FXUS62 KFFC 241518
AFDFFC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
1018 AM EST THU DEC 24 2009
.UPDATE...
PATCHY LIGHT RAIN SPREADING INTO PORTIONS OF WESTERN GEORGIA THIS
MORNING...WITH MOST LOCATIONS SO FAR RECEIVING ONLY A TRACE. EXPECT
PATCHES OF LIGHT RAIN TO CONTINUE THROUGH THE AFTERNOON...WITH
COVERAGE AND INTENSITY PICKING UP LATE DAY INTO THIS EVENING.
CURRENT FORECAST WITH SLIGHT CHC EAST TO LIKELY EXTREME WEST SECTS
STILL LOOK OKAY FOR THE AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 530 AM EST THU DEC 24 2009/
SHORT TERM /TODAY THROUGH SATURDAY/...
MAJOR STORM SYSTEM STILL ON TRACK FOR THE CWA LATER TODAY THROUGH
EARLY FRIDAY. WHILE EARLIER RUNS WERE SHOWING LIMITED INSTABILITY...
NEW MODEL GUIDANCE IN AGREEMENT WITH INCREASING INSTABILITY ACROSS
THE EASTERN PART OF THE CWA...AS FAR NORTH S THE AHN AREA AFTER
MIDNIGHT THURSDAY NIGHT IN RESPONSE TO SURFACE LOW PRESSURE
DEVELOPING ALONG THE FRONT OVER CENTRAL/SOUTHERN GEORGIA TONIGHT. IF
THIS HAPPENS...THE SOUTHERN BOUNDARY OF THE WEDGE WILL LIFT
NORTHWARD OVER EASTERN GEORGIA TONIGHT ALLOWING THE MOIST UNSTABLE
AIR TO SPREAD NORTHWARD. THIS WILL BRING A CHANCE OF THUNDERSTORMS
TO CENTRAL AND EASTERN PARTS OF THE CWA TONIGHT. HELICITIES TOPPING
THE SCALES AND THERE WILL INCLUDE ISOLATED SEVERE FOR CENTRAL AND
EASTERN PARTS OF THE CWA AS FAR NORTH AS MADISON COUNTY. NEXT
PROBLEM WILL BE THE RAINFALL. MODELS IN AGREEMENT WITH 1 TO 1 1/2
INCHES OVER THE CWA. THIS IS BORDER LINE FOR THE POTENTIAL FOR
FLOODING. K-INDEX VALUES INCREASE OVER THE CWA...HOWEVER ISENTROPIC
LIFT NOT AS IMPRESSIVE AS IT COULD BE. WILL HOLD OFF ON ISSUING A
FLOOD WATCH AT THIS TIME...HOWEVER IS THE 12Z RUN OF THE MODELS
INCREASE QPF...A FLOOD WATCH MAY BE NEEDED. LAST ITEM TO ADDRESS ARE
THE WINDS. MAV GUIDANCE INCREASES WINDS AT ATL TO 24KTS BY 03Z
FRI...FTY 22KTS...MCN 17KTS. 925 MB WINDS INCREASING TO 50 TO 60 KTS
OVER THE CWA THIS EVENING. ENOUGH TO ISSUE A WIND ADVISORY FOR THIS
AFTERNOON THROUGH TONIGHT FOR THE ENTIRE CWA.
THE COLD FRONT SWEEPS ACROSS THE CWA TONIGHT...AND BY 12Z FRI THE
LAST OF THE SHOWERS WILL BE EXITING THE EASTERN PART OF THE CWA.
WRAP AROUND MOISTURE WILL RETURN TO EXTREME NORTH GA BRINGING CLOUDY
SKIES...MAYBE A SPRINKLE...ELSEWHERE IT WILL SKIES WILL BE CLEARING
DURING THE DAY FRIDAY. IT WILL REMAIN WINDY WITH H8 WINDS 40 TO 45
KTS AND 925 MB WINDS AROUND 30 KTS. THE WIND ADVISORY MAY NEED TO BE
EXTENDED INTO FRIDAY BUT WILL HOLD OFF ON THAT FOR NOW.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THROUGH AT LEAST TUESDAY THE LARGE H5 LOW OVER THE MIDWEST WILL TAKE
ITS TIME FILLING AND LIFTING NORTHEAST. THIS WILL KEEP THE CWA IN A
DRY NORTHWEST FLOW. BY TUESDAY AN H5 TROUGH MOVES OUT OF THE PACIFIC
AND INTO THE SOUTHERN ROCKIES...THEN INTO THE SOUTHERN PLAINS ON
WEDNESDAY. GFS AND ECMWF DIFFER ON LOCATION AND STRENGTH OF THE
MOISTURE ASSOCIATED WITH THIS FEATURE. GFS WEAKENS THE FIRST WAVE BY
THE TIME IT GETS HERE WITH ANOTHER WAVE DEEPENING OVER THE DESERT
SOUTHWEST. ECMWF STRENGTHENS THE 1ST S/W AND SPREADS MOISTURE OVER
THE CWA ON WEDNESDAY. WILL GO WITH SLIGHT CHANCE POPS WEDNESDAY.
TEMPS WILL REMAIN SEASONAL THROUGH THE LONG TERM.
17
AVIATION...
STRONG EASTERLY SURFACE FLOW WILL CONTINUE THROUGH MOST OF THE
PERIOD...WITH SUSTAINED 15-20KT AND GUSTS 25-30KT...OCCASIONALLY
HIGHER. EXPECT FROPA AND ASSOCIATED WIND SHIFT SOMETIME CHRISTMAS
MORNING...CURRENTLY PROGGED NEAR SUNRISE. SOUTHEASTERLY FLOW JUST
OFF THE SURFACE WILL BRING A MOIST ATLANTIC FETCH TO THE AREA...WITH
LOW MVFR CONDITIONS DEVELOPING NEAR OR JUST AFTER SUNRISE THIS
MORNING. CIGS WILL LOWER TO IFR LATER THIS MORNING...AND SHOULD
HOVER NEAR IFR/MVFR THRESHOLD THROUGH THE BULK OF THE PERIOD. RAIN
DEVELOPING THIS EVENING WILL LEAD TO MVFR VSBY. SOME THUNDER WILL BE
POSSIBLE AT MCN AND CSG...WILL ADD CB TO THE CLOUD GROUP OVERNIGHT.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 52 45 54 33 54 / 30 100 30 5 10
ATLANTA 52 45 52 28 52 / 60 100 10 5 10
BLAIRSVILLE 47 38 45 25 47 / 40 100 20 10 10
CARTERSVILLE 53 43 49 26 50 / 70 100 10 5 10
COLUMBUS 59 46 56 31 55 / 80 100 5 10 10
GAINESVILLE 50 42 49 28 51 / 40 100 20 5 10
MACON 61 53 58 30 57 / 40 100 20 5 10
ROME 56 43 47 28 50 / 80 100 10 10 10
PEACHTREE CITY 53 46 51 28 53 / 60 100 10 5 10
VIDALIA 62 57 65 38 56 / 20 100 50 5 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST FRIDAY 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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