810 FXUS64 KBMX 191931 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 231 PM CDT Tue Jun 19 2018 .SHORT TERM... Through Tonight. Upper level and surface ridging centered pretty much right over the area combined with warm air aloft have put a lid on anything more than isolated deeper convection so far today...and expect the trend to continue through the evening. Expect any showers that develop to be on the periphery of the ridge and/or over higher terrain north and east, but those will still remain few and far between. Dewpoints have finally mixed out a bit, but the exchange of humidity for heat is still resulting in a slightly warmer than normal hot June day. Any rain chances will diminish rapidly with sunset this evening as temperatures fall through the 80s under mostly clear skies to rest in the lower 70s mainly by morning. 02 .LONG TERM... Wednesday through Tuesday. High pressure continues to be in place over Central AL early Wednesday as troughing digs into the Central Plains, developing a low pressure system in Kansas. The troughing acts to flatten the ridge over the Gulf States through the day on Wednesday, which will shift our southerly winds more to the southwest. This more westerly shift will bring in the tropical moisture plume currently in South Texas up through MS and into northern portions of AL. As the troughing digs further into the Mid MS Valley, expect synoptic height falls and a few shortwave impulses to move through the base of the trough, helping to aid in thunderstorm development, mainly in northwestern portions of Central AL Wednesday night into Thursday. NAEFS, GEFS, and ENS all highlight anomalously high PWAT values nearing or reaching max climatology and 2-3 standard deviations above the mean for this time of year; therefore, expect efficient rain producers with these storms. The low pressure system strengthens Thursday into Friday as it moves through Missouri and into the Mid-MS River Valley. A few more shortwave impulses move through the base of the trough, aiding in afternoon convection. Considering the proximity of the upper trough and low pressure system, expect numerous showers and storms Thursday and Friday afternoons, with the best chances in the northwest portions of Central AL. I have increased PoPs to the 60% mark for the afternoons in these areas. I wouldn't be surprised to see some stronger storms, possibly borderline severe both Thursday and Friday afternoons across Central AL. At this point, my main concern would be for Friday afternoon as the trough axis pushes through the area. Ahead of the axis, upper level diffluence, CAPE values 2000-3000+ J/kg, and DCAPE exceeding 1000 J/kg should allow for stronger storms to develop and produce strong to marginally severe winds. The problem is with the lack of any substantial deep layer shear, even with the proximity of the low. Therefore, I don't expect any organized severe threat that would warrant an addition to the HWO this far in advance. Instead, expect scattered convection capable of heavy rainfall, gusty winds, and small hail with a slightly higher coverage compared to the typical summer day. After the trough axis passes Friday afternoon, models pick up on the ridge lifting slightly northward into our area again. Both the GFS and ECMWF show the frontal boundary from that low pressure system becoming stationary just to our north under generally zonal flow aloft. Therefore, along with the typical afternoon showers across most of Central AL, there could be higher coverage in the north closer to the stalled boundary. Southerly to southwesterly flow continues to bring in Gulf moisture into the area, so expect a return to the warm and muggy conditions for the weekend and into the beginning of next week. Model blends bring in heat indices that borderline heat advisory criteria Sunday through Tuesday thanks to the GFS component being on the warmer side. The GEFS does show anomalously high geopotential heights for the beginning of next week that would support the operational GFS , but the NAEFs and ENS aren't picking up on anything anomalous in the geopotential height or temp fields. Therefore, will go more towards climo on highs, dewpoints, and PoPs that far in advance until we get better model and ensemble agreement. 25/Owen && .AVIATION... 18Z TAF Discussion. VFR conds expected to prevail thru the forecast period. A deep layered ridge over Alabama will suppress cloud development and convective activity this afternoon with only isolated TSRA expected. Latest satellite indicates cumulus field developing in eastern sections of Alabama so could see brief broken clds around 4-5k ft vcnty ANB but sct clds should generally prevail. Coverage of TSRA will be too low to include at any specific TAF site. A light northerly flow will prevail across the forecast area throughout the period averaging 6 to 10 knots this afternoon and becoming light below 5 knots across the area after 00z. No significant restrictions due to fog overnight. 41 && .FIRE WEATHER... Lower rain chances continue for this afternoon and tomorrow, but cannot rule out few and far between isolated coverage each afternoon, especially over higher terrain. Patchy light fog and/or low clouds are by morning, mainly near locations that receive rainfall the previous day/evening. RH values remain well above critical values. There are no fire weather concerns at this time. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 71 91 71 87 71 / 10 20 40 60 50 Anniston 72 92 72 88 72 / 10 20 20 60 40 Birmingham 73 92 73 88 73 / 10 30 30 60 50 Tuscaloosa 74 94 74 90 74 / 10 30 30 60 50 Calera 73 92 73 88 73 / 10 20 20 60 40 Auburn 74 92 74 89 74 / 10 20 20 50 30 Montgomery 74 94 74 91 74 / 10 20 20 50 40 Troy 74 93 74 90 74 / 10 20 20 40 30 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$