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Area Forecast Discussion

280
FXUS62 KGSP 010829
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
429 AM EDT WED JUL 1 2015

.SYNOPSIS...
A SERIES OF SYSTEMS WILL MOVE THOUGH AN UPPER LEVEL TROUGH INTO THE
WEEKEND...WITH MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS DEVELOPING
EACH DAY. HIGH TEMPERATURES WILL WARM TO ABOVE NORMAL BY EARLY NEXT
WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
0815 UTC UPDATE...POPS WERE LOWERED BASED ON RADAR TRENDS. SKY COVER
WAS REDUCED BASED ON INFRARED SATELLITE IMAGERY.

AT 230 AM EDT WEDNESDAY...JULY KICKS OFF WITH AN ANOMALOUS UPPER
PATTER FEATURING AND EASTERN TROUGH AND A WESTERN RIDGE. ONE
SHORTWAVE WILL BE EXITING THE TROUGH THIS MORNING...WHILE ANOTHER
DIVES INTO IT AND TOWARD THE SOUTHERN APPALACHIANS. THE SECOND
SHORTWAVE CROSSES THE MOUNTAINS AROUND MIDDAY..FOLLOWED BY A THIRD
ONE THIS EVENING.

AT THE SURFACE...A COLD FRONT APPEARS TO STALL TO OUR NORTH
TODAY...WHILE A LEE TROUGH REMAINS TO OUR EAST. MODEL FORECAST
SOUNDINGS SHOW SUFFICIENT CAPE FOR CONVECTION THIS AFTERNOON...WITH
PLENTY OF DRY AIR ALOFT FOR EVAPORATIVE COOLING...HOWEVER SHEAR
APPEARS RATHER LIMITED...AND MAINLY ABOVE 700 MB. STEERING FLOW WILL
KEEPS CELLS MOVING...AND LOW LEVEL FLOW WILL BE PARALLEL TO THE BLUE
RIDGE...LIMITING UPLOPE FLOW. TEMPERATURES WILL RUN SLIGHTLY BELOW
NORMAL UNDER THE UPPER TROUGH.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 245 AM WEDNESDAY...THE SHORT TERM FCST PICKS UP AT 12Z ON
THURSDAY WITH THE UPPER TROF FLATTENING OUT TO OUR WEST AND THE
NORTHERN STREAM LIFTING NE WHILE NUMEROUS LOBES OF SHORTWAVE ENERGY
STREAM ACROSS THE FCST AREA.

ON THURSDAY...A BROAD PLUME OF DEEP LYR MOISTURE WILL HAVE
OVERSPREAD THE CWFA FROM THE WEST BY THE START OF THE PERIOD WITH
ANOTHER ROUND OF LEE TROFFING EXPECTED TO SET UP FOR THE AFTERNOON.
POPS STEADILY RAMP UP THRU THE DAY/EVENING FROM WEST TO EAST WITH
CATEGORICAL VALUES CARRIED ALONG THE NC/TENN BORDER REGION AND
LIKELY OVER THE NW HALF OF THE CWFA. SPC STILL HAS OUR CWFA IN THE
MARGINAL RISK AREA WITH THE SLIGHT RISK AREA NOW INCLUDING OUR
WESTERN CORNER...AS OF THEIR MOST RECENT UPDATE THIS MORNING.

