cw3e-web - Center for Western Weather and Water Extremes

CW3E Welcomes Garrett McGurk

November 16, 2021

Garrett McGurk joined CW3E as a Hydrology Engineer in November, 2021. He received a BS in Environmental Studies from the University of California Santa Barbara (UCSB) in 2015 and a MS in Geography, with a focus on watershed science, from San Diego State University (SDSU) in 2019 under the advisement of Professor Trent Biggs. His thesis research utilized a geochemical endmember mixing analysis on sediment samples collected from an urbanized canyon with high rates of erosion in Tijuana, Mexico to evaluate the impact of discrete sediment groups on downstream sedimentation in the Tijuana River Estuary.

Upon completion of his masters degree, Garrett joined a private scientific research and engineering firm in San Diego where he worked on projects including BMP effectiveness studies, source investigation studies, dry weather flow monitoring, and stormwater sampling.

As a passionate surfer, snow sports enthusiast, and all-around outdoor adventurer, Garrett has deep personal interests in the water cycle and the atmospheric processes that dictate conditions in the water and on the mountain. As a native of north county San Diego, Garrett has aspired to join the team at Scripps Institution of Oceanography to further his own understanding of the hydrologic processes in these environments while conducting impactful research for a like-minded organization.

His role at CW3E will be serving as a field hydrologist and engineer to support Forecast Informed Reservoir Operations (FIRO), hydrological modeling, and any future CW3E projects where his experience can be applied. He looks forward to bringing his observational and technical field experience to CW3E research efforts and collaborating with stakeholders to enhance CW3E’s ability to provide 21^st Century water cycle science, technology and outreach to support effective policies and practices that address the impacts of extreme weather and water events on the environment, people and the economy of Western North America.

CW3E AR Update: 12 November 2021 Outlook

November 12, 2021

Click here for a pdf of this information.

Unsettled Weather to Continue through the Weekend in Pacific Northwest

A strong atmospheric river (AR) made landfall on Wednesday, bringing AR 3/AR 4 conditions (based on the Ralph et al. 2019 AR Scale) to southern coastal Washington and coastal Oregon
Another strong AR is forecasted to make landfall in Washington and northern Oregon tomorrow
AR 3/AR 4 conditions are once again likely across portions of coastal Washington and Oregon
The first AR produced heavy rainfall in western Washington and northwestern Oregon yesterday into this morning
An additional 5–10 inches of precipitation are forecasted over the Olympic Peninsula and Washington Cascades during the next 5 days
Widespread riverine flooding is expected in western Washington in association with these two ARs
Snowfall accumulations will be limited due to high initial freezing levels, but significant snow is possible in the North Cascades toward the end of the second event

Click images to see loops of GFS IVT & IWV forecasts Valid 1200 UTC 12 November – 1200 UTC 16 November 2021

Summary provided by C. Castellano, C. Hecht, J. Kalansky, and F. M. Ralph; 12 November 2021

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*Outlook products are con

CW3E is Seeking a Forecaster to Join the AR Reconnaissance Forecasting Team

CW3E is Seeking a Meteorologist to Join the Atmospheric River Reconnaissance Forecasting Team

November 10, 2021

The Center for Western Weather and Water Extremes is seeking a skilled forecaster to serve as a member of the forecasting team for Atmospheric River Reconnaissance (AR Recon). The AR Recon forecasting team presents succinct and productive daily weather briefings to the larger AR Recon group in an effort to identify potential flight targets and inform the group for potential aircraft flight plans. Forecast briefings include the interpretation of global, high-resolution, and ensemble meteorological forecast model information pertaining, but not limited to, atmospheric river characteristics, synoptic to mesoscale features, and potential impacts over the western United States. Briefings also aim to identify where potential uncertainties in model forecasts may originate in relation to the formation, evolution, and landfall of Eastern Pacific atmospheric rivers. Each day the forecast team consists of one lead forecaster who will represent the forecasting team and conduct the weather briefing and one or more support forecasters who assist in the development of the briefing and offer support to the lead forecaster. The hired employee will be tasked with serving as both a lead forecaster and support forecasted throughout the AR Recon campaign.

The preferred candidate will have experience interpreting model data across scales, creating forecasts specific to user needs, and working productively in a team setting. The preferred candidate will have strong knowledge and understanding of atmospheric processes and dynamics and be able to communicate these details to a broad audience. Due to the nature of the position, the forecaster will need to possess excellent verbal communication skills and be able to provide high quality, succinct, and detailed presentations. Experience in a Linux environment working with atmospheric model data as well as experience generating visualizations through languages such as NCL, Python, MATLAB or others is preferred but not required.

