FXUS62 KFFC 080110 AAB
AFDFFC
AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
810 PM EST MON DEC 7 2009
.UPDATE...
NOT MUCH TO UPDATE. CLOUDS WILL BE INCREASING OVER AREAS WHERE NOT
MUCH CLOUD COVER IS CURRENTLY. CHANCE OF SPRINKLES OVER THE FAR NW
BEFORE MIDNIGHT. LOW TEMPERATURES DIFFICULT DUE TO CLOUD COVER AND
LACK OFF IT FOR SOME LOCATIONS. BDL
&&
.PREVIOUS DISCUSSION...
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
HIGH CLOUDS ALREADY IN PLACE AHEAD OF THE NEXT SYSTEM WHICH IS
GEARING UP IN THE LEE OF THE ROCKIES. AS LEE CYCLOGENESIS
CONTINUES...SHORTWAVE MOVING OFF THE NORTHERN MEXICO COAST WILL
SPAWN A GULF LOW OFF THE TEXAS COAST...SPREADING ADDITIONAL
MOISTURE ACROSS THE SOUTHEAST. MEANWHILE...SURFACE HIGH MOVING
EAST ACROSS SOUTHERN CANADA WILL BEGIN TO RIDGE DOWN THE EASTERN
SLOPES OF THE APPALACHIANS IN A DIABATICALLY ENHANCED DAMMING
SCENARIO. WARM/WEDGE FRONT WILL LIFT NORTH ACROSS THE AREA ON
TUESDAY...WITH WIDESPREAD OVERRUNNING PRECIP FORCED BY STRONG
ISENTROPIC LIFT. STRONG SURFACE LOW WILL BEGIN TO OCCLUDE OVER THE
MIDDLE MISSISSIPPI VALLEY...WITH COLD FRONT EXTENDING INTO THE
SOUTHEAST BY TUESDAY NIGHT.
FIRST CONCERN IS THE RAINFALL. EXPECT WIDESPREAD 1-2" ACROSS NORTH
GEORGIA...WITH SOME AREAS IN THE MOUNTAINS PUSHING 2.5". AT THIS
POINT...DO NOT FEEL THAT A FLOOD WATCH IS NECESSARY...AS WE WOULD
PROBABLY NEED WIDESPREAD 2+" TO PUSH MOST AREA CREEKS AND RIVERS
BACK INTO FLOOD. A COUPLE WILL LIKELY FLOOD...BUT MINOR FLOOD
STAGE AT BEST. WILL HAVE TO REEVALUATE THE RAINFALL AS LATER
MODELS COME IN.
OTHER CONCERN IS SEVERE WEATHER THREAT TUESDAY NIGHT. STRONG LOW
LEVEL SHEAR ASSOCIATED WITH THE CAD AND DEEP LAYER SHEAR
ASSOCIATED WITH THE VERY DYNAMIC SYSTEM IS THE MAIN ISSUE.
INSTABILITY IS LACKING OVERALL WITH SREF MLCAPE RANGING FROM
100-200 J/KG AND INDIVIDUAL MODEL CAPES ANYWHERE FROM 200-600
J/KG. HOWEVER...WITH COOL SEASON EVENTS...300-500 J/KG CAPE IS
REALLY ALL WE NEED GIVEN SUFFICIENT SHEAR. CURRENT DAY2 OUTLOOK
DOES NOT INCLUDE GEORGIA IN THE SLIGHT RISK. WITH STORMS ELEVATED
AT FIRST...SURGE OF TROPICAL MOISTURE INTO THE AREA TUESDAY NIGHT
MAY HELP TO MAKE STORMS SURFACE-BASED. HAVE NOT INCLUDED ANY
SEVERE WORDING IN THE GRIDS YET...BUT WE'LL PROBABLY GET
SOMETHING...AND WITH THE ENVIRONMENTAL SHEAR WOULD NOT BE
SURPRISED TO SEE A TORNADO OR TWO.
ONE LAST CONCERN IS THE POTENTIAL FOR STRONG WINDS...AT LEAST
ADVISORY CRITERIA...IN THE MOUNTAINS TUESDAY NIGHT INTO WEDNESDAY.
