Why Lightning And Thunder Caught LA By Surprise

This time exposure photo shows a series of lightning strikes over Santa Barbara on Tuesday night.(Mike Eliason/Santa Barbara County Fire Department via AP)

How unusual is lightning in Southern California?

It's so uncommon that the National Weather Service had to send out this tweet reminding people not to stand in water during the storm:

Last night, reactions ranged from excited to more excited as the storm rolled through. And you have to admit ... it was really cool! Especially since we almost never get to see lightning around here.

WHY DON'T WE SEE LIGHTNING MORE OFTEN?

Thank the Pacific Ocean.

The Pacific Ocean at Dan Blocker Beach in Malibu (AP Photo/Reed Saxon)

The relatively cool water keeps the air above it cool as well, which in turn means things stay more stable in the atmosphere.

Compare that to what happens in the Midwest and East Coast, where thunderstorms are a regular occurrence.

"The Midwest doesn't have mountain ranges blocking the moisture from the Gulf Coast. And so, all of the moisture from the Gulf Coast comes up and inundates the East Coast," said Casey Oswant, with NWS.

That warm, moist air, collides with colder air inland, creating instability in the atmosphere, which often means thunderstorms.

WHY WAS THERE LIGHTNING LAST NIGHT?

According to NWS, a cold front from the northwest crashed into an atmospheric river that was carrying heavy, warm moisture up from the southwest.

"It was kind of like a goldilocks thing right? You had just enough of what's needed for thunderstorms," said Bob Henson, meteorologist with Weather Underground.

As the weather systems met, the cold front acted as a lifting mechanism, forcing some of the warm air from the atmospheric river skyward, creating instability, and perfect conditions for thunder and lightning.

A parting picture shows a time-lapse of Tuesday night's lightning strikes (Mike Eliason/Santa Barbara County Fire Department via AP)

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