FXUS62 KFFC 171813 AAB AFDFFC AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 210 PM EDT MON MAR 17 2014 .PREV DISCUSSION... /ISSUED 404 AM EDT MON MAR 17 2014/ SHORT TERM /TODAY THROUGH TUESDAY/... GUIDANCE REMAINS IN PRETTY GOOD AGREEMENT ON THE SYNOPTIC PATTERN FOR THE SHORT TERM...WITH DEEP NEGATIVELY TILTED UPPER TROUGH PUSHING ACROSS THE DEEP SOUTH TODAY WHILE A SURFACE LOW OVER ALABAMA DIVES SOUTHEAST ACROSS GEORGIA AND TOWARD THE COAST THROUGH THE DAY...AS A STRONG CAD EVENT BUILDS IN FROM THE NORTHEAST. AS ALWAYS HOWEVER...THE DEVIL IS IN THE DETAILS WHERE THERE ARE SOME MORE SIGNIFICANT DIFFERENCES. SO LETS TALK ABOUT TEMPERATURES FIRST. AS FAR AS VERIFICATION NUMBERS GO...YESTERDAY WORKED OUT PRETTY DARN WELL AS MAV WAS TOO WARM...MET WAS TOO COOL...SO THE BLENDED APPROACH WAS DEFINITELY THE WAY TO GO. MAV CONTINUES ON THE WARM SIDE THROUGH THE SHORT TERM... RUNNING ABOUT 5 DEGREES WARMER THAN THE MET. OF COURSE THIS WILL BE HIGHLY DEPENDENT ON THE LOCATION OF THE WEDGE FRONT. THE 00Z GFS HOLDS OFF ON BUILDING THE COLD DOME INTO ATLANTA UNTIL LATER TODAY /HENCE THE WARMER TEMPS/...AND WITH THAT THE SURFACE LOW TRACK IS INITIALLY JUST NORTH OF THE CITY...THEN EAST...FINALLY DIVING SOUTH TOWARD THE COAST. THE 00Z NAM ON THE OTHER HAND REALLY BARRELS THE WEDGE FRONT SOUTHWEST THIS MORNING /HENCE THE COOLER TEMPS/... FORCING THE SURFACE LOW TO STAY ON THE WEST AND SOUTH SIDE OF THE METRO AREA. TAKING A BLEND OF THE TWO IT MAY VERY WELL LIKELY BE THAT THE WEDGE FRONT JUST REMAINS OVER THE METRO ARA. SO WITHOUT ANY REASON TO GO AGAINST IT...AGAIN TOOK A BLEND THROUGH THE SHORT TERM...PULLING BACK ON BIAS-CORRECTED VALUES. IN THE COLD DOME... HIGHS WILL BE SEVERAL DEGREES BELOW SEASONAL AVERAGES. OF COURSE THE UNCERTAINTY IN LOCATION OF THE WEDGE FRONT HAS FRUSTRATING IMPLICATIONS ON WINDS BUT THAT IS MORE OF AN AVIATION CONCERN THAN ANYTHING...BUT MAY MEAN THE DIFFERENCE BETWEEN WEST-SOUTHWEST WINDS /OUTSIDE OF THE COLD DOME PER THE GFS/ OR EAST WINDS /PER THE NAM/. EVENTUALLY THE CAD WILL BECOME FIRMLY ENTRENCHED AND WINDS WILL ALL BE OUT OF THE EAST. IF THE TEMPERATURES AND WINDS WERE NOT INTERESTING ENOUGH...ADD THE COMPLICATION OF POPS AND WX. THE WIDESPREAD RAIN FROM YESTERDAY HAS PUSHED SOUTH AND EAST BUT THERE IS STILL QUITE A BIT OF MOISTURE IN PLACE AND WITH THE APPROACHING UPPER/SURFACE SYSTEMS...PLENTY OF SYNOPTIC SCALE LIFT AS WELL. MODEL SOUNDINGS DO SHOW SOME WEAK ELEVATED INSTABILITY AND SHOWERS MOVING ACROSS NORTH GEORGIA THIS MORNING HAVE INTERMITTENTLY WORKED ALL THE WAY UP TO 50DBZ...SO WOULD NOT BE SURPRISED TO HEAR A FEW RUMBLES OF THUNDER IN THERE. SPC ONLY HAS GENERAL THUNDER THROUGH 