cw3e-web - Center for Western Weather and Water Extremes

CW3E Publication Notice: Rainfall intensification amplifies exposure of American Southwest to conditions that trigger postfire debris flows

CW3E Publication Notice

Rainfall intensification amplifies exposure of American Southwest to conditions that trigger postfire debris flows

June 12, 2024

A new paper entitled “Rainfall intensification amplifies exposure of American Southwest to conditions that trigger postfire debris flows” was recently published in Nature’s journal npj Natural Hazards. This work was authored by Matt Thomas (U.S. Geological Survey), Allison Michaelis (Northern Illinois University/CW3E affiliate), Nina Oakley (California Geological Survey/CW3E affiliate), Jason Kean (U.S. Geological Survey), Victor Gensini (Northern Illinois University) and Walker Ashley (Northern Illinois University).

Postfire debris flows pose a threat to life, property, and infrastructure in many mountainous areas of the Southwest. When areas of steep terrain with susceptible geologic and hydrologic characteristics are burned at moderate to high severity, short duration (<1 hour), high-intensity rainfall can trigger postfire debris flows. For some areas, debris-flow triggering rainfall intensities can be as low as 0.25 inches in 15 minutes. Minimum triggering thresholds in the Southwest are often less than the 2-year recurrence interval at the 15-minute duration. In a changing climate, with increasing wildfire activity and rainfall intensification, the question arises, how will postfire debris flow hazard change? Previous work demonstrated that debris flow probability is most sensitive to rainfall intensification. Thus, this study focuses on exceedance of estimated debris-flow rainfall thresholds across the Southwest using downscaled climate model projections to address this question.

In this work, authors use dynamically downscaled (3.75 km) convection-permitting simulations of short duration (15-min) rainfall for a historic period (1990-2005) and late century period (2085-2100) using both the RCP 4.5 and RCP 8.5 emission scenarios, developed by Gensini et al. (2022 ). Model output at high spatial and temporal resolutions relevant to postfire debris flows are very recent; we are just beginning to have sufficient information to address the questions of postfire debris-flow hazard changes in a warming climate. Statistical methods were applied to allow for comparison between the downscaled model output and rainfall thresholds for debris flows issued by the USGS for burn areas across the Southwest.

Figure 1. (Fig. 4 from Thomas et al., 2024): a) Box and whisker plots that track changes in the exceedance ratio of 15-minute rainfall intensity thresholds for the HIST, FUT4.5, and FUT8.5 simulation scenarios for mountainous terrain throughout California and Colorado (Figs. 2, 3, Supplementary Fig. 1), as well as for 175 burned areas across the American Southwest (i.e., Arizona, California, Colorado, Nevada, New Mexico, and Utah) where the U.S. Geological Survey issued rainfall thresholds as part of emergency assessments of postfire debris-flow hazards between 2014 and 2022 (Fig. 1a, Supplementary Fig. 1). The boxes in (a) are bound by the first and third quartile, with the median indicated by a line, and the whiskers extend from the boxes to the farthest data point within 1.5 times the inter-quartile range. The bar plots illustrate differences in the seasonality of rainfall threshold exceedance for mountainous terrain throughout (b) California and (c) Colorado.

Results indicate that while seasonality of over threshold precipitation events remains similar in climate projections for the regions studied (b and c above), both the magnitude (a, above) and frequency (below) of threshold exceedances increases in both RCP 4.5 and 8.5 scenarios compared to historic. A greater magnitude of threshold exceedance indicates the potential for larger volume, more damaging debris flows. An increased frequency of over-threshold events indicates we may expect more opportunities for debris flows to occur before burn areas can sufficiently recover.

For California in particular, the largest increases in threshold exceedances per year are most prominent in the North Coast Range and Klamath Mountain geomorphic provinces in the RCP 4.5 scenario. Threshold exceedance frequency further increases in these areas and expands to include the Sierra Nevada province in the RCP 8.5 scenario (figure below). These areas historically have experienced less frequent postfire debris-flow activity than Southern California, where damaging events are commonplace. Communities, emergency managers, and weather forecasters in the Northern California areas projected to see an increase in over-threshold precipitation may be less accustomed to contending with postfire debris flow hazards as compared to their counterparts in Southern California. This study highlights the increased hazard potential and benefits of prefire planning, education, and outreach for postfire hazards.

