FXUS62 KFFC 071309
AFDFFC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PEACHTREE CITY GA
809 AM EST MON DEC 7 2009
.UPDATE...
QUICK UPDATE TO SHOW RAIN/SLEET MIX ACROSS NW GA THROUGH 10AM THIS
MORNING BASED ON SFC REPORTS. SFC AND H8-H7 WARM LAYER TEMPS
SHOULD RISE SUFFICIENTLY TO CHANGE PRECIP TYPE TO ALL RAIN
PARTICULARLY AS INITIAL EVAPORATIONAL COOLING OF FIRST
HYDROMETEORS ENDS AND PRECIP RATES SLOWLY INCREASE. SOME TWEAKS TO
TEMP AND DEWPOINT GRIDS BASED ON OBSERVED CONDITIONS WHICH ARE
SLIGHTLY WARMER THAN FCST. NO IMPACT EXPECTED ON ROADWAYS.
SNELSON
&&
.PREV DISCUSSION... /ISSUED 514 AM EST MON DEC 7 2009/
SHORT TERM /TODAY THROUGH WEDNESDAY/...
HIGH PRESSURE EXTENDING FROM THE MID-ATLANTIC COAST SOUTHWESTWARD
THROUGH THE CAROLINAS AND GEORGIA IS WEAKENING THIS MORNING...AS A
WEAK UPPER LEVEL DISTURBANCE APPROACHED FROM THE LOWER MISSISSIPPI
VALLEY. A REINFORCING HIGH WILL BUILD BACK IN EAST OF THE
APPALACHIANS LATE TODAY AND TONIGHT...LIMITING THE EASTWARD
ADVANCE OF PRECIP INTO OUR AREA. KEPT SLIGHT CHANCE POPS THROUGH
SUNRISE TUESDAY ACROSS NORTHWEST AND FAR NORTH GA. STRONG
ISENTROPIC ASCENT DEVELOPS ACROSS MUCH OF THE SOUTHEASTERN STATES IN
RESPONSE TO STRENGTHENING LLJ ON TUESDAY...AS A POWERFUL LOW
PRESSURE SYSTEM DEVELOPS AND LIFTS NORTHEASTWARD FROM OKLAHOMA TO
MICHIGAN BY WEDNESDAY. MODELS SHOWING WEDGE/WARM FRONT LIFTING
NORTHWARD ACROSS THE LOCAL AREA BY LATE TUESDAY...WITH MODELS
SHOWING SOMEWHAT MODEST INSTABILITY ARRIVING BY EVENING WITH ~500
J/KG OF CAPE. STRONG DEEP LAYER AND LOW LEVEL WIND SHEAR STILL
LOOK MOST IMPRESSIVE...ESPECIALLY OVER THE NORTHERN HALF OF
GEORGIA. THUS...IN ADDITION TO MORE WIDESPREAD HEAVY RAIN
THREAT...A FEW TORNADOES/DAMAGING WIND SEVERE THREAT MAY BE
REALIZED TUESDAY NIGHT. THUNDER POTENTIAL CONTINUES INTO WEDNESDAY
MORNING OVER EAST CENTRAL GA BEFORE THE COLD FRONT PUSHES THROUGH.
WEST WINDS SHOULD BE QUITE GUSTY BEHIND THE FRONT ON WEDNESDAY.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE BUILDS IN FROM THE WEST WEDNESDAY NIGHT AND
THURSDAY...PASSING OVERHEAD ON FRIDAY. BY SATURDAY THIS HIGH WILL
BE POSITIONED OVER THE MID-ATLANTIC SETTING UP ANOTHER WEDGE
SCENARIO FOR SATURDAY WITH THE NEXT APPROACHING LOW PRESSURE
SYSTEM...THIS TIME TAKING A MORE SOUTHERN...GULF COAST TRACK. GFS
AND ECMWF DIFFER QUITE A BIT...ESPECIALLY WITH RESPECT TO THE
THERMAL FIELDS LATE IN THE WEEK...SO WENT WITH A BLEND OF THE
COOLER OPERATIONAL GFS AND ENSEMBLE MOS...WHICH BRING THEM A BIT
CLOSER TO THE WARMER ECMWF.
RRH
AVIATION...
EASTERLY FLOW HAS BROUGHT IN SOME LOW STRATUS ACROSS ACROSS MOST OF
THE STATE. CEILINGS ACROSS THE AREA RANGING FROM 1500FT TO 3000FT.
THIS LOW STRATUS SHOULD STAY IN OVER THE AREA FOR A FEW HOURS AFTER
SUNRISE THEN SLOWLY LIFT THROUGH 18Z TO VFR AND ABOVE CONDITIONS.
WINDS WILL STAY OUT OF THE E TO NE AT 5 TO 10 KTS THROUGH THE TAF
PERIOD. THIS EASTERLY FLOW SHOULD BRING IN MORE LOW STRATUS TONIGHT
FOR TUE MORNING AS WELL. NO PRECIPITATION OR RESTRICTIONS TO VSBYS
EXPECTED THROUGH THE TAF PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 52 40 52 50 68 / 10 5 80 100 50
ATLANTA 54 44 54 54 70 / 10 10 80 100 40
BLAIRSVILLE 49 38 49 46 60 / 20 20 100 100 40
CARTERSVILLE 53 40 52 50 64 / 20 20 100 100 30
COLUMBUS 61 48 64 60 71 / 10 10 70 90 40
GAINESVILLE 49 42 49 47 65 / 10 10 100 100 40
MACON 60 44 64 59 74 / 10 5 60 80 50
ROME 51 41 52 51 65 / 20 30 100 100 30
PEACHTREE CITY 57 40 57 57 70 / 10 10 80 90 40
VIDALIA 63 43 67 60 73 / 10 5 50 70 50
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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