April 02, 2016

Taste of Summer in Early Spring

The last few days have been the warmest since October, with Seattle Tacoma Airport reaching 70F twice (see image below).  We are talking about being 15F above normal!
Let's compare this to the same 4 week period last year.   Generally similar, although last year had more days above normal.

And during the last few days we have been seeing the classic summertime low clouds on the coast, with a minor marine push this morning.  Enough to bring some light drizzle to the early visitors to the new 520 bridge.  Friday morning was the first try for the marine air, as shown by the image at 9:30 AM, with tendrils through the Strait and the Chehalis Gap south of the Olympics.

 By 2 PM, the shallow low clouds had retreated to the the coast.  Still plenty of snow in the mountains.

Last night and this morning, an upper level trough moved towards the coast (see 500 hPa, roughly 18,000 ft at 11 PM Friday).
This weak trough, and its associate upward motion, deepened the low level marine layer and enhanced the onshore pressure gradient.  The result:  more persistent clouds and some very light drizzle.  Here is the visible satellite picture at 9:15 AM Saturday--Puget Sound was covered.

 At 2:30 PM most of the low clouds had burned off, with a remnant left to the NE of the Olympics.  No wonder folks on the 520 bridge got a sunburn.

The dry conditions will end tomorrow night as a modest front moves to the coast during the late afternoon and into the interior around midnight (see forecast precipitation for the three hours ending 8 PM).

But don't be too depressed.  ANOTHER strong ridge will develop midweek with more temperatures near 70F.


  1. Dr.Mass
    "ANOTHER strong ridge for next week"
    The Rex block that the ECMWF is displaying,over the week,for the northeastern pacific.Is this a sign of the 'BLOB' returning ?

  2. Thank you Cliff!

    It is indeed very true that we are FAR better off than this time last year both of terms of snowpack and overall precip, which is somewhat reassuring.

    However, we all can't help but be anxious with this persistent and sudden summer-like pattern, given what we endured last year.

    Is this indeed simply a "taste" as you stated above? Nothing more than a temporary aberration giving us a reprieve from the relentless overcast and rain of this past winter? If so, we welcome this weather with open arms.

    However, we would like to know if you have any reason, atmospherically and meteorologically (apart from that of the healthy snowpack and such) to believe that this is indeed nothing more than a "taste", and that a repeat of last year's unprecedented and prolonged Phoenix-like heat is, at least at this point, not in the cards?

    Much unlike our friends to the south, this area of the country is neither prepared in terms of infrastructure, nor on terms of plant life for another Phoenix-like repeat summer of last year. Snowpack or no snowpack, the scorching heat is most challenging to endure in this city.

    I greatly appreciate the attention you gave to my entry last week, and I hope you can take a minute to let us know what you really think on terms of the apparent likelihood of a Phoenix repeat. Thank you!

  3. Great... For wet Siide farmers... We still got substantial flooding in eastern Jefferson county. Water is SLOWLY going down.... Would like to know just how record wet it was was.

    The sun and dry is welcome. Get our crops in....

  4. The NOAA climate prediction is that we'll bake: http://www.cpc.ncep.noaa.gov/products/predictions/long_range/lead01/off01_temp.gif and char: http://www.cpc.ncep.noaa.gov/products/predictions/long_range/lead01/off01_prcp.gif

    On the other hand, they've been seemingly far off for the last eight months. Sadly, this seems to match last year's prediction around this time: http://www.cpc.ncep.noaa.gov/products/archives/long_lead/gifs/2015/201503month.rev.gif

    I think we should all chip in, each make a tray of ice cubes, and then take a super cargo ship to the center of where the blob was, and dump them all. :D

  5. "phoenix like"? hyperbole much? I don't recall any 116 degree temps last year. last summer was glorious, perhaps the best of all. I say bring on another summer like that!

  6. @tracksdc89 your comparison of our weather to Phoenix is pretty funny, really. They had a heatwave with 10 days over 115F last summer. We had a heatwave with 10 days over 90F. Those 25 degrees make a HUGE difference. Yes, 93 is uncomfortable without air conditioning, but my family managed it (again). 117F is much worse. I found 91 on March 20th quite shocking, to be honest.

    March 20, 2016
    PHX - 91 F 20% avg rel hum (Phoenix Sky Harbor)
    BFI - 55 F 86% avg rel hum (Boeing Field, Seattle)

    Summer record last year
    PHX - 117 F, 23% avg rel hum (08/14/15)
    BFI - 93 F, 33% avg rel hum (07/31/15)

    I'll admit it -- I'm not anxious about this summer in Bellevue. There's been enough snow and tons of rain. Even the farmers on the eastside are cautiously optimistic since they've had rain and their reservoirs are nice and full.

    If you're that worried, do two things: put solar panels on your roof, and buy air conditioning for your house. (Flying into Phoenix a few weeks ago, it really hit me -- all that wasted roof, baking in the sun, that should be cranking megawatts into the grid instead!)

    P.S. The royal "we" is pretty annoying. Speak for yourself.

