Area Forecast Discussion
Issued by NWS Atlanta, GA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KFFC 251459 AFDFFC AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 1100 AM EDT SAT APR 25 2015 .UPDATE... HAVE UPDATED POPS BASED ON RADAR. FIRST ROUND OF SHOWERS/THUNDERSTORMS HAVE MOVED RAPIDLY SOUTH. STILL POSSIBLE FOR ANOTHER ROUND OF STORMS LATER THIS AFTERNOON. 41 .PREV DISCUSSION... /ISSUED 341 AM EDT SAT APR 25 2015/ SHORT TERM /TODAY THROUGH SUNDAY/... COMPLICATED SURFACE PATTERN ACROSS THE EASTERN HALF OF THE THE U.S. ACROSS THE CWFA...HIGH PRESSURE HAS MOVED OFFSHORE AND AN OLD NEARLY DIFFUSE SURFACE BOUNDARY IS ACROSS NORTHERN GA. FURTHER WEST...LOW PRESSURE ACROSS THE PLAINS STATES WILL MOVE EAST TODAY ALONG ANOTHER OLD SURFACE BOUNDARY...INTO THE TN AND OH VALLEYS. REGIONAL RADAR SHOWS A LARGE AREA OF CONVECTION...AN MCS...MOVING EAST/SLIGHTLY NORTHEAST ACROSS MISSISSIPPI INTO WESTERN AL. IN THE MID LEVELS...AN UPPER LOW/STRONG SHORTWAVE ACROSS THE CENTRAL U.S. WILL MOVE EAST INTO THE TN/OH VALLEYS. FURTHER SOUTH...STRONG SHORTWAVE ENERGY ASSOCIATED WITH THE MCS CURRENTLY ACROSS MISSISSIPPI WILL CONTINUE TO TREK EASTWARD/SLIGHTLY NORTHEASTWARD THIS MORNING. DON`T THINK THAT THE SYNOPTIC OR HI-RES MODELS INITIALIZED THIS FEATURE VERY WELL. IN ADDITION...THE MID LEVEL LAPSE RATES ARE SOMEWHAT STEEPER THAN PROGGED. SPEAKING OF THE HI-RES MODELS...THEY ALL HAVE DIFFERENT SOLUTIONS FOR TODAYS SYSTEM...ESPECIALLY THE AFTERNOON CONVECTION. ALL OF THE HI-RES MODELS AGREE THAT THE ACTIVITY MOVING IN FROM ALABAMA WILL IMPACT THE CWFA BY AROUND 09Z. THE SECOND AREA OF STRONGER CONVECTION...BACK OVER MISSISSIPPI...DRIVEN BY THE STRONG SHORTWAVE ENERGY MAY NOT WEAKEN AS MUCH AS SOME OF THE HI-RES MODELS ARE PROGGING. AT THIS TIME...THE WRF SEEMS TO HAVE A PRETTY DECENT HANDLE ON WHAT IS GOING ON NOW...INCLUDING THE STRONGER ACTIVITY ACROSS MISSISSIPPI. SO...HAVE LEANED CLOSER TO THE WRF SOLUTION FOR THE VERY SHORT TERM PORTION OF THE FORECAST. THE AFTERNOON FORECAST BECOMES A LITTLE MORE MURKY. BELIEVE AFTERNOON CONVECTION WILL DEPEND VERY HEAVILY ON THAT HAPPENS THIS MORNING. THE HI-RES MODELS REALLY BEGIN TO DIVERGE AT THIS POINT. ALL THE PARAMETERS FOR SEVERE WEATHER WILL BE IN PLACE...INCLUDING FAVORABLE CONDITIONS FOR A FEW TORNADOES. HOWEVER...EXACTLY WHEN/WHERE THE AFTERNOON CONVECTION WILL DEVELOP IS THE DIFFICULT PART OF THE FORECAST. CONVECTIVE INITIATION FOR THE AFTERNOON WILL DEPEND HEAVILY ON ANY OUTFLOW/DIFFERENTIAL HEATING BOUNDARIES THAT THE OVERNIGHT/EARLY MORNING CONVECTION LAYS DOWN. THIS COULD BE A PRIMARY FOCUS FOR CONVECTION/SURFACE CONVERGENCE. AS MENTIONED BEFORE...ALL OF THE PARAMETERS FOR SEVERE WEATHER WILL BE PRESENT TODAY...ESPECIALLY IN THE AFTERNOON. GOOD