000 FXUS62 KFFC 100344 AAB AFDFFC AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 1044 PM EST THU FEB 9 2012 .UPDATE... GOING FCST LOOKS GOOD. TEMPS COOLED QUITE A BIT THIS EVENING AS EXPECTED AS WINDS HAVE GONE CALM EVERYWHERE...INCLUDING A RARE CALM WIND AT KATL. THICK HIGH CLOUDS APPEARANT ON IR IMAGERY TO THE WEST AND CURRENTLY STREAMING IN. SHOULD NOT HAVE A BIG IMPACT ON TEMPS BUT HAVE BUMPED UP SKY GRIDS A LITTLE. 00Z NAM STILL HAS SOME LIGHT SNOW ON THE UPSLOPE SIDES OF THE SRN APPALACHIANS IN FAR NORTHCENTRAL GA EARLY SAT MORNING. EVEN THIS IS LESS THAN AN INCH WHICH IS LOW FOR THE SNOW GOOSE NAM. MAIN STORY SATURDAY WILL BE BLUSTERY WINDS OF 20-30MPH WITH TEMPS MOSTLY IN THE UPPER 30S IN NORTH GA. WILL ACTUALLY FEEL LIKE WINTER. SNELSON && .PREV DISCUSSION... /ISSUED 645 PM EST THU FEB 9 2012/ SHORT TERM /TONIGHT THROUGH SATURDAY/... NO MAJOR CHANGES TO PREVIOUS MODEL TRENDS THROUGH THE SHORT TERM FORECAST PERIOD. FAST MOVING AND FAIRLY WEAK SHORT WAVE SWEEPS THROUGH THE TIGHT...WESTERLY UPPER LEVEL FLOW ACROSS THE OHIO AND TENNESSEE VALLEYS FRIDAY NIGHT. ONLY CHANGE OF ANY CONSEQUENCE FOR THIS TIME FRAME IS THE SLIGHTLY STRONGER SOUTHERN BRANCH WAVE ACROSS THE NORTHERN GULF AT THIS SAME TIME WHICH HAS RESULTED IN SLIGHTLY HIGHER POPS ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. MODEL AND HPC QPF REMAIN VERY LOW WITH BOTH THESE FEATURES. TEMPERATURES FRIDAY NIGHT WILL LIKELY SUPPORT SOME RAIN/SNOW MIX AS WE HEAD THROUGH THE EVENING...MAINLY IN THE FAR NORTH AND HIGHER ELEVATIONS. MOST FAVORABLE TEMPERATURES ARE NOT REALIZED MOST AREAS UNTIL AFTER MIDNIGHT WHEN MOST OF THE PRECIPITATION HAS PASSED...AND WITH VERY LOW QPF AMOUNTS EXPECTED...NO SIGNIFICANT ACCUMULATIONS ARE ANTICIPATED AT THIS TIME. FOR SATURDAY...MUCH COOLER AND DRIER AIR SPILLS INTO THE AREA BEHIND THE EXITING UPPER LEVEL WAVE AND ASSOCIATED COLD FRONT. 20/25 LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... NO SIGNIFICANT CHANGES TO THE EXTENDED FORECAST MODEL TRENDS SO I HAVE NOT MADE ANY SIGNIFICANT CHANGES TO THE LONG TERM FORECAST GRIDS AT THIS TIME. FOR DETAILS SEE PREVIOUS LONG TERM FORECAST DISCUSSION BELOW. PREVIOUS LONG TERM DISCUSSION... SATURDAY...CONTINUED AGREEMENT FROM 00Z GFS AND 00Z ECMWF...EVEN THE 00Z NAM HAS JOINED THE FRAY...WITH TROUGH PASSAGE EXPECTED BETWEEN 06Z AND 12Z. THIS TIMING OPENS THE WINDOW FOR THE POSSIBILITY OF A WINTRY WAKE-UP IN THE NORTH GEORGIA MOUNTAINS ON SATURDAY MORNING. 