FXUS62 KFFC 110911
AFDFFC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
411 AM EST SAT FEB 11 2012
...SURGE OF ARCTIC AIR STILL ON TRACK FOR THE AREA THIS WEEKEND...
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL SWEEP THROUGH THE SOUTHEAST U.S.
TODAY...BRINGING ONLY THE SECOND SURGE OF ARCTIC AIR TO THE REGION
THIS WINTER SEASON. THE AIR MASS WILL QUICKLY MODIFY BY MON AS
ARCTIC HIGH PRESSURE SLIDES EAST OF THE REGION...WITH SEASONABLE
TEMPERATURES EXPECTED FOR MOST OF NEXT WEEK. A SERIES OF FAST MOVING
UPPER DISTURBANCES WILL BRING CHANCES OF RAIN TO THE AREA TUESDAY
AND AGAIN THURSDAY. ANOTHER COLD FRONT WILL BRING SEASONABLY COOL
CONDITIONS TO THE REGION BY THE END OF THE WEEK.
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&&
.SHORT TERM /TODAY THROUGH SUNDAY NIGHT/...
ESSENTIALLY ONLY THE SECOND ARCTIC COLD FRONT OF THIS VERY MILD
WINTER REMAINS ON TRACK TO IMPACT THE REGION THIS WEEKEND WITH A
SIGNIFICANT...YET BRIEF SURGE OF ARCTIC AIR. THE HEART OF THIS
ARCTIC AIR MASS WAS EVIDENT IN THE 850MB TEMP FIELDS ACROSS THE
UPPER MID-WEST...WHERE CURRENT 850MB TEMPS ARE NEAR -25C. A STRONG
SHORT WAVE ROTATING AROUND A DEEP POLAR VORTEX ANCHORED ACROSS SE
CANADA WILL PROVIDE LOW/MID-LEVEL NW TRAJECTORIES AND SEND THE HEART
OF THIS ARCTIC AIR INTO THE SE U.S. DURING THE NEXT 24 HOURS. 850MB
TEMPS SHOULD BOTTOM OUT AROUND -15C IN FAR N GA TONIGHT/EARLY
SUN...A GOOD 15C DROP FROM CURRENT 850MB TEMPS. THE ASSOCIATED COLD
FRONT WAS NEAR A BNA-JAN LINE EARLY THIS MORNING...BUT SHOULD
ACCELERATE EASTWARD AND CLEAR THE ENTIRE CWA BY MID-DAY IN
ACCORDANCE WITH THE INTENSIFYING NW FLOW ALOFT. ANTECEDENT PCPN WAS
EXITING THE EASTERN COUNTIES EARLY THIS MORNING AND ADDITIONAL -SHRA
ARE NOT EXPECTED AS THE AIR MASS DRIES SIGNIFICANTLY.
HOWEVER...STRONG CAA AND SIGNIFICANT OROGRAPHIC LIFTING WILL
UNDOUBTEDLY SUPPORT -SHSN ACROSS THE HIGHER ELEVATIONS OF N
GA...ESPECIALLY THE NE GA MOUNTAINS INTO EARLY THIS EVENING...BEFORE
THE AIR MASS SIMPLY BECOMES TOO DRY TO FURTHER SUPPORT SUCH
ACTIVITY. WITH TEMPERATURES FALLING TO NEAR OR BELOW FREEZING BY
AFTERNOON IN THESE AREAS...MINOR ACCUMULATIONS OF SNOW CAN BE
EXPECTED IN THE HIGHER ELEVATIONS. WAS ON THE FENCE BETWEEN AN SPS
AND WSW FOR THE NE GA MOUNTAINS REGARDING SNOW ACCUMULATIONS...BUT
WITH NEIGHBORING OFFICES NOT POSTING ANY SUCH PRODUCTS UP AGAINST US
AND ACCUMULATIONS LESS THAN ONE INCH AND CONFINED TO NORTHWEST
FACING SLOPES AT THE HIGHER ELEVATIONS...HAVE OPTED TO REFRESH SPS
FOR NOW. DAY SHIFT WILL NEED TO CLOSELY MONITOR THIS SITUATION. SOME
ROADS IN THE NE MOUNTAINS AT THE HIGHER ELEVATIONS WILL BE IMPACTED
WITH LIGHT SNOW ACCUMULATIONS DURING THE MORNING AND EARLY AFTERNOON.
OTHERWISE...FOR THE SHORT TERM...MAIN CONCERNS WILL BE WIND AND
COLD. THIS EVENT WILL RIVAL THE JAN 3-5 EVENT...PERHAPS EVEN
SLIGHTLY MORE SIGNIFICANT THAN THAT...BUT DURATION WILL BE SIMILAR.
