Area Forecast Discussion
Issued by NWS Birmingham, AL
Issued by NWS Birmingham, AL
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989 FXUS64 KBMX 231753 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 1253 PM CDT Sun Jun 23 2024 ...New SHORT TERM, AVIATION... .SHORT TERM... (This afternoon through Monday) Issued at 1247 PM CDT SUN JUN 23 2024 The base of a broad, low-amplitude trough is moving across the Ohio and Tennessee Valleys this afternoon. At the surface, a cold front is extending from the low near Quebec southwest through Indiana and towards the Missouri Bootheel. Some isolated showers are ongoing ahead of the front across parts of Tennessee and Arkansas, but it`s evident that the ridge is suppressing development. The center of the ridge is over the Desert Southwest and deep west to northwesterly flow has developed across Central Alabama. The front will make gradual progress towards the Gulf Coast region through tomorrow afternoon as the surface low shifts eastward across New England. Well above normal temperatures are set to continue through tomorrow and, as is typical of any frontal passage in June, a cooldown is not expected. Highs will reach the mid to upper 90s, and although dewpoints have already mixed down into the mid 60s this afternoon, they`re likely not to mix as much tomorrow due to the large increase in deep-layer moisture that will accompany the front. Dewpoints in the lower 70s will likely be focused across the southern half of the area during the hottest part of the day. There will be higher chances of seeing some heat indices at 105F in those areas, and a Heat Advisory may need to be coordinated soon. Additionally, CAMs continue to paint an opportunity for scattered showers and thunderstorms overnight as the front moves south. Not a lot of rain, but hopefully enough to wet some areas that have been drying out after repeated days in the 90s. A few storms may produce gusty winds, but organized severe weather is not expected due to poor lapse rates, weak shear, and relatively weak forcing. Drier air will quickly return across the north during the day tomorrow, so the increase in moisture looks to be short-lived. 86/Martin && .LONG TERM... (Monday night through next Saturday) Issued at 301 AM CDT SUN JUN 23 2024 Key messages: - The heat wave continues Tuesday with temperatures near 100 degrees areawide. Humidity levels have trended downward but heat indices may still reach 105 degrees in portions of West Alabama. - Showers and storms may be strong on Wednesday with gusty winds. - After a slight respite, the heat wave returns Friday through the weekend with potential for a prolonged period of heat indices near 105 degrees. While the center of the subtropical ridge will remain centered over New Mexico and the Texas Trans-Pecos on Tuesday, weak shortwave ridging will be present over Central Alabama aloft and at low-levels. An old frontal boundary/dry line like feature will be draped somewhere near our southern and western borders. With this feature trending further south and west, have reduced PoPs for isolated convection developing near the boundary, and also lowered dew points. The dry air mass and dry ground conditions will warm efficiently, with air temperatures near 100F across much of the area. With dew points mixing out more, heat indices have trended downward but may still reach 105 in parts of West Alabama. A weak convectively enhanced shortwave in northwest flow aloft will approach the area Wednesday with weak troughing developing over the Southeast and PWATs increasing to near 2 inches. Spread in the timing and placement of this feature has increased in the guidance, with some indications of slower/westward trend in some of the guidance. PoPs have decreased slightly in East Alabama where temperatures have increased. Will continue to monitor for any upstream MCS development with typical uncertainty regarding where this occurs and any gusty wind potential with thunderstorm clusters. The trough may linger near our southeast counties with enhanced rain chances there on Thursday, while ridging begins to build back to the east over the Lower Mississippi Valley. Thursday looks like the "coolest" day of the period with highs in the low to mid 90s. Strong subtropical ridging builds across the Southeast and Southern Plains Friday through the weekend while a couple weak easterly waves move near the Gulf Coast. The heat wave returns for Central Alabama but PWATs will be higher than the previous ridge, meaning more humidity and some isolated to scattered showers and storms. A prolonged period of heat indices near 105 may be setting up Friday through next weekend and beyond. 32/Davis && .AVIATION... (18Z TAFS) Issued at 1247 PM CDT SUN JUN 23 2024 VFR conditions are expected to continue for much of this period. A weak front will move south through the area overnight resulting in an increase in cloud cover. Scattered convection along the front may produce some aviation impacts, but improvement is expected at all sites towards the end of this period. Sfc winds are from the west today at 5 to 10 kts with an occasional gust up to 15 kts, but speeds will decrease after 00Z. Winds take on more of a northwesterly heading tomorrow morning as the front moves south of the area. 86/Martin && .FIRE WEATHER... Dry conditions will continue through this afternoon. 20 foot winds become westerly at 4 to 6 mph. Afternoon RH values should range from 30 to 40 percent this afternoon. Overnight RH values will be above 80 percent. Scattered rain chances return tonight into Monday, with an increase in minimum RH values. RH values drop down into the 30 to 35 percent range on Tuesday in many areas. Isolated storms may be possible across the south and southwest on Tuesday, with better chances on Wednesday and Thursday. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 72 97 68 97 / 40 10 0 10 Anniston 73 96 69 97 / 40 10 0 10 Birmingham 76 98 74 99 / 40 10 0 10 Tuscaloosa 75 98 74 99 / 30 20 0 20 Calera 75 98 72 99 / 30 20 0 10 Auburn 73 95 73 97 / 30 30 10 10 Montgomery 75 96 74 98 / 20 30 10 20 Troy 74 97 73 98 / 10 30 10 20 && .BMX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...86/Martin LONG TERM....32 AVIATION...86/Martin