140 
FXUS62 KFFC 290000
AFDFFC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
800 PM EDT SUN APR 28 2013


.UPDATE...
LATEST SURFACE ANALYSIS SHOWS LOW PRESSURE ACROSS THE FLORIDA 
PANHANDLE. COOL AIR WEDGE REMAINS SITUATED ACROSS PORTIONS OF NORTH 
AND CENTRAL GA THIS EVENING. RAIN CONTINUES TO REINFORCE THE WEDGE 
THIS EVENING...AND DON'T EXPECT WINDS TO SWITCH AROUND TO THE SE 
UNTIL TOMORROW. 

THUNDERSTORMS CONTINUE TO DEVELOP ACROSS EASTERN ALABAMA...BUT WHEN 
THEY RUN INTO THE WEDGE...THE BECOME ELEVATED AND EVENTUALLY BECOME 
STRATIFORM. HAVE REDUCED THE THUNDER WORDING WITHIN THE WEDGE FOR 
OVERNIGHT. ACROSS SOUTH CENTRAL GA...STORMS REMAIN SURFACE BASED. 

SEVERE POTENTIAL HAS DECREASED WITH THE LOSS OF HEATING. 
HOWEVER...STORMS SOUTH OF THE WEDGE COULD BECOME STRONG AND PRODUCE 
GUSTY WINDS AND SMALL HAIL FOR THE NEXT SEVERAL HOURS. 

LOCALLY HEAVY RAINFALL WILL BE THE PRIMARY THREAT THIS EVENING AND 
OVERNIGHT. THE HEAVIEST RAINFALL IN THE LAST 24 HOURS HAS FALLEN 
ACROSS NORTHERN GA. MPE ESTIMATES INDICATE THAT 2 TO 4 INCHES OF 
RAIN HAS FALLEN ACROSS NORTH GA...WITH SOME LOCALLY HIGHER AMOUNTS 
UP TO 5 INCHES. ACROSS THE METRO ATLANTA AREA AND SOUTHWARD...UP TO 
AN INCH TO AN INCH AND A HALF HAS FALLEN. DO THINK THE PRIMARY AXIS 
FOR HEAVIER RAIN WILL BE ACROSS CENTRAL GA THIS EVENING. WILL LET
THE FF WATCH EXPIRE.

&&

.PREV DISCUSSION... /ISSUED 329 PM EDT SUN APR 28 2013/ 

SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
THE ACTIVE REGION OF AN APPROACHING UPPER LEVEL TROUGH IS SPARKING
WIDESPREAD CONVECTION ACROSS THE DEEP SOUTH... CURRENTLY STRETCHING
FROM EAST CENTRAL MS...ACROSS AL AND INTO NORTH AND MUCH OF
CENTRAL GA. FLOODING CONTINUES TO BE A MAIN CONCERN ACROSS NORTH
GA AS SHOWERS AND THUNDERSTORMS TRAIN ACROSS AN ALREADY SATURATED
GROUND...WHERE 2 TO 3 INCHES OF RAIN HAS FALLEN AND AN ADDITIONAL
1 TO 2 INCHES IS POSSIBLE. A FLASH FLOOD WARNING HAS ALREADY BEEN
POSTED FOR CHATTOOGA AND FLOYD COUNTIES DUE TO INUNDATED ROADWAYS.
A FLASH FLOOD WATCH WILL CONTINUE FOR MUCH OF NORTH GA THROUGH 8
PM THIS EVENING.

ADDITIONAL CONCERNS ARE INCREASING POTENTIAL FOR ISOLATED SEVERE
STORMS...MAINLY FOR AREAS SOUTH OF ATLANTA AND INTO CENTRAL GA
WHERE DISCRETE THUNDERSTORMS ARE NOTED AHEAD OF THE MAIN RAIN
SHIELD. ONE DISCRETE STORM HAS PRODUCED LARGE HAIL IN THE LA GRANGE
AREA... AND ANOTHER FURTHER EAST IS SHOWING STRONG ROTATION. THE
MAIN CONCERNS FROM DISCRETE CELLS WILL BE LARGE HAIL...DAMAGING
WINDS AND POSSIBLY AN ISOLATED TORNADO THROUGH EARLY EVENING...
ESPECIALLY AS STRONG LOW LEVEL WIND SHEAR CONTINUES TO PRODUCE 300+
HELICITY DURING DAYTIME HEATING. 

OTHERWISE... EXPECT THE FLOOD AND SEVERE THREAT TO GREATLY
DIMINISH BY 8-9 PM THIS EVENING AS THE STRONGER UPPER SUPPORT
SLIPS FURTHER EAST AND WE CONTINUE TO LOSS DAYTIME HEATING. 

