The primary in a doable wave of moist storms is anticipated to hit California this week and lengthen into subsequent week, bringing vital rainfall that might trigger some localized flooding, particularly within the state’s most northern and southern coastal corners.
Only a week after areas of downtown San Diego have been hit by harmful flash flooding from a historic deluge of rain — inundating properties and highways — forecasters say the world must be ready for comparable circumstances Thursday.
“There’s positively an opportunity for heavy rain in addition to thunderstorms, and which means we do have a danger of flooding on Thursday,” mentioned Brandt Maxwell, a Nationwide Climate Service meteorologist in San Diego. “It will be troublesome to get a repeat efficiency of what occurred final Monday, however we are able to’t rule it out.”
With the storm nonetheless a number of days out, Maxwell mentioned it’s nonetheless onerous to pinpoint precisely the place a lot of the rain will fall, and how briskly. However it’s doable that coastal areas in each Orange and San Diego counties may get one inch of rain inside an hour — nicely above quantities that may immediate flash flooding, he mentioned. However such excessive charges are anticipated to be short-lived, with rain totals seemingly remaining underneath 2 inches Thursday for a lot of Southern California.
No flood advisories have but been issued within the state, however climate officers mentioned it’s seemingly they’ll come because the storm strikes nearer.
As of Monday morning, California’s northwestern nook has the very best chance for some flooding, together with round Eureka, Fort Bragg and Redding, the place precipitation may start as early as Tuesday, in accordance with the most recent forecasts. However coastal areas throughout Northern California and the Bay Space are anticipated to see vital rain, totally on Wednesday. Within the North Bay and San Francisco’s coastal areas, forecasters are warning of the chance for “shallow landslides and roadway flooding” Wednesday, in addition to robust winds.
Because the storm strikes throughout the state, the Sierra are additionally anticipated to report vital snowfall, and the Southern California mountains above 5,000 ft may get anyplace from a number of inches to greater than a foot in increased elevations.
Average rainfall will attain Central California and Los Angeles County, however no vital flooding is anticipated for the area, mentioned Lisa Phillips, a Nationwide Climate Service meteorologist in Oxnard.
“We’ll possibly see some flooding on roads, minor creek flooding,” Phillips mentioned, “however [we’re] not anticipating a flood watch.”
And whereas forecasters warn this week’s storm is probably going the primary in a doable string of moisture-heavy storms, there have been no projections for any sort of statewide “megaflood” — as has been rumored in some corners of the web.
“There’s not at the moment any indication in anyway of a particularly extreme, statewide, catastrophic flood occasion, ensuing from a multi-week sequence of storms,” mentioned Daniel Swain, a UCLA local weather scientist, in a Friday webinar. That phenomenon, dubbed the ARkStorm Situation, has been projected as a 1-in-a-1,000-year megastorm occasion that may trigger huge flooding, as devastating because the Nice Flood of 1862.
Researchers in 2022 discovered that because of the worsening results of local weather change, such a large storm is projected to develop into extra frequent and intense, with a 2% probability of occurring in any given yr, versus a 1% probability pre-global warming.
“It’s a actual factor however it isn’t one thing that’s headed for California imminently,” Swain mentioned. “The percentages of it occurring this yr stay very low, and the percentages of it occurring within the subsequent two weeks are near zero.”
Even nonetheless, this week’s storm, which is anticipated to be a part of an ongoing climate sample, is what Swain referred to as a “doubtlessly high-impact storm sample.” The forecast of the system falls consistent with the everyday El Niño sample, fueled by a heat atmospheric river transferring alongside a powerful Pacific jet stream.
A weaker, but nonetheless moist, system is forecast to carry colder temperatures to Southern California on Friday, with some showers seemingly, Phillips mentioned. After which one other storm is anticipated by Monday.
“Early subsequent week, we may get a fairly substantial storm system — proper now it seems slower transferring, so the rain may last more,” Maxwell mentioned. “It may very well be fairly a moist February, not less than a moist begin.”
