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.


Comments

Post a Comment

Popular posts from this blog

Why so little lightning in the Pacific Northwest? And a very nice weekend ahead.

Image
During the past 24-hours, there have been a few lightning strokes over the region (see below) but nothing to write home about (see below). It turns out that the Pacific Northwest and the remainder of the West Coast have some of the lowest frequencies of thunderstorms in the entire country (see below). But why?    My podcast provides the answer. And I also give the weekend forecast....and I think most will like what I have to say. To listen to my podcast, use the link below or access it through your favorite podcast service. Some major podcast servers:     Like the podcast? Support on Patreon 
Read more

The Time of Year You Can See the Air Move

Image
  Most of the time, you can not see the air move.   You can feel it, but the complex, turbulent motions are invisible to you, except when it interacts with leaves and branches on trees and plants. But for a few weeks of the year, the sky is full of small, cotton-like tuffs that like a natural MRI machine reveals the complex three-dimensional motions of the atmosphere.   Cottonwood season.  And we right in the middle of it.   Being cottonwood aware is of particular value this year.  It reveals the active dispersion and movement of air that makes the outdoors essentially COVID safe, and thus should be of some comfort for those nervous about transmission outside. Cottonwood seeds are embedded in small cotton-like fibers.   A million seeds weigh about 3 pounds.  Yes, each seed and tuff weights about .000003 pounds.   And that fact, plus the cottonwood tuff, means that these seeds fall VERY, VERY, VERY slowly.   So slowly that they are excellent markers for the three-dimensional flow of the
Read more

A Much Colder Than Normal April: But How Unusual?

Image
  April was a chilly month over the Northwest, but how chilly?     It turns out the answer depends on where you are located. The difference between this April's temperatures from normal across Washington State (below) shows that the entire state was well below normal.  The eastern side of the state was particularly frigid:  some areas were more than 6 degrees below normal.   Considering the west side of the state, the April mean temperatures at SeaTac Airport are plotted below.   This April was the coolest since 2011. April 2020 was in 15th place for the coolest April since the mid-1940s and was a bit more than 4F below normal.  So if you felt that you were cheated out of normal spring warmth...you are right. But if you really wanted to experience extraordinary April cold you had to be east of the Cascade crest. Consider Yakima.  Wow.  It had the third coldest April temperature since the mid-1940s.   And the all-time record in 1955 was only slightly colder. If you want a longer-te
Read more