cw3e-web - Center for Western Weather and Water Extremes

CW3E Director Participates in Alaska AR Webinar

August 22, 2019

CW3E Director, Marty Ralph, participated in a webinar along with Aaron Jacobs, forecaster for the National Weather Service Juneau office, jointly hosted by the Alaska Center for Climate Assessment and Policy (ACCAP), a NOAA RISA team and the Geographic Information Network of Alaska (GINA). The webinar initially focused on atmospheric rivers (ARs). Marty began the webinar by explaining about AR research broadly and current efforts to better understand the dynamics and improve forecasts. Then Aaron spoke more explicitly about ARs impacts to Alaska, how the events are forecasted and communicated, and future areas of research related to Alaska ARs. Together the presentation provided foundational information about Alaska ARs to multiple stakeholders across the seven states with primary participation from Alaska. Stakeholders included 40+ participants from federal and state agencies as well as academic institutions, tribal organizations, and power utilities.

To view a recording of the webinar, click here.

Sixth Annual FIRO Workshop

August 12, 2019

The Center for Western Weather and Water Extremes (CW3E), Sonoma Water, Orange County Water District and Yuba Water Agency co-hosted the 6^th Annual Forecast Informed Reservoir Operations (FIRO) workshop at Scripps Institution of Oceanography on August 6^th-8^th. The three-day meeting brought together over 100 US Army Corps of Engineers (USACE), National Oceanic and Atmospheric Administration and Bureau of Reclamation officials, dam operators, local water agencies, researchers, and academics to discuss the progress and future of FIRO.

The meeting began with CW3E Director, Marty Ralph welcoming attendees, providing a brief retrospective of FIRO over the past 5 years and thanking workshop co-sponsors as well as FIRO funders. USACE FIRO Program manager, Cary Talbot, provided opening remarks. The first session highlighted the three current FIRO projects, Lake Mendocino, Prado Dam and Yuba-Feather (New Bullards Bar and Oroville Dams), followed by presentations on the utilization of FIRO decision support tools over the last year.

The second day began with a review of the current FIRO operations and challenges as well as the environmental concerns at the three FIRO project locations. These were followed by presentations and discussions about forecast challenges, novel observations that support improved forecasts and watershed understanding, and hydrologic modeling efforts. Lively discussion focused on how research addresses operational changes both in forecasting and water management. Presentations ended with a perspective of how science and technology enable FIRO. The last panel provided different perspectives on potential adaptive management strategies that could leverage improved forecast skill over time. The day wrapped up with a reception and poster session highlighting FIRO related research.

The last day was a look toward the future of FIRO. The morning session focused on subseasonal-to-seasonal forecasting and the climate change-FIRO nexus. The final session centered on potential future FIRO applications. CW3E Director Marty Ralph provided closing remarks.

The range of participants and expertise in the room demonstrated the highly collaborative community of agencies, institutions, and individuals who have taken FIRO from concept to application and continue to learn from each other.

CW3E in the News

August 2, 2019

El Niño has long been known to cause extensive flooding in Southern California, just as its oppositely-phased sister La Niña has been associated with increased precipitation and flooding in the Pacific Northwest, but the economic impacts had not been systematically quantified.

Newly published research by CW3E postdoctoral researcher Tom Corringham and coauthor Dan Cayan measures the damages in the western United States resulting from storms during both phases of the El Niño Southern Oscillation (ENSO), finding that El Niño causes substantially more losses than La Niña in Southern California while the opposite pattern is observed in the Pacific Northwest.

Mike Branom of the Washington Post’s Capital Weather Gang highlights the work with a July 30^th article interviewing Dr. Corringham.

In the interview, Corringham describes the importance of the severe West Coast storms known as atmospheric rivers (ARs), especially the most damaging AR4 and AR5s, referring to the recently developed AR scale developed by CW3E researchers and colleagues. Over the 40-year period from 1978 to 2017, just one percent of flood events caused more than two thirds of total losses, and most of these extreme losses were caused by atmospheric rivers.

Corringham also highlights the economic value of ongoing research to improve subseasonal to seasonal (S2S) predictability of extreme weather events. Increased lead time would assist property owners, policymakers, and emergency responders in planning for these high impact events and reducing their toll.

The journal article “The Effect of El Niño on Flood Damages in the Western United States” is available online in the July edition of Weather Climate and Society at https://doi.org/10.1175/WCAS-D-18-0071.1. The Washington Post article can be found at https://wapo.st/2GEccCC.