Figure 1. (Fig. 2 from Thomas et al., 2024): State of California with an overlay of scatter plots that reflect 15-min rainfall intensity threshold (equivalent to a one-year recurrence interval under the present climate) exceedances in mountainous terrain for the WRF-BCC HIST, FUT4.5, and FUT8.5 simulation scenarios. Several areas are labeled for reference, including “KLM” (Klamath Mountains), “NCR” (Northern Coast Ranges), “Sierra Nevada” (SNV), “SCR” (Southern Coast Ranges), “TRV” (Transverse Ranges), and “PNR” (Peninsular Ranges). State boundaries provided by U.S. Census Bureau.

This work addresses the CW3E Strategic Plan priority area of “Monitoring and Projections of Climate Variability and Change”, and the area goal of advancing understanding and projections of extreme precipitation events. This work provides insight into how short-duration rainfall intensities conducive to postfire debris flows may change in the future in frequency, magnitude, space, and seasonality. The work also addresses the CW3E core value of Collaboration, as authors represent university as well as state and federal agencies.

Thomas, M.A., Michaelis, A.C., Oakley, N.S. et al. Rainfall intensification amplifies exposure of American Southwest to conditions that trigger postfire debris flows. npj Nat. Hazards 1, 14 (2024). https://doi.org/10.1038/s44304-024-00017-8

CW3E Welcomes Heather Dopke

June 4, 2024

Heather is currently an undergraduate student at UCSD with a double major in Political Science – Public Law and Sociocultural Anthropology with minors in Law and Society and Psychology graduating in June 2025. She will be working with CW3E as a fiscal and administrative assistant under Lillian Gilmore and Laura Martin.

CW3E Welcomes Dr. Erfan Goharian

May 21, 2024

We are excited to announce that Dr. Erfan Goharian has joined the Center for Western Weather and Water Extremes (CW3E) as the Water Resources Engineering R&D Manager.

Dr. Goharian is an Associate Professor of Civil and Environmental Engineering at the University of South Carolina (USC). His research, education, and practice nexus is centered on developing multi-source heterogeneous data fusion, artificial intelligence (AI), and systems analysis techniques to advance the smart and informed operation and management of water resources systems. Dr. Goharian and his team develop and deploy cutting-edge systems and modeling techniques to enhance informed decision-making of integrated water and environmental resources systems in the face of climate change and extreme events.

Moving to CW3E, Dr. Goharian will establish and lead the Water Resources Engineering Research and Development (WRE R&D) program. The CW3E WRE R&D Group is dedicated to advancing knowledge, fostering collaboration, and driving innovation at the intersection of academia, community, and partnerships. This initiative will promote multidisciplinary collaborations, with a focus on advancing intelligent and integrated modeling techniques, particularly to support the implementation of Forecast-Informed Reservoir Operations (FIRO). Our mission is to pioneer cutting-edge solutions in FIRO, comprehensive monitoring and forecasting of floods and droughts, integrated water resources modeling and management, and the application of machine learning and AI through fostering strong partnerships with local communities and stakeholders, and a focus on global leadership.

Previously, Dr. Goharian has led various projects funded by national agencies such as NOAA, NSF, USGS, and DoD, state agencies like the SC Sea Grants Consortium and SCDOT, and companies including Microsoft and Amazon. His publication record includes over 60 top-notch peer-reviewed journal papers and over 100 invited talks and conference presentations. Dr. Goharian has been honored with numerous prestigious awards, including the NSF CAREER Award, ASCE Young Civil Engineer of the Year, UCOWR Early Career Award, ASCE’s Best Research-Oriented Paper of the Year, ASCE Outstanding Reviewer awards, and served as a member of the South Carolina Floodwater Commission, appointed by Governor McMaster. He also serves as an associate editor of Nature’s Scientific Reports and the Journal of Water Resources Planning and Management.

CW3E is thrilled to welcome Dr. Erfan Goharian and looks forward to the significant contributions he will bring to our team and the broader water resources community.

Kyle Hurley Recognized as a 2024 Triton Student Employee of the Year for His Role in the 2024 AR Recon Season

May 13, 2024

At this year’s CW3E Annual Meeting we will be acknowledging the achievement of Kyle Hurley, a UCSD undergraduate student, as a 2024 UCSD Triton Student Employee of the Year, for his role in AR Recon.

