FXUS62 KFFC 221801
AFDFFC
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
100 PM EST WED FEB 22 2012
.UPDATE...
STARTING TO SEE VSBYS IMPROVE AND CIGS IMPROVE BUT LOW CLOUDS AND
FOG HAVE HELD ON MUCH LONGER THAN EXPECTED THIS MORNING.
CONDITIONS SHOULD CONTINUE TO IMPROVE BUT ONLY EXPECT PARTLY
SUNNY TO MOSTLY CLOUDY SKIES TODAY...EXCEPT FOR THE SOUTHEAST
PORTION OF THE CWA THAT IS CURRENTLY CLEAR.
MODELS ARE CONSISTENT WITH HOLDING OFF ON THE BEST PRECIP UNTIL
TONIGHT WITH THE BEST CHANCES OF RAIN BETWEEN 00 AND 06Z AND THE
BEST LOCATION BEING ACROSS THE NORTH. THE MAIN CHALLENGE WITH THE
SCENARIO TONIGHT IS THAT THE BEST INSTABILITY AND SHEAR IS SOUTH
OF THE AREA OF BEST POPS. NAM IS SLIGHTLY MORE AGGRESSIVE WITH
INSTABILITY/SHEAR THAN THE GFS WITH MUCAPE VALUES AROUND 1000 J/KG
AND 0-1KM SHEAR AROUND 35KTS. SO ALTHOUGH THE PARAMETERS ARE THERE
FOR SEVERE WEATHER THE CHALLENGE WILL BE TO GET THIS CO-LOCATED
WITH THE BEST MOISTURE. WILL CONTINUE TO MENTION CHANCE OF THUNDER
IN THE ZONES AND ISOLATED SEVERE POSSIBLE IN THE HAZARDOUS WEATHER
OUTLOOK.
&&
.PREV DISCUSSION...
SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...
/ISSUED 358 AM EST WED FEB 22 2012/
MAIN CONCERN IN THE SHORT TERM IS THE POTENTIAL FOR ISOLATED STRONG
TO SEVERE STORMS THIS AFTERNOON AND EVENING...MAINLY ACROSS NORTH
GEORGIA WHERE SPC HAS POSTED A SLIGHT RISK AREA. THIS COURTESY OF
A SERIES OF UPPER DISTURBANCES THAT WILL INTERACT WITH INCREASING
LOW LEVEL MOISTURE (55-60 DEWPOINTS) AND MODERATE INSTABILITIES (500+
MUCAPE AND -2 LI'S) TO AID THE DEVELOPMENT OF ISOLATED TO SCATTERED
SURFACE BASED THUNDERSTORMS. THIS COUPLED WITH STRONG VEERING WIND
PROFILES PRODUCING 200+ STORM RELATIVE HELICITY AND 35KT BULK SHEAR
ALONG WITH EXPECTED FAST MOVING STORMS ALL SUGGEST THE POTENTIAL
FOR ISOLATED DISCRETE SUPERCELLS... WITH DAMAGING WIND... LARGE
HAIL AND EVEN A FEW TORNADOES POSSIBLE IN THE SLIGHT RISK AREA.
THIS THREAT SEEMS TO BE GREATEST BETWEEN 3 PM AND 10 PM TODAY...
AND GENERALLY ALONG AND NORTH OF A LA GRANGE TO MONTICELLO TO WASHINGTON
LINE. ANY SEVERE THREAT SHOULD GREATLY DIMINISH BY MIDNIGHT AS THE
UPPER SHORT WAVE ENERGY PUSHES EAST... ALTHO EXPECT SHOWER ACTIVITY
TO LINGER THROUGH EARLY THURSDAY MORNING. AT THIS TIME... EXPECTING
A BREAK FROM ANY CONVECTIVE ACTIVITY ON THURSDAY. THEN NAM AND GFS
SHOW A COLD FRONT PUSHING INTO NW GEORGIA THURSDAY NIGHT... WITH
SUFFICIENT FORCING AND INSTABILITY TO SUPPORT AT LEAST ISOLATED
THUNDERSTORMS ACROSS NORTH GEORGIA THURSDAY NIGHT. A NOTED 50KT
LOW LEVEL JET AND 55-60+ DEWPOINTS COUPLED WITH 200+ CAPE SUGGEST
A FEW OF THESE STORMS COULD BE STRONG...BUT SUSPECT ANY SEVERE
THREAT WILL HOLD OFF UNTIL FRIDAY. HOWEVER...WE WILL HAVE TO MONITOR
THE POTENTIAL FOR STRONG TO SEVERE STORMS CLOSELY THURSDAY NIGHT
AHEAD OF THE FRONT. OTHERWISE...MOS GUIDANCE TEMPS WERE CLOSE SO
ELECTED TO TAKE MAINLY A BLEND THROUGH THE SHORT TERM.
