534
FXUS62 KFFC 210002
AFDFFC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
702 PM EST MON JAN 20 2025
..NEW 00Z AVIATION DISCUSSION
SHORT TERM
(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 247 PM EST MON JAN 20 2025
KEY MESSAGES:
- WINTER STORM WARNING ISSUED FOR AREAS GENERALLY BETWEEN MACON-COLUMBUS
SOUTH. WINTER WEATHER ADVISORY TO THE NORTH ABOUT TO THE I85
CORRIDOR.
- LIGHT SNOW FLURRIES COULD BEGIN ACROSS CENTRAL AND PARTS OF NORTH
GA AS EARLY AS 9AM ON TUESDAY.
- TEMPERATURES IN THE UPPER TEENS WITH MODERATE WINDS MAY LEAD TO
WINDCHILLS BETWEEN 5 AND 15 DEGREES. A COLD WEATHER ADVISORY
HAS BEEN ISSUED FOR THE ENTIRE WFO.
TO KEEP THINGS AT A REASONABLE LENGTH, PLEASE REFER TO THE PREVIOUS
AFD FOR A GOOD ANALYSIS OF THE INCOMING WINTER WEATHER POTENTIAL.
THIS AFD WILL COVER CHANGES/UPDATES AS WELL AS CONCERNS WITH MODEL
OUTPUT GOING INTO THE NEXT 24-48 HOURS. WITH THAT, LETS BEGIN BY
ADDRESSING THE LIMITING FACTORS WITH THIS SYSTEM.
THE MAIN POINT OF CONCERN CAN BE CONDENSED (*DUM DUM TSSS*) DOWN TO
THE "WHERE" AND "HOW MUCH" OF MOISTURE. MOST MODELS ARE IN AGREEMENT
THAT OVER-RIDING MOISTURE WILL BE PLENTIFUL ABOVE 700MB.
SIGNIFICANTLY GREATER UNCERTAINTY EXISTS AT THE 900-800MB LEVEL.
MODELS HAVE ACTUALLY TRENDED AT A WEAKENING OF THE DRY LAYER AT
THESE LOWER LEVELS (AT LEAST IN RECENT RUNS). THE 12Z HREF SOUNDING
BETWEEN COLUMBUS-MACON AND ATL BEING A GREAT EXAMPLE OF THIS (SEE
SUNDAY 12Z SOUNDING AT 1PM TUESDAY AND CURRENT 1PM TUESDAY
SOUNDING). THE CONTROLLING FACTOR THERE IS THE STRENGTH OF
SHORT/LONG LIVED SOUTHWESTERLY FLOW. THE LENGTH OF TIME OVER WHICH
SW FLOW OCCURS WILL BE INVERSELY PROPORTIONAL TO THE AMOUNT OF
SUBLIMATION. WITH ALL THAT SAID, THERE REMAINS THE POTENTIAL THAT
HIRES GUIDANCE IS UNDER-REPRESENTING THE POTENTIAL FOR SNOWFALL AS
FAR NORTH AS THE I20/I85 CORRIDOR. ONE WONDERS IF THE ~1000FT LESS
FOR THE PRECIP TO FALL TO THE SURFACE MAY PLAY ASSIST SNOWFALL TO
THE SURFACE.
GIVEN THIS INFORMATION, SNOWFALL AMOUNTS HAVE REMAINED RELATIVELY
UNCHANGED IF INCREASED ACROSS THE SOUTHERN COUNTIES (SEE WINTER
STORM WARNING). THIS COMES WITH A MAJOR ASTRIX. SHOULD MID LEVEL
MOISTURE UNDERPERFORM AREAS IN THE ADVISORY MAY VERY WELL SEE LITTLE
TO NO SNOW (YAY, LESS IMPACTS!). CONVERSELY, SHOULD MOISTURE PERFORM
AS DISCUSSED ABOVE, SNOWFALL MAY VERY WELL LIKELY OVERPERFORM
CURRENT FORECAST SNOW TOTALS (YAY, SNOW DAY!). EITHER WAY, IT'S
GOING TO BE COLD, AS HIGHS WILL LIKELY STRUGGLE TO GET OUT OF THE
30S. THOUGH THIS IS ALSO HIGHLY DEPENDENT ON SNOWFALL START TIME AND
WHEN SFC TEMPS REACH THE WETBULB (DRY CONDITIONS MEAN TW IS WELL
BELOW FREEZING). LOWS TONIGHT AND WEDNESDAY NIGHT WILL BE FRIGID,
WITH LOWS OF 10 TO 20 DEGREES AND WIND CHILLS AS LOW AS THE SINGLE
DIGITS.
