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Scientists See a La Niña Coming. What Does That Mean for the Dry American Southwest?

The wet winter the American south-west has hoped for as it battles extreme drought and heat is increasingly unlikely to materialize as scientists now predict that a phenomenon known as La Niña will develop for the second year in a row.

The weather system could intensify the worst effects of the drought that much of the region already finds itself in, including higher wildfire risks and water shortages through 2022.

La Niña Brings More Worries Amid Drought

Though it’s unclear what the effects of the La Niña climate expected this winter will be for Northern California, drought-ending rain is likely not among them.

The climate pattern brought on by cooler-than-usual surface water in parts of the Pacific Ocean creates varying weather globally, but historically the phenomena has meant drier conditions in the southern part of the state and wetter conditions in the Pacific Northwest.

Atmospheric Rivers-Water Year 2021-drought-climate

Atmospheric Rivers Left California Mostly Dry in Water Year 2021

The Center for Western Weather and Water Extremes, or CW3E, at Scripps Institution of Oceanography, released its report October 11 on atmospheric rivers during Water Year 2021.

The report, “Distribution of Landfalling Atmospheric Rivers over the U.S. West Coast During Water Year 2021: End of Water Year Summary” shows that more atmospheric rivers landed on the U.S. West Coast in Water Year 2021 than in Water Year 2020. But the majority of those storms reached the Pacific Northwest, not California, where drought conditions have impacted water supply.

“The report on atmospheric rivers shows the variability in weather across the state from year to year,” said Jeff Stephenson, Water Resources Manager with the San Diego County Water Authority. “Through our partnership with CW3E and the AR forecasting tools they’ve developed, it better prepares us in management of our water resources using regional storage. This storage, in conjunction with developing multiple water supply sources in the San Diego region, has prepared us for years when rainfall levels are below normal in the region.”

The summary report from CW3E

Water Year 2021 experienced a total of 69 landfalling ARs over the U.S. West Coast, 4 more than Water Year 2020.
• While WY 2021 experienced more ARs, a much larger majority of the ARs only impacted the Pacific Northwest.
• California only experienced AR conditions (IVT >250 kg m–1 s–1) from 36 separate ARs during WY 2021, compared to 43
during WY 2020.

Atmospheric Rivers-Water Year 2021-drought-climate

Distribution of Landfalling Atmospheric Rivers over the U.S. West Coast During Water Year 2021: End of Water Year Summary. Graphic: Center for Western Weather and Water Extremes

Fewer Atmospheric Rivers in California

The lack of AR activity over California for two consecutive water years has resulted in a substantial lack of precipitation.
• A large portion of California received <30% of the normal precipitation for both Water Year 2020 and 2021.
• Coastal Washington and Oregon was the only location in the Western U.S. to receive near or above normal precipitation
during both water years, which is also the region that received a majority of the AR activity.

California experienced strong or greater magnitude AR conditions only three times during WY 2020 and 2021 combined

Atmospheric Rivers-CW3E-drought-climate

Atmospheric Rivers-CW3E-drought

The San Diego County Water Authority partnered with the Scripps Institution of Oceanography, Center for Western Weather and Water Extremes, at UC San Diego in 2020 to better predict atmospheric rivers and improve water management before, during, and after those seasonal storms. The Center and its partners share best practices in forecast-informed reservoir operations, increased research around atmospheric rivers and droughts, and develop strategies for mitigating flood risk and increasing water supply reliability.

For additional details and graphics go to: https://bit.ly/3mKhkcR

‘Extreme Year’: Past 12 Months Among the Driest Ever in California History

The current ongoing two-year dry period in California, punctuated by the third-driest water year on record for the Central Sierra, is part of California’s overall arid fate so far in the 21st century, according to the state Department of Water Resources.

The Golden State’s hydrology now increasingly resembles conditions in the Colorado River Basin this century, where multiple, consecutive, drier-than-average years are mixed with an occasional wet year. California’s last wet water year was 2016-2017, the second-wettest on record.

Here’s How Much Rain Fell in 30 Greater San Diego Communities During the Big Storm

The massive electrical storm that hit San Diego County on Monday and early Tuesday brought significant rain to a county badly in need of precipitation. Here’s a sample of rainfall across the region, as compiled by the National Weather Service. A new storm might arrive on Thursday.

What is La Niña ?

The term La Niña may be one that casual weather observers as well as aficionados hear meteorologists using from time to time, especially when breaking down long-term weather trends or providing a sneak peek at conditions expected during an upcoming winter or hurricane season. But, what exactly is La Niña? Let’s take an in-depth look.

The key to how winter in the United States may unfold often lies thousands of miles away in the open waters of the equatorial Pacific Ocean. It’s there where the roots of a climatological phenomenon known as La Niña originate and eventually help shape weather patterns worldwide.

