Area Forecast Discussion
Issued by NWS Atlanta, GA

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000
FXUS62 KFFC 010026
AFDFFC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
826 PM EDT TUE SEP 30 2014



.PREV DISCUSSION... /ISSUED 345 PM EDT TUE SEP 30 2014/

SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
LATEST REGIONAL SURFACE ANALYSIS SHOWS LOW PRESSURE CONTINUING TO
MOVE WELL OFF SHORE THE SOUTHEAST ATLANTIC COAST WITH ASSOCIATED
TRAILING FRONT TROUGH FLORIDA. LOW LEVEL MOISTURE EXODUS CONTINUES
TO LAG THE FRONT WITH CONSIDERABLE LOW CLOUDS ALONG AND SOUTH OF A
COLUMBUS TO MACON LINE. WELL DEFINED BOUNDARY IS HELPING SHUNT THIS
MOISTURE SOUTHWARD WITH JUST SCATTERED MID LEVEL CLOUDS IN ITS WAKE
FOR THE REMAINDER OF NORTH AND CENTRAL GEORGIA.

FOR TONIGHT...MODELS SHOW DRYING FOR ALL BUT THE LAST 25MB TO 50MB
OF THE ATMOSPHERE WHICH LEADS ME TO BELIEVE WE MAY HAVE MORE OF A
FOG PROBLEM THAN LOW CLOUDS FOR TONIGHT. LOW LEVEL WIND FLOW
CONFIRMS THIS AND SATURATION PRESSURE DEFICIT FORECASTS INDICATE
TWO DISTINCT AREAS...ONE OVER FAR NORTH GEORGIA AND ANOTHER OVER
CENTRAL GEORGIA. WILL UPDATE HWO TO INCLUDE POSSIBILITY OF SOME
PATCHY DENSE FOG AND ADD SOME MENTION TO GRIDS AS WELL FOR THE
OVERNIGHT PERIOD.

OTHERWISE...LOCALLY DEVELOPING ZONAL FLOW ALOFT COMBINED WITH A
LIGHT SOUTHERLY FLOW AT THE SURFACE WILL LEAD TO CONTINUED DRY
CONDITIONS AND INCREASING TEMPERATURES. EXPECTING A RETURN TO THE
LOWER TO MID 80S BY WED WITH JUST MID 80S ON THU FAVORING A BIAS
CORRECTED BLEND.

BY THE END OF THE SHORT TERM PERIOD WE SHOULD SEE ENOUGH OF A
RETURN OF DEEP LAYER MOISTURE WITH PRECIPITABLE WATER AT 1.50
INCHES TO WARRANT SLIGHT CHANCE POPS FOR THE FAR SW ZONES. OVERALL
COVERAGE WILL BE LOOTED BY THE DEVELOPMENT OF A SUBTLE RIDGE ALOFT
IN ADVANCE OF STRONG SHORTWAVE OVER THE CENTRAL PLAINS.

DEESE

LONG TERM /THURSDAY THROUGH TUESDAY/...
MODELS CONTINUE TO BE IN GOOD AGREEMENT WITH THE COLD FRONT ON
FRIDAY AND VERY LITTLE IN TERMS OF CHANGES TO TIMING AND THINKING.
STILL THE POTENTIAL FOR SOME STRONG STORMS WITH 35KTS OF LOW LEVEL
SHEAR FRIDAY MORNING AND UP TO 2000 J/KG OF MUCAPE BY THE
AFTERNOON. CANNOT RULE OUT A SEVERE STORM WITH THIS SYSTEM.
RAINFALL AMOUNTS APPEAR TO BE 1.5 INCHES OR LESS WITH THE SYSTEM
SO NO FLOODING CONCERNS AT THIS TIME.

