The threat for stronger to severe storms on Monday night is beginning to look a little more clear this evening as the latest model runs continue to show that the ingredients will be in place across Central Alabama late on Monday and into early Tuesday.
NWS Birmingham has updated the severe storm outlook for the event, with the Enhanced Risk pretty much staying similar to the earlier update, while the rest of Central Alabama is now in A Slight Risk for severe storms. The main window for severe storms continues to be from 4:00 pm Monday afternoon to 6:00 am Tuesday morning. The above graphic shows the breakdown in timing by location.
All modes of severe weather still remain possible: tornadoes, damaging winds up to or exceeding 70 MPH, and hail up to 1-inch in diameter or greater.
Here is the latest from the high-resolution NAM (18z run)…
Surface-based instability continues to be shown in the 500-1200 J/kg range, especially along and south of the I-59/20 and I-20 corridors. These values are more than enough to support and prolong any strong to severe storms.
Shear continues to look to be supportive and prolonging stronger to severe storms with values continuing to be above 40 knots and as high as 64 knots out ahead of the front.
Helicity looks to be just a tad weaker with this run, but values continue to be well over 250 m2s2. That means there is an increased threat of rotating updrafts which could lead to tornadoes within a supercell thunderstorm.
The significant tornado parameter values are still a little worrisome as those numbers are coming in as high as 4.5 over the extreme southern portions of the area, along with the 2.0s and 3.0s surrounding those higher values. The higher the value, the greater potential there is for a significant tornado.
While it doesn’t look like the main line of storms will move in until after 5:00 pm in the northwestern parts of the area, we could see a few cells form in the unstable air out in front of the line. If this occurs, we’ll have to watch those carefully as they could start spinning and potentially drop a tornado. While the odds for that are extremely low at this point, it is something that we’ll have to watch for. This is our secondary severe weather season for Central Alabama.
The line will be weakening slowly as it moves eastward through the area, but there will be enough instability and dynamics in place for the potential of strong to severe storms to continue through 6:00 am on Tuesday morning. I wouldn’t be surprised if those may stretch on a little longer into Tuesday morning until completely exiting the area.
Go ahead and have your safety kits prepared and your safe place ready to go just in case your location goes under a warning during the event on Monday night into Tuesday morning. Since this will be affecting some people while asleep, have multiple ways of getting an alert that will wake you up. If you have your Wireless Emergency Alerts deactivated on your phone, go ahead and reactivate them for this event. Be sure to have fresh batteries in your flashlights and in your NOAA WeatherRadios. Keep your smartphones charged and have a reliable news app downloaded that has the capability to show a live video feed so you can watch tornado coverage from your safe place.
I do not believe this is going to be a large outbreak, but all it takes is for one tornado to come down your street to make it a huge life-altering event. Be smart and be prepared. Be sure that your neighbors and the elderly know about the situation as well. If you live in a mobile or manufactured home, be sure you have a plan in place if a warning is issued for your location.
Have a great evening. If any updates are needed later tonight, I’ll have those posted. If not, I’ll have updates all throughout the day tomorrow and Tuesday.
Central Alabama Weather 