Temperature Records On Wednesday. Why?

Yesterday was a very warm day across the region, with many locations 15-20F above normal and several stations achieving daily records. 

Here are the highs on Wednesday.  The lowlands of western Oregon and Washington were in the low to mid 60sF, with some favored locations (south of Tacoma) hitting 70F. 

Some daily records were broken.  Here is a nice graphic produced by the Seattle NWS Office, showing the high temps, with the stars indicating daily records.

The reason for this warmth was that we had the perfect set up for a strong atmospheric river event, with warm/moist tropical air moving northward.  The map below shows the upper level flow at 500 hPa (about 18,000 ft) at 4 PM Wednesday.  Big ridge of high pressure over the southwest U.S. and a strong trough over the eastern Pacific.  The perfect configuration to produce a narrow current of warm, moist from the southwest that hits the NW. 

 To see what is unusual about this pattern, here are the anomalies--the differences of the heights (or pressures) at that level from normal.  Unusual ridge centered on Utah, with anomalous low pressure to the east and west.

The following figures shows the climatology of  4 PM surface temperature at Quillayte, on the WA coast, based on over a half-century of data.  The red lines show the daily maximum and the circle shows yesterday's observation.  You will note that we were near the daily maximum, but there were several days in November with similar (or even higher temperatures).   This pattern has happened before.

Now, Seattle's wacky local alternative newspaper (the Stranger) is making claims that this is proof of global warming (see below), but that claim has little basis in truth.

One can only make a case for global warming based on trends over an extended period, not one extreme event.  So why don't we look at the long-term (1900-2016) trend of average November maximum temperature over the Puget Sound lowlands for a period of more than a century (this is from the NOAA/NWS climate division data)?    Not much trend there!

And this lack of trend makes perfect sense because the surface eastern Pacific Ocean is warming up more slowly than almost any place on the planet.   And there is no research to suggest that the anomaly patterns shown above will become more frequent under global warming....this is an areas of research that I am working on.

The air above us is rapidly cooling and the Aloha breezes will fade.  Something to contemplate while you eat your turkey today.

from Cliff Mass Weather and Climate Blog http://ift.tt/2A1PJgP