122 FXUS64 KBMX 251145 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 645 AM CDT Sat Mar 25 2017 .UPDATE... For 12Z Aviation. && .SHORT TERM... Taking a peek at current radar this morning the prefrontal moistening boundary is currently working into the area this morning. This are may provide just a few isolated showers to the northwest. No real impact from it at this time. Further west the main line that we will be watching today is already fairly strong to isolated severe this morning. Individual cells are moving northeast along the line while the line itself is working eastward and will continue to do so during the morning. Overall timing will put the edge of the line into the far western counties by 9 to 10 AM and then move eastward through the day. Showers and storms are a pretty much given for most of the area through tonight with activity generally staying west of an Auburn to Brundidge line during the day. Temperatures of course will be a nightmare trying to stay on top of but the warmest will be in the southeast where he rain holds off. If we get any more sun than forecasted in the southeast then mid 80s can not not be ruled out. As for temperatures in the west, look for readings to stay in the 60s to low 70s with the clouds and rain. As the rain moves out temperatures may warm into the low 70s in the northwest, where less sky cover is expected. For areas in between these two areas. the high will depend on the exact timing of the onset of the rain. Temperatures in the forecast are based on the HRRR and then smoothed so there could be some variability in the forecast versus the observed temperatures. So what about the severe potential. Most of the western half of the area is under a slight risk, while most of the eastern half is under a marginal threat. Main impacts will be damaging winds and possibly some hail. Winds overall are uni-directional so not much in the way of rotation to play with. We will also see some of the wind fields begin to decrease during the afternoon. Lapse rates are also weak across the area as well. So while there are some negatives to the overall strength of the storms, there are some positives as well. Just the pure dynamical forcing of the line itself, precipitation loading and warm spring temperatures during the peak heating of the day will help increase the potential of marginally severe winds with the strongest storms, especially with any line segment bowing observed on radar. Most of the activity will exit stage right by 7 to 8 PM tonight and the severe threat will decrease. 16 .LONG TERM... Moist southwesterly low-level flow will remain in place on Sunday as the upper trough takes a poleward turn toward the Ohio Valley, causing the surface cold front to fizzle to our west. Daytime heating will aid in the development of scattered showers and perhaps a few thunderstorms. The next system in the parade will move eastward from the Plains on Monday with our next chance of storms. SBCAPE is still expected to reach 1000-2000 J/kg with steep lapse rates spreading eastward across MS into West AL. The compact nature of the trough should allow a moderate amount of lift/forcing to overlap with appreciable instability. 0-6km shear of 35-45 kt will support storm clusters and supercells capable of producing hail possibly larger than quarter size and damaging winds. The tornado threat continues to appear very low due to marginal surface to 700mb shear. Convection could linger into Tuesday morning across the North with a moist southwesterly fetch remaining in place. We should get a bit of a break for Wednesday as a 500 mb ridge amplifies over the region ahead of yet another upper trough. This system will probably carry another chance for severe storms on Thursday and could end up being the most impressive in the series. By this time, a large warm sector should be in place with the ECMWF indicating the potential for CAPE in the 2000-3000 J/kg range. 87/Grantham && .AVIATION... 12Z TAF Discussion. Shifting all eyes to the west as we watch a storm system slide toward the area. This system will affect all terminals today, tracking west to east across the state. We should begin with spotty/VCSH showers before a line of thunderstorms moves through. Sub-VFR conditions are expected with the convection (visibility and/or ceilings). Given the surface front hanging upstream, areas of lingering showers/storms are possible through 06Z. There could be some redevelopment along the front overnight and will need to monitor that to see if any inclusion of showers and storms will need to be added then. 16 && .FIRE WEATHER... Low level moisture will gradually increases today from west to east as a line of strong to possibly severe storms moves across central Alabama during the day. Rain chances will continue tonight and into Sunday due to a moist southwest flow holding over the area. An active weather pattern will continue into next week. Critical fire weather conditions are not expected through the next 7 days. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 78 59 75 58 77 / 90 90 60 20 60 Anniston 77 59 76 59 78 / 80 90 50 20 60 Birmingham 78 60 78 60 79 / 90 80 50 20 60 Tuscaloosa 74 60 81 60 79 / 90 70 40 10 60 Calera 77 59 78 61 78 / 90 80 50 10 60 Auburn 79 58 77 59 78 / 60 70 40 10 40 Montgomery 79 60 83 61 81 / 90 90 40 10 40 Troy 79 60 81 61 82 / 60 80 40 10 30 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$