April 09, 2020

Super Spring Weather Ahead

After a startlingly cool March, we are going to get paid back in spades in April:  an extraordinary week is ahead, with the only exception being Saturday morning...and even that won't be that bad.

Every day but Saturday will get into the 60s.  Dry, except perhaps a sprinkle Saturday morning, and temperatures gliding up to near 70F on Thursday.

On several days, weather will be far better in Seattle than Los Angeles.  And that was particularly true today.

The SpaceNeedle cam and the Long Beach Cams show perfect weather here in Washington State:

The Del Mar Beach, CA cam is rainy, misty, wind and cold.

And the seen in Hollywood, is well...wet.

As noted in a previous blog, our perfect weather is the result of an atmospheric blocking situation, in which the atmosphere gets temporarily frozen in a certain configuration.  The upper level map for 5 AM this morning shows you the pattern we have been stuck in....an omega block, with ridge of high pressure over the Northwest and deep troughs/lows over the southwest U.S. and north of Hawaii.  Very stale and persistent.

So what about the future?  The ridge will be depressed slightly on Saturday morning as a weak trough moves through and then the ridge will return with a vengeance but in a slightly different form:  a Rex Block in which the ridge is undercut with a low center (see below for 8 PM Tuesday).  Named after a forecaster named Rex, not some king, by the way.

With a ridge parked over the eastern Pacific, the eastern half of the U.S. should be cool and wet.

To give you some idea of our future, here are temperatures at Seattle Tacoma Airport from the U.S. GEFS ensemble system, in which the model is run many times, each run starting slightly differently.  Nice and toasty tomorrow (Friday), cooling over the weekend, but then progressive warming the rest of the week.  Very nice.  The folks in Los Angeles will be jealous. 

Strangely, Seattle is closing its major parks on Saturday and Sunday due to "warm weather", even though weather will be much cooler/cloudier on Saturday and Sunday than Thursday or Friday or next week.  This simply does not make any sense based on the forecast.  These closures will endanger folks, pushing more people into fewer parks and thus lessen the ability for social distancing.  Furthermore, the larger parks near the water generally have stronger winds and thus better ventilation (more dispersal of any droplets exhaled by people).


  1. I'm afraid you're right that throngs of people will end up descending on smaller parks like Madison Beach which is much less conducive to social distancing than a park like Seward or Magnuson.

  2. Interesting prediction that the park closures will endanger people by pushing more people into fewer parks. I certainly don't envy the public officials making these decisions. Hopefully this decision will have the marginal effect of convincing more people to take social distance and stay at home orders more seriously.. I certainly will enjoy some of the good weather!

  3. Cliff,

    Thanks for the good news! In the winter, I forget how beautiful weather can be in spring and summer in Seattle. I can understand why the parks will be closed this weekend to maintain sheltering in place. They may announce closing on all of the good weather days.

  4. Absolutely LOVING this warmer, sunny weather! Finally, some relief! <3

  5. Those officials calling for park closures are doing what they think is right. The number of people out, not distancing, has skyrocketed in our neighborhood. Maybe some will stay home?

    1. Unknown... I am sure they are. I am suggesting they may be in error about this. If you want to have folks have more distance between them, you give them more area to spread around, not less. Crowds will increase at the parks that remain open. There is no evidence that there is significant transmission outside in the sun and free air. ...cliff

  6. You hear that, Jenny?? The more parks you let people visit, the farther apart they will be. Simple math.

    As you admitted on the news, we have been cooped up for six months. Let us out!

  7. The Rex block looks like a T Rex! It even has an eye in the right place.

  8. The closure might not make sense based on the forecast, but it makes sense due the fact that it's a holiday weekend. Something to consider is that a lot of people would need to drive to these larger parks that will be closed, thus causing areas where people will inherently need to congregate (i.e., the parking lots). Closing these parks (hopefully) will cause more people to stick to the areas around their homes. I think that's the idea.

  9. Hi Cliff, looks like the trough that nudged through resulted in rain in Redmond,wa starting at 11:00 through 13:30 tapering now. Interestingly in CA andN this weekend they have closed major roads, freeways etc to cars to allow people to get outside and walk, ride etc. The Sammamish trail is Redmond is a conga line of people, bikes, scooters etc as everything is closed. Noone is taking the social distancing seriously which is worrying as this could prolong the closures. More research needs to be done on transmission rates outdoors but that seems a long way off since we don't even have mass testing. The local tech companies like Amazon are now working on this for their own employees however.

  10. I think they need to close the hiking trails as the narrow trails make it impossible to social distance. Furthermore the higher elevation trails are snow covered, so the options are rather limited. Some trails have been way too crowded. Parks should remain open (as they are big wide open spaces) but with strict social distancing measures in place as well as enforcement and fines for those not social distancing.

  11. Exceptionally dry weather in NW Bellingham today. Thus far, I've measured a minimum relative humidity of 16% and a minimum dew point of 14F. These values are far below the previous lowest such values I've measured during April in my 5-year period of record. The RH value of 16% is the all-time minimum record for my location for any month by a substantial margin.

  12. My garden plants regret to inform all endless sun bunnies that vegies need water to grow. Ditto chickens, cattle, hogs and other sources of food. Enjoy the sun but regular rain (unlikely for next 4-5 months) is best. And, not everyone growing food has endless faucets that tap into snow melt reservoirs.

  13. Finally today we’re breaking 60 degrees in Shoreline for the first time since last September. What a long cold winter and early spring it has been. 🥶


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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