767 FXUS64 KBMX 190624 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 124 AM CDT Tue Oct 19 2021 .UPDATE... For 06Z Aviation. && .SHORT TERM... /Updated at 655 PM CDT Mon Oct 18 2021/ High pressure remains parked over the region. This high has produced cooler than normal conditions the past few days. The airmass will continue a slow moderation into Tuesday. Overnight lows will be a few degrees warmer than last night, but still below normal for mid October. Mostly clear skies continue tomorrow with temperatures near normal, 72 to 80 degrees. 75 Previous short-term discussion: /Updated at 146 PM CDT Mon Oct 18 2021/ Through Tuesday. A very nice mid-October day is currently upon us over Central Alabama, with only a few high cirrus clouds streaming overhead as a weak upper level shortwave moves across the Gulf Coast. Very dry air remains in place with low to mid 40s dewpoints currently being observed. We're a bit warmer than yesterday as the previous continental polar airmass begins to modify over the region following chilly overnight lows in the 30s and 40s. Good radiational cooling can be expected once again overnight tonight, but a touch warmer in the low to mid 40s. Surface high pressure will move off to our northeast over the southern Appalachians by Tuesday afternoon, producing a southeasterly flow at the surface across Central Alabama. As a result, moisture will increase slightly and temps will start to warm close to the 80 degree mark across the southern half of the area. Additional high clouds will stream from west to east as another weak shortwave moves in with southwesterly flow aloft and upper level ridging begins over the much of the Southeast. 56/GDG .LONG TERM... /Updated at 246 PM CDT Mon Oct 18 2021/ Looking at the next frontal system, have adjusted rain chances on the backside of the system, increasing rain chances for Thursday night across the east and Friday across the south. Models show the front lingering or potentially stalling. Moisture will eventually move out of the area, ending rain chances Friday night. Instability will increase ahead of the front Thursday, enough for a few thunderstorms. Forcing continues to pull away from the area and the best wind shear support does not quite line up with increased instability. Will cap rain chances around 50% and not include strong/severe storms. 14 Previous long-term discussion: /Updated at 234 AM CDT Mon Oct 18 2021/ Wednesday through Sunday. The center of the high pressure has moved just to our east by Wednesday morning, allowing for moisture advection to begin across MS and far southwestern portions of AL. We could see some isolated showers reach Marengo and Sumter Counties by Wednesday afternoon as a weak upper shortwave lifts through the area. A low pressure system will lift through the Upper Midwest and into the Great Lakes region Wednesday night into Thursday. As this takes place, a cold front gets pushed southeastward through the Gulf States, leading to increased rain chances, especially during the day on Thursday. Model guidance suggests that instability could work its way into the area just before the front moves in, so there could be some thunderstorm activity with this system. However, overall forcing will be decreasing with time as the center of the low lifts into Quebec around the time the frontal boundary reaches Central AL. Therefore, I don't think there would be enough shear to support strong/severe storm development. The front is expected to push to our south and east by Friday morning, ending rain/storm chances for most of Central AL. There's been some recent hints in model guidance that the frontal boundary could slow/stall across the region, but that solution isn't really supported in the ensembles, so I'll go with the more consistent model guidance that shows high pressure building back in across Central AL over the weekend under generally zonal flow aloft, limiting any rain chances through Sunday. 25/Owen && .AVIATION... 06Z TAF Discussion. Surface ridging is in place across E 1/3 of Conus and will remain generally so through the TAF period. Satellite is currently indicating some SCT cirrus about. With cool temperatures and near calm winds, some patchy valley and river fog may occur at times through early morning. Have only a mention at MGM at this time for MVFR vis. Light E-SE winds are expected during the late morning into the afternoon with mixing ~5-7kts. Note: AMD NOT SKED is appended at KBHM due to ASOS power loss until further notice. 08 && .FIRE WEATHER... A dry airmass will remain in place through tomorrow, with afternoon minimum RH values in the 35-45% range Tuesday. Increasing moisture ahead of a cold front will keep afternoon RH values above 50% Wednesday afternoon. Rain chances return late Wednesday night through Friday afternoon as a cold front moves through the region. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 75 49 77 57 76 / 0 0 0 30 50 Anniston 77 52 79 60 78 / 0 0 0 30 50 Birmingham 75 54 78 61 77 / 0 0 10 30 50 Tuscaloosa 76 56 78 63 78 / 0 0 10 40 50 Calera 75 55 78 62 76 / 0 0 10 40 50 Auburn 75 54 78 60 76 / 0 0 0 20 40 Montgomery 80 54 82 62 80 / 0 0 10 40 50 Troy 78 55 80 62 80 / 0 0 10 30 50 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$ 75/56/14/25/08