CW3E Graduate Student Accepted into Science Policy Fellows Program

CW3E Graduate Student Accepted into Science Policy Fellows Program

October 3, 2017

Third-year graduate student, Meredith Fish, has been accepted into the Science Policy Fellows Program at the School of Global Policy and Strategy (GPS). The fellowship, which is open to Ph.D. candidates at Scripps Institution of Oceanography, Jacobs School of Engineering and School of Medicine, works with GPS faculty to discover the policy relevance and potential implications of their dissertation. Created with the goal of bridging physical and social sciences across the UC San Diego campus, the students gain an understanding of the benefits of using a multidisciplinary approach to help solve some of our global issues.

Meredith will be working with GPS faculty members, Kate Ricke and Jennifer Burney, on the policy implications of successive atmospheric rivers (ARs). ARs are a large contributor to California’s water supply, providing approximately 50% of it’s water year precipitation, but can also have negative impacts, such as widespread flooding and debris flows. Families of events, which are defined as ARs that successively occur within 120 hours of each other, can have enhanced impacts as pre-conditioning from the first AR can elevate the chances of high streamflow and saturated soils, which leads to shorter time frames to safely release stored water downstream. She will work with her GPS mentors on the issues of aging infrastructure, snowpack becoming a less reliable water storage system, and the potentials of implementing a flexible rule curve for dam operators.

The fellowship will conclude with a presentation of the fellow’s research findings in the spring quarter. The fellow will also have the opportunity to attend policy-related seminars, workshops and courses.

CW3E graduate student, Meredith Fish (center), with her GPS Faculty Mentors Kate Ricke (left), and Jennifer Burney (right).

CW3E Accepted as a National Oceanic and Atmospheric Administration Weather Ready Nation Ambassador

CW3E Accepted as a National Oceanic and Atmospheric Administration Weather-Ready Nation Ambassador

September 7, 2017

CW3E recently became a NOAA Weather-Ready Nation (WRN) Ambassador. The Weather-Ready Nation Ambassador Initiative is a collaborative entity that brings numerous organizations, businesses, and people together in order to strengthen national resilience against extreme weather and water events.

CW3E is being recognized as a WRN Ambassador because it promotes the Weather-Ready Nation messages and themes to their stakeholders and engages with NOAA personnel on potential collaboration opportunities. CW3E is doing this through scientific research to improve forecasts of extreme precipitation and flooding on the west coast, as well as communicating about extreme events through the hydrometeorological outlooks and post-event summaries on the CW3E website and Twitter. CW3E in collaboration with NOAA, will assist in improving the nation’s readiness, responsiveness, and overall resilience against extreme weather.

Becoming a WRN Ambassador advances CW3E one step further in executing our mission to provide 21st 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.

Visit NOAA’s WRN website to learn more about the initiative, its goals, and its participants.

CW3E Field Trip to Experience the North American Monsoon in Southern Arizona

CW3E Field Trip to Experience the North American Monsoon in Southern Arizona

August 14, 2017

Several members of CW3E spent a recent weekend observing the North American monsoon in the Tucson, Arizona area, including Nogales and Sonoita. It provided an opportunity to experience an iconic type of “extreme event” that occurs in the Western U.S.

Activities included early-morning hiking in Ventana Canyon (Fig. 1), touring southern Arizona from Tucson to Nogales, Patagonia and Sonoita, learning about Sonoran Desert and nearby grassland landscapes and climate (Fig. 2), observing long-lived monsoon convection and its impacts, and discussing active topics of research related to the North American monsoon, including a recent paper on the role of the Chiricahua Gap (Ralph and Galerneau 2017 –

Fig.1. The CW3E group with a saguaro during the Ventana Canyon hike. From left Marty Ralph, Brian Henn, Anna Wilson, and Maryam Asgari-Lamjiri.

Fig.2. Example of landscape 30 miles southeast of Tucson, near Sonoita, AZ on 29July 2017 at about 5000 ft MSL.

A highlight was observing flood water in normally dry washes, such as Tanque Verde Wash in northeast Tucson (Fig. 3).

Fig.3. The Tanque Verde River looking east from the bridge on Kolb Road after monsoon storms in the Tucson area. The Rincon Mountains, including their high point at 8664 ft MSL, are in the background. Photograph taken at 6:45 pm local time on 29 July 2017.

