Area Forecast Discussion
Issued by NWS Birmingham, AL
Issued by NWS Birmingham, AL
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034 FXUS64 KBMX 081822 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 122 PM CDT Wed May 8 2024 ...New SHORT TERM... .SHORT TERM... (This evening through Thursday) Issued at 122 PM CDT WED MAY 8 2024 Key Messages: - Isolated showers and some thunderstorms this afternoon and evening, a few strong storms may develop. - A Mesoscale Convective System dives southeast into the area after midnight tonight and pushes southeast through the morning and into the afternoon hours. While gradually weakening in the morning, it may re-intensify before it exists our southeast counties Thursday afternoon. Damaging winds will be the primary risk, with large hail and a few tornadoes being possible as well. - Some thunderstorms may redevelop across North-Central Alabama Thursday late afternoon into the early evening that will have large hail potential, this risk will decrease in the evening as another MCS approaches our south-central counties from the west. This afternoon. The forecast area remains between a potent upper low over Southern South Dakota and mid-level ridging over the Gulf of Mexico, extending over the Southeast Atlantic Coast. A few areas of lower pressure were analyzed across the Central and Northern Plains where a cold front extended from near Omaha south to near Tulsa then southwest extending into Southwest Texas. A warm front extended from near Omaha east across the Ohio River Valley and into Western New York. An outflow boundary from ongoing widespread convection across the Northern Tennessee Valley Region extended from Southeast Missouri into Northeast Tennessee. Surface high pressure remains centered over the Southwest Atlantic Basin, continuing to extend westward across much of Florida. Isolated to scattered showers continue to move east-northeast across much of east-central Alabama as a weak disturbance is moving east over the area. Expect partly to mostly cloudy skies through the afternoon with continued chances for showers and some thunderstorm activity later this afternoon and into the early evening with the better potential across the northern third of the forecast area. A few storms may become strong, but organized severe storms are not forecast this afternoon. Winds will be from the south to southwest at 7-14 mph. High temperatures will range from the mid 80s far north to the low 90s far south. Tonight. The upper low over the North-Central Plains is forecast to open into a longwave trough this evening, with the eastern portion becoming highly amplified as it absorbs an embedded shortwave diving south over Minnesota. The increased upward forcing along with favorable jet dynamics will create conditions favoring the development of a Mesoscale Convective System (MCS) across southeast Missouri this evening then advance southeast across the Mid Mississippi River Valley Region and into the Tennessee Valley Region overnight. This activity will approach our far northwest counties just after midnight and will continue to push southeast, affecting the northern half of the area through the remainder of the morning hours. The primary risk will be with damaging straight- line winds, though large hail will be possible and we can not rule out a tornado or two given the combination of instability and wind shear associated with this system. Winds will be from the southwest at 6-12 mph, the low levels will remain well mixed to limit any potential fog development. Low temperatures will range from the mid 60s far north to the mid 70s southwest. Thursday. The MCS will continue moving southeast, affecting much of the southern half of the area through the afternoon hours. There are concerns for re-intensification of the MCS as it encounters a more buoyant and unstable airmass due to daytime heating. The primary risk will be with damaging straight-line winds, though large hail will be possible and we can not rule out a tornado or two given the combination of instability and wind shear associated with this system. There will remain chances for some redeveloping shower and thunderstorm activity behind the MCS, most likely during the late afternoon and into the early evening across at least the north- central counties. Residual favorable shear profiles would support a conditional risk for large hail in the heavier cores that manage to develop. This activity will give way to more widespread heavy convection that will be approaching the southern half of the forecast area from the west in the form of another MCS that will be pushing across Mississippi during the afternoon and early evening hours, which impacts to our south-central counties will be messaged in the first portion of the long-term forecast discussion. Through Thursday afternoon, expect winds outside of convection to remain from the southwest at 7-14 mph. High temperatures will range from the low 80s far east to around 90 southwest and far south. 05 && .LONG TERM... (Thursday night through next Tuesday) Issued at 355 AM CDT WED MAY 8 2024 A subtle mid-level speed max/southern stream shortwave is expected to help initiate convection ahead of the front over the ArkLaTex Thursday afternoon. As this feature moves eastward, it`s unclear if these storms will grow upscale into an MCS or if there will just be various clusters of storms. With a very unstable air mass and steep mid-level lapse rates of 7.5 to 8 C/km persisting south of the front, as well as strong bulk shear, the severe threat is expected to persist or re-develop Thursday evening through the overnight hours. In addition, a shortwave digging across the Mid- South will result in height falls across the area. Will indicate a Level 2 out of 5 slight risk focused across the southern half of the area for a continued threat of damaging winds as well as large hail with any supercells. Low-level shear appears too weak for a threat of tornadoes at this time. The cold front will push through the area Friday morning, providing welcome relief from the heat and storms. The upper low over the southwest CONUS will eventually move eastward early next week. Models have trended a bit quicker and wetter with this system 32/Davis && .AVIATION... (18Z TAFS) Issued at 1232 PM CDT WED MAY 8 2024 Scattered to broken clouds in the mid and upper levels will persist over the area today with isolated showers through early afternoon followed by some thunderstorm activity later this afternoon persisting into the evening, becoming more and more confined to the far northern portion of the area overnight, then expanding southward through the early to mid morning hours Thursday across the northern half of the area, then expanding southward encompassing our south-central counties toward midday and persisting through much of the afternoon. Thunderstorm potential today is too limited to mention at any terminal, but thunderstorm potential will increase through the morning and into the afternoon hours Thursday as widespread shower and storm activity push southeast across the area. Cloud cover will increase tonight across the north with MVFR ceilings possible overnight, then becoming more likely through the morning hours north and into then through the early afternoon hours south on Thursday. 05 && .FIRE WEATHER... Isolated to scattered showers and storms are possible this afternoon with greater rain chances overnight and Thursday. Rainfall amounts will average 0.5-1.0 inch under heavier storms. Afternoon minimum RH values will be above 45-50 percent this afternoon and then higher on Thursday. 20-foot winds will be 8-12 mph this afternoon and Thursday. Wind gusts to around 25 to 30 mph are possible near convection. Most of the rain will end by Friday afternoon, with a dry forecast through the weekend and first of next week. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 66 86 61 78 / 70 70 40 20 Anniston 68 84 64 78 / 50 70 50 20 Birmingham 71 87 63 78 / 50 70 50 20 Tuscaloosa 72 90 65 80 / 40 60 50 10 Calera 71 86 64 79 / 40 60 60 20 Auburn 71 82 67 80 / 30 60 60 40 Montgomery 73 89 67 82 / 20 60 60 40 Troy 72 90 68 83 / 20 60 60 50 && .BMX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...05 LONG TERM....32 AVIATION...05