FXUS62 KFFC 150536 AAC AFDFFC AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 136 AM EDT SAT MAR 15 2014 .PREV DISCUSSION... /ISSUED 1006 PM EDT FRI MAR 14 2014/ UPDATE... WEAK SHORTWAVE AND MAINLY MID-UPPER LEVEL MOISTURE HAS RESULTED IN PRETTY DECENT REFLECTIVITY ACROSS NORTH GEORGIA. CANNOT RULE OUT SOME LIGHT PRECIP MAKING IT DOWN TO THE GROUND AND WINNING AGAINST THE LOWER DRY LEVELS THOUGH HAS LARGELY BEEN VIRGA. HAVE THEREFORE INCLUDED JUST A SLIGHT CHANCE OF SHOWERS MAINLY BEFORE MIDNIGHT. MIDLEVEL DECK ADVECTED ITS WAY IN JUST IN TIME TO TRAP IN THE DAYTIME RADIATIVE HEAT AND TEMP TRENDS SO FAR STARTING MUCH WARMER. HAVE BUMPED UP OVERNIGHT MINS CONSIDERABLY KEEPING MUCH OF THE AREA IN THE MID TO UPPER 40S...THOUGH MIGHT EVEN STAY WARMER THAN THIS. REST OF FORECAST LOOKS TO BE ON TRACK AND PREVIOUS DISCUSSION FOLLOWS... BAKER PREV DISCUSSION... /ISSUED 732 PM EDT FRI MAR 14 2014/ PREV DISCUSSION... /ISSUED 318 PM EDT FRI MAR 14 2014/ SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... HIGH PRESSURE THAT HAS BROUGHT SUNNY SKIES TO THE AREA THE LAST FEW DAYS HAS FINALLY SHIFTED TO THE EAST. SHORTWAVE EXPECTED TONIGHT HAS A FEW MODELS SPITTING LIGHT RAINFALL OVER THE AREA TONIGHT AND EARLY SATURDAY...BUT WITH DRY MID LEVELS...EXPECT A LARGE PORTION OF THIS TO NOT REACH THE GROUND OR BE JUST SPRINKLES. HAVE CONTINUED WITH THE INCREASE IN CLOUDS ACROSS THE AREA AS WELL. UPPER LEVEL MOISTURE PERSISTS THROUGH THE DAY SATURDAY AS THE NEXT SYSTEM APPROACHES. SHORT TERM MODELS CONTINUE TO SUGGEST THAT ONSET OF PRECIPITATION WITH THIS NEXT SYSTEM WILL BE LATE SATURDAY NIGHT. HAVE CONTINUED WITH QUICKLY INCREASING POP CHANCES WITH SLIGHT CHANCE MOVING INTO WEST AND NORTHWEST GEORGIA SATURDAY EVENING...AND LIKELY TO CATEGORICAL POPS BY THE WEE SUNDAY MORNING HOURS. MODELS CONTINUE TO SHOW LIMITED INSTABILITY SATURDAY AND HAVE LEFT OUT MENTION OF THUNDER THROUGH SUNDAY MORNING. QPF CONTINUES TO BE IN THE 1-2 INCH RANGE THROUGH THE WEEKEND WITH THIS SYSTEM. FOR NOW...FFG VALUES SUGGEST WE SHOULD BE ABLE TO HANDLE THIS AMOUNT OF RAINFALL WITH MINIMAL TO NO FLOODING CONCERNS. 31 LONG TERM /SUNDAY THROUGH FRIDAY/... ONLY MINOR CHANGES TO THE EXTENDED FORECAST. WITH THE RAIN HOLDING ON INTO THE BEGINNING OF NEXT WEEK...HAVE GONE AHEAD AND INCREASED POPS SUNDAY NIGHT INTO MONDAY. STILL ON TRACK WITH THUNDER POTENTIAL FOR SUNDAY AND SUNDAY NIGHT GIVEN MUCAPE VALUES UP TO 500 J/KG. HAVE CONTINUED THE SLIGHT CHANCE TO CHANCE OF THUNDERSTORMS IN THE GRIDS WITH NEAR 100 POPS. SEEMS THE MAIN THREAT WITH THIS SYSTEM AT THIS TIME APPEARS TO BE RAINFALL AMOUNTS...SEE THE HYDRO SECTION FOR MORE DETAILS. STILL DIFFERENCES WITH THE MID WEEK SYSTEM BETWEEN THE GFS AND ECMWF. GFS REMAINS THE DRY SOLUTION WHILE THE ECMWF BRINGS RAIN THOUGH WEDNESDAY NIGHT INTO THURSDAY WITH THE FRONT. HAVE LEANED TOWARDS THE GFS FOR NOW WHICH IS CONSISTENT WITH THE PREVIOUS DRY FORECAST. 