LOW LEVEL SHEAR/HELICITY AND STRONG SURFACE INSTABILITY WHERE GOOD HEATING WILL OCCUR. PLUS...A SURFACE BOUNDARY FOR CONVECTION TO FOCUS UPON. DAMAGING WIND GUSTS WILL BE LIKELY WITHIN ANY SEVERE THUNDERSTORMS. WITH THE STRONG SHEAR PRESENT...A FEW TORNADOES ARE NOT OUT OF THE QUESTION. THE BEST/STRONGEST MID LEVEL SHORTWAVE ENERGY SHOULD BE ACROSS THE OH/TN VALLEYS...SO THE BEST CHANCES FOR LARGE HAIL SHOULD BE TO THE NORTH OF THE CWFA. HOWEVER...SINCE MID LEVEL LAPSE RATES ARE CURRENTLY STEEPER THAN THE MODELS CURRENTLY HAVE FORECAST...WOULDN`T RULE OUT A LARGE HAIL PRODUCING THUNDERSTORM AT THIS TIME. CONVECTION SHOULD LAST INTO THE EVENING HOURS...ALONG WITH THE CHANCES FOR SEVERE WEATHER. DO EXPECT ACTIVITY TO LOSE SOME STEAM WITH THE LOSS OF HEATING...BUT MAY NOT COMPLETELY DIMINISH WITH THE SETTING OF THE SUN. HAVE LEFT SOME POPS IN FOR SUNDAY...AS THE ACTUAL FRONTAL BOUNDARY DOESN`T MOVE THROUGH UNTIL THEN. NLISTEMAA LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... WEAK RIDGING AT THE SFC AND MOSTLY DRY CONDITIONS TO BEGIN THE LONG TERM. SHORTWAVE SLIDES FROM THE MS VALLEY INTO THE TN VALLEY TUESDAY NIGHT INTO WEDNESDAY WHILE A SFC LOW TRACKS ALONG THE GULF COAST. THIS RESULTS IN THE RETURN OF SHOWERS AND THUNDERSTORMS TUESDAY NIGHT INTO WEDNESDAY NIGHT. GFS IS SLOWER THAN MODEL RUN LAST NIGHT IN CLEARING OUT THE PRECIPITATION AND HOLDS ONTO IT THROUGH THURSDAY NIGHT. ALTHOUGH THERE ARE SLIGHT DIFFERENCES IN FEATURES BETWEEN THE GFS AND THE ECMWF THE TIMING OF DIMINISHING PRECIPITATION IS FAIRLY SIMILAR. HIGH PRESSURE BUILDS IN BEHIND THAT SYSTEM AND SHOULD LEAD TO A FEW DRY DAYS. 11 && .AVIATION... 12Z UPDATE... MCS CURRENTLY MOVING THROUGH THE CWFA. EMBEDDED THUNDERSTORMS SHOULD ONLY LAST UNTIL 13Z OR SO...BUT THE SHOWERS MAY LINGER A LITTLE LONGER. HI-RES MODELS ARE ALL OVER THE PLACE WITH THE DEVELOPMENT OF AFTERNOON CONVECTION. CONFIDENCE IS LOW ON THE WHEN/WHERE CONVECTION WILL INITIATE. WINDS WILL FLIRT WITH DUE SOUTH THIS MORNING. THE CURRENT RAINFALL MAY REINFORCE THE SE WINDS FOR A FEW HOURS LONGER...BUT SUSTAINED SPEEDS SHOULD BE PRETTY LIGHT. A SWITCH OVER TO THE SW SHOULD OCCUR BY THE EARLY //ATL CONFIDENCE...12Z UPDATE... LOW CONFIDENCE ON WHEN/WHERE AFTERNOON CONVECTION WILL OCCUR. MEDIUM CONFIDENCE REMAINING ELEMENTS. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 74 63 81 55 / 90 50 20 10 ATLANTA 75 65 80 56 / 100 30 20 5 BLAIRSVILLE 68 58 71 46 / 100 50 20 10 CARTERSVILLE 76 63 78 51 / 100 30 20 10 COLUMBUS 80 67 85 60 / 90 30 30 5 GAINESVILLE 71 63 77 54 / 100 40 20 5 MACON 79 67 86 58 / 90 50 30 5 ROME 75 62 78 51 / 100 30 20 5 PEACHTREE CITY 77 64 82 54 / 100 30 20 5 VIDALIA 81 69 87 62 / 90 50 30 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.