000
FXUS62 KFFC 161920
AFDFFC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
320 PM EDT SUN JUN 16 2013

.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISOLATED LIGHT SHOWERS CONTINUE TO DEVELOP WITH DAYTIME HEATING THIS
AFTERNOON ACROSS WEST AND NORTH GEORGIA. A WEAK SHORT WAVE WILL
MOVE INTO THE TENNESSEE VALLEY THIS EVENING BRINGING AN INCREASED
CHANCE OF SHOWERS/TSTORMS TO NORTH GEORGIA. THIS WAVE WILL MOVE
OUT OF THE CWA BY MIDNIGHT...HOWEVER ANOTHER BUT STRONGER SHORT
WAVE WILL BRING AN INCREASING CHANCE OF SHOWERS/ISOLATED TSTORMS
TO ABOUT THE NORTHERN HALF OF THE CWA LATE TONIGHT INTO MONDAY
MORNING. A CONTINUED SERIES OF SHORT WAVES WILL KEEP SCATTERED TO
NUMEROUS SHOWERS/TSTORMS GOING FOR MONDAY AFTERNOON AND MONDAY
NIGHT. THE BEST CHANCES WILL BE ACROSS NORTH GEORGIA. RAINFALL
AMOUNTS THROUGH MONDAY NIGHT SHOULD RANGE FROM AROUND 1 INCH
ACROSS NORTHG EORGIA TO LESS THAN A HALF INCH ACROSS CENTRAL
GEORGIA. INCREASING DEW POINTS WILL KEEP TEMPS IN THE UPPER 60S
AND 70S TONIGHT AND MONDAY NIGHT AND GUIDANCE HAS A GOOD HANDLE ON
THIS.

17

.LONG TERM /TUESDAY THROUGH SUNDAY/...
REVISIONS TO THE EXTENDED FORECAST WERE CONCENTRATED ON THE FIRST
FEW DAYS OF THE PERIOD. MODELS STILL INDICATING UPPER LEVEL
SHORTWAVE AND ENHANCED DEEP LAYER MOISTURE ACROSS THE REGION THROUGH
THE DAY TUESDAY...WITH A SURFACE LOW FEATURE DEVELOPING OVER THE
TENNESSEE VALLEY. GFS STILL APPEARS TO BE THE MOST AGGRESSIVE WITH
THE SURFACE LOW...AND CONTINUED TO OPT FOR MORE OF AN ECMWF SOLUTION
THROUGH THE PERIOD. SUPPORTED BY MODELED INSTABILITY AND
SHEAR...HAVE CONTINUED WITH LIKELY SHOWERS AND THUNDERSTORMS THROUGH
THE DAY TUESDAY...TAPERING OFF TO CHANCE POPS BY TUESDAY NIGHT.

FOR THE REMAINDER OF THE FORECAST...MODELS STILL SHOWING DIVERGENT
SOLUTIONS AND HAVE MADE LITTLE CHANGES ASIDE FROM MINOR TEMPERATURE
ADJUSTMENTS. THE PREVIOUS FORECAST DISCUSSION...ESPECIALLY FOR
BEYOND MID WEEK...IS STILL APPLICABLE AND IS INCLUDED BELOW.

31


/ISSUED 439 AM EDT SUN JUN 16 2013/
MAIN FOCUS IN LONG TERM IS PRECIP POTENTIAL MONDAY NIGHT THROUGH
TUESDAY DUE TO INFLUENCE OF UPPER SHORTWAVE TROUGH AND AMPLE DEEP
LAYER MOISTURE IN PLACE. THIS SHOULD ALLOW FOR FAIRLY WIDESPREAD
SHOWERS AND THUNDERSTORMS ACROSS THE AREA WITH THE BEST CHANCE
ACROSS NORTH GA. THE GFS CONTINUES TO BE A MORE ROBUST SOLUTION WITH
A STRONGER TRANSLATED SFC LOW AND PUSHES AN ASSOCIATED COLD FRONT
THROUGH THE AREA TUESDAY NIGHT. THE ECMWF CONTRASTINGLY LINGERS THE
MOISTURE FIELD AND STALLS A RATHER DIFFUSE FRONT ACROSS THE REGION.
HAVE DECIDED TO WEIGH IN ON THE ECMWF AS THE END OF THE SHORT TERM
GUIDANCE BETTER AGREES WITH. FOR QPF THROUGH TUESDAY...A BLEND OF
GUIDANCE RESULTS IN NEARLY 1 INCH ACROSS THE NORTH TO 0.5 INCHES
ELSEWHERE. DECENT FORECAST INSTABILITY AND RELATIVELY WEAK SHEAR
WILL CONTINUE TO ALLOW FOR GUSTY WINDS...LIGHTNING...AND PERIODS OF
HEAVY RAIN AS THE MAIN THREATS WITH ANY STORM DEVELOPMENT.

