Area Forecast Discussion
Issued by NWS Birmingham, AL
Issued by NWS Birmingham, AL
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204 FXUS64 KBMX 170540 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 1240 AM CDT Tue Sep 17 2024 ...New AVIATION... .SHORT TERM... (Tonight through Wednesday) Issued at 834 PM CDT MON SEP 16 2024 Mid and upper level cloudiness covered much of the southwestern two thirds of the area this evening. Showers will remain limited to the far southwest and it will diminish completely by 10 pm. Drier air will continue slowly filtering in from the northeast overnight. These clouds and drier conditions will allow a low temperature gradient from northeast to southwest overnight. Due to the cooling and residual ground moisture, some localized fog may develop around sunrise. Otherwise, no changes planned to the messages overnight into Tuesday. 75 Previous short-term discussion: (This afternoon through Tuesday) Issued at 1253 PM CDT MON SEP 16 2024 Mostly rain-free conditions are ongoing across much of Central Alabama today, thanks to some drier air advecting in from the northeast both at the surface and at the mid-levels of the atmosphere. Mostly sunny skies aside from some scattered cu is being observed across eastern and northeastern counties, where highs today should be able to reach into the mid 80s. Meanwhile, the remnant low of what`s left of Francine continues to slowly move westward across Louisiana. A narrow corridor of showers continues to persist thanks to some lingering isentropic lift across Sumter and Marengo Counties this afternoon, along with broken mid-level clouds present across the southwestern half of Central Alabama. As drier air continues to filter into the region, clouds are expected to gradually decrease by this afternoon and evening, with rain chances also coming to an end. Highs are currently on track for the most part, but have been raised a few degrees where clouds have dissipated a bit earlier than expected. Highs should reach close to 80 degrees in the far southwest counties with mid to upper 80s expected elsewhere. Clouds are expected to mostly clear out overnight tonight, with temperatures dropping down into 60s areawide. As the temperatures drop toward the dewpoint with moist ground conditions and mostly calm winds, patchy fog will likely form during the early morning hours on Tuesday. There are still some uncertainties in terms of how low visibilities may get, but guidance trends are indicating that the boundary layer will likely decouple. We`ve added in at least patchy fog to the forecast to trend in that direction, and that may need to be updated as we go into the evening hours. Going into the day on Tuesday, an overall weakness in the 500mb pattern will emerge over much of the region, stretching from the central Gulf Coast northeastward to the Mid-Atlantic states. The potential tropical cyclone located just off the South Carolina coast will move inland to the northwest and become cut off from the main upper level flow. As the center of the low moves over the heart of the Smoky Mountains, we`ll stay on the dry southwest side of the system. The only mention of PoPs will be across the extreme southern counties as as warm front tries to lift northward from the Gulf Coast. The front should eventually stall across southern Alabama as it encounters northerly to northwesterly surface flow on the west side of the closed low over the Smokies. Dewpoints should be fairly comfortable with the northerly flow Tuesday afternoon in the 60s and even upper 50s across the far northeast counties. High temperatures with plenty of sunshine should top out in the mid to upper 80s areawide. 56/GDG && .LONG TERM... (Tuesday night through Sunday) Issued at 327 PM CDT MON SEP 16 2024 A slow-moving closed low will be centered over North Carolina on Wednesday with northwest flow across Alabama. As the low wobbles westward PWAT values may modestly increase, potentially supporting a non-zero chance of showers over eastern Alabama aided by daytime heating. However, there is not enough confidence to include rain in our newest forecast. As the trough begins to move eastward and a ridge amplifies to our west, a drier airmass will move in from the north. This pattern should continue through Sunday, resulting in an extended period of dry weather. 87/Grantham && .AVIATION... (06Z TAFS) Issued at 1238 AM CDT TUE SEP 17 2024 Mid and upper level cloudiness will continue over a large part of the area overnight. But some clear to partly cloudy conditions will develop as the drier air moves in from the northeast. Due to some cooling overnight and the residual moist ground conditions, some patchy fog may develop toward sunrise. Winds become northwest around 5 to 7 kts after 15 to 17z, with generally scattered mid to upper clouds and a few cumulus. Any rain activity should remain south of the TAF locations. 16 && .FIRE WEATHER... A low chance of rain will persist across the southern and southwestern portions of our area through Tuesday. Drier conditions with northwesterly flow is expected for the second half of the week. 20 foot winds should remain less than 10 mph through Thursday. Afternoon RH values above 40 percent are expected through Thursday. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 87 59 86 61 / 0 0 10 0 Anniston 86 61 86 63 / 0 0 10 0 Birmingham 86 62 86 64 / 0 0 10 0 Tuscaloosa 87 62 88 64 / 0 0 0 0 Calera 87 63 87 66 / 0 0 10 0 Auburn 86 64 87 66 / 0 0 10 0 Montgomery 87 66 89 66 / 10 10 10 0 Troy 85 65 86 65 / 20 10 20 0 && .BMX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...75 LONG TERM....87 AVIATION...16