Area Forecast Discussion
Issued by NWS Atlanta, GA

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238 FXUS62 KFFC 270608 AFDFFC Area Forecast Discussion National Weather Service Peachtree City GA 108 AM EST Mon Feb 27 2017 .PREV DISCUSSION... /Issued 1031 PM EST Sun Feb 26 2017/ .UPDATE... Current temps already approaching overnight lows so have therefore made adjustments to min temps tonight. Cirrus will overspread the CWA after midnight which should slow down the temp drop keeping temps from bottoming out. No other changes planned. && PREV DISCUSSION... /Issued 224 PM EST Sun Feb 26 2017/ .SHORT TERM /Tonight through Monday Night/... Latest RAP analysis of the eastern half of the US shows high pressure centered right along the spine of the Appalachians providing for a very light wind flow over the local area. Right around normal for the temps thus far which for this year is seasonably cool with mostly upper 50s and lower 60s. Building high clouds to the west but for the local area it is high and dry. Speaking of dry...dewpoints remain in the single digits and teens across a vast majority of the area driving the RH values in the teens as well with current Fire Danger Statement certainly on track. Moisture will be on the increase through tonight and especially into Monday as high pressure quickly shifts offshore in zonal flow aloft allowing for good return flow off the gulf. A warm front should setup across the deep south in response and act as the focus along with embedded shortwaves in mid level flow for shower development west of the area initially. This activity will eventually translate east to affect NW GA Mon afternoon although instability axis will remain outside these areas such that only SHRA are expected at onset. Instability does build through the late afternoon and into the overnight and have included slight chance thunder for primarily the southern and western zones. Confident in categorical pops for NW zones but much uncertainty with models on if and how quickly this activity translates east and south through the overnight period. Have favored a more progressive solution for now. Deese && .LONG TERM /Tuesday through Sunday/... Start of the long-term forecast period brings us to the last day of February...where the synoptic pattern in the mid levels will feature long-wave trough over the Western US/Intermountain West...with a subtropical ridge parked over the Caribbean. This would leave the eastern two-thirds of the US in a quasi-zonal/weakly anticyclonic flow regime. Down at the sfc...strong high pressure centered well offshore of the Atlantic coast will still have enough ridge influence over the Mid-Atlantic and SE states...while low pressure will get spun up over the Central Plains as perturbations within long wave trough induce cyclogenesis. Sensible weather will be somewhat disturbed on Tuesday as moist southerly flow regime promotes persistent WAA pattern in the wake of a warm frontal passage from Monday. GFS/Euro backing off on QPF...but still looks like north Georgia will see at least scattered showers during the day. Moist boundary layer looks to allow for enough destabilization for thunderstorms /sub-severe/. Temps will once again be well-above normal with highs 70s north 80s central Tuesday afternoon and near 60 Tuesday night. Wednesday and Wednesday night will be the most interesting periods of the long-term as a cold front approaches. SPC more aggressive with 15-30% severe weather outlook across the SE US/state of Georgia. Will have to fine tune things the next few days...but GFS/ECMWF consistent in bringing a strong shortwave across the Southern Plains into the OH Valley...with associated 90kt+ mid level jet streak spreading across this area and right entrance region open to the SE. At the sfc...continued promotion of high theta-e air from Gulf from southerly flow in the warm sector should allow enough instability develop...despite cooler mid level air displaced to our northwest. Strong SW flow aloft atop weaker S/SW surface flow should promote strong deep layer shear /at least 40-70kts/...albeit unidirectional. All this undoubtedly raises concern for severe weather...but will have to wait to see if dynamics will actually line up...which never really seems to be the true case. Strongest forcing already seems to be displaced a little too far north and west...but still warrants attention at this point. Rest of extended remains dry Thursday-Saturday night under sfc high pressure and weak NW flow aloft. Temps should be more "seasonal" in the 60s during this time. Still evidence of moisture return just outside of this forecast period as models continue to hint at a southern stream trough over northern Mexico. Looks like another warm up as well. Kovacik && .AVIATION... 06Z Update... VFR conditions for majority of fcst period with gradual building in of alto deck from west ahead of next disturbance. Cu/stratocu field in 3-5 kft range should develop around 18-22z today along with increased shower chances (slight timing differences among sites). Lull in precip should occur after 03-06z into early Tuesday...though cigs should start trending lower in MVFR and possible IFR levels along with MVFR VSBYs. Winds initially light SE to calm increasing later today but less than 10 kts. //ATL Confidence...06Z Update... Medium on late period precip timing and cigs. High on all else. Baker && .PRELIMINARY POINT TEMPS/POPS... Athens 67 52 75 59 / 30 40 40 20 Atlanta 65 55 74 61 / 70 50 40 20 Blairsville 57 47 66 54 / 30 50 60 50 Cartersville 61 53 72 59 / 70 40 50 40 Columbus 72 57 80 62 / 30 30 20 10 Gainesville 62 51 70 59 / 70 50 50 40 Macon 74 56 82 59 / 30 40 20 10 Rome 60 52 73 59 / 70 50 60 40 Peachtree City 67 53 76 59 / 50 50 30 20 Vidalia 78 61 84 63 / 30 30 20 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Deese LONG TERM....Kovacik AVIATION...Baker

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