The position will be hired as a temporary position to serve during the AR Recon season. Anticipated start date is December 1, 2021 and go through to March 30, 2022. Remote work is an option. Please send CV, resume to Chad Hecht (checht@ucsd.edu) and include three references. The interview process will include leading a mock forecast discussion on the atmospheric event of the candidate’s choosing. Candidates that submit their application before Nov. 23rd will be given priority, but the position will remain open until filled.

CW3E Launches New S2S Precipitation Forecast Product Using Machine Learning Models

November 12, 2021

The Center for Western Weather and Water Extremes (CW3E), in partnership with the NASA Jet Propulsion Laboratory (NASA JPL), recently launched a new S2S precipitation forecast product that uses machine learning models, along with models from the North American Multi-Model Ensemble (NMME), to predict wintertime seasonal precipitation patterns across the western U.S. This effort was funded and sponsored by the California Department of Water Resources (DWR), including support from the Atmospheric River Program. The research methodology and supporting hindcast skill assessment are described in Gibson et al. 2021.

This new machine learning-based forecast product predicts likely patterns of precipitation anomalies over the western U.S. for November 2021 – January 2022. A second forecast will be made in early January for January 2022 – March 2022. Four different machine learning models (Random Forest, XGBoost, LSTM, and neural networks) were pretrained based on learning relationships between remote ocean and atmospheric patterns and characteristic seasonal precipitation anomalies over the Western United States. Instead of training on observations, the machine learning models were here trained on a large climate model ensemble, which enabled more robust relationships to be established due to the very large sample size in the training phase (Gibson et al. 2021). Seasonal forecast skill is also enhanced by focusing on four characteristic large-scale precipitation patterns across the Western United States.

The top row of the forecast product displays the four possible precipitation anomaly patterns identified in Gibson et al. 2021. The percentage ensemble agreement represents the fraction of machine learning models and NMME models predicting each pattern for the November 2021 – January 2022 period. The middle and bottom rows show the individual machine learning model and NMME model forecasts, respectively. These forecasts are available on the subseasonal to seasonal experimental forecasts webpage.

Gibson, P. B., W. E. Chapman, A. Altinok, L. Delle Monache, M. J. DeFlorio, and D. E. Waliser (2021), Training machine learning models on climate model output yields skillful interpretable seasonal precipitation forecasts. Nature Communications Earth & Environment, 2, 159. https://doi.org/10.1038/s43247-021-00225-4.

CW3E AR Update: 10 November 2021 Outlook

November 10, 2021

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Multiple atmospheric rivers are forecast to bring moderate to strong AR conditions to the Pacific Northwest

The first AR is forecast to make landfall over coastal Washington tomorrow, bringing AR 4 conditions to much of the Coast
Current precipitation forecasts indicate that this first AR could bring more than 5 inches of precipitation to the Cascade, Olympic, and Coastal Mountains in Oregon and Washington
A second AR is forecast to make landfall over the Olympic Peninsula during the weekend
There is currently large model uncertainty pertaining to the timing, maximum intensity, and overall duration of the second AR, though several GEFS ensemble members are predicting AR 4 conditions for South-Coastal Washington
In total, the Coastal, Olympic, and Cascade Mts. could receive >7 inches of precipitation during the next 7-days

Click images to see loops of GFS IVT & IWV forecasts Valid 1200 UTC 10 November – 1200 UTC 20 November 2021

Summary provided by C. Hecht, C. Castellano, Shawn Roj, J. Kalansky, B. Kawzenuk and F. M. Ralph; 10 November 2021

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*Outlook products are considered experimental

CW3E Publication Notice: Genesis Locations of the Costliest Atmospheric Rivers Impacting the Western United States

CW3E Publication Notice

Genesis Locations of the Costliest Atmospheric Rivers Impacting the Western United States

November 7, 2021

Hamish Prince, an intern at CW3E (studying at the University of Wisconsin), recently published a paper (Prince et al., 2021) in Geophysical Research Letters along with co-authors from CW3E and JPL including Peter Gibson (now at NIWA, New Zealand), Mike DeFlorio, Thomas Corringham, Alison Cobb, Bin Guan, Marty Ralph, and Duane Waliser. This study contributes to the goals of CW3E’s 2019-2024 Strategic Plan to support Atmospheric River (AR) Research and Applications by furthering our understanding of AR dynamics.

