seasonal averages of precipitation and temperature are not exceptional. Most locations in Washington have received 65-80% of normal precipitation since October 1. This is considerably more than in 1977 or 2001. Temperatures also have been only about 1F above normal. Precip % of normal since Oct 1
Why? The proximate cause was a large number of days with a split jet stream around a blocking ridge located over the NW region Was it El Niño? –Definitely not “typical” of past El Niño events Ocean temperature anomalies Jet stream wind patterns R
Oct 2004-Feb 2005 200mb ht anomalies The tropical atmosphere has been warm!
Are we in a situation like the early 1990s with multiyear warmth in the western eq. Pacific?
summary It has been a warm and dry winter, but not of “record” extremes in either temperature or precipitation The tropics have been very warm, yet not in a “classic” El Niño pattern –part of longer term and broader scale atmospheric warming? Official CPC forecast calls for increased odds for a warm spring
CPC forecast for July-August- September 2005 Temperature Precipitation