Bomb cyclone to unleash life-threatening flooding in California
By Alex Sosnowski, AccuWeather senior meteorologist
Published Jan 3, 2023 12:33 PM
EST | Updated Jan 5, 2
(I didn’t even knew this was happening until my brother sent videos of trees and crap on the beaches there in Santa Barbara. He said:That's incoming from ocean or debris washed down from mountains?)
An atmospheric river, or massive plume of moisture that originated from the tropical Pacific Ocean some 2,500 miles away at midweek, will continue to fuel the heavy precipitation, even though the fire hose effect was beginning to weaken on Thursday. Such a weather setup can lead to excessive rainfall and flooding, as well as a thump of snow that can shut down travel where the atmosphere is cold enough. In this particular case, the event can be classified as a Pineapple Express, since the plume of moisture originated from near Hawaii.
"There is a significant risk for flash flooding, and people should watch for and avoid rapidly rising water which can quickly become life-threatening," AccuWeather Chief Meteorologist Jon Porter said, adding that flooding may result in street and highway closures. “This will be a dangerous and high-impact storm for California, capable of producing life-threatening conditions and significant disruption which may last several days.”
Mudslides are among the dangers that can persist for several days even after the rain ends, Porter explained.
“Not only will this storm be intense tapping into a substantial atmospheric river, but it is also arriving just days after the previous storm brought heavy rainfall and created significant flooding, increasing the impacts and risks that can occur,” he said.
The rapid intensification of the storm, in a process known as bombogenesis, will add to the dangers it poses, including strong winds on top of the extreme precipitation. When the barometric pressure falls at least 0.71 of an inch (24 millibars) in 24 hours, a storm has undergone bombogenesis, and meteorologists will often refer to this type of strengthening system as a bomb cyclone. From Tuesday morning to Wednesday morning, the central pressure in the storm plummeted 0.86 of an inch of mercury (29 millibars) and exceeded the official criteria for a bomb cyclone.
"The atmospheric river was first directed into Northern California from Wednesday to Wednesday evening and Central California Wednesday night," AccuWeather Senior Meteorologist Brett Anderson said.
The Los Angeles and San Diego areas were bearing the brunt of the fire hose effect on Thursday morning.
"Rainfall rates may exceed 2 inches per hour in some areas, especially over higher terrain," Anderson warned…
https://www.accuweather.com/en/severe-weather/bomb-cyclone-to-unleash-life-threatening-flooding-in-california/1433756