Precipitation totals in Tucson were significantly above normal. Fig. 4 shows the July 2017 climate summary from NWS. In fact, the CW3E team experienced the heavy downpour near the Tucson airport on Saturday, 29 July 2017 that broke the all-time record for July monthly precipitation (now 6.8 inches; previously 6.24 inches in July 1921).

Fig.4. National Weather Service July 2017 climate summary with dates of the CW3E field trip highlighted.

CW3E’s goal is to revolutionize the physical understanding, observations, weather predictions and climate projections of extreme events in Western North America (, including the North American summer monsoon.

Points of contact: Anna Wilson, Marty Ralph.

CW3E Announces 4 New Post-Doctoral Positions

Post-Doctoral Positions Available at the Center for Western Weather and Water Extremes

August 3, 2017

Location: La Jolla, California
Deadline: Positions are available immediately. Applications will be considered until positions are filled. Preference will be given to applications received by 1 September 2017.
Number of new positions available: 4

The Center for Western Weather and Water Extremes (CW3E), is a research and applications center established in 2013 at Scripps Institution of Oceanography by its Director, Dr. F. Martin Ralph. CW3E focuses on the physical understanding, observations, weather predictions, seasonal outlooks and climate projections of extreme weather and water events to support effective policies and practices to improve resilience in the Western U.S. Funding for this set of Postdoctoral positions is in place from several federal, state and local agencies, with a major emphasis on the unique science and applications needs associated with water supply and flood risk in the Western United States. CW3E carries out its goals with a diverse network of research and operational partners at more than ten other institutions across the U.S. Individuals will be joining a group of several existing Postdoctoral scholars and graduate students, and a number of experienced faculty, researchers and staff at Scripps who are involved with CW3E.

Per normal Postdoctoral appointment policies, all positions are envisioned as being initially for 1-year, with extension possible contingent upon performance and availability of funding. The University of California, San Diego is an AA/EOE.

Interested individuals are encouraged to submit their resumes and a 1-page statement of relevant personal interests, goals, range of potential start dates and at minimum two references. These should be sent to the person listed below as the “position coordinator” for the position you are interested in.

Applicants should have 0-2 years of Postdoctoral experience, or be nearing completion of their Ph.D. (estimated within 3 months), and be self-motivated and hard-working. Good written and verbal communication skills, including the ability to produce scientific publications and presentations and meet project milestones are required. Strong analytical backgrounds with a Ph.D. in atmospheric science, meteorology, atmospheric chemistry, climate science, hydrology or environmental engineering is preferred. Programming experience working in a Unix environment with experience in scripting languages such as Python, Perl, R and Matlab along with true programming language experience in C and Fortran is highly desired. Experience with using high performance computing is also desired. Successful applicants should be comfortable independently working with large code libraries and producing novel visualizations.


Position 1: Hydrometeorological Advancements for Management Decision Support

CW3E position coordinator – Dr. Brian Henn;

CW3E seeks a Postdoctoral researcher to design and contribute to efforts that lead toward improved operational application of distributed hydrologic and hydrometeorological sciences. The position would work on research that improves hydrologic model performance associated with extreme events. Anticipated methodologies include data assimilation (DA) techniques that leverage in-situ soil moisture observations and remotely sensed observations, improving hydrologic model parameterization and determining the most appropriate unbiased atmospheric forcing’s for hydrologic model applications from NWP output. Additionally the candidate would develop guidelines for parsimonious application of hydrologic models in time and space and evaluation processes and metrics for hydrologic model simulations and forecasts that isolate areas of potential improvement. The research would support the development, by the candidate, of a prototype decision support system that combines a variety of observed and forecast information to aid in operational decision making. Through the research the candidate would continually develop and support a connection between CW3E and California-Nevada River Forecast Center operational forecasts systems. The candidate should have experience with hydrological model development, calibration, application, and verification. Additional experience in developing observed datasets for forcing hydrologic models and operating hydrologic and hydraulic models in a forecasting mode using NWPs or other sources is also desired.


Position 2: Aerosols Influence on Winter Precipitation

CW3E position coordinator – Dr. Amato Evan;

CW3E seeks a Postdoctoral researcher to investigate the manner by which aerosols influence wintertime precipitation in the western US, with a focus on ice nuclei from marine and terrestrial sources, using high-resolution numerical modeling. The goal of this work is to improve basic understanding of aerosol-cloud interactions and their affect upon precipitation from atmospheric rivers to improve forecasts of precipitation from such events. In order to address the scientific needs of the project the postdoctoral scholar will be expected to design, implement and validate aerosol emission, transport, removal, cloud condensation and ice nuclei activation models within West-WRF, which is a version of the Weather Research and Forecast Model (WRF) that has been developed at CW3E to improve the accuracy of forecasting extreme precipitation events and as a testbed for understanding the physical processes that drive extremes in weather. These activities will be conducted in collaboration with a team of students, faculty and scientists at CW3E. The successful candidate will have the opportunity to present at conferences and will be expected to publish major results in peer-reviewed journals as first author.


