CW3E Welcomes Dr. Minghua Zheng

CW3E welcomes Dr. Minghua Zheng

January 16 2017

Dr. Minghua Zheng started at CW3E in January 2017 as a Postdoctoral Scholar. Minghua received her Ph.D. in Atmospheric Sciences from the State University of New York at Stony Brook under the advisement of Dr. Edmund Chang. Her dissertation focused on understanding the growth of forecast errors and uncertainties in ensemble forecasting of U.S. East Coast winter storms. Specifically, her research used ensemble sensitivity analysis, a data mining method, the Ensemble Transform Kalman Filter (ETKF), and other statistical tools to investigate the predictability of winter storms and to improve forecast skill. In addition, she investigated the role of large-scale processes, such as Rossby wave packet behavior, on the predictability of winter storms. In her new position, she will work on real-time data assimilation in CW3E’s “West-WRF” model using the Data Assimilation Research Testbed (DART) and four-dimensional variational (4DVAR) system. The assimilation will be used to estimate the model biases, improve initial conditions, and identify the sources of forecast errors and uncertainties associated with Atmospheric River events.

CW3E Participates in Water in the West: A Science Policy Roundtable

CW3E Participates in Water in the West: A Science Policy Roundtable

December 10, 2016

CW3E was represented in a December 8, 2016 panel discussion hosted by UCSD’s School of Global Policy and Strategy (GPS)’s Science Policy Fellows Program and SIO’s Science Policy Discussion Group, titled “Water in the West: A Science Policy Roundtable”. The purpose of the event was to bring together our different communities and explore the sources of California’s water supply, how water supply can change, how it is used throughout the state and best practices for optimal regulation of its use.

CW3E director Dr. F. Martin Ralph acted as moderator. Other panel members were Dr. Jennifer Burney of GPS, Sandra Kerl of the San Diego County Water Authority, and Dr. Dan Cayan of SIO and a CW3E collaborator. Dr. Scott Sellars, the leader of the Science Policy Discussion Group, was involved in organizing the event. Other CW3E postdocs and graduate students assisted with logistics. The attendance was just over 100 people, with a very engaged audience. Questions were asked on topics ranging from specific projects run by the SD County Water Authority, to potential changes to academic funding sources with the incoming federal administration, to questions on groundwater and atmospheric rivers science. The event was recorded and can be viewed here.

More details are available in the GPS news story.

At podium: Marty Ralph (Scripps/CW3E); Left to right at table: Sandra Kerl (San Diego County Water Authority), Dan Cayan (Scripps/CW3E and USGS), Jennifer Burney (GPS)

CW3E partners with California Department of Water Resources, California Geological Survey, US Geological Survey, and the Western Regional Climate Center to assess post-fire debris flow hazards in northern California

CW3E partners with California Department of Water Resources, California Geological Survey, US Geological Survey, and the Western Regional Climate Center to assess post-fire debris flow hazards in northern California

December 2, 2016


Atmospheric River knowledge and tools support post-fire debris flow hazard mitigation and fast-response studies of debris flow-meteorology linkages

An important consequence of the recent record drought in parts of California is the occurrence of major wildfires. The Butte, Valley and Soberanes fires occurred in the last 18 months and have been some of the largest in California history. These tragic burns caused many adverse impacts at the time, and continue to create natural hazards due to the increased risk of damaging debris flows that can occur after the rains return.

California’s burned steeplands are prone to hazardous debris flows during winter storms. Wildfires remove vegetation and alter soil properties, increasing the likelihood of debris flows, even for relatively low intensity storms. When rainfall of sufficient intensity and duration impacts recently burned steeplands, landslides and surface runoff can mobilize ash, rocks, and other material into debris flows that devastate life and property.

California’s Department of Water Resources (DWR) is sponsoring work to examine the role of Atmospheric Rivers on flooding and landslide occurrence and magnitude. The project is led by the Center for Western Weather and Water Extremes (CW3E) at Scripps Institution of Oceanography and includes a team of experts from Scripps, California Geological Survey (CGS) and the U.S. Geological Survey (USGS) Landslide Hazards Team.

Within these burn areas, the geology team, led by Jeremy Lancaster of CGS, is deploying sensors and making measurements in the burn areas when conditions warrant. Doing so requires making decisions on whether to make observations at a study site following a storm event. In support of this, CW3E Graduate Student researchers Nina Oakley and Meredith Fish are using new knowledge of weather systems capable of producing intense precipitation, especially Atmospheric Rivers, to evaluate the potential for high-intensity precipitation over the Soberanes Fire, Butte Fire, and Valley Fire burn areas to advise Lancaster. Key to these preparations and day-to-day decisions are the new Atmospheric River forecasting tools at CW3E. Additionally, post-storm, CW3E scientists will compile meteorological data relevant to the storm event such as maximum precipitation intensity, storm total precipitation, radar imagery, an evaluation of Atmospheric River variables, and any information unique to that storm. For events that produce a debris flow response, a more in-depth case study will be conducted combining both geologic and atmospheric information.

