FXUS62 KFFC 130837 AFDFFC AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PEACHTREE CITY GA 437 AM EDT MON OCT 13 2014 .SHORT TERM /TODAY THROUGH TUESDAY NIGHT/... LATEST SURFACE ANALYSIS SHOWS A STRONG CAD WEDGE HAS PUSHED TO NEAR AN ELLIJAY TO CARROLLTON TO GRIFFIN TO MILLEDGEVILLE LINE... WITH THE ASSOCIATED COOL EASTERLY FLOW SPREADING AMPLE LOW CLOUDS...DRIZZLE AND FOG ACROSS MUCH OF NORTH GA THIS MORNING. THE LOW CLOUDS WILL LIKELY SPREAD INTO MACON AND POSSIBLY EVEN COLUMBUS THIS MORNING AS WELL. THE STRONG WEDGE AND ASSOCIATED CLOUDINESS WILL BE SLOW TO ERODE TODAY... WITH THE BREEZY... COOL EASTERLY WINDS AND CLOUDS HOLDING MUCH OF NORTH GA IN THE 70S. AREAS ACROSS CENTRAL GA AND POSSIBLY NW GA SHOULD SCATTERED OUT LATER THIS AFTERNOON AS A WARM SE FLOW DEVELOPS...WHICH SHOULD ALLOW TEMPS THERE TO CLIMB INTO THE LOWER TO MID 80S... WITH SOME UPPER 80S TO THE FAR SOUTH AND SW. STILL EXPECTING THE GREATER CHANCES FOR SHOWERS AND THUNDERSTORMS TODAY TO BE WELL TO THE WEST IN MS AND AL...BUT WILL CONTINUE TO SHOW A LOW CHANCE ACROSS THE FAR WESTERN ZONES...AND SLIGHT CHANCE INTO ATLANTA AND NE GA WHERE AN ISOLATED SHOWER OR EVEN THUNDERSTORM IS POSSIBLE DUE TO A DEVELOPING DEEP... MOIST SOUTHERLY FLOW DURING DAYTIME HEATING. HOWEVER... THE GREATER DYNAMICS FOR CONVECTION WILL BE FOCUSED MAINLY ACROSS THE LOWER MS VALLEY TODAY AS A CUT OFF UPPER LOW OVER THE SOUTHERN PLAINS PUSHES A COLD FRONT TO NEAR THE MS RIVER BY LATE THIS AFTERNOON. THE MAIN FORECAST CONCERN AND CHALLENGE WILL BE NAILING DOWN THE TIMING AND STRENGTH OF THE ASSOCIATED SQUALL LINE THAT IS EXPECTED TO DEVELOP AHEAD OF THE COLD FRONT. AT THIS TIME...SHORT RANGE MODELS ARE INDICATING THE SQUALL LINE COULD PUSH TO NEAR THE AL/GA STATE LINE AS EARLY AS 4 TO 6 AM TUE MORNING...THEN PUSH ACROSS THE REST OF THE FORECAST AREA INTO TUE AFTERNOON. HOWEVER...IT IS IMPORTANT TO NOTE...THAT THE MODELS ALSO DO NOT PUSH THE ACTUAL COLD FRONT ACROSS THE AREA UNTIL TUE AFTERNOON AND EVENING... SUGGESTING THE POTENTIAL FOR REDEVELOPING STORMS ALONG THE FRONT...AFTER THE SQUALL LINE HAS PUSHED EAST OF YOUR AREA. THEREFORE...IT IS IMPORTANT THAT ALL CONCERNED STAY ALERT FOR POTENTIAL THREATENING WEATHER UNTIL THE ACTUAL COLD FRONT PUSHES EAST OF THE AREA SOMETIME TUE EVENING. MODELS ARE SHOWING AMPLE DEEP LAYER SHEAR WITH MODERATE SURFACE BASED CAPE VALUES OF 1000-1500 J/KG AHEAD OF THE EXPECTED SQUALL LINE ON TUE. THIS SUGGEST THE POTENTIAL FOR DAMAGING WINDS AND ISOLATED TORNADOES...ESPECIALLY WITH ANY DISCRETE CELLS DEVELOPING AHEAD OF THE SQUALL LINE...AND ANY BOWING SEGMENTS ALONG THE SQUALL LINE ITSELF. SPC HAS PLACED THE ENTIRE FORECAST AREA IN A SLIGHT RISK FOR SEVERE STORMS ON TUE...WHICH INCLUDES EARLY TUE MORNING. OTHERWISE... ANY ASSOCIATED STORMS SHOULD PUSH EAST OF THE AREA TUE EVENING WITH THE COLD FRONT PUSHING EAST TUE NIGHT. EXPECT ASSOCIATED WRAP AROUND CLOUDS AND MOISTURE TO POSSIBLY SPREAD SOME SPOTTY SHOWERS AND LIGHT RAIN TO THE AREA TUE NIGHT... SO NOT EXPECTING TO CLEAR OUT ANYTIME SOON BEHIND THE FRONT... EXCEPT FOR POSSIBLY PARTS OF CENTRAL GA WHERE A DRY SLOT MAY ALLOW CLEARING TO PERSIST. 