“Tornadoes are possible in this storm system,” said Brian Carcione. “Damaging winds, large hail, flash flooding, severe thunderstorms could accompany this system. It is the most impressive storm system we’ve seen in the past couple of years. It’ll be the first big storm of the spring season, and unfortunately, we have severe weather this time of the year.”

Carcione said thunder and lightning likely will occur in storms moving through Wednesday morning. “A first round of storms won’t be widespread early Wednesday,” he said. “It could be noisy in the morning, and if your area doesn’t see any storms that doesn’t mean it won’t develop. Our main concerns are during the day.

The NWS said Lawrence, Morgan and Limestone counties could be impacted by the storms from 2 p.m. Wednesday through 2 a.m. Thursday. It said that timeline could change and the latest updates would be posted on the service’s social media pages on Facebook and Twitter.

Area emergency management agencies said storm shelters will open at different times Wednesday. Morgan and Limestone shelters will open if a tornado watch in the respective counties is issued. Austin and Decatur high schools will have storm shelters open to the public after school hours.

Emergency management officials encouraged residents to know where the shelters are, have batteries for weather radios and flashlights, phones charged, weather apps downloaded and have a safe room available.

“Everyone needs to prepare for this potential weather event,” said Brandy Davis, Morgan County EMA director. “We have been given about two days to prepare. Now is the time to plan.”

Lawrence County EMA Director Chris Waldrep said his department plans to open the shelters Wednesday morning. “You need to be sure you have a way to see or hear what is going on with the weather,” he said.

Pets and smoking are not allowed in public storm shelters.

Daphne Ellison, spokeswoman for Limestone EMA, said Limestone residents need to give themselves time to get to the shelters.

“If there is a tornado warning in (neighboring) Lauderdale County, that is your signal to start seeking shelter,” she said. “Don’t wait until you hear sirens. If you hear sirens, it’s too late to go to shelters. You might drive into the severe weather.”

NWS Meteorologist Ashley Ravenscraft said residents should have their supplies in a backpack so they are easy to locate and carry. “If there is severe weather, there’s no need to panic. Have a plan,” she said.

The NWS will update EMA officials in a video briefing today at 2:30 p.m.

Carcione said the high temperatures today and Wednesday will be in the low 70s. On Thursday, with a 40% chance of rain, the high will be in the low 60s and Friday’s high will be in the upper 50s, he said.