BY MON...THE ARCTIC HIGH SLIDES EAST OF THE REGION AND TEMPERATURE
MODIFICATION WILL BE QUICK AS ZONAL FLOW ALOFT RAPIDLY RETURNS TO
THE REGION. SUN WILL BE THE COLDEST MORNING OVERALL...BOTH WITH
TEMPS AND WIND CHILLS. MINS 15 TO 20 NORTH AND 20 TO 25 CENTRAL WILL
COMBINE WITH WINDS OF 10-15 MPH TO PRODUCE WIND CHILLS IN THE SINGLE
DIGITS ACROSS THE NORTH...BUT WILL ONLY COME CLOSE TO WIND CHILL
ADVISORY CRITERIA IN ISOLATED SPOTS OF THE NE GA MOUNTAINS. A WIND
ADVISORY HAS ALREADY BEEN POSTED AND THIS LOOKS VERY SOLID...WITH
FORECAST WIND SPEEDS/GUSTS EVEN APPROACHING THE UPPER END OF THE
WIND ADVISORY ENVELOPE.
FOR TEMPS...PLAN TO LEAN TOWARD THE COLDER MAV MOS WHICH USUALLY
DOES BETTER DURING EXTREME TEMPERATURE EVENTS. THE FACT THAT IT DID
CONSIDERABLY BETTER THAN THE MET MOS FRI HAS NO BEARING ON TODAYS OR
TOMORROWS TEMPS...AS YESTERDAYS TEMPS WERE IMPACTED WITH MORE
EXTENSIVE CLOUD COVER AND PCPN THAN EXPECTED.
.LONG TERM /MONDAY THROUGH FRIDAY/...
ARCTIC HIGH PRESSURE WILL QUICKLY SLIDE EAST OF THE AREA MON AS
PROGRESSIVE...ZONAL FLOW RETURNS TO THE REGION ALONG WITH A SERIES
OF EMBEDDED SOUTHERN STREAM SHORT WAVES. THE FIRST SYSTEM COMES
QUICKLY ON THE HEELS OF THE RETREATING ARCTIC AIR MASS AROUSING SOME
CONCERN FOR WINTER PCPN EARLY TUE ACROSS N GA. LATEST MODEL RUNS NOT
SHOWING THE COLD AIR ACROSS NC/NE GA TO BE AS DEEP AS INDICATED
YESTERDAY. HOWEVER...MODEL SOUNDINGS STILL SUPPORT A -SN/-IP MIXTURE
TUE MORNING ACROSS NC/NE GA...ESPECIALLY THE MOUNTAINS...CHANGING TO
ALL RAIN BY MID-DAY. WILL CONTINUE TO DEPICT SOME WINTER PCPN IN
THIS TIME FRAME ACROSS FAR N/NE GA EARLY TUE. OVERALL QPF REMAINS
LIGHT AND THE SYSTEM IS FAST MOVING...SO DO NOT ANTICIPATE ANY
FURTHER PROBLEMS WITH THIS SYSTEM. AFTER A BRIEF BREAK WED...THE
NEXT SYSTEM MOVES INTO THE AREA FROM THE WEST THU. THE LATEST GFS
HAS CHANGED CONSIDERABLY FROM YESTERDAY...NOW SHOWING A MORE
EXPANSIVE POLAR VORTEX ACROSS THE NE U.S. DURING THE LATER HALF OF
THE WEEK...RESULTING IN AN INCREASINGLY SPLIT/CONFLUENT FLOW PATTERN
ACROSS THE EASTERN U.S...WITH THE PARENT UPPER LOW REMAINING BACK IN
THE SW U.S. UNTIL WELL INTO THE WEEKEND. THIS RESULTS IN A MUCH
DRIER FORECAST THROUGH THE LATER PORTIONS OF THE EXTENDED PERIODS
THAN PREVIOUSLY INDICATED. MEANWHILE...THE LATEST ECMWF APPEARS MORE
CONSISTENT WITH PREVIOUS RUNS...STILL FAVORING A SLOWER
MOVING...WETTER SYSTEM FOR THU-FRI...AND RETAINING AT LEAST SOME
THREAT FOR TSRA. HPC ANALYSIS PREFERS THE ECENS GIVEN THE CHAOTIC
NATURE OF THE ADVERTISED SPLIT FLOW PATTERN...THROUGH WHICH SHORT
WAVES WOULD HAVE VASTLY DIFFERING INFLUENCES. FOR THIS REASON...WILL
RETAIN ISOLD TSRA FOR THE WESTERN AND SOUTHERN ZONES THU/THU NIGHT
UNTIL GREATER MODEL CONSISTENCY IS OBTAINED. OTHER THAN TUE WHEN
EVAPORATIVE COOLING FROM PCPN IN THE REMNANT ARCTIC AIR MASS WILL
HOLD TEMPS WELL BELOW NORMAL...ESPECIALLY NORTH...TEMPERATURES WILL
RETURN TO ABOVE SEASONAL LEVELS ONCE THE TUE SYSTEM EXITS THE AREA.
