Record late-winter cold wave hits the western U.S.

 The western U.S. is experiencing one of the coldest end-of-winter periods in the historical record, with too many cold records to list.

To illustrate, let me "warm up" by considering the departure from normal of the average maximum temperatures across the region (below).   

Unbelievable-- in some parts of the region highs have been down by OVER 15F from normal.


Consider the long-term trend of the average high temperature at Los Angeles for the same period (2/20-3/5)

You will not believe it (below).  The last two weeks were the coldest for the entire record, going back to the mid-1930s.   LA residents are probably staying in their hot tubs.


For San Francisco, the past two weeks have had the coolest maximum temperatures since the latest 1960s.


Portland?   The latest two weeks tied for the second coldest for the entire record.


During the past few weeks, a large number of major low-temperature records were broken in the West.  Not only were a huge number of daily records broken,  but MONTHLY low-temperature records as well. That is very, very unusual.

 Below are the locations of monthly temperature records noted during the past several weeks. What has happened in California is extraordinary. 


So why such a profoundly cold period?

It is due to high amplitude, and unusual large-scale circulation in the atmosphere.

Below is a map showing the difference from normal for the heights (like pressure) around 18,000 ft (500 hPa pressure). 

You will note a HUGE high-pressure anomaly over the northeast Pacific (red/orange) and a strong trough of lower heights/pressure over the west coast (blue colors).  This pattern is a very cold one for the West Coast, with northerly flow over the northeast Pacific.

by considering the departure from normal of the Record late-winter cold wave hits the western U.S.

What is the predicted surface temperature anomaly for the next 7 days?  You guessed it, colder than normal (see European Center ensemble system prediction below).

by considering the departure from normal of the Record late-winter cold wave hits the western U.S.

Now I can't help noting something.

If this was a record-breaking warm anomaly of the same magnitude, the media would be going crazy talking about climate change and global warming.   The Seattle Times cartoonist David Horsey would have gone to town.

 What will you hear from them regarding the cold wave and climate? (see below)

by considering the departure from normal of the Record late-winter cold wave hits the western U.S.


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