Area Forecast Discussion
Issued by NWS Birmingham, AL
Issued by NWS Birmingham, AL
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
904 FXUS64 KBMX 251837 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 137 PM CDT Wed Sep 25 2024 ...New SHORT TERM, AVIATION... .SHORT TERM... (This evening through Thursday) Issued at 1218 PM CDT WED SEP 25 2024 A weak boundary will move through the state today, from northwest to southeast. Ahead of this boundary, winds will be from the south, with instability around 2000 j/kg and decent shear. Scattered to widespread showers and thunderstorms will be moving through this area, with training possible as storms will move from southwest to northeast. While storms may be strong, the severe threat seems to be diminishing through the afternoon with convection more widespread. PW values will be around the 90th percentile today, and with training storms, a lot of areas will receive high rainfall rates with isolated flash flooding possible. Tonight, there could be a break in rain as the boundary weakens and the outer bands of Helene move approach the coast. Scattered activity will be possible, mainly in the east through the early morning hours. The outermost bands of helene will begin to impact the area beginning early Thursday, with widespread rain moving south to north, with coverage increasing through the day as Helene moves north. PW values will be at absolute max for this time of year, with more consistent coverage, and higher accumulation values in the east, with amounts decreasing incrementally the farther west of I65 the bands reach. A Flood Watch will remain in effect through Friday morning to account for the rain accumulations from the scattered activity today, and the widespread heavy rain expected to increase from Helene. Winds will begin increasing in response to Helene by early Thursday afternoon. with sustained winds up to 20 mph possible in the far southeastern counties, and winds around 15 mph throughout the rest of the area. A Tropical Storm Warning will be in effect through Friday morning to account for increasing winds and high rainfall totals. 24 && .LONG TERM... (Friday through next Tuesday) Issued at 337 AM CDT WED SEP 25 2024 Helene is expected to weaken to a tropical depression by Friday morning and then quickly becomes absorbed into the larger-scale cut- off low by Friday evening. There will be some wrap-around rainfall across the northern half of Central AL during the day on Friday before dry air gets wrapped in, decreasing the footprint of rainfall around the cut-off low Saturday through Sunday. This cut-off low persists over the region through at least Monday before shifting to our east Monday night into Tuesday. I won`t completely rule out some lingering shower activity under the closed upper level low over the weekend, but most guidance keeps the area rain-free, so my confidence to mention any rain chances is too low right now, but it`s something we`ll need to watch for in the next few days. 25/Owen && .AVIATION... (18Z TAFS) Issued at 1218 PM CDT WED SEP 25 2024 A boundary will allow for scattered to widespread showers and thunderstorms in the southeastern third of the area, with widespread showers in the northern two thirds of the area. A few sites may have a VC in the prevailing due to uncertainty in timing and coverage. Activity should weaken in the evening, with rain increasing from southeast to northwest through the day Thursday. Rainfall rates will be high with this activity so IFR conditions are possible in any activity over a TAF site. Winds will increase late in the TAF period as Helene approaches. 24 && .FIRE WEATHER... Increasing rain chances expected today through Thursday as a frontal boundary stalls across the area. Tropical moisture builds into the area ahead of the potential tropical cyclone today through Friday keeping Min RHs 60-70%+. Winds increase substantially on Thursday as the tropical system approaches. Gusts could exceed 30mph in the eastern half of Central AL. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 63 72 62 74 / 50 80 90 50 Anniston 65 73 65 77 / 70 90 90 40 Birmingham 64 73 64 75 / 30 80 80 50 Tuscaloosa 63 77 64 77 / 20 50 60 40 Calera 64 73 65 78 / 40 80 80 40 Auburn 67 74 65 78 / 90 100 90 20 Montgomery 68 75 65 80 / 80 80 80 20 Troy 69 75 64 79 / 80 90 80 10 && .BMX WATCHES/WARNINGS/ADVISORIES... Flood Watch through Friday morning for the following counties: Barbour-Bullock-Calhoun-Chambers-Cherokee-Clay-Cleburne-Coosa- Elmore-Etowah-Lee-Macon-Montgomery-Pike-Randolph-Russell-St. Clair-Talladega-Tallapoosa. Tropical Storm Warning for the following counties: Barbour- Bullock-Chambers-Lee-Macon-Pike-Russell. && $$ SHORT TERM...24 LONG TERM....25 AVIATION...24