Monday, May 4, 2020

Heat Wave over the Northwest, Cold Wave over the Northeast

This weekend temperatures will zoom into the 80s here in western Oregon and Washington, while snow may hit portions of the Northeast U.S.   The latest 6-10 day forecasts from the NOAA Climate Prediction Center (CDC) illustrates the stark contrasts that will even continue into next week (red indicates a high probability of warmer than normal temperature, dark blue indicates a near certainty)


This kind of temperatures pattern is always the result of a high amplitude upper level wave pattern, with a ridge of high pressure over the West Coast and a trough of low pressure over the east.    Here is the forecast upper level map (500hPa..about 18,000 ft) for Saturday morning at 5 AM. The colors reflected differences from normal (red--above normal, purple--well below normal).  As expected--a huge ridge over the West Coast, which extends all the way to northern Alaska, while a very, very deep trough is center over the Great Lakes.


The latest NOAA/National Weather Service ensemble forecast of many predictions shows temperatures zooming up to around 80F on BOTH Saturday and Sunday.  There will be some happy mothers on Sunday, ready to enjoy the warm temperatures outside.


Will we hit any high-temperature records this weekend?   

It is doubtful.  Getting into the 80s is no big deal this time of the year.  In fact, it is very typical to have a heat wave during the second to third week of May, something indicated by the extreme daily temperature records at Seattle (see below)..   The sun is very strong now and if we get strong offshore flow (which we will), temperatures can zoom up.


Now, while we are sizzling on the West Coast, it will be downright chilly on the eastern side of the country in the cold trough. 

Now I will show you something that will put a cold chill down your spine...the accumulated snow forecast through from the European Center through 5 AM Sunday.  Unbelievable...nearly a foot over northern New England and several inches in update New York.  This is quite unusual.


8 comments:

  1. Wow! Not too hot and should be a delightful Mother’s Day weekend!!

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  2. 23 May 1969 stays in my mind...the daytime temp soared to 90 degrees...in the evening, I attended a Jimi Hrndrix concert at the Seattle Center Coliseum...it was still warm as I entered the venue...but towards the end of the magnificent Hendrix performance, flashed of lightning and peals of heavy thunder were happening outside!...torrential rain beat down on the exiting concertgoers...the temperature had dropped a good 30 degrees in two hours or so!...the high temperature earlier stood as a record for 23 May for many years...Yes, May can offer freaky weather in Seattle!

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    1. I was also at that same Jimi Hendrix concert! Elbow bump!

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    2. Unforgettable day/night!...we are survivors of the best music scene ever.

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  3. The record highs at Sea-Tac for this Saturday and Sunday (83/86) were set all the way back in...
    ..2019.

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  4. Hopefully the sun and heat is not very friendly to Mr. Corona

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  5. I wish I had seen Jimi Hendrix live!

    I am looking forward to eighty degrees weather especially on Mother's Day! It will at least seem like life's rhythms are in place--even when we know the reality of the pandemic. The east coast has my sympathy for the snow! Unusual times in many ways.

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  6. @Cliff, you didn't tell us about the thunder, lightening, hail, and rain precusor to the 80 degree weather this weekend. ;-)

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