Area Forecast Discussion
Issued by NWS Birmingham, AL
Issued by NWS Birmingham, AL
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918 FXUS64 KBMX 181604 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 1104 AM CDT Sat May 18 2024 ...New SHORT TERM, AVIATION... .SHORT TERM... (This afternoon through Sunday) Issued at 1102 AM CDT SAT MAY 18 2024 As has been the case the past 24 to 36 hours, the heaviest rain and convective activity has remained well to our south over the Gulf Coast region. A quasi-stationary boundary stretching from west to east along a New Orleans to Mobile to Dothan line continues to remain the focus for shower and storm development. Southwesterly deep layer shear across the atmospheric profile and plenty of tropical moisture will keep strong to severe storms and flash flood potential across the Florida Panhandle and far southeastern Alabama through the morning. Meanwhile, a surface low is spinning close to Memphis helping to trigger scattered to numerous showers and storms as cooler air works in aloft. We should continue to see storm development as we go through the remainder of the day, spreading southeastward with time. Areas along and north of the I-20 corridor will see the best coverage of showers and storms with sunshine starting to make an appearance following low clouds and fog early this morning. As low level instability increases, we`ll see enough shear aloft (60kts at 500mb) with steep lapse rates to support strong to isolated severe storms. With unidirectional shear profiles, isolated damaging wind gusts and large hail will be the hazards this afternoon through the early evening hours. Storms are expected to decrease in coverage with the loss of daytime heating during the evening hours tonight as the 500mb trough axis pushes off into Georgia. We`ll have to keep an eye on the potential for fog and low stratus development overnight tonight. High-res guidance is hinting that we may get enough clearing with calm winds for the development of fog between midnight tonight and sunrise Sunday morning. I`ve added in patchy fog in the forecast to trend that direction, but more widespread fog may need to be added in the next forecast update. Sunday will feature much drier conditions with northerly flow at 700mb. A surface ridge over the Mid-Atlantic and Carolinas will build southwestward by Sunday afternoon. What appears to be a "back door" surface boundary will creep westward into our far eastern counties, with some upper level shortwave energy to work with. A few isolated showers and perhaps a storm can`t be ruled out across the far east as a result. Otherwise, everyone else will be dry and warm as upper heights begin to rise. Mid to upper 80s will be common for highs by Sunday afternoon. 56/GDG && .LONG TERM... (Sunday night through next Friday) Issued at 304 AM CDT SAT MAY 18 2024 Early to mid next week appears warm and dry across the Deep South. A low-level ridge is progged to establish across the eastern CONUS with a broad zone of split upper-level flow. Southerly surface winds return to our area by Tuesday as high pressure centers near the East Coast, and this will help tilt afternoon highs into the 90s for some locations Tue & Wed. Meanwhile a lingering surface front will drape from near the ArkLaTex through the Ohio Valley on Thursday, behind a departing Great Lakes low pressure system. Medium-range guidance depicts this front near/north of the I-40 corridor, but with an axis of higher PWs spreading into the Tennessee Valley. As such, there could be isolated to scattered afternoon convection Thursday, but better PoPs are on Friday due to a shortwave currently progged to pass over the Tennessee Valley. It`s too early to tell if there will be any impacts. 40/Sizemore && .AVIATION... (18Z TAFS) Issued at 1102 AM CDT SAT MAY 18 2024 Lower ceilings will continue to mix out between 16 and 18z, with most terminals observing VFR conditions through the afternoon. SHRA/TSRA development is expected to impact northern terminals between 18z and 01z, with less coverage expected at MGM and TOI. Amendments can be expected this afternoon, with rapid reductions in visibility due to heavy rains along with variably gusty winds within thunderstorms. SHRA/TSRA will decrease in coverage during the evening hours between 03z and 06z. Low clouds and/or fog is then expected to develop areawide after 09z with IFR ceilings. Lower ceilings and fog should mix out between 13z and 15z Sunday morning with VFR conditions expected through 18z Sunday. 56/GDG && .FIRE WEATHER... An area of showers and storms will move across south Central Alabama this morning, before scattered to numerous showers and storms are expected area wide this afternoon and evening. Min RH values today will range from 65 to 75 percent, with southwesterly 20ft winds at less than 10mph. Rain chances decrease Sunday, and along with warmer daytime temperatures, minimum RH values will be in the 50 to 60 percent range. 20ft winds become north to northwesterly, but remain at 5-8mph. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 80 61 85 61 / 80 40 20 0 Anniston 79 62 84 63 / 70 50 20 0 Birmingham 81 63 85 65 / 80 40 10 0 Tuscaloosa 82 64 87 65 / 70 30 0 0 Calera 80 64 85 65 / 70 40 10 0 Auburn 77 64 82 64 / 70 50 20 0 Montgomery 81 65 85 65 / 60 50 10 0 Troy 79 65 84 64 / 80 40 10 0 && .BMX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...56/GDG LONG TERM....40 AVIATION...56/GDG