Update: 3 Massachusetts counties under a tornado warning ...

On Tuesday at 8:11 p.m. an updated tornado warning was issued by the National Weather Service in effect until 8:30 p.m. for Franklin, Hampshire and Worcester counties.

"At 8:10 p.m., a severe thunderstorm capable of producing a tornado was located over New Salem, or 10 miles south of Orange, moving east at 55 mph," states the weather service. "Flying debris will be dangerous to those caught without shelter. Mobile homes will be damaged or destroyed. Damage to roofs, windows, and vehicles will occur. Tree damage is likely."

The tornado is projected to affect Barre, Hardwick, Petersham, and New Salem around 8:15 p.m.

The weather service adds, "Take cover now! Move to a basement or an interior room on the lowest floor of a sturdy building. Avoid windows. If you are outdoors, in a mobile home, or in a vehicle, move to the closest substantial shelter and protect yourself from flying debris."

Tornado watches and warnings: What you need to know

When it comes to tornadoes, understanding the distinction between a Tornado watch and a Tornado warning can be a matter of life and death. Here's a breakdown:

Tornado watch: Be prepared!

A Tornado watch is your advance warning that conditions are ripe for tornado formation.It's your cue to review and discuss your emergency plans, check your supplies, and locate your safe room.While it doesn't mean a tornado is imminent, it's a heads-up that you should be ready to act quickly if a Tornado warning is issued or if you suspect a tornado is approaching.Watches come from the Storm Prediction Center and often cover a large area, potentially spanning multiple counties or even states.

Tornado warning: Take action!

A Tornado warning signifies that a tornado has been spotted or detected by weather radar.This is the real deal – there's an immediate danger to life and property.Your response should be quick: seek shelter in an interior room on the lowest floor of a sturdy building, away from windows.If you're in a mobile home, a vehicle, or caught outdoors, find the nearest substantial shelter and protect yourself from flying debris.Warnings are issued by your local forecast office and pinpoint a much smaller area, typically the size of a city or a small county, where a tornado has been identified, either by radar or by trained spotters and law enforcement.

Knowing the difference between these two alerts is essential in staying safe during tornado season. Stay informed, have a plan, and act promptly when danger approaches.

Prepare for a tornado

Stay weather-ready:

Check the forecast regularly to see if you're at risk for tornadoes. Listen to local news or a NOAA Weather Radio to stay informed about tornado watches and warnings.

Sign up for notifications:

Familiarize yourself with your community's warning systems. Some places have outdoor sirens, while others rely on media and smartphone alerts for severe storm notifications.

Create a communication plan:

Have a family plan that includes an emergency meeting place and related information. If you live in a mobile home or home without a basement, identify a nearby safe building you can get to quickly, such as a church or family member.

Choose a secure shelter:

Pick a safe room in your home, such as a basement, storm cellar, or an interior room on the lowest floor with no windows.

Practice your plan:

Conduct a family severe thunderstorm drill regularly so everyone knows what to do if a tornado is approaching. Make sure all members of your family know to go there when tornado warnings are issued. Don't forget pets if time allows.

Prepare your home:

Consider reinforcing your safe room for added protection. You can find plans for fortifying an interior room on the Federal Emergency Management Agency website.

Extend a helping hand:

Encourage your neighbors and loved ones to prepare for possible tornadoes. Consider taking CPR training to be of assistance in case of injuries.

What to do when a tornado strikes

When a tornado strikes, taking swift action is crucial to ensuring your safety and minimizing potential harm. Follow these guidelines from the weather service:

Stay informed:

Stay vigilant and stay informed by tuning in to local news broadcasts or using a NOAA Weather Radio to receive updates on tornado watches and warnings.

At home:

If you are at home and a tornado warning is issued, make your way to the basement, a designated safe room, or an interior space away from windows. Don't forget to ensure the safety of your pets if time allows.

At work or school:

In the workplace or at school, adhere to tornado drill procedures and proceed promptly and calmly to your designated tornado shelter. Avoid areas with large, open spaces like cafeterias, gymnasiums, or auditoriums, and stay away from windows.

Outdoors:

When you are outdoors and a tornado is approaching, seek immediate refuge inside a sturdy building. Remember that sheds, storage facilities, mobile homes, and tents are not safe options. If there is sufficient time, make your way to a secure structure.

In a vehicle:

Being in a vehicle during a tornado is highly unsafe. Your best option is to drive to the nearest shelter. If reaching shelter is not possible, either stay inside your car, covering your head, or abandon the vehicle and seek refuge in a low-lying area like a ditch or ravine.

Remember, acting swiftly and following safety protocols are essential for your well-being when a tornado is imminent.

Advance Local Weather Alerts is a service provided by United Robots, which uses machine learning to compile the latest data from the National Weather Service.