072 FXUS64 KBMX 031122 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 622 AM CDT Sun Apr 3 2022 .UPDATE... For 12Z Aviation. && .SHORT TERM... /Updated at 342 AM CDT Sun Apr 03 2022/ Today through Monday. A weak frontal boundary will scrape the NRN half of AL before fizzling out today as the main low moves EWD out of OH, across PA/NY, and into the Atlantic Ocean by this evening. Although a few clouds will pass across the NRN third of the state today in conjunction with the front, overall moisture will be shallow. No precipitation is expected with this boundary. Otherwise, once again after a cool start, we will have pleasant spring readings today. Similar temperatures are anticipated for tonight as this AM, but with our temperature gradient of coldest to warmest from NE-SW instead of N-S as the overall ridge across E Conus begins to shift toward the Atlantic Coast. Our airmass will modify some on Monday as winds turn to the SE and then S during the day with warmer air filtering back into the area from the Gulf of Mexico. 08 .LONG TERM... /Updated at 342 AM CDT Sun Apr 03 2022/ Tuesday through Saturday. Strong to severe storms possible both Tuesday and Wednesday. A positively tilted shortwave trough is expected to move through the Deep South on Tuesday, developing a weak surface low that will lift through the Mid-MS Valley into the TN Valley during the morning hours. Rain and thunderstorms will likely be ongoing late Monday night into early Tuesday as the warm front is slowly lifted northward across Central AL. South of the warm front, a broad warm sector will advect in across most of the region. A strengthening low level jet is expected to slide across the state with upper level diffluence aloft. However, guidance doesn't really show any surface- based convergent boundaries (cold front) moving through the area, which results in broad convection in the modestly unstable warm sector due to the mid and upper level forcing without any specific surface trigger mechanism. This evolution of the system casts quite a bit of uncertainty in regards to severe potential. The environment remains highly sheared and modestly unstable, so if any storms are able to become more organized, they could be strong to severe. Therefore, I'll continue mention a low-end severe threat for Tuesday with the best chances being across the southern counties (generally south of Hwy 80 corridor) where the better instability should be. There's relatively higher confidence in the potential for flooding across Central AL with this system as it moves through. The track of the system could result in some training of storms somewhere across our area, though the exact axis of heaviest rain has been bouncing around in model guidance. There could be 3-5" of rain in the axis of heaviest rain, wherever it sets up. If it ends up being over some of our urban areas, this could lead to flash flooding. The system moves quickly eastward and out of our area by Tuesday night, ending any significant rain chances by midnight. On Wednesday, a strong cold front is expected to push into Central AL. This cold front is associated with an occluding surface low in the Upper Midwest. Since we don't really see a frontal passage with the Tuesday system, surface winds remain generally southerly to southwesterly ahead of the front on Wednesday, which maintains the moist/unstable airmass across the area ahead of the frontal passage. Since we have the surface forcing and instability, we could see strong to severe storms develop along the boundary as it moves through Wednesday afternoon into the night. The major limiting factor with this system is the lack of upper level dynamic and little directional shear. Latest model guidance also develops a shortwave trough along the Gulf Coast well ahead of the frontal passage, which could lead to coastal convection contaminating the pre-frontal environment. However, if any storms are able to develop along the front, they certainly could pose a risk for gusty winds and large hail. The tornado threat continues to look low as surface winds veer to the southwest and become largely parallel to the front, which is expected when the surface low is displaced so far to the north. With that said, I can't completely rule out a tornado threat given the potential for storm interactions that are more mesoscale in nature and will need to be resolved closer to the event. The cold front is expected to move out of our area by Thursday morning, ending rain chances across Central AL. Colder and drier air will build in across the region as the deep upper level low slowly meanders through the Ohio Valley and the broader trough axis slides through towards the end of the week. It's possible we could see another early-season frost by Saturday morning with current forecast lows in the 34-37 degree range generally north of I-20 and I-22. 25/Owen && .AVIATION... 12Z TAF Discussion. VFR TAFs are expected to continue for the next 24 hours thanks to continued surface ridging. A weak frontal boundary scrapes by the region today to the N. Little if any clouds are expected over C AL. Most on satellite at this hour are over TN and far N AL, and they are not expected to make sufficient progress into C AL. Winds are light to near calm and will be northerly today in the wake of the boundary ~7-11kts. 08 && .FIRE WEATHER... Dry weather will continue through Monday. Min RHs will be 20-35% this afternoon and Monday afternoon. Sfc winds will be light northerly today, becoming southerly on Monday. A strong storm system will bring widespread showers and thunderstorms to the area on Tuesday. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 69 38 76 48 71 / 0 0 0 20 90 Anniston 69 41 76 53 73 / 0 0 0 20 100 Birmingham 70 45 77 54 72 / 0 0 0 30 100 Tuscaloosa 73 45 79 55 75 / 0 0 0 40 100 Calera 71 46 78 57 74 / 0 0 0 30 100 Auburn 72 46 76 55 71 / 0 0 0 20 100 Montgomery 76 45 80 56 76 / 0 0 0 30 100 Troy 77 47 81 57 75 / 0 0 0 30 100 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$ 08/25