-082-501>510.
SC...NONE.

&&

$$
SYNOPSIS...CDG/JPT
NEAR TERM...NED/PM
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...PM



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