11-12-2009

NOAA/NWS/NCEP/Ocean Prediction Center, Camp Springs, MD ABSTRACT  The NASA QuikSCAT scatterometer provides near global coverage of ocean surface vector winds each day.  The combined coverage of the QuikSCAT instrument and high retrievable wind range to 40 m s-1 or more in non-raining conditions has revolutionized the high seas warning and short-term forecast process at the NOAA Ocean Prediction Center (OPC).  OPC forecasters routinely see the wind field of entire extratropical cyclones, including winds of hurricane force using the QuikSCAT winds.  To date we have learned that hurricane force winds are much more common than thought in extratropical cyclones.  There are preferred areas and times of year for increased frequency.  The onset of extreme conditions most often occurs during the rapidly deepening phase of the cyclone and the conditions are short lived on average less than 24 hours in duration.  This talk will first give a short overview of the Ocean Prediction Center and forecasting for the ocean environment, then an updated climatology of hurricane force extratropical cyclones over the North Pacific and North Atlantic Oceans for the years 2001-2009 will be presented.  Thirdly, results from the Weather Research and Forecast (WRF) numerical model illustrating the evolution of several hurricane force extratropical cyclones will be shown.  Lastly, wind field composites based on QuikSCAT showing the storm relative frequency of occurrence of hurricane force winds will be presented.