Low, thick, gray clouds and cold air this late-afternoon Saturday here in California’s Central Valley – once again we’re awaiting another ‘atmospheric river‘ (AR) to come crashing onto us, bringing rain and more rain. Expected beginning maybe tomorrow evening through Monday morning, the incoming AR is reportedly way bigger than last Wednesday/Thursday’s episode.
Although we here in the Valley don’t experience the full wrath of these systems like the coasts, there’s still a shitload of rain.
The central shoreline is expected to catch a pounding (CNN): ‘The Weather Prediction Center has issued a rare Level 4 of 4 risk of excessive rainfall for Santa Barbara and Oxnard on Sunday. A more widespread Level 3 risk exists for much of coastal California, including San Francisco down through Los Angeles. It’s hard to emphasize how big of a deal and how rare a Level 4 “high risk” area is. They are issued on fewer than 4 percent of days per year on average, but are responsible for more than 80 percent of all flood-related damage and 39 percent of all flood-related deaths.‘
And the visuals paint the picture:
Remarkable satellite imagery today depicting a rapidly strengthening storm at an unusually southerly position SW of California. Note the prominent "baroclinic leaf" cloud to the NE of the circulation center & deep subtropical moisture tap extending well south of Hawaii! #CAwx pic.twitter.com/QWbJ8gFQqN
— Dr. Daniel Swain (@Weather_West) February 3, 2024
This afternoon Nancy Ward, director of the California Governor’s Office of Emergency Services, noted the urgency: ‘“These next storms are going to be impactful and dangerous … They pose a threat to our state, and they’re the most dangerous natural disasters that we have – killing more people from storm damages and flooding than wildfires every year.”‘
Hopefully, the rain break will continue — we’ve been fairly dry here since yesterday morning with just a few sprinkles — until at least through tomorrow afternoon, and here in the Valley until maybe Monday morning. The LA basin area is expected to encounter eight-inch plus rainfall once the AR starts to really hit beaches and the rain-shit gets heavy duty.
Of course, a major impact on all this wet shit is the warm ocean water just off those beaches: ‘“Anytime you have these rainfall amounts intersecting with terrain and the built environment, you’re going to have trouble,” said Greg Carbin, the branch chief of forecast operations for the National Weather Service.‘
And the real factor in shit like this is the dreaded climate change taking place, and quickly.
Yet despite the actual, real-time weather:
— Wendy Bohon, PhD ? (@DrWendyRocks) February 2, 2024
Reality’s influence on our current environment occurring right now — via The LA Times yesterday:
But the powerful atmospheric river — worrisome enough on its own — is being supercharged by climate change and El Niño, which together are warming ocean waters, upping the odds of significant downpours and offering a preview of the state’s future in a warming world, experts say.
The incoming storm is feeding off unusually warm waters between California and Hawaii where a significant marine heat wave has persisted for months, said Daniel Swain, a climate scientist with UCLA.
Last year — the planet’s hottest year on record — saw global ocean heat content soar to a record high.
“As ocean temperatures warm, and as atmospheric temperatures warm, those rates of evaporation of water vapor into the lower atmosphere are going to increase quite quickly,” Swain said during a briefing Friday. “A few degrees of warming of nearshore and offshore water temperatures means that there’s more moisture in that lower atmosphere.”
In other words, extra heat and moisture from the warm sea surface are moistening the atmospheric river storms as they approach California, making them more likely to deliver heavy rainfall.
The heated ocean waters are partly due to El Niño, a climate pattern in the tropical Pacific associated with warm, wet conditions in Southern California, Swain said. But climate change is also driving up marine temperatures.
“It’s a combination of El Niño and global warming as to why the oceans are so warm over such a broad region,” Swain said. “It’s not 100% clear exactly the extent to which each is a relevant player, but they’re both significant. The long-term trend, of course, is mainly because of climate change and the warming of the oceans associated with that.”
The warm waters are partly why California has seen so many thunderstorms marked by intense downpours this season.
In December, a storm that barreled through Oxnard delivered a month’s worth of rain in less than an hour.
Last month, a similarly historic event drenched San Diego with more rain in a few hours than the area typically sees in all of January.
In the wake of those storms, experts said warm ocean waters were likely a contributing factor. Both were called “thousand-year events” — or events with 0.1% likelihood in a given year.
Yet the same pattern has already reappeared — though to a lesser degree — as another atmospheric river rolled in Thursday, Swain said. Parts of downtown San Francisco saw more than an inch of rain in an hour, while Long Beach also saw major flash flooding.
“We’ve now seen this happen at least four times this year in California — in San Francisco, Ventura, Long Beach and San Diego,” Swain said, noting that in each incident, warm ocean temperatures were an important ingredient.
“I think it really tells us maybe something about what California’s future winters may look increasingly like in a warming climate,” he said.
Umbrellas won’t help.
How about some poetic locution-like images from Miss Emily Dickinson — “Like Rain It Sounded Till It Curved”
Like Rain it sounded till it curved
And then I new ’twas Wind—
It walked as wet as any Wave
But swept as dry as sand—
When it had pushed itself away
To some remotest Plain
A coming as of Hosts was heard
It filled the Wells, it pleased the Pools
It warbled in the Road—
It pulled the spigot from the Hills
And let the Floods abroad—
It loosened acres, lifted seas
The sites of Centres stirred
Then like Elijah rode away
Upon a Wheel of Cloud.
Or music maybe — first: Oh shit, that freaking rain again:
And who’ll fricking stop it:
Singin’ in the rain, or not, yet here we are once again…
(Illustration out front from the UN’s International Children’s Painting Competition, and found here.)