On the Western U.S. ARs are responsible for the vast majority of flooding, with mean annual flood costs of USD$1.1 billion, 88% of the total annual flood damage. The economic impact of ARs in the Western U.S. was first examined by Corringham et al. (2019) in a benchmark study, presenting a clear exponential increase in flooding damage with increases in AR rank (intensity and duration). Building on this important work, Prince et al. (2021) identifies the genesis location and associated atmospheric dynamics of damaging ARs in the Western U.S. This study makes use of the recently developed AR tracking algorithm developed by Guan and Waliser (2019) to identify the genesis locations of ARs that make landfall on the West Coast of North America and pairs this with 40 years of daily economic flood impact, based on the methodology developed by Corringham et al. (2019). The combination of these two techniques allows for a novel assessment of atmospheric dynamics, namely AR genesis characteristics based on the economic impact observed at landfall.

When considering the most damaging ARs (exceeding the 90th percentile of damage following landfall) genesis locations display a significant shift westward, further from the coastline compared to all ARs that make landfall on the U.S. West Coast. (with median latitudes 8-27 further westward). The most damaging ARs also tend to have landfalling moisture fluxes 57%-82% greater than all other ARs (IVT increases of 224-369 kg m-1 s-1). The enhanced zonal winds that allow for propagation of ARs from further across the Pacific may themselves facilitate increased surface windspeeds and consequently increased moisture fluxes. Along-track moisture scavenging from previous cyclonic and frontal systems may intensify a migrating AR which has a distant genesis location; however, this phenomenon remains open for further interpretation.

Identifying regions of preferential genesis of damaging ARs elicits important implications for AR observation campaigns. AR Recon, which is designed to improve forecasts of both ARs that have the potential to be hazardous and those likely to be mostly beneficial, includes the geographic areas where ARs that caused damages on the US West Coast usually originate. These results reinforce the value of including the central and western North Pacific in the area covered by AR Recon (Ralph et al. 2020), which in 2021 reached as far west the dateline (Cobb et al. 2021 subm.). The study also makes a connection between the occurrence of AR families, the rapid progression of multiple ARs. ARs associated with families with recorded genesis in the West Pacific are over 3 times more likely to cause damage exceeding the 75th percentile than all other ARs with distant genesis. These results highlight the importance of antecedent conditions and begin to explore the possibility of impact-based forecasting. The results may also aid in understanding future climate AR impacts by identifying the key atmospheric drivers and specific regions of the Pacific Ocean which are of interest for impactful flooding for different landfall regions.

Figure 1: Median AR genesis locations for damage percentile for each region of the U.S. West Coast. Damaging ARs exceeding the 90th percentile (>$11 million), have genesis locations 8° – 27° further west. The extend of 2021 AR Recon shown with the dotted line.

Figure 2: The relationship between economic damage, genesis location and the landfalling moisture flux (IVT). Damaging ARs (90th perc.) have 57-82% greater moisture flux compared to all ARs that make landfall.

Prince, H. D., Gibson, P. B., DeFlorio, M. J., Corringham, T. W, Cobb, A., Guan, B., Ralph, F.M., Waliser, D.E. (2021). Genesis Locations of the Costliest Atmospheric Rivers Impacting the Western United States. Geophysical Research Letters, 48, e2021GL093947. https://doi.org/10.1029/2021GL093947

CW3E AR Update: 5 November 2021 Outlook

November 5, 2021

Click here for a pdf of this information.

Model Forecasts Show Potential for Another Strong AR in California Next Week

A weak atmospheric river (AR) made landfall along the US West Coast this morning and will continue to impact Northern California, Oregon, and Washington through tomorrow
A stronger AR is forecasted to make landfall across California next week, but there is considerable uncertainty in the timing, duration, and magnitude of AR conditions
The 00Z GEFS control run is forecasting an AR 3 near Point Reyes, CA, and AR 1/AR 2 conditions elsewhere along the coast in Central and Northern California
The 00Z ECMWF EPS control run is forecasting an AR 2 in the San Francisco Bay Area and AR 1 conditions elsewhere in Central and Northern California
The second AR is forecasted to bring 2–4 inches of precipitation to the higher terrain in Northern California
There is also potential for significant snowfall accumulations in the Cascades and Sierra Nevada

Click images to see loops of GFS IVT & IWV forecasts Valid 1200 UTC 5 November – 1200 UTC 10 November 2021

Summary provided by C. Castellano, J. Kalansky, B. Kawzenuk, and F. M. Ralph; 5 November 2021

To sign up for email alerts when CW3E post new AR updates click here.