In 2022, Kyle met with one of CW3E’s Atmospheric River Reconnaissance (AR Recon) program mission directors and expressed interest in becoming involved. He joined the team for the 2022-2023 season to support the AR Recon flight planning process and continued in this role through the 2023-2024 season. Flight tracks for these missions are developed in Google Earth and finalized using IDL coding on a Linux server and require close coordination between CW3E staff and collaborators around the world. Kyle’s position requires him to start as early as 6 am, update a variety of background fields in Google Earth to support flight track design decision-making by the team, create draft flight tracks, present them during weather briefings, revise them on-the-fly as needed with feedback from senior scientists and aircraft personnel, and then produce and provide dropsonde coordinate and spacing information on a tight and inflexible timeline. He quickly learned this process during his first season and has even helped improve upon its functionality. During his training, he was able to provide key support that streamlined the process ahead of briefings. However, he quickly showed enough skill that empowered him to lead the tool on his own without much supervision. Kyle fully embraced this opportunity and excelled in the high-pressure work. This year, there were several pre-flight issues due to the position of the jet stream causing turbulence along our tracks. So, in addition to his regular duties, Kyle was asked to make last-minute flight track adjustments for same-day flights. He took this on with grace even though it further shrunk his already limited preparation time. He is always enthusiastic to get started each morning and can complete his tasks on deadline which requires close collaboration with the AR Recon team, including Air Force and NOAA personnel. As a bonus, he even brought in donuts and coffee for the group on several occasions.

The AR Recon team is very thankful for his contributions during the past two AR Recon seasons, and we hope he can join us again next season.

Congratulations Kyle, and job well done!

CW3E Authors Featured in latest volume of Mountain Views Chronicle

May 9, 2024

In the most recent volume of the Mountain Views Chronicle, CW3E authors Jeri Wilcox, Jacob Morgan, Anna Wilson, and El Knappe, were featured for writing a short article about the Y-BASIN Project, together with project collaborators Madison Muxworthy and Nathan Stewart. The Mountain Views Chronicle is the newsletter of the US Forest Service’s Consortium for Integrated Climate Research in Western Mountains (CIRMOUNT). This newsletter is published to help inform citizens and scientists alike about developments in mountain research in the western US.

Volume 17 of the Mountain Views Chronicle, published on Earth Day 2024 (22nd April), encompasses a theme of “an exploration of science in community.” It highlights the interconnectedness of science with not only the environment that is being studied, but also the people who are a part of it. For this newsletter, the Y-BASIN collaborators submitted a short article, termed “Brevia,” which describes the collaborative nature of the Y-BASIN project and the benefits this has brought. The article explores the origins of the project, through the Yampa Basin Rendezvous, and how this origin set up the Y-BASIN effort to be one that is inherently connected to an interdisciplinary network of stakeholders, regional experts, and community members. The authors highlight the collaboration that is integrated throughout the project: during the station siting, station installations, data management, and engagement with the community surrounding the project.

To read the entire Brevia, check out the newsletter at the following link:https://www.fs.usda.gov/research/sites/default/files/2024-04/rmrs-cirmount_mountainviewsnewsletter_april2024.pdf

CW3E Hosts 5th Grade Students for Outreach Event on Scripps Pier

May 2, 2024

CW3E’s Jacob Morgan discusses the components of a
radiosonde while preparing a weather balloon for launch

On Tuesday, April 30th, CW3E staff hosted 90 students from the San Diego Unified School District for an educational outreach event on the Scripps Pier. The group included three classes of 5th grade students from the Chollas Creek Elementary School. During their visit to campus, CW3E staff spoke with the students about their research into atmospheric rivers and other types of high-impact precipitation conducted by our researchers. This event was hosted as part of an ongoing collaboration with Groundwork San Diego’s EarthLab Program, with the goal of providing students hands-on learning opportunities related to research conducted by CW3E and our partners.

The outreach event consisted of three stations – including a weather-centric station on the Scripps Pier, a tide-pooling activity on the beach adjacent to Scripps campus, and an educational activity on Pawka Green. CW3E staff educated students on the important precipitation-related research conducted by the center, showed students the various weather sensing instruments employed by CW3E’s field team across California, and gave students hands-on demonstrations of our various equipment. Additionally, the students were able to participate in multiple weather balloon launch demonstrations from the pier, during which multiple students were able to help with the logistics of getting the balloon off the ground. Although these balloons were launched as part of an educational outreach event, their observations were transmitted in near real-time and assimilated into the global forecast models. In total, eight members of CW3E staff participated in this outreach event, including Ali Wolman, Jeri Wilcox, Adolfo Lopez-Miranda, Jacob Morgan, Sam Bartlett, Cody Poulsen, Pat Mulrooney, Shawn Roj, and Ricardo Vilela.

