EXPLAINER: The ‘Fujiwhara Effect’ and how it lashed California’s Bay Area with high wind Tuesday

There were nearly 100 reports of wind damage in California due to intense areas of low pressure Tuesday afternoon

The Fujiwhara Effect around 1 p.m. Pacific Time Tuesday

ROANOKE, Va. – California has been in the news a lot lately, due to the relentless snow on its mountains and flooding in the lowlands. On Tuesday, it was once again in the weather spotlight.

By this point, you may have heard the term ‘atmospheric river.’ It’s become a catchy buzz-phrase, especially in national media. To boil it down, it means a narrow band of moisture in the lowest levels of the atmosphere.

California has seen a lot of these in recent months.

In the most recent one Tuesday, there were two small areas of low pressure that got close to one another. Instead of merging together, the stronger one became the dominant one.

For a brief moment in time, the two ‘danced’ around a common point. This is known as the Fujiwhara Effect. You can see it in motion in the video I posted to Twitter early Wednesday morning.

This became a crucial point in their weather Tuesday, as it wound up producing several reports of wind damage in-and-near California’s Bay Area.

Wind and wind damage reports from Tuesday's weather in California

The storm even proved deadly, while also causing a train to derail near Porta Costa.

This storm system will eventually produce showers and storms in our area Saturday, though the widespread wind damage they saw in California is unlikely to repeat itself here at home.

Read more on our local forecast by clicking here.


About the Author

Meteorologist Chris Michaels is an American Meteorological Society (AMS) Certified Broadcaster, forecasting weather conditions in southwest Virginia on WSLS 10 News from 5 a.m. to 7 a.m. weekdays on Virginia Today.

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