Position 3: Terrestrial Water Storage

CW3E position coordinator – Dr. Julie Kalansky;

We seek a postdoctoral researcher to investigate variability in regional terrestrial water storage, including groundwater and snowpack, as revealed by a growing archive of GPS crustal displacements collected throughout California and across the United States. The GPS-inferred water storage contains variability over a range of time scales, much of which is driven by extreme events from synoptic scale storm activity to interannual wet and dry spells. Regionally, the high density of the GPS network may afford resolution at 10’s of km scales and thus provide new insight into catchment water balances. This investigation will require synthesis and comparison with other observational data, along with model-simulated hydrological variability. The postdoc will use the GPS data for information about snowpack and groundwater and relate these to weather and climate events. As part of the project, the postdoc may develop online tools for tracking this information for decision support. Support for this position will come from CW3E, in partnering with CNAP ( and the Institute of Geophysics and Planetary Physics ( The post-doc should be familiar with climate and hydrological phenomena in western North America.


Position 4: Mesoscale Dynamics and Predictability of Atmospheric Rivers

CW3E position coordinator – Dr. Jason Cordeira;

The position will explore the mesoscale dynamics and predictability of ARs affecting the western U.S. coast. The research will use a variety of observational and modeling-based tools and analysis techniques to diagnose the multiscale processes associated with persistent AR conditions culminating in extreme precipitation. The candidate should have experience forecasting extreme events from an operational or modeling perspective, and the ability to conduct in depth case studies and verification analyses. The position will involve participation in an atmospheric river airborne reconnaissance project “AR Recon” effort that is aimed at improving the 1-to-3-day skill of AR landfall forecasts. For example, the incumbent will develop methods to utilize targeting observations in order to improve prediction of mesoscale frontal waves that are key to determining position and duration errors associated with landfalling ARs. The project involves active collaboration with NCEP (GFS) and the Navy (COAMPS) to identify, analyze, and diagnose dynamical processes associated with skillful AR landfall and precipitation characteristics. The candidate should have strong knowledge of mesoscale and synoptic-scale atmospheric dynamics and forecasting techniques, including but not limited to frontal circulations, jet streaks, cyclone kinematics, multiscale precipitation processes, data assimilation, and mesoscale modeling.

American Geophysical Union Publishes Collection of Atmospheric River Publications in Geophysical Research Letters

American Geophysical Union Publishes Collection of Atmospheric River Publications in Geophysical Research Letters

July 27, 2017

The American Geophysical Union recently published a special hand selected collection of papers on atmospheric rivers that have been published in Geophysical Research Letters.​​

Atmospheric rivers are a relatively new phenomena in atmospheric science that have become a popular subject of meteorological, hydrological, and climatological research due to their influence on global moisture transport, extreme precipitation, flooding, drought mitigation, and water supply. The collection in GRL highlights the research that has been published over the past three decades beginning with Newell et al’s seminal paper, which introduced the term “tropospheric river.”

Papers from numerous CW3E researchers and collaborators are featured in the collection which discuss topics ranging from extreme precipitation to the influence of climate change on atmospheric river characteristics. The collection of papers can be found here

CW3E Begins Installation of Instrumentation in the Russian River Watershed

CW3E Begins Installation of Instrumentation in the Russian River Watershed

July 7, 2017

CW3E began its summer fieldwork campaign in the Russian River watershed last week with the installation of surface meteorology, soil moisture and streamflow instruments. Pictured are CW3E members and collaborators from the U.S. Army Corps of Engineers and Sonoma County Water Agency after installing soil moisture sensors on the Corps’ property at Lake Mendocino. The observations from the fieldwork campaign will provide information on precipitation, soil moisture and streamflow during cool-season atmospheric rivers (ARs) that produce the majority of the inflows to Lake Mendocino. The reservoir is a focus of the Forecast Informed Reservoir Operations project, which assesses the potential to enhance water resources and flood control operations with hydrometeorological forecast data. The surface meteorology and hydrology data from the field campaign will complement additional observations of the atmosphere made by CW3E, NOAA and other project collaborators.​​

CW3E members and collaborators stand near the finished instrumentation tower with Lake Mendocino in the background. From left to right: Chad Hecht (CW3E), Will Chapman (CW3E), Kyle Evans (Sonoma County Water Agency), Steve Turnbull (US Army Corps of Engineers), Anna Wilson (CW3E), Douglas Alden (CW3E).