CW3E staff teach students about the various types of meteorological instruments
located on a weather stations CW3E maintains on the Scripps Pier

AR Recon Program Endorsement by World Meteorological Organization

April 26, 2024

Atmospheric River Reconnaissance (AR Recon), a CW3E-led program in partnership with the National Centers for Environmental Prediction and the U.S. Air Force, was recently endorsed by the World Meteorological Organization (WMO) as a World Weather Research Programme (WWRP) endorsed project.

The WMO WWRP promotes research to improve weather prediction and its impacts on society. The improvements in science and operational predictions are driven by international cooperation, and intended to drive sustainable development. As one of 10 WWRP endorsed projects, this represents a strong show of support for a key mission and a major programmatic milestone for AR Recon, which works to support improved prediction of landfalling atmospheric rivers on the U.S. West Coast.

Consistent with WWRP’s key objectives, AR Recon has developed the tools and network necessary to incrementally improve the warning process for extreme weather events, and reduce prediction uncertainty. Key sponsors have been the U.S. Army Corps of Engineers and the California Department of Water Resources, who are working with CW3E and other partners to advance their goals of using improved AR prediction to inform water and infrastructure management (e.g., for Forecast Informed Reservoir Operations – FIRO).

Since program inception, AR Recon observational campaigns have been conducted in collaboration with international experts from organizations including CW3E, Scripps Institution of Oceanograpy, the National Oceanic and Atmospheric Administration, the Naval Research Laboratory, the National Weather Service, the National Center for Atmospheric Research, the European Centre for Medium-Range Weather Forecasts, the U.S. Air Force, and other academic institutions. The operations to support these observational campaigns, which now run from November 1st through March 31st, continue to increase in pace and intensity as capability is added and the geographic area of interest expands globally.

We would like to express our appreciation to the WMO for selecting AR Recon for the WWRP. We look forward to engaging further with the WMO and international partners to support WWRP objectives through AR Recon.

For more detailed information about the AR Recon program, please see the AR Recon webpage.

Summary of CW3E Outlooks During Water Year 2024

April 22, 2024

CW3E summarizes and disseminates key forecast information about potentially hazardous weather over the Western US, with a strong emphasis on landfalling ARs, as part of the California Atmospheric River (AR) and Forecast Informed Reservoir Operations (FIRO) programs. These activities consist of written outlooks, “quick looks”, and post-event summaries of high-impact storms. The outlooks and quick looks provide valuable information and situational awareness guidance to stakeholders, such as the California Department of Water Resources and local water agencies, as well as the general public.

CW3E created and posted a total of 25 outlooks, 27 quick looks/Twitter threads, and 10 event summaries during October 2023 through March 2024. During a particularly active four-week period between 21 January 2024 and 17 February 2024, CW3E posted six outlooks and five quick looks. This period included the record-breaking precipitation and severe flooding event in San Diego County on 22 January 2024 and a strong AR in early February 2024 that produced >10 inches of rain in the Los Angeles metro area. Some locations in Southern California received more than a year’s worth of precipitation in the first 3 weeks of February 2024.

The CW3E outlooks and post-event summaries focus on storm events over the Western US; however, the team also prepared outlooks and event summaries for two exceptionally strong ARs that produced extreme precipitation and widespread flooding over the Eastern US in mid-December 2023 and early January 2024. These activities were sponsored by the nationwide expansion efforts of the FIRO program and funded projects with the NOAA Cooperative Institute for Research to Operations in Hydrology (CIROH).

A more recent initiative supported by the AR Program has involved the creation and posting of subseasonal-to-seasonal (S2S) forecast information via regularly scheduled Subseasonal and Seasonal Outlooks. While the AR outlooks and quick looks focus on weather time scales (forecast lead times of up to 10 days), the Subseasonal and Seasonal Outlooks focus on 2–6 week and 1–3 month lead times, respectively, and are posted between November and March. These longer time scales are a primary concern for the water resource management community, especially given the implications of cool-season precipitation and snowpack for drought and water supply in the Western US. CW3E posted its first S2S outlook in December 2021, and the S2S outlooks team has continuously worked to augment and improve the content in these updates based on an iterative process with direct input provided by practitioners.