    1. Thank you to both Domenic and Jewelyaz for calling me out on my Phoenix comparison... I was not clear enough. A colleague made that statement, and I thought it best summed up the desert-like heat of last summer in the most relatable terms. A 96 in Phoenix feels nothing like 96 in DC, as we all know.

      Ar first, the 96 in Phoenix feels far more comfortable than the 96 in DC. However, the DC 96 forces most people to do an immediate about-face and go back into the A/C, whereas the relative comfort of the Phoenix 96 gives unexperienced folk (WHICH IS US!!) the false impresion that there is no real danger. People go about their days with no modification to their routine - walking in the mid-day sun thinking "it's actually pleasantly warm!", etc. Then it hits you - severe dehydration, sunstroke, and any other maladies related to heat exposure. Nowhere was it stated that Seattle and Phoenix's summers were, or ever will be, comparable, or that Seattle could have 90s in March. The reference was not to Phoenix's hottest days, but more to what is regularly experienced there, In fact, exactly like the 91-degree March day astutely pointed out by Jewelyaz -

      speaking of whom: my apologies for using "we". You could not be more correct; the royal "we" is beyond simply being "pretty annoying". I failed to mention that my entry was the result of a fascinating conversation with my colleagues about how last summer shaped up, how it felt, and the unanimous anxiety we were all feeling at the suuden switch to sun and heat (or so it seemed to us). I appreciate your calling me out on that; I am pretty certain everyone else who read it was equally annoyed. You have given me the chance to explain my arrogance (j/k).

  7. I must add my "méfiance" to any long-range forecast, given everyone's (apart from Cliff, of course ;) miserable failure of predicting our weather of this past winter. Drier and warmer than normal? HA! The reality is this was the wettest winter in Seattle's history - kinda something warranting some kind of foresight. Could they possibly have been any further off the mark (and, how much do these people get paid again for making utterly inaccurate forecasts? An infant rolling dice could have done a better job)?

    If those exact same people are making a summer outlook I would take it with a VERY LARGE grain of salt. To me, I wouldn't even turn to them to predict the time of tomorrow's sunrise.

    Their incompetence should not be rewarded by our placing any faith in their "dart-board" forecasting.

    That's why I'm here, asking Cliff. At least there is someone out there who is genuinely taking the time and effort to keep us as accurately updated as possible.

    It is somewhat reassuring that today (the 4th) has returned to more "normal" Seattle early April weather - the clouds are back racing through the sky. Despite the rain being less than expected, and the sun now shining hot and bright here in Seattle, this "air" is most certainly different from the warmth of last week. And (a final word, sorry I've gone on and on) - after Thursday's near 80, I see a drop back to 60s ...and not a continuation of 80+ weather this early in the season - whew. Even though we are well above normal precip-wise, the vegetation will still need occasional showers, which I hope are in the cards for the balance of the spring.

  8. Tracsdc89,

    I can deal with the Phoenix-like heat I don't like forest fires. And coming from the East Coast as I do, rain and heat aren't incompatible. But here, they are... with few convective showers here, our gardens get bone dry and the woods go up in smoke...

    1. Hey Ansel, I was born and raised in Boston, so I get you completely. The common thunderstorm during a Boston summer heatwave would mainly be absent here. Thankfully, Seattle heat normally has low dewpoints - a stark contrast to the heat of back east - which would not allow the formation of t-storms.

  9. Replies
    1. Agreed! Thank you again for calling me out on that.

  10. @JewlelyaZ 

    "If you're that worried, do two things: put solar panels on your roof, and buy air conditioning for your house."

    Entitled much?

    I am very glad that you have the financial means and also own property in the PNW which affords you the luxury of installing air conditioning so that your life continues as normal during heatwave periods.

    There are many thousands of struggling families in the Puget Sound area many of whom are elderly, disabled and vulnerable and simply cannot afford a/c. Since many do not own a home due to stratospheric property prices then retrofitting solar panels onto rented accommodation is not an option. This leaves an inefficient portable a/c unit which generates more heat in the return air vent than it actually removes.

    I think the point the previous poster was trying to make is that Seattle is not a city that is prepared for strong heatwaves. For example most non-commercial buildings even at the high end do not have a/c nor efficient methods to draw in cooler air from outside during the night. This is particularly acute in Seattle due to the growing inequality in the area which forces lower income families into poor quality rented accommodation without cooling methods. Contrast this to the south of the US and even the poorest have access to a/c in Dallas, Georgia, Louisiana etc.

    Perhaps when heatwaves in the PNW become longer with higher 'minimum' temperatures and increased relative humidity then cities will be forced to modify building codes so that property developers cannot construct multi-family dwellings and save $millions by not installing or even thinking about how to cool a building, it should not be an afterthought.

    Climate Scientists have always maintained that it will be the world's poorest and most vulnerable who will be most affected by Climate Change.

  11. "Contrast this to the south of the US and even the poorest have access to a/c in Dallas, Georgia, Louisiana etc."

    those places have real heat, for extended periods of time. in the pnw heat waves are merely uncomfortable, not life threatening.


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