Some western residents are breathing a sigh of relief after recent atmospheric river storms have drenched the drought-parched region, and more are on the way. However, scientists caution that it is too early to celebrate. “At this point in time, we still have another four or five months in our snow season and in our typical rainy season,” said Andrew Schwartz, lead scientist at the Central Sierra Snow Lab.
The atmospheric river currently impacting the West Coast, while creating dangerous weather conditions for millions of people, could possibly have a chance of temporarily reversing drought conditions in states that desperately need water, experts say. The National Oceanic and Atmospheric Administration describes atmospheric rivers as “rivers in the sky” because they’re somewhat long and narrow regions in the atmosphere that send most of the water vapor outside the tropics.
As the United States begins to recover from a week of severe weather that left dozens dead, more storms are already in the forecast. An atmospheric river began moving through California on Tuesday, with another atmospheric river predicted for later in the week.
An expanded Atmospheric River Reconnaissance program began last month as a result of the unexpected “bomb cyclone” in October 2021 that hit North America’s West Coast, followed by another atmospheric river less than a month later that caused severe flooding in Washington.
“Climatologically, November and December can bring some of the worst floods for that part of the world,” said research meteorologist Marty Ralph, director of the Center for Western Weather and Water Extremes (CW3E) at UC San Diego’s Scripps Institution of Oceanography. Ralph leads the AR Recon program, along with Vijay Tallapragada, Ph.D., Senior Scientist at NOAA’s Environmental Modeling Center, in partnership with the U.S. Army Corps of Engineers, the California Dept. of Water Resources, NOAA Office of Marine and Aviation Operations, and the U.S. Air Force Reserve 53rd Weather Reconnaissance Squadron “Hurricane Hunters.”
A strong low-pressure system associated with an upper-level shortwave trough will impact much of the US West Coast today through Thursday, with the development of an atmospheric river over Northern California. After the initial AR, a second low-pressure system will develop offshore and travel down the coast, bringing another round of precipitation to the region Friday into Sunday.
I was eating breakfast on a Monday morning at Sears Fine Food in downtown San Francisco, casually watching the local five-day weather forecast on a television screen behind the counter. A little symbol along the bottom showed a happy-looking sun for the rest of the day. Wednesday had a friendly-looking cloud and a few raindrops, and Thursday had a dark, threatening cloud with heavier drops.
I knew Thursday’s conditions would be much rougher than the symbol conveyed. I had been studying detailed satellite data and weather models, and they indicated that a major atmospheric river (AR) was likely to hit the city. The symbol was completely inadequate for communicating the threat of the approaching storm.
A stubborn La Niña climate pattern in the tropical Pacific is likely to persist through the summer and may hang on into 2023, forecasters say.
La Niña has been implicated not only in the unrelenting drought in the U.S. Southwest, but also in drought and flooding in various parts of the world, including ongoing drought and famine in the Horn of Africa.
Memorial Day, the unofficial start of summer, is Monday. What’s in store for the upcoming season of beach days and barbecues in Southern California?
To start with, it will be dry. That’s not just because California’s Mediterranean climate means rain mostly falls during a few wet winter months, but because the state is in its third year of drought.
Bombtober” some called it, when an incredible atmospheric river drenched the drought-stricken soils and mountains of California. We all danced and rejoiced, and much thought, and may still think, that we made it through the recent stretch of drought. Was it realistic to believe that a few days of heavy rain could undo the harm of months and years of drought? Only if it continued to rain, but it never did.
This winter we experienced the driest January and February in recorded history, which are typically our wettest. And we will not have a “Miracle March”.
The Oroville Dam in northern California is the nation’s tallest dam and it creates the state’s second-largest reservoir. In February of 2017, an atmospheric river dumped a huge amount of snow then a huge amount of rain into the reservoir’s watershed.
A 30-foot wall at the top of the dam, called the weir, nearly gave way to the volumes of water and 188,000 people had to be evacuated.
