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Near Miss; Atmospheric River Shifts Toward Southern California

After weeks of atmospheric rivers slamming into Northern California, triggering flooding and landslides, the jet stream has shifted the latest blast of subtropical moisture toward Southern California, forecasters said.

But it won’t be a complete miss on Tuesday. The northern edge of the river will bring moderate rain to parts of the Bay Area and 2 inches or more to the waterlogged Santa Cruz Mountains and the flooded communities in Monterey County.

NOAA Spring Outlook: California Drought Cut by Half with More Relief to Come

NOAA’s U.S. Spring Outlook indicates the abnormally wet winter will further improve drought across much of the western U.S. as the snowpack melts in the coming months. Winter precipitation, combined with recent storms, wiped out exceptional and extreme drought in California for the first time since 2020, and is expected to further improve drought conditions this spring.

Significant flooding in the western U.S., especially in California, followed another series of strong Pacific storms that battered the region in March, and piled on to an already historic snowpack.

NOAA Spring Outlook-drought-snowpack-flooding

NOAA Spring Outlook: California Drought Cut by Half with More Relief to Come

NOAA’s U.S. Spring Outlook indicates the abnormally wet winter will further improve drought across much of the western U.S. as the snowpack melts in the coming months. Winter precipitation, combined with recent storms, wiped out exceptional and extreme drought in California for the first time since 2020, and is expected to further improve drought conditions this spring.

Significant flooding in the western U.S., especially in California, followed another series of strong Pacific storms that battered the region in March, and piled on to an already historic snowpack.

NOAA’s U.S. Spring Outlook highlights temperature, precipitation, drought and flood predictions for April through June to help the nation prepare for potential weather and climate threats to lives and livelihoods.

Climate change – wet and dry extremes

​“Climate change is driving both wet and dry extremes, as illustrated by NOAA’s observations and data that inform this seasonal outlook,” said NOAA Administrator Rick Spinrad, Ph.D.​​ “​Under the Bipartisan Infrastructure Law​ and Inflation Reduction Act, and in support of the Biden Administration’s priority to tackle the climate crisis​, NOAA ​will invest significant resources ​to build a Climate-Ready Nation that gives communities tailored information about changing conditions so that residents and economies are protected.”

Spring Outlook for drought, temperature and precipitation

On March 9, NOAA forecasters declared La Niña over. The El Niño-Southern Oscillation (ENSO) is a climate pattern, based on changes in rainfall and sea surface temperatures across the equatorial Pacific Ocean, that influences temperature and precipitation around the world. La Niña occurs when ocean temperatures are cooler than normal and rainfall is reduced in the eastern to central Pacific Ocean.

El Niño and La Niña

“La Niña has finally ended after being in place nearly continuously for more than two years,” said Jon Gottschalck, chief of the operational prediction branch at NOAA’s Climate Prediction Center, a division of the National Weather Service. “ENSO-neutral —  the transition period between El Niño and La Niña — is likely to continue into the early summer with elevated chances of El Niño developing thereafter. ENSO-neutral is factored into NOAA’s Spring Outlook.”

Moderate to exceptional drought coverage across the U.S. is at its lowest since August 2020 and is likely to continue improving, or end entirely, across much of California and the Great Basin. The spring wet season is expected to improve drought conditions across parts of the northern and central Plains. Current drought conditions in Florida are expected to improve or go away during the next three months.

Areas of extreme to exceptional drought across parts of the southern High Plains are likely to persist through the spring season, with drought also expected to develop into parts of New Mexico. Across parts of the Northwest U.S. and northern Rockies, drought conditions are also expected to continue. Drought may develop into parts of Washington state.

Above-average temperatures are favored for much of the southern and eastern half of the U.S. For April through June, the greatest chance for above-average temperatures exists from the southern High Plains eastward to Florida, and northward along the East Coast. Above-average temperatures are also likely for Hawaii and northern parts of Alaska. Below-average temperatures are predicted for the central Great Basin and the northern Plains.

California endures flooding, landslides, and evacuations

Parts of central and southern California that were still reeling from heavy snowfall earlier this month received yet another powerful atmospheric river which exited the region on March 15. Flooding, landslides, power outages, and evacuations are among the many impacts residents faced from the recent storm. The above graphic depicts most of the state receiving between 300-600% of normal precipitation over the last seven days. — USDA Water and Climate Update

Below-average precipitation like for the Southwest

NOAA forecasters predict above-average precipitation this spring across the Great Lakes, Ohio Valley, and into parts of the mid-Atlantic and Northeast. Below-average precipitation is most likely for the Southwest and parts of the Pacific Northwest.

Opinion: Why Rain-On-Snow Floods From Atmospheric Rivers Could Get Much Worse

California’s latest atmospheric rivers are sending rainfall higher into the mountains and onto the state’s crucial snowpack. The rain alone is a problem for low-lying areas already dealing with destructive flooding, but the prospect of rain on the deep mountain snow has triggered widespread flood warnings.

When rain falls on snow, it creates complex flood risks that are hard to forecast. Those risks are also rising with climate change.

Water Use Restrictions Eased

As atmospheric rivers continue to pummel the state and reservoirs are filling beyond their historical levels, the Palmdale Water District is rolling back mandated water use restrictions.

The Board of Directors on Monday voted to change mandated water conservation measures to voluntary, removing fines and patrols for landscape watering outside the prescribed schedules.

Newsom Loosens Rules to Allow More Floodwater to Flow Into Underground Reservoirs

As another round of heavy storms battered California, Gov. Gavin Newsom announced Friday that he would ease state rules to allow local water agencies to more easily redirect floodwaters to replenish the state’s severely depleted groundwater supplies.

The move comes amid criticism that California has flushed trillions of gallons of water out to sea during this winter’s repeated deluges. Water agencies and experts say the state’s strict rules that limit who can take water from streams and creeks have prohibited the local agencies from capturing the excessive flows, though California desperately needs to bank water for its next drought.

Update: How the Recent Storms Impacted San Diego’s Water Supply in Reservoirs

With recent storm systems that swept through the west, California has seen more precipitation this year than normal, bringing the water supply stored in reservoirs — both locally and across the state — up from historic lows to levels that are some of the highest in years.

And with drought conditions having improved in much of California, experts say that the amount of water captured from this year’s particularly wet winter could help ease the impact of hotter, drier weather in San Diego, as the state recovers its depleted water supplies.

How the Recent Storms Impacted San Diego’s Water Supply in Reservoirs

With recent storm systems that swept through the west, California has seen more precipitation this year than normal, bringing the water supply stored in reservoirs — both locally and across the state — up from historic lows to levels that are some of the highest in years.

And with drought conditions having improved in much of California, experts say that the amount of water captured from this year’s particularly wet winter could help ease the impact of hotter, drier weather in San Diego, as the state recovers its depleted water supplies.

Reservoir Releases Underway as California Braces for Atmospheric Rivers

Once mired in drought, California now has too much of a good thing and has opened spillways on key reservoirs as the first of two atmospheric rivers made landfall Thursday afternoon.

The Golden State activated the Flood Operation Center ahead of the incoming storms, to notify officials of high water levels and support local flood relief efforts.

Calif. Reservoir Levels Show Signs of Improvement After Recent Winter Storms

All of this rain in California has had positive impacts on some of the state’s main reservoirs. Though officials say reservoir levels have seen major improvements, we’re not out of the drought yet.

“California, statewide is at 131% of average precipitation,” said Jeanine Jones, interstate resources manager for the California Department of Water Resources, “What that means is that a lot of our reservoirs have had the opportunity to improve significantly, compared to last year or the year before. Most of our reservoirs are fairly close to full.”