Discussion will begin at 3:30pm
Refreshments will be served at 3:00pm in the coffee lounge

Hosted by Steve Miller

This talk is associated with the ATS/CIRA Colloquium series.

Costal storms account for 71% ($7B) of U.S. disaster losses annually. In addition, over 50% of the U.S. population lives in coastal areas that account for less than 20% of the nation's land, and coastal development still is increasing. As a result, more homes, businesses and lives will be vulnerable to coastal storms and more accurate forecasts will be required to reduce the risks associated with hazardous weather. Over the last decade, research conducted by NOAA's Earth System Research Laboratory (ESRL) has begun to address these issues through a series of focused wintertime field experiments conducted along the U.S. West Coast. These experiments collected new meteorological observations, both to support research on the physical processes related to coastal storms and to aid operational 0-48 h weather forecasting. In particular, a new bulk water vapor transport tool has been developed to help improve short-term (<~6 h) precipitation forecasts in mountainous terrain. The tool uses coastal Doppler wind profilers to measure the upslope component of the flow aloft and collocated GPS receivers to measure the integrated water vapor content. The product of these two variables produces a bulk water vapor flux. Greatly enhanced water vapor fluxes are observed in the land-falling atmospheric rivers that fuel orographic precipitation. The flow at the surface often bears little resemblance to that at a controlling level (where the correlation between the water vapor flux and mountain precipitation is maximized) due to the ubiquitous presence of shallow terrain-blocked flows, thus highlighting the need to obtain upper-air wind measurements for this particular application. The tool is described in the context of the intense West Coast storm that inundated California with heavy precipitation in early January 2008. Numerical weather prediction results are also shown to highlight the deficiency of model and human forecasts of heavy precipitation enhanced by orography. Although NOAA's HMT program is wrapping up in California in early 2010, California's Department of Water Resources has embarked on a project with ESRL and Scripps Institution of Oceanography to bring 21st century observation and modeling capabilities to bear on the state's water resource and flood protection issues. This project will provide an HMT legacy for California , extending lessons learned in the HMT-focused American River Watershed to other watersheds throughout the state. Finally, improving the forecast lead time of coastal storms impacting the Western U.S. will require a winter storms reconnaissance program analogous to NOAA's hurricane reconnaissance mission. NOAA's Unmanned Aircraft System (UAS) Program will test and evaluate the use of unmanned aircraft to provide much needed offshore measurements in developing storms.