022 FXUS64 KBMX 130052 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 652 PM CST Sun Dec 12 2021 .UPDATE... Evening Update and 00Z Aviation. && .SHORT TERM... /Updated at 0640 PM CST Sun Dec 12 2021/ Satellite imagery is completely absent of cloud cover this evening. The 00z BMX Raob has a very dry atmosphere overhead where Precipitable Water is .13 inches. The sounding also displays a subsidence inversion and a near surface inversion. This has led to temperatures dropping quickly after sunset. Many locations are already in the 30s. The crossover temperature dropped into the mid 20s in spots north today, so we will monitor for potential of lower overnight lows. At this point, left lows as is and adjusted the trends. Surface high moves eastward on Monday allowing low level thicknesses and 850 temps to increase. Current forecast handles this well. 75 Previous short-term discussion: /Updated at 1134 AM CST Sun Dec 12 2021/ Through Monday. It's a crystal clear sky day across a vast majority of the Southeast this morning with a 1030mb surface ridge centered over Central Tennessee. Drier and cooler air has advected into the region from the north and northeast with most observation locations observing 20s and 30s dewpoints. Under sunny skies, 1000-850mb thicknesses will support highs reaching the low to mid 50s north to the lower 60s south. The current forecast is very much on track, and minimal changes have been made. We'll see frosty conditions in several locations by sunrise on Monday with good radiational cooling and light winds. Valley locations in the north will likely see a light freeze with temps in the upper 20s. Surface flow will quickly turn back from the southeast by midday on Monday as the surface ridge becomes centered over the east coast. We'll see modifying temperatures as a result, but low level moisture will remain fairly dry with dewpoints in the 30s and 40s. A few more clouds can be expected, especially across the south where additional moisture will be present from the surface to 700mb. Rain chances will remain at zero through the short term period. 56/GDG .LONG TERM... /Updated at 1217 PM CST Sun Dec 12 2021/ Tuesday through Saturday. Deep-layer ridging over the Southwest Gulf of Mexico will persist through the period, resulting in a generally zonal flow over the forecast area from Tuesday through Thursday. As a result, dry conditions will begin the long-term forecast period. Surface high pressure will reside to our east on Tuesday, supporting a dry conditions while a developing southerly flow in the low levels will result in gradually increasing temperatures and a return of higher low-level humidity values into the area. We will experience a noticable airmass change as lows will be in the 30s across the northeast Tuesday morning followed by highs approaching 70 Tuesday afternoon across the far southern counties. The ridging aloft will continue to build and amplify over the area, resulting in unseasonably high temperatures in the 70s across much of the forecast area Wednesday through Friday. Chances for a few showers are expected across the far north and northwest on Thursday through Friday as a cold front will push southeast into the Mid South Region. The front looks to stall to the northwest due to persistent high pressure to our southeast during this time. Surface high pressure is forecast to push further east of the area as mid-level troughing digs as it moves over the Ohio River Valley Friday into Saturday. A stalling cold front is expected to push into the Tennessee Valley Region at this time. The result will be increasing rain chances look from the northwest from Friday evening through Saturday as the front potentially stalls across the area acting as a low-level convergence focus. I capped PoPs in the isolated category range Friday into Saturday due to the inherent uncertainties of the pattern at this extended time frame. 05 && .AVIATION... 00Z TAF Discussion. Bone dry atmosphere will keep clouds away through the period. Localized fog may develop near waterways overnight, but no mention at any terminals. Calm winds overnight become southeast around 5kts on Monday. VFR the entire way. Note: AMD NOT SKED is appended at KBHM due to ASOS power loss until further notice. 75 && .FIRE WEATHER... Dry conditions with cooler temperatures will continue today through Monday. Minimum afternoon RH values will dip into the 35 to 45 percent range during this time. A southerly flow will develop in the lower levels Tuesday and persist through the end of the week resulting in a gradual increase in humidity and low- level moisture values. There will be the chance for isolated showers northwest Thursday followed by rain chances areawide on Friday through Saturday. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 29 61 34 64 42 / 0 0 0 0 0 Anniston 33 64 37 68 45 / 0 0 0 0 0 Birmingham 36 63 42 66 49 / 0 0 0 0 0 Tuscaloosa 34 63 44 68 50 / 0 0 0 0 0 Calera 35 63 44 68 50 / 0 0 0 0 0 Auburn 38 63 42 66 48 / 0 0 0 0 0 Montgomery 37 65 45 70 49 / 0 0 0 0 0 Troy 39 68 45 70 50 / 0 0 0 0 0 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$