MODEL PROFILES CONTINUE TO SHOW A HEALTHY AMOUNT OF INSTABILITY AND
SOME DECENT LOW LVL SHEAR...ESPECIALLY OVER THE HIGHER TERRAIN ON
BOTH THURS AND FRI. THE MODELS KEEP DEEP LYR MOISTURE OVER THE FCST
AREA WELL INTO FRI AS A CENTRAL PLAINS LOW APPROACHES THE AREA FRI
MORNING. THE LOW MOVES NE OF THE CWFA LATER IN THE DAY AND ANOTHER
LEE TROF DEVELOPS IN ITS WAKE KEEPING WINDS OUT OF THE SW. PW VALUES
REMAIN HIGH THRU MOST OF THE SHORT TERM...SO WIDESPREAD FLOODING
WILL BE A CONCERN GOING FORWARD. TEMPS HAVE TRENDED A BIT COOLER IN
THE MODEL GUIDANCE SINCE YESTERDAY AND START OUT JUST BELOW CLIMO ON
THURS. THEY WARM A FEW DEGREES OVER THE NEXT COUPLE OF DAYS AND END
UP RIGHT AROUND NORMAL FOR EARLY JULY.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 155 AM WEDNESDAY...THE MEDIUM RANGE FCST PICKS UP AT 12Z ON
SATURDAY WITH HEIGHTS GRADUALLY RISING AS THE UPPER PATTERN FLATTENS
OUT OVER THE SE REGION. THE LONG RANGE MODELS GENERATE MULTIPLE WEAK
UPPER SHORTWAVES ON SAT AND INTO SUN WITH A MORE DEFINED SHORTWAVE
MOVING BY JUST TO OUR NORTH LATE SUN/EARLY MON. AFTER THIS FEATURE
LIFTS TO THE NE ON MON...HEIGHTS REBOUND AGAIN AND THE PATTERN
REMAINS FLAT THRU DAY 7. AT THE SFC...THE REGION WILL REMAIN FAIRLY
UNSETTLED THRU MOST OF THE PERIOD WITH PREVAILING SWLY LOW LVL FLOW.
THE CWFA IS EXPECTED TO REMAIN UNDER WEAK LEE TROFFING OVER THE
WEEKEND AS A SERIES OF SHORT LIVED MESO LOWS ATTEMPT TO SPIN UP OVER
THE CAROLINAS. THE MODELS GENERALLY AGREE THAT DEEP LYR MOISTURE
WILL PERSIST OVER THE REGION THRU MUCH OF THE PERIOD WITH THE
HIGHEST PW VALUES GENERALLY OVER THE NORTHERN ZONES. AS FOR THE
SENSIBLE FCST...I KEPT DIURNAL HIGH END CHANCES FOR CONVECTION EACH
DAY/EVENING WITH SOME LIKELY POPS OVER THE NC/TENN BORDER REGION FOR
SAT AND SUN. TEMPS START OUT AROUND CLIMATOLOGY ON SAT AND WARM OVER
THE NEXT FEW DAYS WITH HIGHS OVER THE SOUTHERNMOST ZONES TOPPING OUT
ABOUT A CATEGORY ABOVE CLIMO BY EARLY NEXT WEEK.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...VFR. MODEL TIME HEIGHTS SUPPORT LOW VFR CLOUDS FOR MUCH OF
THE FORECAST...WITH ENOUGH CLOUD COVER FOR A LOW VFR CIG WEDNESDAY
AFTERNOON AND EVENING IN ASSOCIATION WITH CONVECTION. GUIDANCE DOES
NOT SUPPORT A DAYBREAK FOG RESTRICTION. WINDS WILL FAVOR THE
SW...WITH MODEST DAYTIME GUSTS.

ELSEWHERE...OTHER THAN DAYBREAK MVFR FOG AT KAVL AND KAND...AND AN
OBSERVED IFR CIG AT KGMU WITH POSSIBLE MVFR FOG AT DAYBREAK...VFR
CONDITIONS ARE EXPECTED. GUIDANCE FAVORS A LOW VFR DAYBREAK CIG AT
KAVL THAT BREAKS UP WITH MORNING HEATING...THEN SPREADS LOW VFR CIGS
EAST ACROSS ALL SITES IN THE EARLY AFTERNOON IN ASSOCIATION WITH
CONVECTION. WINDS WILL GENERALLY FAVOR THE WSW...WITH MODEST DAYTIME
GUSTS...EXCEPT AT KAVL WHERE WINDS WILL CHANNEL UP VALLEY FROM THE
NW.

OUTLOOK...A UPPER TROUGH WILL SUPPORT MAINLY AFTERNOON AND EVENING
THUNDERSTORMS THROUGH THE WEEKEND. RESTRICTIONS MAY OCCUR WITH
PASSING STORMS...AND EACH MORNING OVER RAIN SOAKED AREAS.

CONFIDENCE TABLE...

            08-14Z        14-20Z        20-02Z        02-06Z
KCLT       HIGH  97%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH  95%     HIGH  97%     HIGH 100%     HIGH 100%
KHKY       HIGH  95%     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...NONE.
SC...NONE.

&&

$$
SYNOPSIS...JAT
NEAR TERM...JAT
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...JAT



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