Conditions improving in Pacific Northwest; Santa Ana winds to develop in southern California.
A series of storms rotating inland from a deep offshore low pressure system brought record rainfall, gale – force winds and spawned a confirmed tornado near Seattle Monday morning. The tornado reportedly touched down around 7:30 am in the town of Fredrickson some 45 miles south of Seattle, Washington.
Categorized as an EF-1 on the Fujita scale, the tornado's winds were estimated at 110 mph and caused some minor structural damage, as well as downing power lines. The damage path was some 75 yards wide and about a mile long. The tornado's duration was about 5 minutes and it was strong enough to damage roofs, tip over railroad cars and fully lift an auto off the ground. Damage estimates were about $25,000. There were no reported injuries.
The tornado was generated by a Pacific storm complex which has been affecting the entire Pacific Northwest during the past several days. Record September rainfall has been reported at numerous locations including Seattle.
Conditions had moderated somewhat as of late Monday. Low pressure continued along and off the coast of Washington and British Columbia, but had weakened considerably.
Rain was still falling as of Monday evening across western Oregon and Washington, but the bulk of severe weather warnings and advisories had been discontinued. Winter storm warnings, however, continued for Washington's Cascade range. Flooding was still possible in some coastal areas of western Washington, and the state's Olympic mountain areas were still under a winter weather advisory.
Latest models suggest off and on showery periods should continue in Oregon and Washington for the next several days with considerably less intensity. At the same time, building high pressure following a weak frontal passage in California is expected to generate at least moderate Santa Ana winds beginning late Thursday in southern California. Fire weather watches currently in effect may be upgraded and expanded to red flag fire warnings from late Thursday into Saturday. Low relative humidities, above normal temperatures and local strong gusty canyon and pass winds will increase fire danger.