How weather balloons work in the skies above the Carolinas

CHARLOTTE — Three unidentified objects were shot down by U.S. fighter jets over the weekend.

A U.S. official told ABC News they are almost certain the three objects were weather balloons.

There have now been at least four incidents in the past nine days that led the U.S. military to shoot down objects, including a Chinese spy balloon off the coast of South Carolina.

Nearly 1,800 weather balloons are launched across the world every day.

There are three different weather service offices in North Carolina and officials will send out two a day -- once in the morning and once at night.

“On a given day, there will be about 10 weather balloons sent out,” said Channel 9 meteorologist John Ahrens.

Universities, such as UNC Charlotte or UNC Asheville, will send one occasionally as well.

The balloons are essential for meteorologists because they measure temperature, dew point, and the thickness level in every layer of the atmosphere from top to bottom.

They are especially useful to forecast snow because the temperature changes wildly as you go up and that can alter the type of precipitation, Ahrens said.

Balloons are also helpful when severe weather looms.

They can show when the air rises sharply, which is a precursor for tornadoes.

Regulations from the FAA require the balloon’s operator to record the position every two hours.

However, a university usually sends the information out ahead of time on a weather service chat.

The balloons are about 8 feet tall with a data-collecting radiosonde attached.

A protective casing, such as Styrofoam, is added to the device so that when it falls from the sky, it’s less likely to hurt someone.

A weather balloon will reach between 31,000 and 41,000 feet above the ground until it pops. The radiosonde has a parachute so it falls back to earth safely.

That usually happens in remote areas and has a tag on them with a return address in case someone finds it.

There is no official word on what the objects shot down last weekend.

VIDEO: US Navy finds debris from Chinese spy balloon off Myrtle Beach coast