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000
FXUS62 KFFC 170536
AFDFFC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
136 AM EDT FRI MAY 17 2013



.PREV DISCUSSION... /ISSUED 919 PM EDT THU MAY 16 2013/

UPDATE...
MAIN CHANGE WAS TO POP AND WEATHER GRIDS. HAVE REMOVED MENTION OF
THUNDER FOR THE REMAINDER OF TONIGHT. HAVE ALSO REDUCED POPS AND
FOCUSED THE SLIGHT CHANCE OF SHOWERS MORE ON THE WESTERN SIDE
GIVEN PROXIMITY TO SOME SHOWERS OVER AL. ALTHOUGH VORT MAX IS
PEGGED TO MOVE ACROSS NW GA AROUND SUNRISE...BETTER CHANCE OF
RAIN APPEARS TO BE IN THE AFTERNOON TOMORROW. DID REDUCE POPS
SLIGHTLY AND CUT BACK ON THE AREA FOR TOMORROW MORNING AND
AFTERNOON AS THE BETTER CHANCES APPEAR TO BE ACROSS NORTH GEORGIA.

BESIDES AFOREMENTIONED CHANGES...REST OF TWEAKS TO THE FORECAST
WERE ONLY MINOR TO ACCOUNT FOR HOURLY TRENDS.

11

PREV DISCUSSION...

SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
/ISSUED 309 PM EDT THU MAY 16 2013/
SCATTERING OF MIDLEVEL CLOUDS CONTINUES WITH A CU FIELD DEVELOPING
ACROSS PORTIONS OF THE NORTH. A SLIGHT CHANCE FOR SHOWERS AND
THUNDERSTORMS SHOULD REMAIN NORTH OF ATL WITH THE GREATEST CHANCE IN
FAR NORTH GEORGIA THIS AFTERNOON AND EVENING.

MODELS ARE IN DECENT AGREEMENT WITH THE MAIN INFLUENCING FEATURES IN
THE SHORT TERM SO HAVE GONE WITH GENERAL BLEND. LOW PRESSURE SYSTEM
ACROSS THE SOUTHERN PLAINS LOOKS TO CONTINUE TO DAMPEN INTO THE MAIN
LONGWAVE ENERGY AS IT MOVES SLOWLY EASTWARD. THIS SHOULD MAINLY
SERVE TO BRING AN ENHANCED MOISTURE FIELD TO THE NORTHERN PORTION OF
THE AREA WITH SOME WEAK SHORTWAVE VORTICITY ADVECTION ADDING SOME
ADDITIONAL FORCING FOR ASCENT. FORECAST CAPE VALUES NEAR 1000-1500
J/KG IN A WEAKLY SHEARED ENVIRONMENT WILL ALLOW FOR THUNDERSTORM
DEVELOPMENT HAVING THE MAIN THREATS OF OCCASIONAL LIGHTNING...GUSTY
WINDS...AND BRIEF HEAVY RAINFALL. MOISTURE AND INSTABILITY WILL BE
ON THE RISE THIS WEEKEND...WHEN THERE WILL BE A GREATER CHANCE FOR SOME
STRONG STORMS.

FOR TEMPS...A GENERAL BLEND OF GUIDANCE LOOKS REASONABLE WITH VALUES
CONTINUING TO BE AROUND 3-5 DEGREES ABOVE NORMAL.

BAKER

LONG TERM /SATURDAY THROUGH THURSDAY/...
/ISSUED 309 PM EDT THU MAY 16 2013/
MODELS STILL IN GENERAL AGREEMENT WITH ENHANCED MOISTURE ACROSS
THE AREA OVER THE WEEKEND AND INTO NEXT WEEK. ALTHOUGH QPF BETWEEN
THE MODELS CONTINUES TO DISAGREE...EVEN THE DRIEST OF THE MODELS
STILL ADVERTISING WIDESPREAD 1-1.5 INCHES OF RAINFALL THROUGH
MONDAY. HAVE GENERALLY MADE ONLY MINOR TWEAKS TO TEMPERATURES AND
POPS TO ACCOUNT FOR LATEST MODEL TRENDS...BUT WITH UNCERTAINTY IN
THE PLACEMENT OF THE PRECIP...HAVE AVOID MAKING WHOLESCALE CHANGES
AT THIS TIME. FOR SATURDAY...MODELS AGREE ENOUGH TO GO AHEAD WITH
LIKELY POPS ACROSS PORTIONS OF NORTHEAST GEORGIA. THUNDERSTORMS
CONTINUE TO BE ADVERTISED IN GRIDS...AND MODELS CONTINUE TO FOCUS
ON MORE DIURNALLY DRIVEN CONVECTION. FOR NOW...HAVE CONTINUED WITH
MUCH OF THE PREVIOUS FORECAST...AND THE PREVIOUS FORECAST
DISCUSSION IS INCLUDED BELOW.

31
&&

.AVIATION...
06Z UPDATE...
CIRRUS SHIELD CONTINUES TO OVERSPREAD MUCH OF N AND C GA EARLY
THIS MORNING. DO THINK THE CIRRUS WILL HANG AROUND THROUGH MOST OF
TODAY...BUT THERE WILL BE PERIODS WHERE THE UPPER CLOUDINESS WILL
BE MORE SCT THAN BKN. DIURNAL CU WILL DEVELOP WITH THE HEATING OF
THE DAY...AROUND 040-050. MODELS/SOUNDINGS WANT TO TAKE THE WIND
DIRECTION A LITTLE EAST OF SOUTH FRIDAY EVE. SPEEDS LESS THAN 5KT
ARE FORECAST SO WILL KEEP WINDS ON THE WEST SOUTH OF SOUTH AT THIS
TIME. CONVECTION WILL REMAIN N OF ATL THIS AFT.

//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ON WINDS THIS EVENING...OTHERWISE HIGH
CONFIDENCE ON REMAINING ELEMENTS.

NLISTEMAA

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          85  62  83  63 /  20  20  60  60
ATLANTA         83  65  82  66 /  20  20  60  60
BLAIRSVILLE     77  60  76  61 /  30  30  70  60
CARTERSVILLE    81  62  81  64 /  30  30  60  60
COLUMBUS        85  65  86  67 /  20  10  40  40
GAINESVILLE     82  63  79  63 /  30  30  70  60
MACON           86  62  86  64 /  10  10  40  50
ROME            82  63  81  64 /  30  30  60  60
PEACHTREE CITY  83  61  83  64 /  20  20  40  60
VIDALIA         87  67  88  67 /  10  10  30  40

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$