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AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
708 PM EST SUN JAN 25 2015

.SHORT TERM /TODAY THROUGH TUESDAY NIGHT/...

NO SIGNIFICANT CHANGES TO THE COMPLEX SHORT TERM FORECAST. LATEST 
MODEL RUNS CONTINUE TO BE IN GOOD AGREEMENT WITH THE TRACK AND 
TIMING OF STRONG UPPER TROUGH TRACKING ACROSS THE AREA TONIGHT 
THROUGH EARLY MONDAY. THE MAIN CONCERNS WILL BE THE POTENTIAL FOR 
WINTRY PRECIP ACROSS NORTH GEORGIA DUE TO THE COLD CORE AND STRONG 
UPPER LEVEL FORCING. ALTHOUGH PORTIONS OF NORTH GEORGIA ARE 
EXPECTING TO SEE 0.5-1.0 INCH OF SNOW WITH LOCALLY HIGHER AMOUNTS 
/LARGELY IN THE HIGHER ELEVATIONS/ OTHER PORTIONS OF NORTH 
GEORGIA WILL BE TOO WARM TO PROMOTE ANY ACCUMULATIONS.

AT THIS TIME...THE ONSET OF THE PRECIPITATION HAS NOT CHANGED 
SIGNIFICANTLY. STILL ANTICIPATE LIGHT RAIN TO PUSH INTO NW GA THIS 
EVENING...SPREADING EASTWARD ACROSS NORTH GEORGIA. ANTICIPATE THE 
TRANSITION TO A RAIN-SNOW MIX TO OCCUR EARLY MONDAY MORNING. HIGHER 
ELEVATIONS ARE EXPECTED TO SEE THE ADDITIONAL TRANSITION TO ALL SNOW 
MONDAY MORNING. ANY ACCUMULATIONS WILL LIKELY BE IN AREAS ABOVE 1500 
FEET AND GENERALLY 0.5 TO 1 INCH OR LESS. SOME PORTIONS OF THE 
NORTHEAST GEORGIA MOUNTAINS COULD SEE HIGHER AMOUNTS. ALTHOUGH THE 
PRECIP WILL EXIT NW GEORGIA BY MID MORNING MONDAY...RESIDUAL 
MOISTURE REMAINS ACROSS NORTHEAST GEORGIA THROUGH THE DAY...TAPERING 
OFF TO SPRINKLES OR FLURRIES BY MONDAY AFTERNOON. THERE IS A CHANCE 
OF ANOTHER SHOT OF PRECIPITATION INTO TUESDAY MORNING...WHICH IS 
DISCUSSED MORE IN THE LONG TERM DISCUSSION BELOW.

HAVE GONE AHEAD AND ISSUED A WINTER WEATHER ADVISORY FOR THE 
EXPECTED SNOWFALL FOR THE NORTHERN TWO TIERS OF COUNTIES IN THE CWA. 
THE ADVISORY MEANS THAT ACCUMULATIONS WILL BE BELOW WARNING CRITERIA 
/OR BELOW 2 INCHES/ BUT THAT INCONVENIENCES ARE ANTICIPATED. FOR 
NOW...THE METRO ATL AREA IS EXPECTED TO REMAIN IN THE MID TO UPPER 
30S...IF NOT A DEGREE OR TWO WARMER...AND ALTHOUGH A TRANSITION FROM 
RAIN TO A WINTRY MIX EARLY MONDAY MORNING IS EXPECTED /PARTICULARLY 
ACROSS THE NORTHERN AND WESTERN SUBURBS/...NO ACCUMULATIONS ARE 
EXPECTED. 

GRADUAL CLEARING IS EXPECTED THROUGH MONDAY...THOUGH RESIDUAL 
MOISTURE WILL CONTINUE TO IMPACT THE FAR NORTHERN COUNTIES INTO 
TUESDAY. 

AND ON AN ENTIRELY DIFFERENT NOTE...HAVE ADDED SLIGHT CHANCE THUNDER 
TO THE GRIDS THROUGH LATE EVENING TONIGHT FOR PORTIONS OF FAR NORTH 
GEORGIA. MODELS HAVE JUST ENOUGH INSTABILITY /100-200 J/KG/ THAT AN 
ISOLATED THUNDERSTORM CAN NOT BE RULED OUT. EXPECT ANY THUNDERSTORM 
POTENTIAL TO DIMINISH INTO THE OVERNIGHT HOURS AND HAVE NOT 
CONTINUED THE THUNDER MENTION BEYOND 03Z. DO NOT ANTICIPATE ANY 
STRONG OR SEVERE STORMS AT THIS TIME.

31


.LONG TERM /TUESDAY THROUGH SATURDAY/...