HOWEVER...THE INCREASING TENDENCY TOWARD NW FLOW ALOFT WILL LIKELY
TEMPER THESE READINGS MORE THAN PREVIOUSLY INDICATED. CONFIDENCE IN
THE LATER PORTION OF THE EXTENDED PERIODS...WITH RESPECT TO BOTH
TEMPS AND PCPN...IS LOW DUE TO MODEL VARIABILITY.
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&&
.FIRE WEATHER...
ALTHOUGH WIND CRITERIA WILL BE MET TODAY AND BOTH WIND AND RH
CRITERIA WILL BE MET SUN...FUELS HAVE ACTUALLY MOISTENED DURING THE
LAST 24 HOURS...WITH MOST AREAS WELL ABOVE 10 PERCENT 10-HR FUEL
MOISTURES LATE FRI. CONSEQUENTLY...NO CRITICAL FIRE WEATHER PRODUCTS
WILL BE ISSUED AT THIS TIME. WILL NEED TO MONITOR FUEL DRYING THIS
AFTERNOON WITH STRONG WINDS AND DEWPOINTS DROPPING TO NEAR 0F BY
EVENING...WHICH MAY PROMPT ENOUGH DRYING TO WARRANT A FIRE DANGER
STATEMENT FOR MUCH OF THE CWA SUN AFTERNOON.
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&&
AVIATION...
06Z UPDATE...
SOME MVFR CEILINGS EXPECTED OVERNIGHT AND INTO EARLY MORNING. STRONG
DRYING SHOULD HELP SCATTER CLOUDS OUT TO VFR BY 15Z THIS MORNING.
WINDS WILL INCREASE RAPIDLY WITH VERY STRONG COLD AIR ADVECTION...A
TIGHT PRESSURE GRADIENT...AND 40KT WINDS AT 950 MB. WILL CONTINUE
NORTHWEST WINDS OF 20 TO 22KT WITH GUSTS TO 30 TO 35KT FROM 18Z TO
00Z ALL AREAS. WINDS WILL SLOWLY DIMINISH AFTER SUNSET.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON MVFR CIGS THIS MORNING.
HIGH ON ALL OTHER ELEMENTS.
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&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 44 22 45 23 / 5 0 0 0
ATLANTA 40 19 42 24 / 10 0 0 0
BLAIRSVILLE 34 14 38 19 / 40 10 0 0
CARTERSVILLE 38 18 41 18 / 20 0 0 0
COLUMBUS 46 25 48 25 / 0 0 0 0
GAINESVILLE 39 20 40 24 / 10 0 0 0
MACON 48 23 48 21 / 0 0 0 0
ROME 37 18 40 21 / 20 0 0 0
PEACHTREE CITY 41 20 43 19 / 5 0 0 0
VIDALIA 53 25 49 28 / 0 0 0 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 10 AM THIS MORNING TO 7 PM EST THIS EVENING
FOR THE FOLLOWING ZONES: BALDWIN...BANKS...BARROW...BARTOW...
BIBB...BLECKLEY...BUTTS...CARROLL...CATOOSA...CHATTAHOOCHEE...
CHATTOOGA...CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...
CRAWFORD...CRISP...DADE...DAWSON...DEKALB...DODGE...DOOLY...
DOUGLAS...EMANUEL...FANNIN...FAYETTE...FLOYD...FORSYTH...
GILMER...GLASCOCK...GORDON...GREENE...GWINNETT...HALL...
HANCOCK...HARALSON...HARRIS...HEARD...HENRY...HOUSTON...
JACKSON...JASPER...JEFFERSON...JOHNSON...JONES...LAMAR...
LAURENS...LUMPKIN...MACON...MADISON...MARION...MERIWETHER...
MONROE...MONTGOMERY...MORGAN...MURRAY...MUSCOGEE...NEWTON...
NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PEACH...
PICKENS...PIKE...POLK...PULASKI...PUTNAM...ROCKDALE...SCHLEY...
SOUTH FULTON...SPALDING...STEWART...SUMTER...TALBOT...
TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...TOWNS...TREUTLEN...
TROUP...TWIGGS...UNION...UPSON...WALKER...WALTON...WARREN...
WASHINGTON...WEBSTER...WHEELER...WHITE...WHITFIELD...WILCOX...
WILKES...WILKINSON.
&&
$$
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