Area Forecast Discussion
Issued by NWS Birmingham, AL
Issued by NWS Birmingham, AL
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739 FXUS64 KBMX 301930 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 230 PM CDT Sun Jun 30 2024 ...New LONG TERM... .SHORT TERM... (This afternoon through Monday) Issued at 1150 AM CDT SUN JUN 30 2024 A boundary will move south through the area this afternoon and evening, with showers and thunderstorms expected to develop ahead the boundary. Instabilities will be between around 3000 J/kg with shear around 30-40 kts. PW values will be max for this time of year, around 2 inches. Would expect a few thunderstorms could be strong with gusty winds and high rainfall rates. Activity will be scattered through the afternoon, becoming more isolated this evening as the boundary moves south and drier air advects into the state. High temperatures are expected to be in the 90s, and with so much low level moisture, heat indices will be between 105 to 110. Will keep the Heat Advisory going through the afternoon and early evening. Tonight, dry air will advect into the state with clearing expected from north to south through the night. High pressure develops over the MS River Valley and northerly flow will prevail tonight and Monday. Low temperatures are expected to be in the upper 60s and lower 70s. Monday, the boundary is expected to slow down and stall somewhere around the southeastern counties, in an area of I85 and southeastward. Areas south of the boundary could see additional showers and thunderstorms through the afternoon Monday, though areas north should remain dry. PW values will remain close to max in the areas south of the boundary, with instabilities around 1000-2500 J/kg. North of the boundary, PW values will be down to the 50th percentile. High temperatures will be in the upper 80s to lower 90s, and thanks the drier air, the heat indices will be in the upper 80s in the north, to the mid 90s mid state, to triple digits in the south, closer to that boundary. Will assess if an additional Heat Advisory is needed for Monday afternoon in the southern counties. 24 && .LONG TERM... (Monday night through next Saturday) Issued at 225 PM CDT SUN JUN 30 2024 The extended model suite has the large scale pattern exhibiting little change from the previous forecast. At the start of the period, the jet stream was meandering on both sides of the US/Canadian Border while a strong upper level ridge was centered just to our immediate west. This ridge hangs over Central Alabama through at least Thursday. Successive systems dive into the trough in the Northern Plains eventually carving out a deeper trough. This trough ends up nudging the ridge eastward by next weekend. Closer to the surface, model guidance has exhibited little change. Therefore, will maintain the previous forecast discussion reasoning for pops and Heat Indices through the week. If you haven`t noticed, summer has arrived. Farther south, the tropics do remain active. But at this juncture, the NHC does not advertise any activity near the Central Gulf Coast. 75 Previous long-term discussion: (Monday night through next Saturday) Issued at 321 AM CDT SUN JUN 30 2024 Key message: - Heat and humidity will build through the week with heat indices at or above 105 degrees across much of Central Alabama by the time the holiday weekend arrives. A strong subtropical ridge will meander across the Southeast through the rest of the week, resulting in continued mainly above normal temperatures and keeping diurnal convection from becoming too widespread. At the surface, a 1025mb high moving eastward into the Mid-Atlantic will cause a "cool" air damming wedge to build down the East Coast. Lingering higher dew points will push westward from Georgia in advance of the wedge front putting an end to the temporary humidity reprieve. With low-level southeasterly flow and weak isentropic lift a couple showers or a storms will be possible in our southeast counties Monday night. The wedge arrives on Tuesday with noticeable easterly winds. It will keep highs in portions of East Alabama in the 80s, while West Alabama remains hot with heat indices just under 105. Isolated to widely scattered showers and storms will be possible with sufficient low-level moisture, but very dry air aloft should limit coverage and think NBM PoPs are too high. The wedge weakens by Wednesday, and expect gradually warming temperatures and heat indices through the rest of the week with coverage of areas with 105+ degree heat indices increasing through the week. Expect just isolated to widely scattered showers and storms Wednesday and Thursday afternoons. Friday into Saturday a weakness in the ridge will eventually develop due to a trough in the westerlies, potentially resulting in an increasing coverage of convection. 32/Davis && .AVIATION... (18Z TAFS) Issued at 1150 AM CDT SUN JUN 30 2024 Scattered to numerous showers and thunderstorms will move through the state this afternoon and evening. Low level moisture is max for this time of year, so any activity that moves over a TAF site will likely drop visibilities to IFR or LIFR. Have included VCSH at most TAF sites for now due to uncertainties in timing, and will amend when confidence increases. The boundary bringing this activity will stall somewhere around or south of KMGM. Fog development is possible at KMGM in the early morning, but left mention out of TAF for now due to uncertainty where the boundary stalls. Mostly clear skies and dry weather is expected through the day Monday. Note: AMD NOT SKED for KASN due to missing ceilings. 24 && .FIRE WEATHER... Scattered to numerous showers and storms will occur through the afternoon hours, with decreasing activity tonight. A drier air mass temporarily moves in on Monday with RH values in the 30 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 8 mph, southeasterly 5 to 10 mph Tuesday. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 71 92 68 91 / 20 0 0 10 Anniston 73 92 72 89 / 20 10 10 20 Birmingham 73 94 73 92 / 20 0 0 20 Tuscaloosa 73 94 71 95 / 20 0 0 20 Calera 74 94 74 92 / 20 10 0 20 Auburn 75 94 74 85 / 30 20 20 40 Montgomery 75 95 74 90 / 40 10 10 50 Troy 73 96 73 87 / 50 20 20 60 && .BMX WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 7 PM CDT this evening 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....75 AVIATION...24