ENSO Impacts Mean differences in monthly October–March losses per $100,000 of coverage reveal an ENSO dipole. Enhanced losses are colored red and reduced losses are blue, with color intensity on a log scale. Boxed grid cells are significantly different from the overall October–March mean at p < 0.1, by analysis of means. Boxed cells with crosses are significant at p < 0.05. Significantly enhanced losses are observed in Southern California during El Niño months and in the Pacific Northwest during La Niña months.

ENSO Predictability Correlations of monthly insured losses by region with leading Multivariate ENSO Index (MEI) indicate the potential predictability of ENSO flood impacts. Significant (p < 0.01) positive correlations are seen in Southern California up to 8 months ahead of time. The signal is positive but not significant in Northern California. Negative and weakly significant (p < 0.1) correlations are seen in Oregon and Washington up to 3 months ahead.

CW3E AR Update: 01 August Outlook

August 1, 2019

Click here for a pdf of this information.

Strong and long-duration atmospheric river forecast to impact Alaska over the next several days

An AR is forecast to make landfall over western Alaska beginning tomorrow, 02 August 2019, and ending on 06 August 2019
IVT magnitudes >1000 kg m–1 s–1 are currently forecast for numerous coastal locations over western Alaska
AR conditions could last between 40 and 96 hours for certain coastal locations
Some locations in north-central Alaska could receive >4 inches of precipitation over the next 72-hours
The Bering Sea at Golovin is currently forecast to rise ~1ft above minor flood stage

Click IVT or IWV image to see loop of 0-180 hour GFS forecasts Valid 1200 UTC 01 August – 0600 UTC 08 August 2019

Summary provided by C. Hecht, D. Steinhoff, J. Kalansky, F. M. Ralph; 3 PM PT 01 August 2019

CW3E Publication Notice: 2018 International Atmospheric Rivers Conference: Multi-disciplinary studies and high-impact applications of atmospheric rivers

CW3E Publication Notice

2018 International Atmospheric Rivers Conference: Multi-disciplinary studies and high-impact applications of atmospheric rivers

July 30, 2019

CW3E scientists Anna Wilson and Mike DeFlorio, along with CW3E director F. Martin Ralph, recently co-authored a meeting report led by Alexandre Ramos and published in the Royal Meteorological Society’s Atmospheric Science Letters: Ramos, A.M., A.M. Wilson, M.J. DeFlorio, M.D. Warner, E.A. Barnes, R. Garreaud, I.V. Gorodetskaya, D.A. Lavers, B. Moore, A. Payne, C. Smallcomb, H. Sodemann, M. Wehner, and F.M. Ralph, 2019: 2018 International Atmospheric Rivers Conference: Multidisciplinary studies and high-impact applications of atmospheric rivers. Atmos. Sci. Lett., e935, https://doi.org/10.1002/asl.935, early online release.

The article highlighted the second International Atmospheric Rivers Conference held during 25-28 June, 2018 at the Scripps Institution of Oceanography, University of California, San Diego. The conference was sponsored by the Center for Western Weather and Water Extremes (CW3E). A total of 120 people attended the Conference with 94 abstracts submitted and 30 participating students (Fig. 1, group photograph). In addition to the conference, CW3E held a Student Forecasting Workshop in the same week. The main goal of this conference was to bring together experts from hydrology, atmospheric, oceanic, and polar sciences, as well as water management, civil engineering, and ecology to advance the state of AR science and to explore the future directions for the field. The conference was organized into traditional oral and poster presentations, along with panel discussions and Breakout Groups. This format allowed enhanced interaction between participants, driving progress within the scientific community and the enhanced communication of societal needs by various stakeholders. Several emerging topics of research were highlighted, including subseasonal-to-seasonal (S2S) prediction of ARs and an overview of the AR Reconnaissance campaign. In addition to providing a forum to disseminate and debate new results from scientific talks and posters, the conference was equally effective and useful in linking scientists to users and decision-makers that require improved knowledge on ARs to manage resources and prepare for hazards.

The third International Atmospheric Rivers Conference will be held in Chile in 2020, and hosted by the University of Chile, Santiago.

Figure 1: Group photo of IARC2018 participants.

