P1.33
A comprehensive climatology of Southwest Oregon windstorms 1948-2002
Wolf Read, Oregon State University, Corvallis, OR; and G. Taylor
A comprehensive climatology of extratropical cyclones that have landed in Southwest Oregon 1948-2002 was undertaken. The primary focus included events that produced high-wind-warning criteria gusts of 50-knots or more on Oregon’s Southwest Coast and/or the Southwest Interior, covering a region that includes Arcata, CA, to Newport, OR, eastward to the Cascade Crest. Though the focus is on Oregon, Northern California offered critical information to the study. Storm track, peak gust distribution, and surface maps are provided for the many different scenarios uncovered by this project, offering a means of quick comparison between storms. The data suggest certain patterns; though, as with most atmospheric phenomena, these should be considered fuzzy sets as opposed to hard rules. A common threshold for high winds for Southwest Oregon storm events was found to be about 995 to 998 millibars (mb) minimum central pressure. Of the sub-998 mb lows, the most potent storms were those undergoing explosive cyclogenesis as they moved into Oregon. Mature lows produced high winds in some situations, but usually not the extreme levels witnessed with rapidly developing cyclones. All sub-1010 mb cyclones that tracked into Southwest Oregon for the period 1948-2002 were evaluated to help examine return frequencies for a spectrum of events. Aside from high winds generated by the near passage of a cyclone, two other classes of events were examined in detail: 1) high-wind-producing open waves, which are sometimes the child-phase of the explosive-cyclogenesis class of windstorm and therefore the two share many features, and 2) trailing fronts which, on occasion, can strike with equal potency to the strongest near-pass cyclone event.
Poster Session 1, Poster Session
Sunday, 11 January 2004, 5:30 PM-7:00 PM, Room 608/609
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