12Z THIS MORNING AND NOTHING THEREAFTER BUT AGAIN JUST CANNOT RULE OUT SOME RUMBLES HERE AND THERE. NO REAL HAZARDS EXPECTED ASIDE FROM BRIEF HEAVY RAIN THOUGH. SO WHAT WE ARE LOOKING AT IS IN ADDITION TO THE MORE STRATIFORM RAIN CURRENTLY ACROSS PORTIONS OF SOUTH AND CENTRAL GEORGIA...EXPECT CONTINUED REGENERATION ACROSS NORTH GEORGIA WITH INCREASING PVA ALOFT. AS THE SURFACE LOW WORKS ITS WAY SOUTH AND EAST...POPS ACROSS NORTH GEORGIA WILL BEGIN TO TAPER OFF TODAY BUT KEPT LIKELY ACROSS CENTRAL ZONES THROUGH TONIGHT. A LOT OF LOW CLOUDS AND INTERMITTENT FOG ISSUES BUT NOT REALLY EXPECTING MUCH IN THE WAY OF DENSE FOG AT LEAST NOT WIDESPREAD WITH STRONG WINDS JUST OFF THE SURFACE HELPING TO KEEP THAT BOUNDARY LAYER MIXED. TDP LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... SHORT AND LONG RANGE MODELS CONTINUE TO SHOW A MOIST SOUTH TO SOUTHWEST MID LEVEL FLOW PRODUCING A FEW PATCHES OF LIGHT RAIN OR DRIZZLE ACROSS PARTS OF NORTH GA TUESDAY NIGHT. THEN THE LONG RANGE MODELS CONTINUE TO AGREE ON A WEAK COLD FRONTAL PASSAGE BY MID WEEK. THIS WILL WARRANT A LOW CHANCE OF POPS ACROSS MAINLY NORTH GA ON WEDNESDAY. ALTHOUGH THE GFS IS STILL SLIGHTLY FASTER WITH THIS FROPA... BOTH ECMWF AND GFS SHOW HIGH PRESSURE AND DRY CONDITIONS FOR THURSDAY AND FRIDAY. LONG RANGE MODELS SHOW GOOD AGREEMENT ON ANOTHER COLD FRONT PUSHING ACROSS THE AREA ON SATURDAY... WITH THE GFS SHOWING SLIGHTLY MORE MOISTURE AND QPF WITH THIS SYSTEM. WILL CONTINUE TO SHOW A CHANCE OF SHOWERS ON SATURDAY...BUT NO THUNDER IS STILL WARRANTED AS BOTH MODELS AGREE ON WEAK UPPER SUPPORT AND NEARLY NIL INSTABILITY. A COOL DOME OF HIGH PRESSURE BUILDS IN FOR SUNDAY. 39 && .AVIATION... 18Z UPDATE... GENERALLY IFR CONDITIONS EXPECTED TO PREDOMINATE THROUGH THIS FORECAST PERIOD. WINDS WILL REMAIN EAST OR BECOME EAST AT ALL LOCATIONS WITH SPEEDS 8-14KT THROUGH 00Z...DIMINISHING SLIGHTLY AFTER 00Z TO 6-10KT. SCATTERED TO NUMEROUS SHOWERS THROUGH THE EVENING EVENTUALLY DIMINISHING AND PUSHING EAST OF THE FORECAST AREA THROUGH THE PERIOD. //ATL CONFIDENCE...18Z UPDATE... MEDIUM. 20 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 48 37 49 42 / 70 50 30 20 ATLANTA 54 38 53 45 / 70 40 20 10 BLAIRSVILLE 48 37 52 41 / 60 40 20 20 CARTERSVILLE 54 39 56 44 / 60 40 20 10 COLUMBUS 63 44 60 45 / 80 50 30 10 GAINESVILLE 46 37 48 43 / 60 40 20 20 MACON 61 42 54 43 / 80 60 30 10 ROME 53 41 59 46 / 60 40 10 10 PEACHTREE CITY 56 39 54 41 / 70 50 20 10 VIDALIA 60 45 55 47 / 90 70 50 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ATWELL LONG TERM....ATWELL AVIATION...TDP
Posted on: Mon, 17 Mar 2014 18:15:23 +0000
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