Area Forecast Discussion
Issued by NWS Atlanta, GA

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FXUS62 KFFC 160541
AFDFFC

AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
141 AM EDT TUE SEP 16 2014

.UPDATE...
/ISSUED AT 1010 PM EDT MON SEP 15 2014/
HAVE TWEAKED POPS BASED ON RADAR. SOME DEVELOPMENT
POSSIBLE THROUGH THE NIGHT WITH PASSAGE OF SHORT WAVE. WILL CONTINUE
TO WATCH SLOW MOVING STORMS FOR POSSIBLE FLOOD PROBLEMS.

41

.PREVIOUS...
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
LATEST SURFACE ANALYSIS SHOWS WEDGE WHICH HAS BEEN THE DOMINANT
FEATURE THE LAST DAYS OVER THE AREA HAS SHIFTED TO THE SOUTHEAST
AND WEAKENED SIGNIFICANTLY. DESPITE THIS...LOW LEVEL MOISTURE HAS
REMAINED ENTRENCHED FOR MUCH OF NORTH AND CENTRAL GEORGIA. THE
MAIN DIFFERENCE HAS BEEN WITH LESS WEDGE RE ENFORCEMENT INFLUENCE
ALONG WITH SUBTLE SOUTHERLY LOW LEVEL WIND MAX...LOW CLOUDS HAVE
BEEN ABLE TO SCOUR OUT MUCH FASTER FOR THE SOUTHERN ZONES. EXPECT
THIS TREND TO CONTINUE FOR THE REMAINDER OF THIS AFTERNOON MAKING
FOR A VERY CHALLENGING TEMP FORECAST WHICH WILL RELY HEAVILY ON
PERSISTENCE TO THE NORTH AND SHORT TERM MODELS FOR THE SOUTH.

CLEARING LINE WILL DICTATE PRECIP CHANCES INTO THE OVERNIGHT AS
WELL AS APPROACHING SHORTWAVE TROUGH WHICH HAS SPAWNED ACTIVITY
OVER ALABAMA SHOULD PROVIDE A FOCUS FOR LOCAL DEVELOPMENT AND
ENHANCEMENT WHERE CAPES AREA ABLE TO REACH 1000 J/KG TO 2000 J/KG.
THIS SHOULD BE NO PROBLEM TO THE SOUTH WHERE VALUES WILL LIKELY
APPROACH 3000 J/KG AND POPS WILL BE HIGHEST THERE INITIALLY.
EXPECT HOWEVER ZONE OF HIGHEST THUNDERSTORM CHANCES TO TRANSITION
TO THE WESTERN ZONES AS SHORTWAVE MOVES THROUGH AND WILL MAINTAIN
A NON DIURNAL HIGH TREND IN POPS THROUGH THE OVERNIGHT PERIOD.

FRONT TO MOVE THROUGH NORTHERN ZONES ON TUESDAY BUT ENOUGH
MOISTURE TO REMAIN FOR SOUTHERN SECTIONS OF THE FORECAST AREA TO
WARRANT CONTINUED LIKELY POPS. CURRENT FORECAST HAS A GOOD HANDLE
ON THIS AND REALLY MADE LIMITED CHANGES TO THESE GRIDS.

DEESE

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
MAINLY ONLY TWEAKS TO THE LONG TERM BASED ON THE LATEST GUIDANCE.

BDL

PREVIOUS DISCUSSION...
THE EXTENDED FORECAST STARTS OUT WITH THE SECOND FRONT SWEEPING
INTO SOUTH GA AND USHERING IN A DRIER AIRMASS ACROSS NORTH GA.
STRONG HIGH PRESSURE RIDGE BUILDS IN BEHIND THE SECOND FRONT WHICH
WILL ALSO HELP TO SUPPRESS ANY PRECIPITATION THROUGH THE WEEKEND.
BOTH THE GFS AND ECMWF AGREE WITH THE DRIER AIR MASS MOVING IN...BUT
THEY ALSO AGREE THAT THERE WILL STILL BE A A BIT OF MOISTURE
LINGERING OVER EASTERN AND SOUTHERN SECTIONS OF THE STATE THROUGH
DAY 7. HAVE DECIDED TO CONTINUE WITH LOWERED POPS IN THE EXTENDED
AND KEEP JUST A SLIGHT CHANCE MAINLY SOUTH AND EAST. MODELS ALSO
CONTINUE TO INDICATE COOLER TEMPS ARE IN STORE FOR THE
STATE...ESPECIALLY WITH THE COOLER DRIER AIR MASS MOVING IN. BY
THE LATTER HALF OF THE WEEK WE COULD BE BELOW SEASONAL NORMALS.

01

&&

.AVIATION...
06Z UPDATE...
MVFR CIGS ARE SETTLING INTO MOST TAF SITES AT 06Z TAF ISSUANCE. AREA
OBS AND MOS GUIDANCE SUPPORTS CIGS LOWERING TO LIFR/IFR LEVELS BY
08-10Z THIS MORNING FOR MOST TAF SITES. THIS AHEAD OF A COLD FRONT
THAT IS PROGGD TO PUSH ACROSS ATLANTA TAF SITES BETWEEN 12-14Z THIS
MORNING... THEN CSG-MCN AREA BY 14-16Z. THIS SHOULD ALLOW A GRADUAL
IMPROVEMENT TO VFR CIGS BY 16Z AT ATL BEHIND FROPA. UPPER
DISTURBANCE AND FRONT WILL RESULT IN A SCT SHOWERS AROUND THROUGH
THE MORNING HOURS...AND POSSIBLY A FEW THUNDERSTORMS AROUND CSG TO
MCN. LIGHT SOUTH WINDS BECOME SW BY 09Z...THEN NW AFTER 12Z...AND
INCREASING TO AROUND 10KTS THIS AFTERNOON.

//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON ALL ELEMENTS.

39

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          67  84  65  83 /  40  30  20  20
ATLANTA         68  84  66  81 /  60  30  20  10
BLAIRSVILLE     61  79  58  76 /  40  20  10  20
CARTERSVILLE    66  84  63  80 /  60  20  10  10
COLUMBUS        71  88  69  87 /  60  50  20  10
GAINESVILLE     67  83  65  79 /  40  20  20  20
MACON           70  87  66  87 /  60  50  20  20
ROME            65  85  62  82 /  60  20  10  10
PEACHTREE CITY  67  86  64  83 /  60  30  20  10
VIDALIA         72  89  70  89 /  60  60  40  20

&&

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

$$

SHORT TERM...41/39
LONG TERM....BDL
AVIATION...39











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