CW3E Participates in Western States Water Council Visit to UC Davis’ Bodega Marine Lab

CW3E Participates in Western States Water Council Visit to UC Davis’ Bodega Marine Lab

July 1, 2017

CW3E members were on hand recently at UC Davis’ Bodega Marine Lab to introduce some of the key instrumentation located there to sample atmospheric rivers (ARs). The audience included members of the Western States Water Council (WSWC), California Department of Water Resources (DWR), and Sonoma County Water Agency (SCWA). The audience toured state-of-the-art onsite instrumentation and learned about its significance for forecasting and research into ARs. This instrumentation included the Atmospheric River Observatory, which was installed as part of the California Enhanced Flood Response and Emergency Preparedness network (partners include DWR, NOAA, and Scripps), and has been making observations consistently at this location since 2004, as well as instrumentation installed during the past winter by CW3E to observe surface microphysics and vertical precipitation structure. CW3E collaborator Bruce Cornuelle gave a talk on the importance of ocean observations for numerical weather prediction at all scales, including subseasonal to seasonal. The conclusion of the visit featured a demonstration radiosonde release at Bodega Bay. 275 sondes in total were released by CW3E during historically wet Jan-Mar 2017 at the Bodega Marine Lab as well as an inland location to assess water vapor transport by ARs as they move inland and interact with the terrain.

Fig.1. Bruce Cornuelle gives a talk on the importance of ocean observations for numerical weather prediction and subseasonal to seasonal forecasting. Image also includes a model of an ARGO float ( Photo courtesy CA DWR.

Fig.2. CW3E (a), WSWC (b), and SCWA (c) members before the demonstration radiosonde launch.
Photos courtesy CA DWR.

Points of contact: Anna Wilson, Marty Ralph.

CW3E Update: Flood Risk From Snow Melt

CW3E Update: Flood Risk From Snow Melt

May 23, 2017

Click here for a pdf of this information.

Anomalously Warm Temperatures Expected to Contribute to Melting Snowpack and Elevated Runoff

  • High temperatures of 60–80˚F (16–26˚F) are forecast for the higher elevations of the Sierra Nevada Mountains over the next several days
  • The higher than normal water year to date precipitation over much of the West Coast has created snow packs that are much greater than normal over most of the Sierra Nevada Mountains
  • The combination of anomalously high temperatures and snow pack is forecast to lead to increased runoff and potential flooding
  • The National Weather Service has issued flood watches and warnings for several locations in California
  • Loop of GFS Forecast Surface Temperatures

    Valid 1200 UTC 23 May – 1200 UTC 30 May 2017




    Summary provided by C. Hecht B. Kawzenuk and F.M. Ralph; 12 PM PT Tuesday 23 May 2017

CW3E Outreach at Local Elementary School

CW3E Outreach at Local Elementary School

May 15, 2017

CW3E’s Brian Kawzenuk, Chad Hecht, and Anna Wilson recently visited La Costa Meadows Elementary School to discuss some of the unique observations and tools that meteorologists use to study the atmosphere. Over 1000 students from kindergarten to fifth grade joined to observe and discuss meteorological ground instrumentation and a weather balloon launch. Discussion focused on how the instrumentation works, what they measure, how the observations can be useful to understanding the atmosphere, and how this knowledge and research can be used to improve forecasting and water resource management. During the demonstration students were actively engaged, asked numerous questions, and two assisted in releasing the weather balloon.

After the balloon launch, fourth and fifth grade students were invited to a more in depth discussion and presentation on meteorology, which focused on several aspects that are related to their science curriculum. Topics covered included data gathered from radiosonde launches, radar and satellite observations, storm systems and fronts, and forecasting and atmospheric models. This discussion gave students the opportunity to discuss and ask more questions about the atmosphere and how it is studied. Overall, the event proved to be a valuable experience for both students and staff.

Left: Anna Wilson and Chad Hecht prepare a radiosonde and weather balloon at La Costa Meadows Elementary School. Right: Brian Kawzenuk describes the process of performing a weather balloon launch while Chad and Anna prepare to hand off the balloon and radiosonde to two students.