In Water Year (WY) 2024, CW3E began posting subseasonal and seasonal forecast information in two unique outlooks; the Subseasonal Outlooks are typically posted weekly, and the Seasonal Outlooks are posted monthly. Both the Subseasonal and Seasonal Outlooks include information from experimental forecast products developed at CW3E and collaborating institutions such as NOAA and the International Research Institute for Climate and Society (IRI), as well as a single prediction based on a synthesis of the products. During WY 2024, CW3E posted 17 Subseasonal Outlooks and 5 Seasonal Outlooks. CW3E will solicit further feedback from users this year and aims to incorporate additional forecast products currently under review into its WY 2025 Subseasonal and Seasonal Outlooks.

Category	Oct	Nov	Dec	Jan	Feb	Mar	Total
AR/Precipitation Outlooks	4	2	5	9	5	0	25
Quick Looks/Twitter Threads	3	4	7	4	3	6	27
Event Summaries	0	0	3	3	3	1	10
Subseasonal Outlooks	0	2	3	5	3	4	17
Seasonal Outlooks	0	1	1	1	1	1	5

Reservoirs-plus-Snowpack Water Storage in the Sierra Nevada

April 19, 2024

Current measures of water stored in Sierra Nevada reservoirs and snowpacks are now continually updated and available from CW3E. Mountain snowpacks provide an “extra” way that water gets stored in California and across the Western US, acting as natural reservoirs that hold winter precipitation (as snow) from the cold wet season until spring and summer when the water is released as snowmelt when water demands for human and environmental uses, including irrigation, are high. Thus the combination of water stored as snow and water stored in human-built reservoirs is a useful indicator of development, persistence, and termination of droughts in many western water-supply systems. As the climate warms in coming decades, the “typical” mix of water in snowpack versus reservoir is projected to change, with far less snow holding far less water in future winters. Whether the water no long stored in snow ends up residing instead in reservoirs for more of the year in the future will depend on a variety of tradeoffs associated with winter-weather and hydrological changes, infrastructure constraints, and flood- and resource-management responses that tracking of the combined storage amounts may help to highlight.

This approach to tracking water-supply status was initially developed for drought early-warning and tracking purposes, but has also demonstrated value in wet years. Notably, last year, these figures attracted widespread attention when they showed that the 2023 snowpack in drainages above the ancient Tulare Lake bed contained as much as three times the total amount of space in the reservoirs in that drainage even if all the water currently in the reservoirs was released to make space. This highlighted that nearly all of the water that entered the reservoirs that year was going to have to be routed out of the Tulare Basin or else flooding would certainly occur. However, that much water could not be routed out of the Basin with existing infrastructures and so flooding did occur, and Tulare Lake refilled, covering large expanses of agricultural land and impacting communities. In the three preceding drought years (2020-2022), by contrast, snowpacks never grew to sizes that would refill Sierra Nevada reservoirs, and so water in storage declined each year.

Since 2015, scientists at Scripps have been developing and circulating simple graphics that showed how the combination of these two forms of storage evolved, in order to better communicate water resource status as the water years progressed. CW3E researcher Mike Dettinger demonstrated the value of tracking of water supply status by tracking these combined storages during the 2012-2015 California drought (Dettinger and Anderson, 2015), and has been producing and circulating them on a roughly monthly (or more frequent, depending on circumstances) basis since. The development and original updates were supported by NOAA’s National Integrated Drought Information System (NIDIS) via the California Nevada Adaptation Program (CNAP).

This spring the process of updating and generating these diagrams was automated so that now they will be updated on a daily basis, with support from the California Department of Water Resources via the AR Program. Updated storage diagrams will be available at:

https://cw3e.ucsd.edu/water_storage_tracking/

along with background information, explanations, and archives of the diagrams from previous years (to put the current year’s progress into historical contexts).

Dettinger, M.D., and Anderson, M.L., 2015, Storage in California’s reservoirs and snowpack in this time of drought: San Francisco Estuary and Watershed Science, 13(2), 5 p., http://dx.doi.org/10.15447/sfews.2015v13iss2art1.

