Area Forecast Discussion
Issued by NWS Birmingham, AL
Issued by NWS Birmingham, AL
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200 FXUS64 KBMX 252104 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 404 PM CDT Sat May 25 2024 ...New LONG TERM... .SHORT TERM... (This evening through Sunday) Issued at 125 PM CDT SAT MAY 25 2024 Strong to severe storms have developed late this morning and into the early afternoon associated with a synoptic upper level shortwave impulse and mesoscale boundary triggers at the surface. There`s no doubt we`ve got plenty of instability to work with, as the 12z KBMX sounding this morning measured almost 3000 J/kg of SBCAPE before sunrise. With daytime heating, sufficient effective bulk shear values between 30 and 40 knots, and DCAPE values between 700 and 1000 J/kg, isolated severe wind gusts along with large hail will be possible across the far southeast counties through this afternoon. For the remainder of the area, the forecast remains quite uncertain in terms of overall coverage of storms. Westerly to northwesterly flow aloft will continue, with upper level shortwave impulses expected to move across Central Alabama. At the very least through the remainder of the afternoon and evening, isolated to scattered showers and storms are expected to develop along and south of the I-20 corridor. These storms are expected to also be on the strong side, with isolated severe storms also not out of the question. Hail and gusty winds will be the main hazards. At this point, we aren`t anticipating any widespread development in the form of an MCS, but mesoscale trends will continue to be monitored through the evening and overnight hours. I`ve adjusted highs a degree or two more this afternoon based on current trends, with most of the western and southwestern locations hitting the 90 degree mark or just above. For now, barring any further development the overnight forecast is fairly quiet with a lingering slight chance of a storm through midnight. Patchy fog development is also possible overnight as low-level clouds eventually clear out with light winds. Sunday appears to be a calmer day, as upper level heights will actually increase as a 594 decameter ridge builds over the central Gulf of Mexico. That will help winds aloft become more westerly to west- southwesterly by Sunday afternoon. If we get any convective activity during the day on Sunday, it should remain across the far northern counties. Rain chances will then increase across the northwest counties in response to the upper trough axis moving eastward over the plains states and approaching surface front in Arkansas. Hot and humid conditions are expected due to the lack of showers and storms with highs in the lower 90s in most locations. Heat indices will approach the 100 degree mark during the peak heating of the day. 56/GDG && .LONG TERM... (Sunday night through next Friday) Issued at 346 PM CDT SAT MAY 25 2024 The main story in the extended continues to be late Sunday night into Monday as the main upper system is expected to move through with some strong to severe storms possible. A second additional wave of convection may occur during the afternoon hours with heating before the surface system is through. After that, milder/ rain free conditions are expected for the second half of the week as ridging takes hold for Tuesday through Friday. 08 Previous long-term discussion: (Sunday night through next Friday) Issued at 327 AM CDT SAT MAY 25 2024 The main upper level trough is expected to slide through the region late Sunday night through the overnight hours into Monday. This upper wave will provide the forcing for showers and thunderstorms across Central AL. There will be enough instability in place, along with modest deep layer shear to support a few strong to severe storms overnight Sunday night into Monday. After the initial upper wave moves through, guidance suggests the surface boundary could trigger additional convection during the afternoon/evening hours on Monday as it moves through. Drier conditions expected Tuesday through Friday as the main trough remains to our east and broad ridging sets up to our west. Some guidance tries to bring a few waves down in this northwesterly flow, but this hasn`t been consistent. Most guidance shows the ridging winning out leading to mostly dry conditions for much of the upcoming week. 25/Owen && .AVIATION... (18Z TAFS) Issued at 125 PM CDT SAT MAY 25 2024 The best chances for TSRA this afternoon will be across the SE TAFs at MGM/TOI closest to a complex of storms that has developed. Elsewhere to the N and W activity will be more scattered and confidence is not as high to include any TS in TAFs ATTM. Have some SH mentioned at times late this afternoon for all but TCL. MVFR and some IFR stratus (possible S...TOI) is possible to develop later tonight after 9/10z until about 15/16z with low level moisture. Only confident with enough moisture to also include MVFR patchy fog at TOI for now. Will be looking at future guidance to see if it is needed to be added elsewhere in next/later issuances. 08 && .FIRE WEATHER... Scattered showers and thunderstorms will continue into this evening. Another round of convection is expected again late Sunday night through Monday. 20 foot winds will be from the south to southwest at less than 5 mph this afternoon, increasing to 6 to 12 mph on Sunday. Patchy fog is possible across the eastern portions of the area as well. Min RH values will be near or above 45 percent through Monday, with overnight recoveries near 100%. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 67 89 68 88 / 20 10 60 60 Anniston 69 89 70 87 / 20 10 50 60 Birmingham 71 91 71 89 / 20 10 60 50 Tuscaloosa 72 92 72 90 / 20 10 60 40 Calera 70 90 72 89 / 20 10 50 50 Auburn 70 88 71 86 / 20 10 20 60 Montgomery 71 92 73 90 / 30 10 20 60 Troy 70 91 72 89 / 30 10 10 50 && .BMX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...56/GDG LONG TERM....08/25/Owen AVIATION...08