CW3E Welcomes Carly Ellis

July 25, 2019

In July of 2019, Carly Ellis joined CW3E full-time as a Field Researcher. Carly has been working with CW3E since December of 2017, when she was brought on to assist with stream sampling and data collection. In 2016, she completed her Masters in Environmental Science and Policy at Plymouth State University in New Hampshire, where she spent two years working at the Hubbard Brook Experimental Forest. Her thesis focused on the variability of toxic aluminum in stream water. Prior to her Masters, Carly earned a BS in Geoscience and a BA in Environmental Studies from Hobart and William Smith Colleges in New York, where she studied water quality of the Finger Lakes and their tributaries.

As a member of the field research team at CW3E, Carly is excited to continue studying water, weather, and climate throughout the beautiful state of California. She primarily supports the observational efforts that are part of the Forecast Informed Reservoir Operations (FIRO) Program and Dr. Dan Cayan’s Hydroclimate Network. She feels lucky to be working on projects with large-scale applications and with such a genuinely engaged and interested group of people. Carly is looking forward to the next several years as CW3E expands its observational efforts in new diverse watersheds.

CW3E Welcomes Dr. Alison Cobb

July 23, 2019

In July 2019 Dr. Alison Cobb joined CW3E as a Postdoctoral Scholar. Alison completed her PhD in early 2019 at Imperial College London, researching ocean-atmosphere interactions in tropical and extra-tropical cyclones with Dr. Arnaud Czaja. Using a combination of model forecasts and observational data, her research highlighted the importance of small scale interactions that are not well represented in climate models. Prior to her PhD, she earned an MSc in Applied Meteorology at the University of Reading and a BSc in Oceanography and Marine Biology at the University of Southampton.

At CW3E Alison will continue to examine high-impact weather, focussing on extreme precipitation related to atmospheric rivers and its predictability. Alison is keen to apply her knowledge of ensemble forecasting and the importance of ocean conditions for predicting atmospheric events. Alison has moved to California from the UK and is looking forward to the new lifestyle.

CW3E Publication Notice: Rapid Cyclogenesis from a Mesoscale Frontal Wave on an Atmospheric River: Impacts on Forecast Skill and Predictability during Atmospheric River Landfall

CW3E Publication Notice

Rapid Cyclogenesis from a Mesoscale Frontal Wave on an Atmospheric River: Impacts on Forecast Skill and Predictability during Atmospheric River Landfall

July 16, 2019

CW3E collaborator Dr. Andrew Martin and co-authors have published a study investigating the impact of a rapidly developing frontal wave on atmospheric river forecast skill. The article is titled “Rapid Cyclogenesis from a Mesoscale Frontal Wave on an Atmospheric River: Impacts on Forecast Skill and Predictability during Atmospheric River Landfall” and is now available in early online release in the Journal of Hydrometeorology at https://journals.ametsoc.org/doi/abs/10.1175/JHM-D-18-0239.1.

The study examined an atmospheric river that briefly produced integrated vapor transport greater than 1000 kg m^-1 s^-1 over the Russian River Watershed and brought minor flooding to the Russian River at Guerneville, CA (see figure, panels b,d). This AR was unique because of a small-scale phenomenon that developed along the offshore section of its cold front during the landfall stage. The phenomenon, known as a mesoscale frontal wave, rapidly intensified and became a secondary extratropical cyclone during the period of greatest AR impacts.

Dr. Martin and co-authors examined observations from the Bodega Bay coastal atmospheric river observatory and forecasts from both the California-Nevada River Forecast Center and the Global Ensemble Forecast System for a range of lead times to demonstrate that the mesoscale frontal wave and secondary cyclone reduced forecast skill and negatively influenced confidence in the Guerneville river stage forecast. In addition, this study demonstrated that the near-shore development of a new warm front during the final stages of secondary cyclone formation acted to shield the topography of the Russian River Watershed from orographic controlling layer vapor flux, leading to a 6-hour hiatus in significant precipitation that acted to reduce the peak of the flood.

Co-authors include Dr. F. Martin Ralph, Dr. Anna Wilson, Laurel DeHaan, and Brian Kawzenuk of CW3E. This study was funded by the US Army Corps of Engineers as part of the FIRO program, with Dr. Ralph serving as Principle Investigator. This study is part of an effort to quantify forecast performance, diagnose the driving factors creating forecast problems, and better understand the role of mesoscale processes in modulating heavy precipitation on the US West Coast.

