Area Forecast Discussion
Issued by NWS Atlanta, GA

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FXUS62 KFFC 260133
AFDFFC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
933 PM EDT SAT APR 25 2015

.UPDATE...WELL THE SEVERE THREAT DID INDEED MATERIALIZE THIS
AFTERNOON AND EVENING BUT IMPACTED MOSTLY CENTRAL GEORGIA RATHER
THAN THE NORTHERN PORTIONS THE MODELS HAD BEEN PEGGING FOR DAYS.
ANALYSIS STILL TO COME BUT LOOKS LIKE IT WAS A COMBINATION OF
EARLY MORNING CONVECTION THAT STABILIZED AND GULF COAST COMPLEX
THAT PROPAGATED ALONG AXIS OF BEST INSTABILITY WHICH WAS CENTRAL
AND NOT NORTH GEORGIA. REGARDLESS...ATMOSPHERE WAS MORE THAN
CAPABLE OF PRODUCING BIG TIME SEVERE STORMS WHERE THEY DID DEVELOP
WITH NEAR 100 PERCENT OF THE ACTIVITY THAT FORMED GOING SEVERE.
LARGEST HAIL REPORT WAS BASEBALL SIZED AND HAD NUMEROUS VERY
STRONG WIND CORES IN EXCESS OF 70 KTS OF WHICH WE ARE STILL
RECEIVING REPORTS AND ASSESSMENTS WHICH WILL CONTINUE THROUGH
SUNDAY.

OTHERWISE...STILL ENOUGH CAPE AROUND IN THE WAKE OF THE STORMS TO
KEEP IN SMALL CHANCES FOR THE OVERNIGHT PERIOD. WILL ALSO BE
WATCHING CLOSELY COMPLEX COMING OUT OF KENTUCKY AND INTO THE
TENNESSEE VALLEY. CAPE VALUES OVER NORTH GEORGIA AND EASTERN
TENNESSEE NOT VERY IMPRESSIVE WHICH WOULD LEND SUPPORT TO HRRR
PROJECTIONS OF LINE DYING RAPIDLY AS IT ARRIVES FOR OUR NORTHERN
MOST COUNTIES. AS WE HAVE SEEN THOUGH...THESE MODELS HAVE
STRUGGLED WITH THIS EVENT AND WILL KEEP HIGHER POPS IN FOR THE
NORTHERN TIER THROUGH THE OVERNIGHT PERIOD UNTIL REGIONAL RADAR
PROVES OTHERWISE.

DEESE

&&

.PREV DISCUSSION... /ISSUED 713 PM EDT SAT APR 25 2015/

PREV DISCUSSION... /ISSUED 552 PM EDT SAT APR 25 2015/

UPDATE...
STRONG TO SEVERE STORMS OVER ALABAMA ARE MOVING INTO CENTRAL AND
SOUTH GEORGIA THIS AFTERNOON. THESE STORMS ARE EXPECTED TO
CONTINUE MOVING ACROSS THE AREA THROUGH TONIGHT. HAVE ISSUES A
SEVERE THUNDERSTORM WATCH THROUGH 1100 PM FOR AREAS ALONG AND SOUTH
OF A NEWNAN TO STOCKBRIDGE TO EATONTON TO WRENS. THE BIGGEST
THREAT WITH THESE STORMS WILL BE STRONG GUSTY WINDS...PERIODS OF
HEAVY RAIN...AND LARGE HAIL. AND ISOLATED TORNADO OR TWO COULD
ALSO OCCUR.

PREV DISCUSSION... /ISSUED 344 PM EDT SAT APR 25 2015/

ANOTHER ROUND OF STORMS /POSSIBLY SEVERE/ COULD DEVELOP LATE
THIS AFTERNOON INTO EVENING...

SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
NORTH AND CENTRAL GA REMAIN BETWEEN THE CONVECTION ACROSS THE
NORTHERN GULF...AND THE SHORT WAVE EXPECTED TO MOVE THROUGH THE
OH/TN VALLEY OVERNIGHT. EARLY MORNING SHOWERS AND THUNDERSTORMS MADE
THE FORECAST AREA MORE STABLE FOR MUCH OF THE DAY AND PLACEMENT AND
TIMING OF ANY REDEVELOPMENT HAS BEEN UNCERTAIN. HOWEVER
BREAKS IN CLOUD COVER AND AFTERNOON HEATING HAVE ALLOWED THE AIR
MASS TO RECOVER SOMEWHAT. CONVECTION IS DEVELOPING ACROSS SOUTHERN
AL AND A FEW SEVERE THUNDERSTORMS REMAIN POSSIBLE FOR NORTH AND
CENTRAL GA INTO THE EVENING. WITH COVERAGE UNCERTAIN...HAVE REDUCED
THE OVERNIGHT POPS TO CHANCE FOR NOW. MODELS SHOW THE TN VALLEY
SHORT WAVE DRAGGING A FRONTAL BOUNDARY SOUTHWARD INTO THE STATE
SUNDAY...SO HAVE LEFT IN SOME SLIGHT CHANCE POPS FOR THE DAY. SUNDAY
NIGHT LOOKS DRY WITH NORTHWEST FLOW. HAVE STAYED CLOSE TO GUIDANCE
TEMPERATURES.