SOME HINTS THAT IT MIGHT BE EVEN WINDIER...AND ADVISORY MAY BE
NEEDED IN MORE AREAS THAN JUST THE MOUNTAINS. VERY STRONG GRADIENT
ALONG AND BEHIND THE FRONT SUPPORTS THIS...BUT IT IS TOO FAR OUT
TO ISSUE ANYTHING AT THIS POINT.
WITH THE MOISTURE SURGE...TEMPERATURES WILL INCREASE ON WEDNESDAY
INTO THE 60S AND 70S BEFORE THE COOLER AIR PUSHES IN WEDNESDAY
NIGHT. NAM CONTINUES TO BE SLOWER WITH THE PROGRESSION OF THE
SYSTEM SO IT HAS COOLER TEMPERATURES TONIGHT AND BRINGS TEMPS UP
EVEN HIGHER ON WEDNESDAY. TOOK A BLEND BUT LEANED TOWARD THE MAV.
.LONG TERM /THURSDAY THROUGH MONDAY/...
THURSDAY SHOULD BE A NICE DAY WITH HIGH PRESSURE BUILDING IN FROM
THE WEST. NEXT SYSTEM MOVES IN FRIDAY NIGHT INTO SATURDAY
ASSOCIATED WITH ANOTHER ROUND OF GULF MOISTURE. HYBRID CAD
BUILDING IN FRIDAY NIGHT MAY POSSIBLY LEAD TO COOL ENOUGH
TEMPERATURES FOR SOME SNOW UP NORTH...BUT HAVE NOT INCLUDED ANY AT
THIS TIME. EXPECT COOL HIGHS ON SATURDAY WITH STRONG DAMMING PLUS
WIDESPREAD MOISTURE. HIGH PRESSURE BACK IN SUNDAY INTO MONDAY AND
THE POSSIBILITY OF ANOTHER ROUND OF RAIN EARLY NEXT WEEK.
DISAGREEMENT BETWEEN THE ECMWF AND NAM CONTINUES...SO HAVE MADE NO
CHANGES TO THE EXTENDED AT THIS TIME.
TDP
&&
.AVIATION...
MOIST EASTERLY FLOW AT THE SURFACE IS EXPECTED TO CONTINUE THROUGH
TONIGHT AS SURFACE HIGH DRIFTS INTO MID-ATLANTIC REGION. WINDS ABOVE
THE BOUNDARY LAYER WILL STRENGTHEN AND BECOME MORE SOUTHERLY
OVERNIGHT...USHERING DEEPER GULF MOISTURE INTO THE REGION.
THEREFORE...WHILE GUIDANCE INDICATES THAT CIGS AT MOST TAF SITES MAY
REMAIN VFR OR MVFR OVERNIGHT...CIGS AT MOST SITES SHOULD DECREASE
INTO IFR RANGE BY TUESDAY MORNING...POSSIBLY SOONER AT CSG AND MCN
WHERE BETTER MOISTURE MAY MOVE IN MORE QUICKLY. EXPECT POSSIBILITY
OF DZ BY TUESDAY MORNING...WITH RA DEVELOPING BY 18Z AS SFC LOW
DEEPENS RAPIDLY ACROSS THE SOUTHERN PLAINS. SFC WINDS EXPECTED TO
BECOME SOUTHERLY LATE TUESDAY AS WARM FRONT MOVES NORTHWARD.
MSR
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 38 49 45 66 37 / 10 100 100 40 10
ATLANTA 41 51 49 64 34 / 10 100 100 40 10
BLAIRSVILLE 36 44 43 57 27 / 20 100 100 40 10
CARTERSVILLE 39 52 49 63 31 / 20 100 100 30 10
COLUMBUS 44 57 55 71 40 / 5 90 90 40 10
GAINESVILLE 39 47 43 62 35 / 10 100 100 40 10
MACON 42 58 57 73 40 / 5 80 90 50 10
ROME 38 51 48 62 32 / 20 100 100 30 10
PEACHTREE CITY 39 55 54 67 33 / 10 100 100 40 10
VIDALIA 43 62 59 74 46 / 10 60 60 60 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
TDP/MSR
