PACJET Workshop

Background	Experience gained during the recent California Land-falling Jets Experiment (CALJET) indicates that real-time use of experimental data from the coast to 1000 km offshore can aid in issuing coastal weather warnings. In particular, the Monterey forecast office of the National Weather Service (NWS) used CALJET research aircraft measurements of the strength of a low-level jet in an approaching storm to help issue a flash flood warning that gave 6 h lead time for a record-breaking flash flood in the region. It has also been shown recently by NCEP that insertion of CALJET aircraft data in storms roughly 24 h before they made land-fall led to improvement in the 24-h operational numerical weather predictions in all of the 5 cases tested. In addition, operational and research profiler networks on the U. S. west coast are now providing real-time monitoring of the coastal environment, albeit fewer are now available than in recent years. In particular, coastal wind profilers provide a real-time view of weather phenomena, such as blocking and barrier jets along the coast that can modify the location of precipitation maxima. These results, along with other research, have motivated the preliminary design of a follow-on experiment referred to as PacJet. A planning letter has been submitted for use of two NOAA research aircraft and NOAA’s state-of-the-art research vessel (the Ron Brown) off the west coast of the United States during the winter of 2000/2001. In addition, data from numerous wind profilers that will be deployed in this region for air quality research will also be available for use. Although the experimental design will be modeled after our 1998 El Ni�o experience, the location of the experiment may be adjusted depending on threats assessments provided several months ahead of time based on seasonal-to-interannual forecasts (i.e., El Ni�o and La Ni�a). The value of seasonal-to-interannual forecasts and forecast uncertainty will also be discussed. This workshop aimed to provide recommendations from the operational weather forecasting community along the US west coast that can aid directly in the detailed design of the field program. The emphasis will be on 0-24 h forecasting of land-falling Pacific winter storms, covering the area from roughly 200 km inland to 1000 km offshore. Illustrations of atmospheric, hydrologic, and ocean sea state forecasting issues are encouraged. This input, combined with the basic research objectives, will set the priorities for the experiment. The concept for this meeting emerged from a joint session of the CALJET Workshop and the National Weather Service Western Region Marine Forecasters Training Course in May 1999 where marine forecasters indicated that such data could be very useful, and provided several novel recommendations on what would be useful and why. Agenda
Experimental Objectives	The experimental objectives identified thus far have been developed out of priorities established in several reports by NOAA, the National Weather Service, the U.S. Weather Research Program (USWRP), and the National Research Council which include research aimed at: improved quantitative precipitation forecasting, studies addressing the optimal mix of observations for weather prediction, effects of topography on local weather regimes, design of a Pacific Coastal Forecast System, and regional assessment of seasonal to inter-annual forecasts.
Meeting Objectives	Familiarize forecast community with recent field programs and the preliminary design for PacJet. Develop a set of recommendations from the forecasting community for use in designing PacJet, with emphasis on needs and opportunities for real-time use of experimental data, and methodologies for evaluating impact/utility of the experimental data in real-time applications. Assimilation of the experimental data into operational numerical models will also be discussed. Decide on approaches to enable operational forecasters to have real-time access to these data.
Dates	9 AM Tuesday August 31 to Noon Wednesday September 1, 1999
Location	Naval Postgraduate School (NPS), Monterey, CA Room 146, Mechanical Engineering building Maps of Monterey and NPS: http://www.nps.navy.mil/on.nps/maps.html
Lodging	A block of rooms has been set aside at the De Anza Inn, but reservations need to be made before August 6th. Ten of the rooms have one king bed while five others have two queens. The cost for a single is $94 while a double is $114 (but they'll let them go for $94 if rented by just 1 person). The phone number for the DeAnza is 831-646-8300; ask for the block of rooms being held for the National Weather Service. This hotel is on Fremont Street about 1 mile east of the Naval Postgraduate School.
Registration	Please contact Marty Ralph by August 5^th (see below for contact information). Presenters, please provide a title and brief outline of your talk (less than 1/2 page
Organizers	Warren Blier, Science Operations Officer NWS Monterey, California Warren.Blier@noaa.gov 831-656-1710 ext 224 Marty Ralph NOAA/ETL, Boulder, Colorado Marty.Ralph@noaa.gov 303-497-7099 Brad Colman Science Operations Officer NWS, Seattle, California Brad.Colman@noaa.gov 206-526-6092 ext 224 Wendell Nuss Naval Postgraduate School, Monterey, California nuss@arashi.met.nps.navy.mil 831-656-2308