41

LONG TERM /MONDAY THROUGH SATURDAY/...
ONLY MINOR TWEAKS TO POPS/WX FOR TUESDAY AND THURSDAY. GUIDANCE
SHOWING DECENTLY LARGE DISCREPANCIES WITH LOW POSITION AND EXPANSE
OF MOISTURE FIELD WITH UPPER TROUGH ACROSS SOUTHEAST CONUS THRU
MIDWEEK. HAVE THEREFORE KEPT MAINLY A PERSISTENCE FORECAST.
PREVIOUS DISCUSSION FOLLOWS...

BAKER

PREV DISCUSSION... /ISSUED 341 AM EDT SAT APR 25 2015/

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
WEAK RIDGING AT THE SFC AND MOSTLY DRY CONDITIONS TO BEGIN THE LONG
TERM. SHORTWAVE SLIDES FROM THE MS VALLEY INTO THE TN VALLEY TUESDAY
NIGHT INTO WEDNESDAY WHILE A SFC LOW TRACKS ALONG THE GULF COAST.
THIS RESULTS IN THE RETURN OF SHOWERS AND THUNDERSTORMS TUESDAY
NIGHT INTO WEDNESDAY NIGHT. GFS IS SLOWER THAN MODEL RUN LAST NIGHT
IN CLEARING OUT THE PRECIPITATION AND HOLDS ONTO IT THROUGH THURSDAY
NIGHT. ALTHOUGH THERE ARE SLIGHT DIFFERENCES IN FEATURES BETWEEN THE
GFS AND THE ECMWF THE TIMING OF DIMINISHING PRECIPITATION IS FAIRLY
SIMILAR. HIGH PRESSURE BUILDS IN BEHIND THAT SYSTEM AND SHOULD LEAD
TO A FEW DRY DAYS.

11

AVIATION...
18Z UPDATE...
MOSTLY VFR CONDITIONS THIS AFTERNOON AND EVENING...HOWEVER SOME
REDEVELOPMENT OF CONVECTION IS EXPECTED WITH POSSIBLY SOME STORMS
BECOMING SEVERE. SOME MVFR CEILINGS POSSIBLE TOWARD MORNING BUT
IMPROVING BY 15Z. WINDS SOUTHWEST 5 TO 10KT WITH SOME GUSTS THIS
AFTERNOON AND EVENING. WINDS BECOMING WEST TO NORTHWEST TOWARD THE
END OF THE TAF PERIOD.


//ATL CONFIDENCE...18Z UPDATE...
LOW CONFIDENCE ON WHEN/WHERE AFTERNOON CONVECTION WILL OCCUR.
MEDIUM CONFIDENCE REMAINING ELEMENTS.

41

AVIATION...
00Z UPDATE...
CLUSTER OF TSRA MOVING OUT OF ALABAMA LOOKS TO SKIRT THE SOUTHERN
FRINGES OF ATL BETWEEN 00Z AND 01Z. OTHERWISE...WILL CONTINUE TO
SEE TSRA STREAM ACROSS MCN AND CSG THROUGH 02Z BEFORE CONDITIONS
BECOME MORE TRANQUIL FOR THE OVERNIGHT PERIOD. ANOTHER BAND OF
TSRA COMING IN FROM TENNESSEE AND KENTUCKY IS EXPECTED TO WEAKEN
BUT WILL NEED TO MONITOR FOR ADDITIONAL ACTIVITY FOR ATL AFTER
MIDNIGHT. SOME CHANCE FOR IFR TONIGHT...ESPECIALLY THOSE LOCATIONS
SUCH AS MCN THAT RECEIVED ABUNDANT RAINFALL. KEPT AT MVFR FOR NOW
TO MONITOR CONDITIONS BUT MAY NEED TO LOWER CIGS.

//ATL CONFIDENCE...00Z UPDATE...
MEDIUM ON IFR AND TSRA POTENTIAL.
HIGH ON REMAINING ELEMENTS.

DEESE

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          63  81  55  73 /  50  20  10   5
ATLANTA         65  80  56  72 /  50  20   5   5
BLAIRSVILLE     58  71  45  66 /  50  20  10   5
CARTERSVILLE    62  78  50  71 /  50  20  10   5
COLUMBUS        67  85  60  78 /  50  20   5  10
GAINESVILLE     63  77  54  70 /  50  20   5   5
MACON           67  85  58  76 /  50  20   5   5
ROME            62  77  50  70 /  50  20   5   5
PEACHTREE CITY  64  82  54  74 /  50  20   5   5
VIDALIA         68  87  61  76 /  50  20  10  10

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
SEVERE THUNDERSTORM WATCH UNTIL 11 PM EDT THIS EVENING FOR THE
FOLLOWING ZONES: BALDWIN...BIBB...BLECKLEY...BUTTS...CRAWFORD...
CRISP...DODGE...DOOLY...EMANUEL...GLASCOCK...HANCOCK...HOUSTON...
JASPER...JEFFERSON...JOHNSON...JONES...LAMAR...LAURENS...
MONROE...MONTGOMERY...PEACH...PULASKI...PUTNAM...TELFAIR...
TOOMBS...TREUTLEN...TWIGGS...WASHINGTON...WHEELER...WILCOX...
WILKINSON.

&&

$$

SHORT TERM...DEESE
LONG TERM....01
AVIATION...DEESE


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