Figure 1: Map of three burn areas that we propose to assess: Soberanes, Valley, and Butte wildfires.

Synthesis of the information collected through these storm and debris flow response logs will provide insight to post-fire debris flow triggering rainfall thresholds across northern California and the meteorological conditions that produce such rainfall. This integrated approach of meteorologists and geologists working together to address the post-fire debris flow issue will help advance our knowledge of these potentially hazardous events. This knowledge will be incorporated into landslide/debris flow hazard outlooks that factor in both landscape conditions (e.g., fire) and meteorology (e.g., extreme precipitation from Atmospheric Rivers)

Figure 2: Debris flow deposits stopped by cement barriers outside the Big Sur Lodge in California. This event was triggered by rain falling on burned steeplands in 2009, near an area now burned again by the Soberanes wildfire. (credit: David Longstreth, CGS).

Figure 3: During Fall 2016, USGS and CGS researchers install a rain near Pfeiffer Falls in the Soberanes Fire burn area to measure the rainfall intensities that trigger post-fire debris flows.

Contacts: Jeremy Lancaster (CGS), Nina Oakley (DRI and CW3E), John Stock (USGS), F.M. Ralph (CW3E)

Congressional Briefing on “A New Frontier in Water Operations: Atmospheric Rivers, Subseasonal-to-Seasonal Predictions and Weather Forecasting Technology”

Congressional Briefing on “A New Frontier in Water Operations: Atmospheric Rivers, Subseasonal-to-Seasonal Predictions and Weather Forecasting Technology”

July 27, 2016

An interagency, cross-disciplinary team of experts recently convened in Washington to provide Congressional staff with a briefing on atmospheric rivers, subseasonal-to-seasonal precipitation prediction needs, and the benefits of enhanced predictive forecasting technology to the future of water management.

Attendees heard from a diverse panel of experts representing a broad spectrum of perspectives, including government engagement by the National Weather Service and the U.S. Army Corps of Engineers, scientific findings presented by the Scripps Institution of Oceanography, and regional impacts to stakeholders represented by the Western States Water Council.

This briefing highlighted CW3E’s major effforts on atmospheric river science, monitoring and predictions, and their application to possible new water management strategies, such as Forecast-Informed Reservoir Operations (FIRO;, which is co-led by CW3E’s Director, F. Martin Ralph. Roughly 40 people attended, including representatives of congressional offices, committees, ACWA, federal agencies and other groups.

Click here for a summary.

Contact: F. Martin Ralph (

CW3E Welcomes Dr. Forest Cannon

CW3E welcomes Dr. Forest Cannon

October 17, 2016

Dr. Forest Cannon joined CW3E as a Postdoctoral Scholar in October 2016. Forest earned his Ph.D. in Geography at the University of California, Santa Barbara, under the direction of Dr. Leila Carvalho. His dissertation focused on understanding large-scale forcing of extreme orographic precipitation in High Mountain Asia, using in-situ and remote sensing observations as well as regional climate modeling. His interest in working on weather and climate problems that affect his home state of California motivated earlier collaboration with the National Weather Service on fire weather forecasting in Santa Barbara, and ultimately led to his desire to pursue research pertaining to California’s water resources, here at CW3E. In his new position, Forest will use advanced atmospheric profiling satellites to evaluate and improve the representation of clouds and precipitation in global and regional climate models during atmospheric river events affecting the western US, with the goal of advancing short-term predictability and long-term projectability of regional water extremes.

CW3E Welcomes Chad Hecht

CW3E welcomes Chad Hecht

October 17, 2016

Chad joins CW3E as a staff research associate from Plymouth State University in Plymouth, New Hampshire. At Plymouth State, Chad worked under the advisement of Dr. Jason Cordeira and investigated the upstream evolution of atmospheric rivers and their impacts over the U.S. West Coast. The work focused on the synoptic-scale patterns that were associated with different “types” of ARs and the role Quasi-Geostrophic forcing played in precipitation accumulations. Chad also investigated the impacts associated with these landfalling ARs by developing an impact scale on a GIS platform. Chad looks forward to using his programming and research based skills to assist the CW3E team develop products and stakeholder tools. Having grown up in the Hudson Valley of New York and spending his whole life in the Northeast, Chad is excited to see what the Southwest and its temperate climate has to offer.

CW3E Hosts Winter Outlook Workshop with California DWR

CW3E Hosts Winter Outlook Workshop with California DWR

November 18, 2016

The California Department of Water Resources (CDWR) and CW3E led a working meeting with researchers at the Scripps Institution of Oceanography in La Jolla, November 16-18, 2016. The workshop focused on efforts to improve sub-seasonal to seasonal prediction of precipitation, which could help agencies better manage water resources.

“We’d all like to know if 2017 will be wet or dry, but determining that is scientifically difficult. We’re trying to emphasize the need for prioritizing this research in the science community,” said Jeanine Jones, Interstate Resources Manager at CDWR.