39 .LONG TERM /WEDNESDAY THROUGH SUNDAY/... CLOSED LOW MEANDERS ACROSS THE MIDWEST INTO WEDNESDAY. EXTENDED MODELS CONTINUE TO DISAGREE ON TIMING THE FRONT EXITS THE FORECAST AREA. GFS CONTINUES 6 HOURS FASTER THAN ECMWF/UKMET...WITH FRONT EXITING BY 12Z WEDNESDAY. HOWEVER GFS CONTINUES TO TREND TOWARD THE ECMWF AS THE WRAPAROUND SHOWERS IN NORTH GA THROUGH WEDNESDAY...SO WOULD NOT BE SURPRISED TO SEE THE SLOWER SOLUTIONS PAN OUT...HAVE TRIED TO TAKE THE MIDDLE GROUND IN EXTENDED FORECASTS AS FAR AS POPS/WEATHER FORECASTS...WITH LINGERING SHOWERS EAST AND NORTHEAST WEDNESDAY. MODELS ARE IN AGREEMENT UPPER LOW WILL SLOWLY LIFT ACROSS THE OHIO VALLEY THROUGH THURSDAY...WITH SOME CLOUDS LINGERING IN NORTH GEORGIA. GENERALLY DRY FORECAST FOR THE END OF THE WEEK AS SURFACE HIGH PRESSURE BUILDS INTO THE SOUTHEAST BY NEXT WEEKEND. THERE ARE ENOUGH DISCREPANCIES IN THE EXTENDED MODELS THAT OVERALL CONFIDENCE IS LACKING. EXPECT TO SEE TEMPERATURES BELOW NORMAL BEHIND THE FRONT FOR MIDWEEK BEFORE MODERATING BACK TOWARDS NORMAL BY THE WEEKEND. ATWELL && .PREV DISCUSSION... /ISSUED 147 AM EDT MON OCT 13 2014/ AVIATION... 06Z UPDATE... A COOL CAD WEDGE AND ASSOCIATED EASTERLY WINDS HAVE SPREAD LIFR/IFR CIGS ACROSS THE ATLANTA TAF SITES. WIDESPREAD LIFR/IFR CIGS WILL BE SLOW TO IMPROVE THIS MORNING... WITH MVFR CIGS POSSIBLY BY 16Z AND VFR CIGS BY 18Z. EXPECT THE GREATER CHANCES FOR SHOWERS AND THUNDERSTORMS TO REMAIN NORTH AND WEST OF ALL TAF SITES TODAY. COULD BEGIN TO SEE SOME SPOTTY SHOWERS SPREAD INTO THE AREA EARLY TUE MORNING AHEAD OF A COLD FRONT PUSHING ACROSS MS AT THAT TIME. GFS AND NAM BUFR SOUNDINGS SHOW MVFR CIGS AT ATL BY 06Z TUE... AND IFR BY 09Z TUE AND THIS LOOKS REASONABLE WITH A DEEP... MOIST SOUTHERLY FLOW IN- PLACE. EAST WINDS AROUND 9-12KTS TODAY WILL BE GUSTY AND VEER SLIGHTLY MORE ESE THIS AFTERNOON AND SE TONIGHT. //ATL CONFIDENCE...06Z UPDATE... MEDIUM CONFIDENCE ON TIMING OF LIFR CIGS IMPROVING THIS MORNING... COULD BE LATER. HIGH ON ALL OTHER ELEMENTS. 39 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 76 66 76 56 / 20 70 100 90 ATLANTA 82 67 75 55 / 30 80 100 50 BLAIRSVILLE 71 62 70 51 / 30 80 100 60 CARTERSVILLE 81 68 75 54 / 40 90 100 40 COLUMBUS 87 70 78 56 / 30 90 100 40 GAINESVILLE 75 66 72 54 / 20 80 100 70 MACON 87 69 79 56 / 10 70 100 80 ROME 82 68 75 53 / 50 90 100 40 PEACHTREE CITY 84 68 75 52 / 30 80 100 50 VIDALIA 88 69 83 66 / 10 30 90 90 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...39 LONG TERM....ATWELL AVIATION...39
Posted on: Mon, 13 Oct 2014 08:40:06 +0000
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