The stormy weather pattern across much of the United States shows “no signs of abating over the next couple of days as we head into the weekend,” the National Weather Service said Thursday morning.
California, which has already faced significant storms this week, including two tornadoes and a bomb cyclone, will see still more snow and rain on Thursday.
A powerful storm is expected to move into the Southwest and then the Southeast after slamming the Golden State, potentially leading to flooding and the threat of more tornadoes in some areas both Thursday and Friday.
In California, the storms were responsible for at least five deaths in the Bay Area in recent days, most from falling trees. In addition, a rare tornado hit a Los Angeles suburb on Wednesday, injuring one person and damaging several buildings.
It was the second tornado to hit the state in the past two days, the weather service in Los Angeles said.
An Amtrak commuter train with 55 passengers struck a downed tree and derailed near Port Costa, California, on Tuesday. No one was injured in the incident.
Here’s what you need to know:
A bomb cyclone in California
A bomb cyclone hit California in recent days, bringing heavy rain and strong winds, AccuWeather meteorologists said.
- What’s a bomb cyclone? Bombogenesis, a term more commonly used by meteorologists, can happen when a cyclone “rapidly intensifies, or strengthens, over a 24-hour period,” according to the National Ocean and Atmospheric Administration.
- Bombogenesis “can happen when a cold air mass collides with a warm air mass, such as air over warm ocean waters.”
The winds, rain and snow in California continued to prompt warnings and advisories in the state on Thursday.
WHAT IS A BOMB CYCLONE?A winter hurricane, explained.
A winter weather advisory is in effect in parts of northern California, which will extend into Friday. Snow accumulations of up to 10 inches is expected in western Plumas County and nearby areas.
In western Siskiyou County, in far northern California, a winter weather advisory is also in effect into Friday, and snow accumulations of up to a foot are expected at higher elevations. Winds could also gust up to 40 mph.
Winter storm warnings and winter weather advisories were also in effect in Oregon and Washington, where heavy snow was forecast.
Flooding fears: Rain, thunderstorms to sweep from Oklahoma to West Virginia
A forecast of rain and thunderstorms prompted the weather service to issue a flood watch from Oklahoma to West Virginia on Thursday. In all, about 19 million people live where a flood watch is in effect.
The storms will “become a significant concern” Thursday afternoon continuing through Friday for parts of the southern Plains, Mississippi Valley and the South, according to the weather service.
States under the flood watch on Thursday include:
- Arkansas
- Illinois
- Indiana
- Kansas
- Kentucky
- Missouri
- Ohio
- Oklahoma
- West Virginia
Rainfall of up to 5 inches is possible in some regions. Excessive runoff may cause flooding of rivers and streams, the weather service warned, and people who live in areas prone to flooding should be “prepared to take action.”
Storms could also turn severe in the South in the next few days. Areas from Houston to Cincinnati should prepare for strong to severe thunderstorms on Friday, according to AccuWeather meteorologists. The storms could include “strong tornadoes,” the Storm Prediction Center said. Portions of Arkansas, Mississippi and Louisiana are in the highest risk zone.
Rainfall and flash flooding maps: Where NWS says risk is highest
Friday’s tornado threat map
‘Springlike’ warmth in the South and East
Elsewhere across the South and many areas of the East ahead of the big storm, very warm temperatures will be in place and many areas will see daytime highs well above average, according to the weather service. “Many areas of the Gulf Coast, Mid-South, and Southeast will see high temperatures well into the 80s through the end of the week, and thus very springlike,” the weather service said.
Winter storm tracker
National weather radar
Contributing: Jordan Mendoza, USA TODAY; The Associated Press