MAIN CHANGE FROM THIS TIME YESTERDAY HAS BEEN THE DEVELOPMENT OF A
SECONDARY TROUGH TO MOVE THROUGH...THE RESULT OF A LOBE OF UPPER
LEVEL ENERGY THAT ROTATES INTO NORTH GEORGIA. INDICATIONS ARE THAT
THIS COULD RESULT IN ADDITIONAL SNOW SHOWERS ACROSS FAR NORTH
GEORGIA THAT WOULD NOT BE LIMITED TO JUST THE MOUNTAINS AS
PROFILES ARE MORE THAN COLD ENOUGH TO SUPPORT SNOW. QPF HOWEVER IS
VERY MEAGER WITH THIS SYSTEM AND JUST NOT SEEING ANY ACCUMULATIONS
PAST 12Z TUE. MORE CONCERNING WILL BE RESIDUAL MOISTURE ON ROADS
AND THE QUICK TRANSITION TO BELOW FREEZING TEMPS. ELEVATED WINDS
WILL HELP IN THE DRYING PROCESS BUT CONTINUED LOW CLOUDS WILL
NOT...NOT TO MENTION ANY RESIDUAL PRECIPITATION AS WELL. MAY BE
THAT A TIER OF COUNTIES WILL NEED TO BE ADDED TO CURRENT ADVISORY
EVENTUALLY FOR BLACK ICE POTENTIAL AND THAT OVERALL ADVISORY IS
EXTENDED IN TIME THROUGH TUESDAY MORNING.

OTHERWISE...LIMITED CHANGES TO THE EXTENDED WITH CONTINUED
ADVERTISEMENT OF LIGHT RAIN/SNOW OVER THE NORTHERN TIER ONCE AGAIN
ON THU NIGHT.

DEESE


&&

.PREV DISCUSSION... /ISSUED 139 PM EST SUN JAN 25 2015/ 

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... 

OTHERWISE ACTIVE PATTERN CONTINUES THROUGH REST OF LONG TERM WITH 
SEVERAL OTHER SHORTWAVE DISTURBANCES TRAVERSING ALONG THE STUBBORN 
BROAD UPPER TROUGH THAT JUST CANNOT SEEM TO SHAKE THE EAST CONUS. 
HOWEVER...LARGE DISCREPANCIES EXIST IN THE MODELS WITH TIMING AND 
AMPLITUDE OF DISTURBANCES. THE NEXT BEST CHANCE OF PRECIP FOR NOW 
LOOKS TO BE THURSDAY INTO THURSDAY NIGHT...THEN AGAIN LATE SATURDAY. 
THE THURSDAY SYSTEM LOOKS TO BE A BIT BETTER ORGANIZED AND MORE OF A 
CLIPPER SYSTEM /ECMWF MUCH MORE BULLISH AND LESS PROGRESSIVE THAN 
THE GFS/...WHILE THE SATURDAY NIGHT IMPULSE HAS MUCH LESS AMPLITUDE 
AND MORE OF A TRAILING COLD FRONT INTO THE NORTH. COLUMN TEMPS BOTH 
PERIODS SUPPORT POSSIBLE SNOW MIXING INTO THE FAR NORTH SO HAVE 
INCLUDED LOW CHANCE MENTION AT THE MOMENT. CONFIDENCE IS VERY LOW AT 
THE MOMENT AND FUTURE CHANGES ARE LIKELY DUE TO THE AFOREMENTIONED 
DIFFERENCES SEEN IN THE SOLUTIONS. PLEASE CONTINUE TO CLOSELY 
MONITOR THE FORECAST.

BAKER

AVIATION...
00Z UPDATE...
VFR CONDITIONS THROUGH THIS EVENING WILL BECOME MVFR AND POSSIBLY
IFR OVERNIGHT...GENERALLY 05-07Z. BANDS OF RAIN DEVELOPING AND SHOULD
MOVE ACROSS THE TAF SITES THIS EVENING AND OVERNIGHT. IN THE NORTHERN 
TAF SITES...MIXED WINTRY PRECIP POSSIBLE MAINLY AFTER 06Z. NO
ACCUMULATIONS ARE EXPECTED AS THE LOWEST 2-3KFT OF THE ATMOSPHERE
WILL BE ABOVE FREEZING. EXPECT IMPROVEMENT TO MVFR BY 17-18Z. AN 
ISOLATED THUNDERSTORM IS POSSIBLE MAINLY NORTHWEST TAF SITES THIS EVENING.
WEST TO SOUTHWEST WINDS 5-8KT OVERNIGHT. NW WINDS AT 12-15KT
WITH GUSTS TO 20-25KT EXPECTED BY MID MORNING MONDAY.

//ATL CONFIDENCE...00Z UPDATE...
MEDIUM CONFIDENCE ON MVFR CEILINGS AND MIXED PRECIPITATION. MEDIUM TO HIGH
ON REMAINING ELEMENTS.


41

&&

.PRELIMINARY POINT TEMPS/POPS...
ATHENS          57  38  51  32 /  10  20  20   5 
ATLANTA         56  40  47  33 /  10  30  20   5 
BLAIRSVILLE     51  36  41  27 /  30  60  40  20 
CARTERSVILLE    57  37  45  30 /  30  50  20   5 
COLUMBUS        60  41  51  34 /   5  10  10   0 
GAINESVILLE     53  38  46  31 /  20  40  40  10 
MACON           60  40  53  32 /   5  10  10   0 
ROME            56  37  44  29 /  40  50  20   5 
PEACHTREE CITY  58  37  48  29 /   5  30  10   0 
VIDALIA         61  42  55  36 /   5  10  10   0 

&&

.FFC WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST MONDAY FOR THE 
FOLLOWING ZONES: CATOOSA...CHATTOOGA...DADE...DAWSON...FANNIN...
GILMER...GORDON...LUMPKIN...MURRAY...PICKENS...TOWNS...UNION...
WALKER...WHITE...WHITFIELD.

&&

$$

SHORT TERM...41
LONG TERM....DEESE
AVIATION...41

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