*Outlook products are considered experimental

CW3E Welcomes Lindsey Jasperse

November 4, 2021

Lindsey Jasperse joined CW3E as a Field Researcher in October 2021. Lindsey is originally from Sonoma, California. After graduating from University of Portland, Oregon, Lindsey worked as a Lab Assistant for the CW3E, helping coordinate and participate in field research campaigns. She then pursued her master’s degree in Climate Science and Policy from Scripps Institution of Oceanography. Lindsey served as Science Program Manager for the Climate Science Alliance, working with climatologists, researchers, Tribal communities, and natural resource managers to advance climate science research and adaptation projects across San Diego County and the southwest.

After moving back home to Sonoma County in 2020, Lindsey worked as a GIS consultant and Climate-Smart Specialist for the UC Cooperative Extension, assisting with the development of fuel mapping tools, participating in geospatial analysis and forest health field research, and coordinating with landowners in Sonoma County. Experiencing devastating wildfires across northern California year after year, she has developed an interest in fire science, land management, and wildfire resilience efforts. She is involved in Sonoma County’s prescribed burn association, as a certified Wildland Firefighter Type II and on-call Wildland Firefighter working with community members and fire practitioners to improve resilience to climate change and wildfire.

As a Field Researcher for CW3E, Lindsey will be located primarily in northern California, helping with field research campaigns, observational efforts, and site maintenance for stations in the Russian River watershed. She is excited to also bring together her interests in GIS, fire science, and climate science, to help contribute to post-fire research. She looks forward to being a part of CW3E’s important research efforts close to home.

CW3E AR Update: 3 November 2021 Outlook

November 3, 2021

Click here for a pdf of this information.

Active Weather Pattern Expected to Continue Along US West Coast

A series of low-pressure systems and atmospheric rivers (ARs) are forecasted to impact the western US this week into early next week
The first AR made landfall last night across Washington and Oregon
AR 4 conditions (based on the Ralph et al. 2019 AR Scale) are forecasted in portions of coastal Oregon
AR 2/AR 3 conditions are forecasted elsewhere along the coast between Northern California and Washington
After the first AR dissipates, multiple weak disturbances are forecasted to bring weak AR conditions to the US West Coast on Friday and Saturday
Another stronger AR may make landfall early next week, but there is considerable uncertainty regarding the AR timing, location, and magnitude
The first AR is forecasted to produce an additional 1–3 inches of precipitation across portions of Northern California, western Oregon, and western Washington, with higher amounts possible in the Olympic Mountains and near the California/Oregon border
At least 3–7 inches of total precipitation is forecasted over the Pacific Coast Ranges, Cascades, and Sierra Nevada during the next 7 days, with more than 10 inches possible in the Olympic Mountains

Click images to see loops of GFS IVT & IWV forecasts Valid 0600 UTC 3 November – 0000 UTC 10 November 2021

Summary provided by C. Castellano, C. Hecht, J. Kalansky, and F. M. Ralph; 3 November 2021

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*Outlook products are considered experimental

CW3E Welcomes Benjamin Downing

November 3, 2021

Benjamin Downing joined CW3E as a Field Researcher in November 2021. He received his B.S. in Biology at Fort Lewis in Durango CO (2011) where he studied plant systematics and evolutionary ecology. He completed his Masters in Geography at SDSU (2021), having researched the affects of rapid land use change on channel geomorphology in a watershed in Tijuana, Mexico. Prior to finishing his Masters, he had worked for a start up aiding in the development of a fertilizer that recycles wastewater nutrients, and then for the San Diego River Park Foundation where he coordinated several programs related to watershed management and trained volunteers to collect data in remote locations. Most recently he worked with San Diego State University and Southern California Coastal Water Research Project (SCCWRP) on several projects involving real time monitoring of water quality, Southern California stream surveys, and storm sampling.

His role at CW3E will be coordinating the installation of instruments in the Santa Ana River Basin and other watersheds in California and the western U.S. to support Forecast Informed Reservoir Operations (FIRO), hydrological modeling, and CW3E’s general research. His long-term research objectives are expanding knowledge about water security and better understanding the relationship between groundwater and plant community composition.