Area Forecast Discussion
Issued by NWS Birmingham, AL
Issued by NWS Birmingham, AL
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169 FXUS64 KBMX 292340 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 640 PM CDT Sat Jun 29 2024 ...New AVIATION... .SHORT TERM... (This evening through Sunday) Issued at 1217 PM CDT SAT JUN 29 2024 Southwest flow through the early afternoon will bring plenty of moisture to the area with PW values around max climatologically for this time of year. Scattered to numerous showers will continue through the rest of the day and into the early evening. Instabilities are around 2000 to 2500 at most, with little to no shear. Would expected mostly rain, with isolated to scattered thunderstorms. Any activity today will produce high rain rates with so much moisture in the air. Later this afternoon into the evening, mid level winds begin to transition to out of the west as high pressure starts developing across the MS Gulf coast. High temperatures today will be in the upper 80s and lower 90s. Will keep a Heat Advisory across the northwestern counties where shower activity is expected to be more isolated and limited. Otherwise, the rest of the area could see heat indices into the lower 100s. Tonight, the mid level winds begin to transition to out of the north, advecting drier and cool air into the midlevels. Low level flow will remain out of the southwest through the morning. Plenty of moisture will remain at the surface for fog development again in the early morning, especially in areas that receive rain late tonight. By Sunday late morning, low level flow will transition to out of the northwest. Showers and thunderstorms are expected again on Sunday late morning through the afternoon. Instabilities will be higher Sunday afternoon thanks to that flow transition, with amounts up to 3000 J/kg possible. Shear will be slightly higher too, with 20-30 kt. Activity should be more isolated to scattered as opposed to the numerous coverage we see today, but there should be a higher chance for lightning and thunderstorms. Rain rates will continue to be high with PW values staying near max for this time of year. Temperatures on Sunday will be in the low to mid 90s. With the high amount of moisture present, heat indices could reach 105 or above for many places across the state. Have issued a Heat Advisory for tomorrow. 24 && .LONG TERM... (Sunday night through next Friday) Issued at 304 PM CDT SAT JUN 29 2024 Continued the trend for lowering rain chances as upper level ridging builds back over the region and drier air remains over the area to start the work week. Moisture returns by mid week and weaknesses in the ridge will keep isolated to scattered pops in the forecast each afternoon though the end of the week. Temperatures will be in the low to mid 90s with dewpoints staying in the low to mid 70s each afternoon. This will keep heat indices in the 103-106F range for portions of the area each afternoon. 14 Previous long-term discussion: (Sunday night through next Friday) Issued at 237 AM CDT SAT JUN 29 2024 Key message: - After a brief respite from the humidity Monday for all but far southern portions of Central Alabama, heat indices will increase through the week with values near or above 105 degrees including on Independence Day. Strong subtropical ridge will be centered over the ArkLaTex Sunday night and Monday, with northerly to northwesterly flow aloft over Central Alabama. Scattered showers and storms will be ongoing Sunday evening along a pre-frontal trough. A much drier air mass will move in on Monday. Have lowered PoPs below NBM and further reductions may be necessary. Heat indices will remain near 105 across the south, but lower humidity levels are expected across the north though the dry air mass will warm efficiently. The subtropical ridge will move eastward over the area Monday night through Tuesday night. The lower dew points will be short-lived as higher dew points return from the east late Monday night in advance of a back door wedge front building down the East Coast. Increasing moisture with southeasterly flow and convergence along the wedge front will result in chances for isolated to widely scattered showers and storms returning. Lower highs will occur on Tuesday in the far eastern counties with the wedge while temperatures remain warm in the west where a few spots could see heat indices reaching 105. Ridging builds aloft Wednesday and Thursday, with some model disagreement on whether a weakness begins to develop by Friday. A tropical-like air mass will result in mainly widely scattered afternoon and evening showers and storms. Increasing temperatures and dew points will result in increasing heat indices near or above 105 each day. 32/Davis && .AVIATION... (00Z TAFS) Issued at 635 PM CDT SAT JUN 29 2024 A bit less convection around compared to this time the last couple days, and I think we can say we`re fairly confident that most (if not all) central Alabama TAF locations will stay free from rain through tonight. Low level air mass is still seems to be quite juicy, although low level moisture forecasts off the computer models suggest that there may be less stratus formation overnight. We`ll see how that works out. On Sunday, winds come around to the northwest and start to bring in some drier low level air. My hunch is that the most coverage of showers and storms Sunday afternoon will be in the south, probably even south of MGM. Therefore, I chose to go with a PROB30 rather than a TEMPO condition in the afternoon. /61/ && .FIRE WEATHER... A humid air mass will remain in place over the weekend with scattered to numerous showers and storms. A drier air mass temporarily moves in on Monday with RH values in the 35 to 40 percent range across the northern half of Central Alabama, and 40 to 50 percent range across the south. Minimum RH values increase to above 45 percent areawide for Tuesday. Winds generally remain light Sunday, and become northerly Monday at 5 to 8mph. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 72 93 70 94 / 20 60 20 0 Anniston 73 93 72 93 / 20 70 20 10 Birmingham 74 93 73 95 / 20 70 20 0 Tuscaloosa 74 94 73 94 / 20 60 20 0 Calera 72 92 74 95 / 20 60 20 0 Auburn 72 92 74 94 / 30 60 40 40 Montgomery 73 94 74 96 / 30 70 40 30 Troy 73 92 73 95 / 40 70 40 50 && .BMX WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 9 PM CDT this evening for the following counties: Fayette-Greene-Lamar-Marion-Pickens-Sumter-Tuscaloosa- Walker-Winston. Heat Advisory from 10 AM to 7 PM CDT Sunday for the following counties: Autauga-Barbour-Bibb-Blount-Bullock-Calhoun-Chambers- Cherokee-Chilton-Clay-Cleburne-Coosa-Dallas-Elmore-Etowah- Fayette-Greene-Hale-Jefferson-Lamar-Lee-Lowndes-Macon-Marengo- Marion-Montgomery-Perry-Pickens-Pike-Randolph-Russell-Shelby-St. Clair-Sumter-Talladega-Tallapoosa-Tuscaloosa-Walker-Winston. && $$ SHORT TERM...24 LONG TERM....14 AVIATION.../61/