11 MODELS ARE COMING INTO GOOD AGREEMENT WITH THE WEEKEND SOLUTION WHICH IS GIVING A MEDIUM TO HIGH CONFIDENCE IN THE LONG TERM. THE SHORT WAVE DEVELOPING OVER THE SOUTHERN PLAINS WILL CONTINUE TO DIG OVER THE SOUTHERN PLAINS EJECTING A SURFACE LOW INTO THE LOWER MISSISSIPPI VALLEY. THIS WILL SPREAD AMPLE AMOUNTS OF MOISTURE INTO THE CWA SATURDAY NIGHT INTO SUNDAY. AS THE SURFACE LOW MOVES CLOSER AND THE SOUTHWEST FLOW INCREASES...INSTABILITY WILL INCREASE BRINGING ISOLATED TO SCATTERED THUNDERSTORMS ALONG WITH THE WIDESPREAD ON SUNDAY AND INTO SUNDAY EVENING. THE MODELS DIFFER SLIGHTLY ON THE STRENGTH OF THE UPPER SYSTEM. GFS DEVELOPS A CLOSED LOW WHILE THE ECMWF KEEPS AN OPEN WAVE. REGARDLESS BOTH MODELS KEEP PRECIP OVER THE CWA MONDAY AND INTO EARLY TUESDAY. MUCH DRIER AIR WILL SPREAD ACROSS THE CWA TUESDAY AFTERNOON AND FOR THE REST OF THE LONG TERM. 17 HYDROLOGY... TOTAL RAINFALL AMOUNTS SATURDAY NIGHT THROUGH TUESDAY WITH THIS NEXT SYSTEM ARE FORECAST TO BE IN THE ONE AND A HALF TO TWO INCH RANGE. THE HIGHEST AMOUNTS ARE EXPECTED TO BE ON SUNDAY WITH MUCH OF NORTH GEORGIA FORECAST TO RECEIVE A HALF INCH TO AN INCH OF RAINFALL IN A SIX HOUR PERIOD. GIVEN THESE AMOUNTS IN A SHORTER TIME PERIOD...WILL HAVE TO CONTINUE TO MONITOR FLOODING CLOSELY. AT THIS POINT...MAIN CONCERN WOULD BE THE POTENTIAL FOR MINOR FLOODING ALONG BIG CREEK BETWEEN CUMMING AND ALPHARETTA. && .AVIATION... 06Z UPDATE... VFR TODAY BUT WITH INCREASING LOW VFR CLOUDINESS. CONDITIONS RAPIDLY DETERIORATE AFTER 06Z SUNDAY WITH MVFR CIGS MOVING IN WITH -SHRA. SSW WINDS WILL VEER TO NEARLY W LATER THIS MORNING...BACK TO SW AND SSE JUST AFTER 00Z...REMAINING SE THROUGH THE END OF THE PERIOD. //ATL CONFIDENCE...06Z UPDATE... MEDIUM ON TIMING OF WIND SHIFTS AND MVFR CIGS. HIGH ON OCCURRENCE OF WIND SHIFTS AND MVFR CIGS. TDP && .PRELIMINARY POINT TEMPS/POPS... ATHENS 71 51 60 48 / 10 60 100 80 ATLANTA 68 52 63 47 / 10 80 100 80 BLAIRSVILLE 64 48 57 45 / 10 90 100 70 CARTERSVILLE 68 52 63 47 / 10 100 100 70 COLUMBUS 70 54 68 50 / 20 80 90 80 GAINESVILLE 66 51 58 49 / 10 80 100 80 MACON 71 53 64 54 / 10 50 90 80 ROME 69 52 62 47 / 20 100 100 60 PEACHTREE CITY 68 51 63 45 / 10 80 100 80 VIDALIA 74 54 71 57 / 10 50 90 80 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
Posted on: Sat, 15 Mar 2014 05:37:08 +0000
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