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
088 FXUS64 KBMX 052053 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 353 PM CDT Sun May 5 2024 ...New LONG TERM... .SHORT TERM... (This afternoon through Monday) Issued at 1159 AM CDT SUN MAY 5 2024 This afternoon, southerly flow will bring moisture and warm air to the area. Isolated diurnal convection is expected across the entire state. A few thunderstorms could be momentarily strong with instabilities between 1500 and 2000 j/kg, and a weak wind profile aloft. Anything that does form could produce high rainfall rates with PW values around the 90th percentile for this time of year. Highs today will be in up to 5-7 degrees above normal. This evening, a weak low will approach from the east and move to the north and northeast across northern MS. Activity associated with this low is expected to move towards Alabama, but weaken as it reaches the state line. Scattered showers and thunderstorms will be expected with this system passing. The main coverage is going to be across the northern half of the state, closer to the system as it moves to the northeast. The southern half of the state could see isolated showers and maybe an isolated thunderstorm, though the greater instability and forcing will be across the northern half of the state. A weak mid level jet will move through overnight, allowing for the wind profile to increase in speed, though instabilities will be decreasing after sunset tonight. Will maintain that a few isolated storms in the northern half of the state could be strong with the forcing present. PW values will remain high with high rainfall rates possible. By early morning Monday, before sunrise, most activity should move east. With plenty of low level moisture, there could be fog in several areas, especially in the south and west where the rain will end earlier in the night, and the clouds are expected to become more broken. In areas of the north and east, overcast skies are expected to remain through much of the night, limiting fog development. Will have to keep an eye on how quickly/slowly the rain moves east to determine coverage of any fog that develops. Monday, upper levels take on a more westerly direction with PW values decreasing from around 1.6 to around 1.2 or 1.3 inches, which is around the 75th percentile. Isolated to scattered diurnal convection is expected through the early afternoon into the evening across all of Central AL. A few CAMs are showing increased instabilities, closer to around 2500 j/kg in the western half of the state , though the wind profile still appears weak. All activity should weaken with sunset. High temperatures on Monday will be several degrees above normal. 24 && .LONG TERM... (Monday night through next Saturday) Issued at 353 PM CDT SUN MAY 5 2024 Made minor adjustments to rain chances/rain areas through the beginning of the week, as a messy westerly to southwesterly flow brings opportunities for rain and storms. Temperatures remain warm, with highs in the upper 80s to lower 90s most days. Looking to the late week system, a cold front arrives Thursday afternoon as the shortwave moves off to the east. The airmass over the area will certainly carry quite a bit of instability with strong shear values for early May, with high lapse rates over 7.5 C/km. Will not include a mention of severe storms for Central Alabama at this time, for a few reasons. A MCS along the front will be ongoing to our northwest Wednesday night, likely racing ahead of any surface boundary. A decaying line of storms will move into the area in Thursday morning, likely stabilizing the airmass. Assuming the airmass recovers, upper level support is moving away from the area with briefly zonal flow aloft, when the front arrives in the northwest mid to late afternoon. Another shortwave rides along the front Thursday evening, resulting in convection across southern areas, where PWs approach 2 inches. The severe focus would likely shift to our south during this timeframe. 14 Previous long-term discussion: (Monday night through next Saturday) Issued at 335 AM CDT SUN MAY 5 2024 An unsettled weather pattern will be in place during the coming week. Shower and thunderstorm chances will run each day through early Friday morning, as a late season cold front sweeps through Central Alabama. Convection across the northwestern counties Tuesday and Wednesday may be strong and will need to be monitored for any isolated severe potential in the form of damaging wind and hail. Meanwhile, strong southerly surface flow will bring some of the warmest days so far this year. Winds may gust as high as 15-20 mph at times Tuesday, Wednesday, and Thursday. High temperatures will soar into the upper 80s, perhaps even lows 90s across the southern counties, Tuesday through Thursday. We are beginning to monitor the Thursday evening timeframe for the potential for strong to severe thunderstorms associated with an MCS- like setup moving west to east across the area. This, in advance of the aforementioned cold front, may pose a damaging wind and hail threat, owing to fairly steep lapse rates around 7.5 C/km and bulk shear values of 50-55 kts. However, the better forcing will be removed to the north of Alabama, so will need to further evaluate the potential over the next few forecast cycles. 12 && .AVIATION... (18Z TAFS) Issued at 1159 AM CDT SUN MAY 5 2024 Scattered showers and thunderstorms will develop across the state this afternoon. Due to uncertainty in timing and coverage, have left VCSH in for now and will update if convection appears to impact any TAF site. Overnight, a low pressure will bring more scattered activity, mainly to all sites but KMGM and KTOI through the early morning Monday. Plenty of low level moisture could keep clouds at MVFR overnight. Depending on timing and amount of rainfall overnight, KMGM and KTOI might see fog development. Confidence was low so left mention out of TAF for now. 24 && .FIRE WEATHER... Isolated to scattered showers and storms are possible each day through Tuesday. Rainfall amounts will average 0.5-1.0 inch under heavier storms. Afternoon minimum RH values will be above 40-45 percent each afternoon. 20- foot winds should average less than 10 mph from the south to southwest, though gusts to around 25 mph will be possible at times. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 65 86 64 87 / 60 40 20 40 Anniston 66 86 66 87 / 50 40 20 30 Birmingham 68 86 67 87 / 50 40 10 40 Tuscaloosa 68 86 68 87 / 50 40 10 40 Calera 68 85 67 85 / 50 40 10 40 Auburn 69 85 67 86 / 30 40 10 20 Montgomery 69 89 67 90 / 20 40 0 20 Troy 67 89 67 89 / 20 40 0 20 && .BMX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...24 LONG TERM....14 AVIATION...24