Rain Helps in California Fire Fight, Lightning Sparks Others

Thunderstorms that dropped light rain gave some breathing room to crews struggling to quench California’s massive wildfires but lightning sparked several new blazes in the drought-stricken north, fire officials said.

The storms that rolled through Thursday night into Friday were followed by weekend forecasts of clear weather and a warming trend in fire areas into next week.

Signs of Drought From Space

As Tracy Schohr goes about her day, water is always on her mind. She’s thinking of it as she rides an all-terrain vehicle around the pasture, looks up hay prices and weather forecasts, and collects data on grazing and invasive weeds for a scientific study.

Schohr is a rancher and farmer in Gridley, California, where her family has raised beef cattle and grown rice for six generations. She also aids in scientific research to study drought and other agricultural issues with the University of California Cooperative Extension.

Climate Change-drought-San Vicente Reservoir in San Diego County

Drought, Water Supply and Climate Change in the San Diego Region

An update on San Diego’s water supply during the current drought, and how climate change affects regional weather, was the main focus of a recent event sponsored by several organizations.

The Citizens Water Academy, Leaders 20/20 and San Diego Green Drinks hosted a lunch and learn session August 17 that also provided details on how weather and climate impacts water supplies, and how prepared the San Diego region is for drought impacts.

San Diego County Water Authority General Manager Sandra L. Kerl and National Oceanic and Atmospheric Administration Warning Coordination Meteorologist Alex Tardy spoke to nearly 90 participants via Zoom.

Climate change impacts and drought

Tardy kicked off the event with an overview of how climate change and drought impact regional weather conditions, and what this means for the region’s water supplies.

“Just here in Southern California, we have extreme heat, extreme precipitation and extreme drought,” said Tardy. “In talking about climate and climate extremes, we are not just talking about the obvious ones like temperature, we are also talking about other impacts like more intense storms, more frequent return of droughts and less normalcy.”

His presentation included highlights of how the past several years have included multiple weather extremes, ranging from wettest single days on record to the hottest and driest years. These included precipitation extremes of varying types and impacts, many of which were fueled by El Niño and La Niña weather patterns. Lack of precipitation and increased evaporation have led to record low water supplies in many reservoirs.

Regional drought preparedness

Kerl spoke about drought concerns throughout the Southwest, which include reduced local water supplies, reduced state supplies and Colorado River supply concerns. Governor Gavin Newsom has asked for voluntary 15% reductions in water use and commonsense conservation measures, which are habits already hard-wired in most San Diego County residents.

“The really good news here in our community is that we are prepared for multiple-year droughts – we have sufficient supplies for 2021, and that’s what water bills go to pay for: safe and reliable supplies,” said Kerl. “It’s also important to note that residents and businesses are hard-wired to conserve – the practices are ingrained in the community. Today we use 50% less per capita per day than we did 30 years ago.”

Kerl also highlighted that our region’s diverse water supplies include drought-resistant sources such as desalinated water, and that the San Diego region is prepared and has enough supplies for multiple dry years.

weather extremes in Southern California

Throughout recent years, Southern California has experienced different types of weather extremes that have impacts on water supplies. Photo: Alex Tardy, NOAA/NWS.

Citizens Water Academy

The Citizens Water Academy provides an opportunity for emerging leaders and professionals in the San Diego region to learn about critical projects and programs related to water. Through the academy, the Water Authority seeks to expand and sustain a diverse network of influencers who are willing to serve as ambassadors on water issues and expand knowledge about the region’s water industry. To learn more, go to sdcwa.org/in-the-community/citizens-water-academy.

Leaders 20/20 is a young professionals network that aims to drive civic engagement to ensure a high quality of life in the San Diego region. Leaders 20/20 provides education on important issues affecting the environment and economy and helps professionals build connections to industry leaders: sandiego.edu/soles/hub-nonprofit/initiatives/leaders-2020.php.

San Diego Green Drinks is a social networking group of professionals in the environmental field who attend events to meet industry professionals, find employment or employees, develop new ideas, discuss issues and solve problems.

Watch a recording of the event, starting with Alex Tardy: https://bit.ly/385EGCP

California Just Recorded Its Hottest July Ever. Charts Show It’s Part of a Trend

California just closed the books on its hottest July on record, a whopping 5.3 degrees above normal.

It was the latest in a rash of record-setting months over the past year, as the state saw its hottest July, June, October, September and August in history, according to the National Oceanic and Atmospheric Administration.

NOAA data shows that the average monthly temperature in July was 80 degrees, 5.3 degrees above normal, or the average temperature from 1901 to 2000. June’s average temperature was 75 degrees, 6.8 degrees above normal.