SM
LONG TERM
(WEDNESDAY MORNING THROUGH NEXT SUNDAY)
ISSUED AT 247 PM EST MON JAN 20 2025
LONG TERM FORECAST BEGINS AFTER THE SNOWFALL HAS MOVED OUT OF THE
AREA AND ZONAL FLOW SETS IN OVER THE AREA INTO THURSDAY. OUR MAIN
THREAT AT THIS TIME WILL BE TEMPERATURES STILL BELOW FREEZING OVER
LARGE PORTIONS OF THE AREA UNTIL THURSDAY AFTERNOON. THIS WILL BE
GOING ON 80-95 HOURS FOR MANY AREAS OF BELOW FREEZING CONDITIONS
WHICH IS LIKELY TO SEE SOME IMPACTS TO PIPES NOT PROPERLY
INSULATED. A BROAD TROUGH IS EXPECTED TO SWING THROUGH THE
CENTRAL US INTO THE EASTERN CONUS BY FRIDAY AFTERNOON BUT MOISTURE
DOES NOT LOOK TO REACH THE GROUND BELOW 850 MB AT THIS TIME WITH
THE EPS AND GEFS IN ALIGNMENT. WITH THIS TEMPS SHOULD BEGIN TO
INCREASE SLOWLY THROUGH THE EXTENDED WITH TEMPS UP TO UPPER 40S TO
MID 50S BY SUNDAY.
LOOKING TOWARDS SUNDAY WE BEGIN TO SEE MOISTURE FILTER INTO THE
AREA ALTHOUGH THERE REMAINS INCONSISTENCIES ON TIMING/AMOUNTS.
THIS IS TO BE EXPECTED THOUGH AT DAY 7/8. HAVE KEPT IN SLIGHT
CHANCE TO CHANCE POPS OVER THE AREA FOR NOW.
HERNANDEZ
AVIATION
(00Z TAFS)
ISSUED AT 652 PM EST MON JAN 20 2025
NO SIGNIFICANT CHANGES TO THE OVERALL FORECAST IN THIS PACKAGE.
THE TIMING OF SNOW FLURRIES LOOKS TO BE MID TO LATE MORNING IN
MOST LOCATIONS, WITH LIGHT SNOW BY AROUND MIDDAY LASTING INTO
EARLY TUE EVENING, WITH LINGERING FLURRIES THROUGH MIDNIGHT. WINDS
WILL GENERALLY BE OUT OF THE NW THROUGH THE PERIOD, ALTHOUGH CSG
AND MCN WILL BE MORE NORTHERLY. FORECAST CIGS AND VSBYS MAY NEED
TO BE LOWERED- PARTICULARLY AT CSG AND MCN- SHOULD SNOWFALL BE
HEAVIER THAN CURRENTLY EXPECTED. THE LATEST STORM TOTAL SNOW
ACCUMULATION AT ATL IS FORECAST TO BE AROUND 1/2 INCH.
//ATL CONFIDENCE...00Z UPDATE...
LOW TO MEDIUM FOR SN INTENSITY AND START TIME, MEDIUM FOR CIGS AND
VSBYS IN SNOW, HIGH FOR OTHER ELEMENTS.
SEC
PRELIMINARY POINT TEMPS/POPS
ATHENS 21 36 17 37 / 0 30 20 0
ATLANTA 21 33 16 37 / 0 30 20 0
BLAIRSVILLE 11 30 5 35 / 0 10 10 0
CARTERSVILLE 15 33 10 38 / 0 20 10 0
COLUMBUS 22 38 17 41 / 0 60 30 0
GAINESVILLE 21 35 15 36 / 0 20 20 0
MACON 22 39 19 40 / 0 60 50 0
ROME 15 33 11 38 / 0 10 10 0
PEACHTREE CITY 19 35 14 39 / 0 30 20 0
VIDALIA 28 44 26 40 / 0 50 80 0
FFC WATCHES/WARNINGS/ADVISORIES
COLD WEATHER ADVISORY FROM 10 PM THIS EVENING TO 9 AM EST
TUESDAY FOR GAZ001>009-011>016-019>025-027-030>039-041>062-
066>076-078>086-089>098-102>113.
COLD WEATHER ADVISORY FROM 10 PM TUESDAY TO 9 AM EST WEDNESDAY
FOR GAZ001>009-011>016-019>025-027-030>039-041>062-066>076-
078>086-089>098-102>113.
WINTER WEATHER ADVISORY FROM 10 AM TUESDAY TO 7 AM EST WEDNESDAY
FOR GAZ022>025-027-031>039-041>062-066>068-070-075.
WINTER STORM WARNING FROM 10 AM TUESDAY TO 7 AM EST WEDNESDAY
FOR GAZ069-071>074-076-078>086-089>098-102>113.
SHORT TERM...SM
LONG TERM....HERNANDEZ
AVIATION...SEC
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