00Z SATURDAY MODEL SOUNDINGS SHOW DRY AIR NEAR THE SURFACE UP IN NORTH GEORGIA THAT WOULD BE RIPE FOR EVAPORATIONAL COOLING. BY 06Z...MODEL SOUNDINGS CLEARLY DEMONSTRATE EVAPORATIONAL COOLING CLOSE TO THE SURFACE THAT HELPS CREATE A BELOW-FREEZING COLUMN WHICH IS NECESSARY FOR SNOW. MODEL SOUNDINGS PERSIST WITH THE MOIST BELOW FREEZING COLUMN THROUGH 12Z. WITH SURFACE TEMPERATURES HOVERING AROUND FREEZING...SNOW MAY STICK LIGHTLY TO GRASSY SURFACES IN THE MOUNTAINS. THE MODEL SOUNDINGS FOR METRO ATLANTA AND POINTS SOUTH SHOW A WARMER COLUMN WHICH WOULD KEEP ANY PRECIPITATION LIQUID. SUNDAY/MONDAY...DRIER AIR FILTERS IN BEHIND THE SYSTEM BRINGING LOWER RELATIVE HUMIDITIES TO NORTH AND CENTRAL GEORGIA. LARGE PORTIONS OF THE CWA COULD FALL BELOW THE 25 PERCENT RELATIVE HUMIDITY THRESHOLD CRITICAL FOR FIRE WEATHER CONCERNS ON SUNDAY AND MONDAY AFTERNOONS. TIMING OF PRECIPITATION ON LATE MONDAY NIGHT/EARLY TUESDAY MORNING MAY COINCIDE WITH COLD AIR...LEADING TO SNOW IN THE NORTH GEORGIA MOUNTAINS AND COLD RAIN WELL INTO METRO ATLANTA. WHILE CONFIDENCE FOR THIS EVENT IS LOW...IT BEARS WATCHING FOR TRENDS. TUESDAY/WEDNESDAY...NEXT SYSTEM MOVES IN WITH A COLD FRONT CLEARING THROUGH NORTH AND CENTRAL GEORGIA. 00Z ECMWF IS MUCH QUICKER WITH THE FRONT BEING THROUGH THE CWA BY 18Z TUESDAY WHILE THE 00Z GFS DELAYS IT UNTIL 18Z WEDNESDAY. WITH THE UNCERTAINTY IN THE MODELS THIS FAR OUT...THIS WILL BEAR WATCHING. INCLUDED HIGHER POPS BUT HELD OFF ON THUNDER FOR NOW AS CONFIDENCE OF FRONTAL TIMING AND INSTABILITY IS TOO LOW TO PINPOINT THIS FAR OUT...GUIDANCE DOES SUGGEST HEALTHY AMOUNTS OF SHEAR FOR THIS EVENT. 10 FIRE WEATHER... INCREASING WINDS AND MUCH DRIER AIR WILL SPILL INTO THE REGION SATURDAY...EVEN WITH SIGNIFICANTLY COOLER TEMPERATURES EXPECTED RELATIVE HUMIDITIES MAY APPROACH CRITICAL FIRE WEATHER VALUES...AS MAY WIND SPEEDS. 20 AVIATION... 00Z UPDATE... LIGHT MAINLY VARIABLE WINDS TONIGHT...WITH A WESTERLY BIAS. THE WESTERLY WINDS WILL GRADUALLY INCREASE TO 5 TO 10 KTS ON FRIDAY. HIGH LEVEL CLOUDS WILL CONTINUE TONIGHT WITH CEILINGS GRADUALLY LOWERING TO AROUND 5000 FEET BY SUNSET FRIDAY AS A LOW PRESSURE SYSTEM RAPIDLY APPROACHES GA. VFR CONDITIONS SHOULD PREVAIL THROUGH THE TAF PERIOD. //ATL CONFIDENCE...00Z UPDATE... HIGH ON ALL ELEMENTS. 16 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 32 57 36 48 / 0 10 20 5 ATLANTA 36 57 38 46 / 0 10 20 5 BLAIRSVILLE 27 52 33 39 / 0 20 40 20 CARTERSVILLE 29 56 34 44 / 0 20 30 5 COLUMBUS 36 63 41 51 / 0 10 20 5 GAINESVILLE 34 54 37 47 / 0 10 30 10 MACON 32 62 40 56 / 0 10 20 5 ROME 29 57 34 43 / 0 30 30 5 PEACHTREE CITY 28 57 35 47 / 0 10 20 5 VIDALIA 40 66 44 60 / 0 20 30 5 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 13