Participants from the following agencies were in attendance: CW3E/Scripps, CDWR, Sonoma County Water Agency (SCWA), National Center for Atmospheric Research (NCAR), Natonal Weather Service (NWS), Western States Federal Agency Support Team (WestFAST), National Oceanic and Atmospheric Administration (NOAA), Plymouth State University (PSU), Oregon State University (OSU), University of California, Los Angeles (UCLA), Salt River Project (SRP), Climate Assessment for the Southwest (CLIMAS), Desert Research Institute (DRI), and Metropolitan Water District of Southern California (MWD).

Images courtesy DWR Photography – Florence Low

CW3E Welcomes Dr. Rachel Weihs

CW3E welcomes Dr. Rachel Weihs

August 8, 2016

Dr. Rachel Weihs started at CW3E in August 2016 as a Postdoctoral Scholar. Rachel earned her Ph.D. in Meteorology at Florida State University in Tallahassee, Florida under the direction of Dr. Mark Bourassa. Her dissertation focused on understanding the role of high frequency variability of sea surface temperatures on the near-surface winds and atmospheric boundary layer as produced by the Weather Research and Forecasting model. In addition, she was able to quantify the relative impact of the local diurnal variability of sea surface temperatures on regional weather and deduce the importance of two-way air-sea feedback processes on the magnitude of diurnal heating in the upper ocean in the extratropical Atlantic. She is excited to have joined the CW3E team in August 2016 to study the influences of the Pacific Ocean on the forecasting of atmospheric rivers as well as examining the role of air-sea interaction on the boundary layer and the low level jet associated with these important weather phenomena.

CW3E Welcomes Dr. Brian Henn

CW3E welcomes Dr. Brian Henn

August 8, 2016

Dr. Brian Henn started at CW3E in August 2016 as a Postdoctoral Scholar. He is a native of Northern California and received undergraduate and master’s degrees from Princeton and Stanford in civil and environmental engineering. With interests in hydrology, water resources and infrastructure, he worked as an engineer on urban stormwater and sustainability projects at Hazen and Sawyer in New York City. Brian pursued doctoral studies at the University of Washington in the research group of Dr. Jessica Lundquist, receiving his Ph.D. in 2015. His dissertation used streamflow observations and novel modeling techniques to better understand orographic precipitation patterns over the Sierra Nevada mountain range. He is also a licensed civil engineer in California.
He is interested in better representing the heavy precipitation associated with Atmospheric Rivers making landfall over mountainous terrain. He looks forward to working with CW3E colleagues on understanding and predicting these events, which are crucial to the water supplies of the Western United States. He is also looking forward to sampling the best of San Diego’s many breweries and exploring Southern California’s mountains and trails.

CW3E represented in recent policy and program meetings

CW3E Represented in Recent Policy and Program Meetings

June 8, 2017

During the last few weeks CW3E’s perspectives have been highlighted at three science policy-oriented meetings. The connection between CW3E’s scientific activities, practical applications and water policy implications is a common theme among them. The meetings and a brief synopsis are provided below:

1) AGU Congressional briefing on role of basic Geoscience in American Security May 2016

AGU invited three speakers to a Congressional briefing they organized to communicate to staff supporting a number of elected officials and policy committees. The goal was to make the connection between basic science advances (and the funding that has supported them), and benefits to American Security. CW3E’s Director, Dr. Ralph, represented the role of basic geoscience research in advancing water security in the Western U.S. His presentation emphasized the critical roles of key science funding strategies, from standard grants programs, to directed research efforts, cooperative agreements and federal labs. And in the end concluded that many breakthrough advances result not from a systems engineering approach to deciding what to do, but from ideas that are “outside the box.” He also highlighted that science, at its core, is fundamentally a creative endeavor that requires long-term support for people in their careers and for the organizations that host them. AGU has posted a video of the briefings here.

2) NOAA Water Information “Listening Session” in Sacramento May 2016

NOAA invited water management stakeholders from across the West to hear about the National Water Center they are creating in Alabama and to listen to stakeholders interests and needs for weather and water information to support water supply, flood mitigation and endangered species restoration in the West. CW3E was represented by Dr. Ralph, who brought Scripps science into the discussion, and supported major points presented by water managers concerning the vital role of atmospheric rivers in western water decisions. NOAA held one other regional “listening session” – in Alabama, and is holding one more “National” session in July. They will be considering input from these meeting as they develop their agency’s strategies in the coming years to support water information needs for the nation.

3) WSWC S2S Workshop San Diego June 2016

The National Academies of Science recently released a report on the subject of science needed to enable subseasonal-to-seasonal predictions to support decisions. The Western States Water Council (a group supporting the Governors of 17 Western States) organized a regional Workshop in San Diego in early June to discuss both the user requirements for better forecasts and the science opportunities to achieve them. CW3E was represented well, including participation by Sasha Gerhunov, Tamara Shulgina and Marty Ralph, including a presentation by Marty on observing system needs to support the goals.