Figure 1: a) IWV (mm – shaded) and SLP (hPa – contours every 4 hPa from 974 to 1018) from ERA-Interim valid 00 UTC on 11 Dec, 2014. The Russian River Watershed (RRW) is shown by blue outline and interior shading. X marks location of mesoscale frontal wave. B) as in a, except shading depicts IVT (kg m^-1 s^-1). C) Six hourly accumulated RRW mean areal QPF issued by CNRFC 12 UTC on 8 Dec, 2014 (mm – green), 12 UTC on 10 Dec, 2014 (mm – blue) and CNRFC QPE (mm – black). Time on ordinate axis refers to forecast or QPE valid time. Inset contains storm-total (12 UTC on 10 Dec to 12 UTC on 13 Dec, 2014) accumulated RRW mean precipitation from each timeseries. D) Guerneville river stage forecast issued by CNRFC near 12 UTC on 8 Dec (mm – green), near 12 UTC on 10 Dec (mm – blue) and observations from river gage (mm – black) Shown for reference are the monitor (orange) and flood (red) stages.

Martin, A.C., F.M. Ralph, A. Wilson, L. DeHaan, and B. Kawzenuk, 2019: Rapid Cyclogenesis from a Mesoscale Frontal Wave on an Atmospheric River: Impacts on Forecast Skill and Predictability during Atmospheric River Landfall. J. Hydrometeor., 0. https://doi.org/10.1175/JHM-D-18-0239.1

Week 2 of the AR Colloquium is Underway!

July 3, 2019

The AR Colloquium hosted by CW3E, which began on Monday June 24th, is currently in its second week of events. Over the past several days, leading researchers in the field taught lectures on the fundamentals of atmospheric dynamics in relation to ARs, short- and long-term forecasting methods, isotopic and numerical weather analysis techniques, and how ARs in the Arctic and Antarctic connect to the tropics and midlatitudes. Attendees also learned important aspects of how to best communicate scientific research and weather forecasts to end-users, such as water resource managers in the area.

Over the weekend, attendees visited the San Diego National Weather Service (NWS) office to speak with Alexander Tardy, the Warning Coordination Meteorologist and Decision Support Services Lead, about hazards and forecasting challenges in Southern California, as well as the career trajectory of an NWS employee. Afterwards, CW3E Engineering Mentor, Douglas Alden, and Field Research Manager, Anna Wilson, led an informative tour of the Scripps Pier, and students participated in launching a weather balloon.

The AR Colloquium will wrap up later this week with a beach-barbeque networking event to celebrate the July 4th holiday, followed by a day of presentations by the students on their Colloquium projects. For their projects, students have been researching AR-related topics including AR variability in South America, summertime impacts of ARs on the Antarctic Peninsula, and the effect of coastal orographic lift on the inland penetration of ARs.

The AR Colloquium is being sponsored by the USACE.

NWS San Diego Warning Coordination Meteorologist and Decision Support Services Lead, Alexander Tardy, teaches AR Colloquium attendees about forecasting techniques and challenges in Southern California.

AR Colloquium attendees participate in launching a weather balloon off of the Scripps Pier.

AR Recon Officially Called for in the National Winter Season Operations Plan

July 1, 2019

Cover of the new National Winter Season Operations Plan

CW3E director F. Martin Ralph has led the Atmospheric River Reconnaissance (AR Recon) program during the 2016, 2018, and 2019 campaigns, in close collaboration with Vijay Tallapragada of the National Center for Environmental Prediction (NCEP) and Jim Doyle of the Naval Research Laboratory (NRL). Recently, the National Winter Season Operations Plan (NWSOP) has been updated for the first time since 2014. This document is maintained by the Office of the Federal Coordinator for Meteorological Services and Supporting Research. The NWSOP highlighted AR Recon and made its execution annually an official requirement. This is a major step forward for programmatic support for this key activity. AR Recon supports improved prediction of landfalling atmospheric rivers on the U.S. west coast. 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). AR Recon campaigns have been operated with the collaboration of experts from organizations including CW3E, Scripps, NCEP, NRL, the National Weather Service, the National Center for Atmospheric Research, University of Albany, University of Arizona, the European Centre for Medium-Range Weather Forecasts (ECMWF), Plymouth State University, the Air Force, and the National Oceanic and Atmospheric Administration (NOAA). All participants have contributed to daily forecasting and flight planning discussions. Aircraft flying AR Recon missions have included two of the Air Force 53rd Weather Reconnaissance Squadron’s WC-130J Hurricane Hunter aircraft, and NOAA’s Gulfstream IV (G-IV), based in Everett, WA. Air Force personnel have been stationed at Scripps to help coordinate flight planning. For more detailed information about the AR Recon program, please see the website.