SOME UNCERTAINTY IN THE FORECAST MONDAY INTO MONDAY NIGHT. BOTH
GFS AND ECMWF ARE BRINGING PRECIP ASSOCIATED WITH A WAVE INTO
NORTH GEORGIA...HOWEVER TIMING IS DIFFERENT. HAVE KEPT 10 PERCENT
POPS IN...BUT WILL LIKELY NEED TO ADD SLIGHT CHANCE ONCE THERE IS
A BIT MORE AGREEMENT IN TIMING BETWEEN MODELS AND RUNS.

11

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
A COLD FRONT IS EXPECTED TO IMPACT THE CWFA BY THE LATE WEEK.

HIGH PRESSURE BEGINS TO SHIFT OFFSHORE WEDNESDAY NIGHT IN ADVANCE OF
AN APPROACHING COLD FRONT. THE FRONT SHOULD BEGIN TO CROSS THE
MISSISSIPPI RIVER BY VERY EARLY FRIDAY MORNING AND APPROACH THE NW
CORNER OF THE CWFA BY MIDDAY FRIDAY. SCATTERED THUNDERSTORMS ARE
EXPECTED ALONG AND AHEAD OF THE FRONT. SINCE THE MAIN MID LEVEL
FORCING GETS SHUNTED WELL NORTH OF THE CWFA...WILL KEEP OUT THE
MENTION OF SEVERE AT THIS TIME. HOWEVER...SINCE THE FRONT WILL BE
COMING THROUGH THE AREA DURING PEAK HEATING AND THERE WILL BE SOME
GOOD SURFACE INSTABILITY...DO THINK A FEW OF THE STORMS COULD BE
STRONG. THE FRONT SHOULD CLEAR THE CWFA BY EARLY SATURDAY MORNING.

HIGH PRESSURE WILL BUILD FOR THE LATTER HALF OF THE WEEKEND INTO THE
EARLY PART OF NEXT WEEK. ACCOMPANYING THE HIGH PRESSURE WILL BE
COOLER TEMPS AND A DRIER AIRMASS. MODELS HAVE BEEN CONSISTENT IN
PROGGING MIDDLE 50S ACROSS MUCH OF THE CWFA FOR LOWS SUNDAY
NIGHT/MONDAY MORNING.

THE COOLER TEMPS SHOULD NOT LAST TOO LONG. RETURN FLOW OFF OF THE
GULF WILL BRING INCREASING MOISTURE AND TEMPS AHEAD OF THE NEXT COLD
FRONT EXPECTED BY THE MIDDLE OF THE WEEK.

NLISTEMAA


&&

.AVIATION...
00Z UPDATE...
CLEARING SKIES THIS EVENING COMBINED WITH LOW LEVEL MOISTURE AND
CALM TO LIGHT WINDS OVERNIGHT WILL PRODUCE IFR VSBYS ACROSS
SOUTHERN AND EASTERN PORTIONS OF THE AREA BY 10Z. FOG THAT
DEVELOPS SHOULD BURN OFF QUICKLY WITH VFR CONDITIONS EXPECTED BY
MID MORNING. EXPECT GENERALLY SOUTH WINDS THROUGH THE PERIOD.

//ATL CONFIDENCE...00Z UPDATE...
MEDIUM ON VSBYS 10Z-14Z.
HIGH ON ALL OTHER ELEMENTS.

31

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          60  84  63  85 /   5   5   5   5
ATLANTA         65  83  67  84 /   5   5  10  10
BLAIRSVILLE     54  79  56  80 /   5   5   5  10
CARTERSVILLE    58  84  60  85 /   5   5   5  10
COLUMBUS        66  85  67  86 /   5   5  20  30
GAINESVILLE     62  82  64  83 /   5   5   5  10
MACON           62  85  63  86 /   5   5  10  10
ROME            58  85  60  86 /   5   5  10  20
PEACHTREE CITY  60  84  62  85 /   5   5  10  20
VIDALIA         64  84  64  85 /   0   0   5   5

&&

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

$$

SHORT TERM...31
LONG TERM....BDL
AVIATION...31





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