LONG TERM /FRIDAY THROUGH TUESDAY/...
/ISSUED 358 AM EST WED FEB 22 2012/
MODELS CONTINUE TO HAVE DIFFICULTY AGREEING ON TIMING AND STRENGTH
OF A SERIES OF FAST MOVING DISTURBANCES EMBEDDED WITHIN THE UPPER
FLOW... RESULTING IN LITTLE CONSISTENCY FROM RUN TO RUN. NAM AND
GFS SHOW A COLD FRONTAL PASSAGE EARLY ON FRIDAY WHILE ECMWF IS
MUCH SLOWER...HOLDING OFF UNTIL FRIDAY EVENING. HAVE LEANED TOWARD
THE FASTER NAM AND GFS SOLUTIONS WITH THIS SYSTEM FOR NOW...WITH
CLEARING EXPECTED FRIDAY NIGHT UNDER STRONG HIGH PRESSURE
INFLUENCE. SHOULD BE BREEZY AND COOL FRIDAY NIGHT BEHIND THE COLD
FRONT. STILL HOLDING ONTO A DRY FORECAST OVER THE WEEKEND... ALTHO
BOTH GFS AND ECMWF ARE SHOWING STRONG ISENTROPIC LIFT SPREADING
RAIN SHOWERS INTO THE STATE BY EARLY MONDAY MORNING. THE GFS IS
MUCH FASTER AND CLEANER WITH THE NEXT COLD FRONT SWEEPING THROUGH
MONDAY NIGHT WHILE THE ECMWF HOLDS OFF UNTIL TUESDAY. WITH MUCH
UNCERTAINTY... WILL TAKE A COMPROMISING APPROACH AND SHOW A CHANCE
TO SLIGHT CHANCE POP FROM SUNDAY NIGHT THROUGH TUESDAY... BUT ALL
SHOWERS WITH NO THUNDER MENTIONED FOR NOW.
39
AVIATION...
18Z UPDATE...
PERSISTENT IFR CONDITIONS THIS MORNING HAVE FINALLY INCREASED TO
MVFR IN MOST LOCATIONS. THE SLOW IMPROVEMENT WAS DUE TO HIGH LEVEL
CLOUDS INHIBITING THE DIURNAL HEATING UNTIL NOW. EXPECTING VFR
CONDITIONS THE REMAINDER OF THE AFTERNOON AND EARLY EVENING WITH A
PREVAILING SOUTHWEST FLOW. A FEW SPRINKLES OR LIGHT SHOWERS WILL BE
POSSIBLE THIS EVENING ASSOCIATED WITH THE PASSING OF A WEAK
DISTURBANCE. OTHERWISE...GULF MOISTURE WILL CONTINUE TO AFFECT INTO
GA TONIGHT RESULTING IN LIFR TO IFR CIGS AND VSBYS RETURNING
AFTER 06Z THROUGH 15Z ON THURSDAY. WARM ADVECTION AND DIURNAL HEATING
ON THURSDAY WILL PRODUCE VFR CONDITIONS BY MIDDAY WHICH WILL
CONTINUE THROUGH THE AFTERNOON.
//ATL CONFIDENCE...18Z UPDATE...
HIGH ON WIND SPEED AND DIRECTION.
MEDIUM ON ALL OTHER ELEMENTS.
16
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 69 52 76 57 / 20 30 10 60
ATLANTA 69 56 74 56 / 20 30 10 70
BLAIRSVILLE 60 47 67 49 / 40 40 10 70
CARTERSVILLE 69 51 74 53 / 30 30 10 70
COLUMBUS 71 56 78 61 / 20 20 10 60
GAINESVILLE 65 51 71 55 / 20 30 10 70
MACON 72 55 78 62 / 10 20 10 50
ROME 69 51 75 55 / 30 40 10 70
PEACHTREE CITY 70 51 74 56 / 20 30 10 70
VIDALIA 73 56 81 64 / 10 20 10 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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