The warmest April day on record at Seattle (89F). The previous record was 85F.
The warmest April day in record at Olympia (88F). Previous record was 87F.
The warmest April day on record at Bellingham (83F). Previous record was 78F.
We tied the record number of days hitting 80F or more at Seattle (two). We will beat that record tomorrow. It was also the warmest day since last August.
A number of local observing sites got to 90F or above. I mean a LOT of locations--here is the map:
Not impressed yet? The temperature at 850 hPa (around 5000 ft) at Quillayute, on the WA coast, was an amazing 16.2C. (see plot, with light red line showing the daily record, and blue dot showing today's temperature).
It was the second warmest temperature at that level ever observed during the first four months of the year. The warmest? Earlier this month, April 7th, with 16.6C.
It was so warm that we started getting weird mirage effects because of superheated air over cold water. Here is a picture sent to me by Tony Nahra, showing a marvelous superior mirage (lofting of objects on the opposite shore). The only other alternative explanation is a new Amazon complex. I like the mirage better.
Why so warm? Big ridge over the western U.S. aloft.
At 850 hPa (about 5000 ft), there was southerly flow with enough of an easterly component to give some offshore flow that reduced the marine influence.