MODELS SHOW THE ASSOCIATED COLD FRONT TO BE SLOW PUSHING ACROSS
THE AREA... SO WILL SHOW A GRADUAL DECREASING OF POPS FROM WEST TO
EAST THROUGH MONDAY AFTERNOON-EARLY EVENING...BEFORE ENDING RAIN
CHANCES ACROSS THE ENTIRE FORECAST AREA BY SOMETIME MONDAY NIGHT. 

AS FOR TEMPS... HAVE LEANED TOWARD A MAV AND MET BLEND THROUGH THE
PERIOD WITH SEASONABLE COOLER LOWS SPREADING INTO THE AREA BY
MONDAY NIGHT BEHIND THE COLD FRONT. 

39

LONG TERM /TUESDAY THROUGH SUNDAY/...
NO MAJOR CHANGES WERE MADE TO THE EXTENDED PERIOD AS MODELS
CONTINUE SHOW RAIN CHANCES SPREADING BACK INTO THE AREA BY TUESDAY
AFTERNOON AND CONTINUING THROUGH THE REMAINDER OF THE WORK WEEK.
SEE THE DISCUSSION BELOW FOR FURTHER DETAILS. /39 

PREV LONG TERM DISCUSSION... /ISSUED 456 AM EDT SUN APR 28 2013/

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
GUIDANCE IS OVERALL IN GOOD AGREEMENT WITH MAIN INFLUENCING
FEATURES THROUGHOUT LONG TERM. AS AN UPPER SHORTWAVE EXITS THE
FORECAST AREA MONDAY NIGHT...THE NEXT MAIN FOCUS WILL BE ON THE
DEVELOPMENT OF A WEAK LOW PRESSURE SYSTEM ACROSS THE NORTHERN GULF
BY MIDWEEK. THIS FEATURE LOOKS TO ADVECT SOME GULF AND ATLANTIC
MOISTURE INTO THE AREA STARTING LATE TUESDAY. A STRENGTHENING
RIDGE OF HIGH PRESSURE ALONG THE EASTERN SEABOARD WILL RESULT IN A
HYBRID CAD WEDGE IMPINGING UPON THE AREA FROM THE NORTHEAST BY
WEDNESDAY. THIS SHOULD SERVE TO PRIMARILY LIMIT INSTABILITY IN
NORTHERN PORTIONS OF THE AREA...SO HAVE KEPT HIGHER CHANCE POPS
FOR SHOWERS AND THUNDERSTORMS IN THE SOUTHWEST AND TRENDED LOWER
TOWARD THE NORTHEAST. THIS LOOKS TO BE THE GENERAL PATTERN THROUGH
FRIDAY.

A LARGE UPPER LEVEL CUTOFF LOW IS FORECAST TO LINGER ACROSS THE 
CENTRAL CONUS BY THE END OF THE WEEK. THIS LOOKS TO PUSH AN OCCLUDED 
FRONT NEAR THE WESTERN PORTION OF THE STATE BY SATURDAY SO HAVE 
INCREASED POPS ACCORDINGLY. FOR NOW GUIDANCE IS IN PRETTY GOOD 
CONSENSUS WITH TIMING OF THE FRONT...THOUGH ANY SHORTWAVE 
PERTURBATIONS ROTATING AROUND THE UPPER TROUGH MAY SERVE TO PROVIDE 
ENHANCEMENTS TO THE PRECIP CHANCE.

BAKER

AVIATION...
00Z UPDATE...
WIDESPREAD RAIN WITH EMBEDDED THUNDERSTORMS CONTINUES ACROSS THE 
REGION THIS EVENING. EXPECT CIGS TO GO LIFR LATER THIS EVENING...AND 
REMAIN UNTIL JUST AFTER SUNRISE TOMORROW. WINDS WILL ALSO BE AN 
ISSUE. CURRENTLY...DO THINK OUTFLOW FROM STORMS TO THE NORTH OF ATL 
ARE PROVIDING SOME OUTFLOW. WINDS SHOULD SWITCH BACK TO THE NE 
SHORTLY. SINCE THE RAINFALL IS REINFORCING THE WEDGE...WINDS SHOULD 
STAY E ALL NIGHT. 

//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ALL ELEMENTS.

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          59  75  54  79 /  70  50  10  10 
ATLANTA         59  76  58  80 /  70  40  10  10 
BLAIRSVILLE     53  72  52  74 /  50  40  10  10 
CARTERSVILLE    57  76  54  82 /  60  40  10  10 
COLUMBUS        60  79  58  81 /  80  40  10  20 
GAINESVILLE     57  74  56  79 /  60  40  10  10 
MACON           61  77  56  82 / 100  50  20  10 
ROME            56  76  51  83 /  50  20   5  10 
PEACHTREE CITY  57  76  51  80 /  70  40  10  10 
VIDALIA         63  78  60  81 / 100  60  30  20 

&&

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

&&

$$