CW3E Publication Notice: Subseasonal Potential Predictability of Horizontal Water Vapor Transport and Precipitation Extremes in the North Pacific

CW3E Publication Notice

Subseasonal Potential Predictability of Horizontal Water Vapor Transport and Precipitation Extremes in the North Pacific

April 17, 2024

A new paper entitled “Subseasonal Potential Predictability of Horizontal Water Vapor Transport and Precipitation Extremes in the North Pacific” was recently published in Weather and Forecasting by CU Boulder PhD Candidate Tim Higgins, Aneesh Subramanian (CU Boulder), Will Chapman (NCAR), David Lavers (ECMWF), and Andrew Winters (CU Boulder). This work This work contributes to the Subseasonal to Seasonal Prediction of Extreme Weather priority area in CW3E’s 2019-2024 Strategic Plan by exploring differences between the predictability of integrated vapor transport (IVT) and precipitation at lead times of 3 weeks and 4 weeks. The results demonstrated that extreme IVT events (exceeding the 90th percentile) have higher predictability in the subseasonal range than extreme precipitation events do. The connection between the differences in predictability to the predictability of the North Pacific Jet, which was shown to have some forecast skill out to a lead time of four weeks in Winters (2021), was also examined.

This work used the “potential predictability” approach, which has also been used to demonstrate differences between the predictability of IVT and precipitation at medium-range lead times (Lavers et al. 2016). When assessing potential predictability, a single member from an ensemble forecast functions as the “model-observation” and the remaining ensemble members function as the forecast. The process is repeated until every ensemble member functions as the “model-observation” one time. This method operates under the assumption of a perfect model, which allows the authors to assess predictability rather than prediction skill and eliminates any potential model bias.

The study primarily focused on predictability in a region off the US West Coast that was defined as the “jet exit region”. This region has some forecast skill out to week 4 of both IVT and precipitation, is relevant to anomalously high precipitation on the coast, and is greatly impacted by regimes of the North Pacific Jet. When both IVT and precipitation were skillfully forecasted, the strength of the jet extension regime was greater than it was when IVT and precipitation were not skillfully forecasted (Figure 1). The connection between the strength of the jet extension regime and 90th percentile IVT was also stronger than the correlation between the jet extension regime and 90th percentile precipitation.

IVT in the jet exit region maintained higher skill than precipitation did at all lead times from week 1 to week 4 (Figure 2). The differences were significant at all lead times when skill was assessed at each individual grid point. When conditions were averaged over the jet exit region before assessing skill to account for local variability, the skill gap decreased, with differences generally remaining significant at subseasonal lead times and no longer being significant at medium-range lead times. The relationship between IVT and a teleconnection (North Pacific Jet regimes) that has some forecast skill in the subseasonal range is a likely cause of differences in predictability.

Figure 1. (Fig. 5 from Higgins et al., 2024): Composites of Principal Component Analysis values of the model-observed NPJ during model-observed (a) 90th percentile precipitation at week 3, (b) 90th percentile IVT at week 3, (c) 90th percentile precipitation at week 4, and (d) 90th percentile IVT at week 4 during skillful (green) and unskillful (red) forecasts. Lighter colors represent earlier lead times and become darker through the progression of the forecasts. Forecasts of wet weeks within all individual points from 31.5°N – 40°N, 139.5°W – 152.5°W were used. Each data point represents a mean of lead times spanning 7 days starting at days 1-7. N (Above) and N (Below) represent the number of unique initialization times in which model-observed 90th percentile conditions existed during skillful and unskillful forecasts, respectively.

Figure 2. (Fig. 4 from Higgins et al., 2024): Mean ROC scores of precipitation and IVT in the jet exit region at all lead times up to 4 weeks. Spatial averaging was not applied in (a) and was applied in (b). A student t-test was used to assess statistical significance at the 95% level at all lead times. The shaded area represents one standard deviation above and below the mean.

Higgins, T. B., Subramanian, A. C., Chapman, W. E., Lavers, D. A., & Winters, A. C. (2024). Subseasonal Potential Predictability of Horizontal Water Vapor Transport and Precipitation Extremes in the North Pacific. Weather and Forecasting, https://doi.org/10.1175/WAF-D-23-0170.1.

Lavers, D.A., D.E. Waliser, F.M. Ralph and M.D. Dettinger, 2016: Predictability of horizontal water vapor transport relative to precipitation: Enhancing situational awareness for forecasting Western U.S. extreme precipitation and flooding. Geophysical Research Letters, 43, 2275-2282. https://doi.org/10.1002/2016GL067765.

Winters, A. C., 2021: Subseasonal Prediction of the State and Evolution of the North Pacific Jet Stream. Journal of Geophysical Research: Atmospheres, 126 (17), https://doi.org/10.1029/2021JD035094..