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PSL Researchers Brief Seattle WFO on Mobile Atmospheric River Monitoring System

November 4, 2009

Deployment of Mobile Atmospheric River Monitoring System in Westport, WA (Photo credit: Clark King, NOAA)

ESRL Physical Sciences Laboratory (PSL) scientists Paul Neiman and Allen White joined Dave Reynolds, Meteorologist in Charge (MIC) of the NOAA National Weather Service (NWS) San Francisco Weather Forecast Office (WFO), for a visit to the NWS Seattle WFO on October 23, 2009, to discuss how ESRL research tools also may be used to assist with forecasting winter extreme precipitation events. Brad Colman, Seattle MIC, first led a discussion about the Howard Hanson Dam, a topic receiving regional and national attention in the past several months due to safety issues identified by the U.S. Army Corps of Engineers. Seattle WFO staff provided an overview of the physical conditions of the dam, repairs being made by the U.S. Army Corp of Engineers, dam operating procedures that will be used this winter, geography of the Green River Basin, and potential flood risks. ESRL scientists and Mr. Reynolds followed this discussion with lessons learned from more than a decade of research into winter storms and flooding in California that had its genesis in a research field program carried out during the El Niño of 1997-1998. Mr. Neiman explained the role of Atmospheric Rivers (ARs), narrow corridors of enhanced water vapor transport associated with winter storms, in producing floods. Dr. White described the NOAA research-quality Mobile Atmospheric River Monitoring System (MARMS) recently deployed on the Washington Coast at Westport, and showed some of the first real-time observations MARMS has collected. Mr. Reynolds then described how research observations from MARMS could be used by forecasters to monitor AR conditions and help calibrate weather prediction models and to improve situational awareness of forecasters in his office; using the recent early season record-breaking storm in California as an example.

ESRL scientists have been studying winter storms impacting the U.S. West Coast since 1998 as part of a larger effort to understand the role of climate variability and change on coastal extreme events. They have developed collaborative working relationships with staff at several Weather Forecast Offices and two regional River Forecast Centers. These interactions have facilitated the prototyping of promising research results into the hands of operational forecasters. The most recent collaborative project being evaluated by forecasters is the Coastal Atmospheric River Monitoring and Early Warning System (CARMEWS). This tool combines several key research results from ESRL's (PSL and GSD) work in California into a single time-height display that is updated hourly on the Internet. The display allows forecasters to monitor the atmospheric forcing associated with ARs and to evaluate the performance of a weather forecast model's prediction of that forcing. The tool has been used since 2008 at a few sites in California and is now available from the MARMS deployed on the coast of Washington.

This meeting was a key step in establishing a collaborative effort between ESRL researchers and NWS operational forecasters in Washington in order to address common goals of protecting lives and property from flooding, to advance mission-oriented research on extreme precipitation, and to educate the public about the hazards associated with West Coast Winter storms.