James Spann: Significant severe weather threat ahead for Alabama as the weekend begins

ONE MORE DRY DAY: With a partly to mostly sunny sky today, we project a high between 75 and 80 degrees. Clouds will increase tonight, and a few showers and thunderstorms are likely Thursday. The Storm Prediction Center (SPC) maintains a marginal risk of severe thunderstorms across much of the state Thursday.

A few of the heavier storms could produce strong wind gusts and small hail, but dynamics are weak, and the overall severe weather threat is low.

Much of the day Friday will be dry; it will be warm and breezy, with a high between 76 and 82 degrees.

SIGNIFICANT SEVERE WEATHER THREAT: A high-end severe weather risk is setting up for Alabama in the broad window from 9 p.m. Friday through 6 a.m. Sunday. All of Alabama is in an enhanced risk as defined by the SPC. There will be two primary rounds of thunderstorms.

FRIDAY NIGHT/SATURDAY MORNING: The first batch of storms associated with this very dynamic storm system will move into northwest Alabama Friday night. These storms will continue into Saturday morning over the northern half of the state; hail and damaging winds are possible, along with an isolated tornado or two.

SATURDAY AFTERNOON/SATURDAY NIGHT: This will likely be the main show. Storms will be capable of producing large hail, damaging winds and tornadoes. Based on forecast parameters, a few strong tornadoes will be possible (EF-2 or higher). These storms should be out of the state by daybreak Sunday.

A few important notes:

• It is helpful to look and see what an atmospheric setup like this has produced in the past. Some of the analogs that are showing up include April 8, 1998, Dec. 16, 2000, and Nov. 24, 2001. These days all featured numerous severe thunderstorms including some very significant tornadoes.
• April 27, 2011, is not an analog for this event. Days like that tend to happen every 40 years or so.
• We have to walk a very fine line between introducing fear and describing the potential for a high-end weather event. For those who have weather anxiety, just remember than even during high-end severe weather events, odds of any spot being hit by a tornado are relatively low. But stronger wording is appropriate for this type of threat.
• Our goal for any severe weather event in Alabama is no loss of life and no serious injuries. It takes us all working together to make that happen. The most important part of preparedness is to be sure you have a reliable way of hearing warnings — never, ever an outdoor siren. Never. A NOAA Weather Radio should be in every Alabama home and business. On your phone, have Wireless Emergency Alerts enabled and have the 33/40 weather app installed.
• In your safe place, have helmets for everyone, including adults. Most serious injuries in tornadoes involve blunt-force trauma above the shoulders.
• If you live in a mobile home, know the location of the nearest shelter, or a business open 24/7 that can serve as a shelter. Have transportation arranged so you can get there quickly.
• If you are reading this, you pay attention to weather. Many people don’t keep up with the weather, so you can be a hero during the severe weather event. If you have a friend or loved one in a tornado warning polygon, be sure and call or text them to let them know of the immediate danger. Let them know now that severe storms are likely late Friday night through early Sunday morning.

Soon we will be within the 60-hour window, when high-resolution model data will be available. This is when we can be more specific about timing and the event in general.

Look for a clearing sky Sunday with a high in the upper 60s and low 70s.

NEXT WEEK: Much of the week will be dry and mild, but we will mention a chance of showers and thunderstorms Wednesday with a surface front passing through. For now, this doesn’t look like a severe weather setup.

ON THIS DATE IN 1993: The generational “Blizzard of ’93” was underway. All 67 Alabama counties had measurable snow. Winds gusted to nearly hurricane force on ridges with white-out conditions. Snow amounts of 1 to 2 feet were common over the northern half of the state, with drifts to 4 feet. There was a lot of eerie green lightning followed by the muffled sound of thunder during the peak of the storm. With the atmosphere overloaded with big snowflakes, part of the sound of thunder was absorbed.

Some had no power for more than a week. We forecast 6 to 16 inches of snow going into the event, but many didn’t listen since it was mid-March, the flowers were blooming and the high on March 10, 1993 (two days before the blizzard) was 75.

The storm dropped 13 inches at the Birmingham International Airport, where the records are kept, and almost 2 feet across parts of southern Jefferson and northern Shelby counties. The heaviest snow across the Southeast was 5 feet recorded at Newfound Gap, where U.S. 441 crosses the Tennessee and North Carolina border.

For more weather news and information from James Spann and his team, visit AlabamaWx.