SAN FRANCISCO (KCBS RADIO) – Severe weather has been impacting people across the U.S. this week due to a bizarre weather phenomenon that hit both the Pacific Northwest and the Northeast.
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Ben Noll, a meteorologist with the Washington Post, discussed this “Fujiwhara effect” phenomenon this week with Audacy.
“And no, meteorologists are not just making these terms up on the fly,” said Noll. “This term has been around for over 70 years. And basically, what it involves is two weather systems kind of pivoting around each other.”
According to the National Weather Service, the Fujiwhara effect happens when two hurricanes moving in the same direction pass close to each other and begin to spin around a common center. Noll described the phenomenon as two skaters spinning around each other in an ice rink.
When there is a size difference between the hurricanes, the larger one often absorbs the smaller one. In other cases, they can either merge or spin away from each other.
This effect contributed to wild weather in the Pacific Northwest this week that included bomb cyclone and an atmospheric river. Bomb cyclones are midlatitude cyclone that rapidly intensifies, per the NWS, and atmospheric rivers are narrow regions in the sky – basically rivers in the sky – that transport most of the water vapor outside of the tropics.
In the San Francisco Bay area, conditions were life threatening. In nearby Seattle, Wash., at least two deaths have been linked to storms this week, Fox 13 reported.
“When we get many, many inches of rain in a very, very short amount of time, we can expect sever conditions like this,” explained Jackson Yip, meteorologist at San Jose State University, in an interview this week with Audacy.
For example, up to 15 inches of rain was reported in North Bay as moisture moved through the area like a “conveyor belt,” he added. Flooding, landslides, downed trees and downed powerline have also made the area dangerous, as well as slushy conditions in the Sierra Nevada mountains.
Across the country, in the Northeast, a separate Fujiwhara effect was also causing weather-related havoc this week.
“On the East Coast, we have a separate Fujiwhara event unfolding,” Noll said. “It’s actually already dropped almost 20 inches of snow in northern New Jersey, which is quite incredible for late November.”
NJ.com reported that students in the snow-covered areas got time off of school. In order parts of the state with lower elevation, snow mixed with rain to create slushier conditions.
“Really, both coastlines are feeling the effect of this unusual phenomena,” Noll added. He said the effect impacting the Northeast will be moving to Canada through the weekend. Back in the West, more flooding was expected in the Bay Area through Monday, as well as more rain in the Los Angeles area on Monday and Tuesday.
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