086 FXUS62 KFFC 211142 AAA AFDFFC Area Forecast Discussion...UPDATED National Weather Service Peachtree City GA 742 AM EDT Sat Aug 21 2021 ...Updated for 12z Aviation Discussion... && .PREV DISCUSSION... /Issued 414 AM EDT Sat Aug 21 2021/ SHORT TERM /Today through Sunday/... Similar to yesterday, the CWA is situated between an upper trough over the Mid-Atlantic States and an upper ridge centered over TX and LA. The GFS and NAM are progging a couple weak 500-mb disturbances to dive southeastward within the NW flow today, which should act as a focus for convection and thus higher PoPs mainly across the western half or so of the CWA. Still, the entire CWA will see the possibility for scattered showers and thunderstorms this afternoon and evening as daytime heating and PWATs of 1.8" to 2.2" help generate SBCAPE values around 1000-2000 J/kg. A few strong storms cannot be ruled out with the main threats being locally heavy rainfall and gusty winds. Progressive storm motion should preclude any isolated flash flooding concerns. A similar synoptic setup is on tap for Sunday, although the upper ridge will amplify a bit across the central U.S. and flatten the upper trough, pushing it further up the Eastern Seaboard. Scattered showers and thunderstorms are expected once again tomorrow afternoon and evening across north and central Georgia, and a few storms could be strong with locally heavy rainfall and gusty winds. Martin LONG TERM /Sunday Night through Friday/... Upper flow pattern begins to shift to the north Sunday evening into Monday as the FA finds itself sandwiched between an upper high to the west and an upper low to the NE. By Monday afternoon the aforementioned upper level low will begin to pull northward allowing the upper high to expand across the southeastern CONUS. In response to this expansion suppression combined with drier air being advected into the mid and upper levels will result in decreased PoP coverage area wide Tuesday. The effects of the upper high will be short lived as it retrogrades westward Wednesday and a Bermuda High sets up to the east. With the CWA now sandwiched between two upper level highs deep layer moisture will be allowed to return to the region thanks in part to a strong return flow off the Atlantic. This pattern will favor increase PoPs each day starting Wednesday through the end of the week. Further enhancing moistures levels will be a weak open tropical wave that will nose into the area from the Florida Big Bend Thursday. All of that being said, one can expect a hot and humid weather pattern with usual summer time diurnal convection mid week and on. 28 && .AVIATION... 12Z Update... IFR and LIFR cigs have overspread much of north GA this morning. Have BKN007 at ATL until 14z, after which cigs should lift to low- MVFR. Upper-MVFR to VFR cigs (around 030-040) are expected through the afternoon. An upper-level disturbance will track southeastward over western GA in the afternoon, so have enough confidence to do a TEMPO at KATL for TSRA from 18z to 22z. Winds will be west around 5-10 kts, aside from any brief, gusty t-storm winds. With ample low-level moisture remaining in place, cigs should drop late tonight into Sunday morning, likely to IFR to LIFR again. //ATL Confidence...12Z Update... Medium confidence on timing of cigs lifting, and on afternoon convection. High confidence on all other elements. Martin && .PRELIMINARY POINT TEMPS/POPS... Athens 88 71 90 71 / 30 20 30 10 Atlanta 86 71 89 72 / 50 30 30 10 Blairsville 83 65 86 64 / 30 20 30 20 Cartersville 85 70 90 71 / 60 30 30 10 Columbus 88 72 90 73 / 60 40 50 30 Gainesville 87 70 89 71 / 30 20 30 20 Macon 89 72 90 72 / 60 30 50 30 Rome 86 71 91 71 / 70 30 30 10 Peachtree City 86 70 89 71 / 50 30 40 20 Vidalia 90 74 89 74 / 40 30 60 40 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Martin LONG TERM....28 AVIATION...Martin