Area Forecast Discussion
Issued by NWS Birmingham, AL
Issued by NWS Birmingham, AL
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964 FXUS64 KBMX 261816 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 116 PM CDT Wed Jun 26 2024 ...New SHORT TERM, AVIATION... .SHORT TERM... (This afternoon through Thursday) Issued at 111 PM CDT WED JUN 26 2024 Contrary to much of the 12Z guidance, a large coverage of showers and thunderstorms have already developed across much of central and eastern Mississippi and into western portions of central Alabama. Once the cu field began developing this morning, it didn`t take long for rain to start falling. This activity is being driven by a large increase in moisture associated with an approaching trough axis and cold front over the Midsouth region. There`s currently a moisture gradient over the area, and there`s still some drier air across the eastern half where dewpoints have once again mixed down into the lower to mid 60s. However, moisture will advect eastward with propagation of the trough, so expect further area-wide development of convection through the afternoon with the highest chance for rain focused generally along and west of I-65. This rain should give us some relief from the heat, but not soon enough as most areas have already reached the mid to upper 90s. Per RAP mesoanalysis, MUCAPE is around 3000-4000 J/kg in our west where dewpoints are in the lower 70s. While shear values are rather weak, some strong downbursts may produce damaging winds, and storms could also produce torrential downpours with PWATs around 2". There`s been an increasing signal of scattered showers and storms continuing overnight and into tomorrow as the cold front and strong PVA move southward into the area. Some hi-res models are even resolving an MVC-like feature over the area early tomorrow morning which would further support additional rain and thunderstorms. So luckily, the odds at receiving beneficial rain seem to be improving for the next 24 hours. The scattered to numerous showers and cloudy skies will keep temperatures in the 80s tomorrow. 86/Martin && .LONG TERM... (Thursday night through next Tuesday) Issued at 346 AM CDT WED JUN 26 2024 Key message: - Hot and increasingly humid conditions are expected this weekend into next week, with heat indices at or above 105 degrees at times, especially Sunday. Scattered showers and storms will also be possible each afternoon. Subtropical ridging will continue to build eastward into northern Alabama Friday, while a weakness in the ridge will remain along the Gulf Coast and up into Central Georgia. Weak low-level flow will become southwesterly, helping maintain lower 70s dew points. PWATs look to range from around 1.6 inches in West Alabama to near 2 inches in East Alabama. Scattered showers and storms are expected to develop with daytime heating, with the highest chances in East Alabama where the best moisture will be and near the weakness in the ridge, and near possible remnants of an MCV. Updraft intensity should be muted by warm mid-level temperatures (500mb temps near -2C) which may limit lightning activity. Guidance has trended slightly lower on highs with the ridge not building in as quick, so heat indices look to remain less than 105 degrees. Subtropical ridging strengthens to around 596 decameters on Saturday. Despite the strength of the ridge, PWATs at or above 2 inches should still allow for some scattered showers and (weak) storms to develop, highest chances once again east. With the moisture, guidance has trended slightly less hot, but with elevated dew points a few spots could see heat indices approaching 105 depending on the competing factors of increasing Gulf moisture and dry ground conditions. Meanwhile a shortwave moving through the Great Lakes will cause a cold front to sink southward into Tennessee on Sunday. Slight height falls occur over Central Alabama as the ridge retrogrades a bit westward. Higher dew points pooling south of the boundary will result in the potential for heat indices to reach 105 degrees across much of Central Alabama depending on how quickly convection initiates in the tropical-like air mass. Latest guidance is suggesting the lower dew points with the front may slip southward into our northern counties Monday and Tuesday. This would result in some reduced rain chances in the north, with a less humid but still hot air mass. Meanwhile, enhanced dew points along and south of the boundary will result in the potential for heat indices in the 105-110 range. Exact placement of this boundary is subject to change, though. Meanwhile, the ridge looks to build back to the east Tuesday resulting in increasing temperatures as we go through the holiday week. 32/Davis && .AVIATION... (18Z TAFS) Issued at 111 PM CDT WED JUN 26 2024 Convection will spread eastward across the area this afternoon as a cold front moves towards the region. Added TEMPOs at most TAF sites for TSRA with PROB30s continuing overnight. Ceilings are expected to plummet overnight with IFR conditions developing as early as 07-08Z. 86/Martin && .FIRE WEATHER... Moisture and chances for showers and storms increase across West Alabama today, while RH values in East Alabama will still drop into the 25 to 35 percent range. Scattered, mainly afternoon and evening showers and storms are expected Thursday into the weekend, with the highest coverage in the southeast. RH values will stay above 45 percent in most areas. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 70 88 70 94 / 40 40 10 30 Anniston 72 89 72 93 / 40 50 10 40 Birmingham 72 89 73 95 / 40 40 10 30 Tuscaloosa 71 88 73 94 / 50 40 10 20 Calera 73 89 73 96 / 40 50 10 30 Auburn 73 89 72 93 / 20 60 20 40 Montgomery 73 90 73 94 / 40 60 20 40 Troy 72 89 71 93 / 30 60 30 50 && .BMX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...86/Martin LONG TERM....32 AVIATION...86/Martin