THE REMAINDER OF THE FORECAST PERIOD HAS DECENT DISCREPANCIES
BETWEEN THE MODELS...THOUGH LOOKS TO BE AT LEAST SLIGHT TO CHANCE
POPS FOR SHOWERS AND THUNDERSTORMS EACH DAY AS WEAK IMPULSES TRACK
ALONG NW FLOW ALOFT. GUIDANCE IS IN FAIRLY GOOD
AGREEMENT...HOWEVER...ON A HYBRID CAD EVENT SETTING UP THURSDAY INTO
THE WEEKEND AS A PARENT SFC HIGH SLIDES EASTWARD ACROSS THE
MID-ATLANTIC COAST. THIS SHOULD SERVE TO LIMIT INSTABILITY ACROSS
THE EASTERN PORTION OF THE AREA AND POTENTIALLY FOCUS CONVECTIVE
DEVELOPMENT NEAR THE PERIPHERY OF THE WEDGE. THE GFS AND ECMWF
DIFFER GREATLY ON PROGGED OVERRIDING LOW LEVEL FLOW AND
MOISTURE...THEREFORE FUTURE RUNS WILL BE MONITORED FOR ANY
CONSISTENCIES OR IMPROVED CONSENSUS AS THIS WOULD AFFECT THE
POTENTIAL PRECIP COVERAGE.

TEMPS LOOK TO STAY NEAR NORMAL THROUGH THE MAJORITY OF THE PERIOD
WITH HIGHS PRIMARILY IN THE MID TO UPPER 80S AND LOWS IN THE 60S.

BAKER


31


&&

.AVIATION...
18Z UPDATE...SCATTERED MVFR CIGS HAVE JUST ABOUT DISSIPATED. CIGS
SHOULD REMAIN VFR FOR THE REST OF THE AFTERNOON AND EVENING.
EXPECT CIGS TO DROP TO THE LOWER END OF VFR LATE TONIGHT AND
MONDAY WITH SOME MVFR CIGS DEVELOPING ACROSS CENTRAL GA LATE
TONIGHT AND EARLY MONDAY. EXPECT ISOLATED SHOWERS TO DEVELOP
ACROSS WEST AND NORTH GA THIS AFTERNOON AND EVENING WITH ISOLATED
THUNDER POSSIBLE AS WELL. SHOWERS WILL INCREASE IN COVERAGE LATE
TONIGHT...PUSHING INTO ATL/AHN AFTER 09Z MON AND CONTINUE INTO THE
DAY ON MONDAY. ALTHOUGH ISOLATED THUNDER COULD OCCUR JUST ABOUT
ANYWHERE IN NORTH GA LATE TONIGHT AND MONDAY...FEEL THE BEST
CHANCE WILL BE BETWEEN 18Z MON AND 00Z TUE. WINDS WILL REMAIN
SOUTHWEST LESS THAN 10 KTS THROUGH THE FORECAST.

//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ON TIMING OF PRECIP...ESPECIALLY MONDAY.
MEDIUM CONFIDENCE ON CIGS AFTER 06Z MONDAY.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          68  88  69  85 /  60  60  60  60
ATLANTA         71  86  70  84 /  60  60  60  60
BLAIRSVILLE     65  81  65  79 /  60  60  70  60
CARTERSVILLE    69  88  68  84 /  60  60  60  60
COLUMBUS        73  91  74  88 /  40  40  40  50
GAINESVILLE     69  86  69  82 /  60  60  60  60
MACON           70  90  71  88 /  30  40  40  40
ROME            69  86  70  85 /  60  60  70  60
PEACHTREE CITY  70  87  70  85 /  50  50  50  60
VIDALIA         72  91  73  89 /  30  40  30  40

&&

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

$$

SHORT TERM...17
LONG TERM....31
AVIATION...17