Our "Extremely Warm" Wave

Monday, July 14, 2014
11:13 a.m.

We are in the midst of a period of extremely warm weather. Highs have been in the upper 80s for an extremely long time, and although I can’t comment on meteorological figures since I have had very limited access to the interwebs (and outside world altogether) at the summer camp I am working at (hence the very limited blog posts), its been hot and dusty in a place that usually receives copious amounts of summertime rainfall.

But there is one limiting factor. It’s not the sunshine we’ve been receiving, or the time of the year. And it’s definitely not because of the Supermoon (however, it would be interesting to see if variations in the distance of the Earth-moon distance would have any sort of impact on temperature, or if they are completely unrelated).

It’s the gradients!

Our gradients, for the most part, have been onshore, meaning that there is lower pressure over the land and higher pressure over the ocean. Air flows towards lower pressure, so Washington has been getting a marine push of air, particularly at night, to help cool things down. gets a seaward flux of air, particularly at night. Therefore, even though we’ve had blazing sunshine with a huge ridge of high pressure giving us warm temperatures, our marine pushes have kept temperatures from getting too extreme. Here are the gradients this morning.

       UIL-  OTH-  PDX-  OLM-  UIL-  HQM-  AST-  BLI-  UKI-  AST-  BLI-  BLI-
DD/HH BLI SEA BLI BLI NUW SEA UIL YZT UIL SEA YQQ YWL
14/18 +1.0 -1.1 -0.1 +0.8 +0.2 +0.5 +0.2 -2.1 -10.2 0.0 +1.2 +0.7
14/16 +1.8 -1.0 +1.2 +1.5 0.0 +0.2 +0.2 -3.1 -9.4 -0.1 -0.5 -0.5
14/14 +1.0 -0.6 +1.0 +1.0 +0.1 +0.6 +0.7 -2.5 -8.9 +0.3 +0.5 -0.3
14/12 +1.7 +0.1 +1.0 +0.8 +0.5 +0.9 +0.3 -2.7 -9.1 +0.7 +0.4 -0.5
14/10 +2.7 +1.7 +2.1 +1.5 +1.1 +1.5 +0.5 -3.6 -9.3 +1.5 0.0 -0.8
14/08 +2.7 +2.0 +2.4 +1.8 +1.9 +1.1 +0.5 -3.6 -8.8 +1.5 +1.0 -0.9
14/06 +4.0 +2.8 +2.3 +1.8 +2.3 +2.7 +0.1 -4.1 -9.2 +2.3 +1.0 -1.4
14/04 +2.7 +4.2 +2.1 +1.2 +0.8 +3.2 +1.5 -4.3 -7.5 +3.2 +1.0 -1.9
14/02 +2.9 +3.9 +2.0 +1.0 +1.4 +0.9 +1.6 -4.5 -7.2 +2.6 -0.1 -2.7
14/00 +2.7 +3.4 +1.2 +0.4 +1.4 +1.6 -0.7 -4.2 -7.4 +0.4 -0.5 -3.4
13/22 +1.1 +3.4 -0.2 -0.2 +0.4 +1.1 +1.1 -3.9 -6.3 +1.3 -0.6 -2.7
13/20 -0.2 +2.2 +0.4 -0.8 -0.8 +0.7 +0.6 -3.3 -5.5 +0.4 -0.2 -2.7
13/18 -0.4 +1.6 -2.0 -0.8 -0.9 +0.8 +0.8 -2.8 -5.0 +0.8 -0.1 -2.2

PDX- UIL- CLM- SEA- SEA- OLM- SEA- YKM- SHN- SHN- SEA- SMP-
DD/HH DLS CLM NUW EAT YKM YKM GEG GEG SEA NUW SMP EAT
14/18 +5.2 +0.9 -0.7 +7.5 +7.5 +7.1 +6.4 -1.1 -0.8 -0.4 M M
14/16 +4.9 +0.9 -0.9 +7.1 +6.7 +6.1 +6.1 -0.6 -1.2 -0.9 +0.9 +6.2
14/14 +4.8 +0.6 -0.5 +6.8 +6.0 +5.6 +6.3 +0.3 -1.2 -0.7 M M
14/12 +4.4 +0.7 -0.2 +6.5 +5.6 +5.1 +5.6 0.0 -0.9 -0.8 M M
14/10 +4.6 +1.9 -0.8 +6.4 +5.5 +5.3 +5.5 0.0 -0.9 -0.8 -0.4 +6.8
14/08 +5.0 +1.7 +0.2 +7.0 +5.5 +5.6 +5.1 -0.4 -1.7 -0.8 M M
14/06 +4.3 +2.6 -0.3 +6.2 +4.8 +4.8 +4.1 -0.7 -0.1 0.0 -0.2 +6.4
14/04 +4.2 +1.8 -1.0 +3.5 +3.4 +3.6 +2.6 -0.8 -0.2 -1.1 M M
14/02 +2.9 +1.5 -0.1 +4.7 +3.4 +2.5 +3.2 -0.2 -1.3 -0.9 -1.5 +6.2
14/00 +4.9 +1.5 -0.1 +4.4 +4.0 +2.8 +2.5 -1.5 -1.3 -1.0 M M
13/22 +2.5 +0.5 -0.1 +4.0 +3.1 +2.0 +1.9 -1.2 -1.8 -1.6 M M
13/20 +4.3 -0.8 0.0 +3.5 +2.9 +2.1 +1.3 -1.6 -1.8 -2.4 M M
13/18 +1.3 -0.6 -0.3 +2.7 +2.7 +2.3 +1.2 -1.5 -1.6 -2.5 M M

HQM-SEA is Hoquiam to Seattle, and you can see that the pressure at Hoquiam is always higher than it is at Seattle, leading to onshore flow. This gradient peaked at 4 a.m. UTC July 14 (9 p.m. PDT July 13) per this table, which is pretty typical for these events in Western Washington. The difference is even more stark across the Cascades… take a look at the SEA-YKM (Seattle to Yakima) gradient, which just peaked at +7.5 at 6 p.m UTC July 14 (11 a.m. PDT July 14) and will likely continue to rise.

No picture gives a better example of onshore flow than the one below. I retrieved this from the graphical area forecast discussion (AFD) from Seattle National Weather Service website. Take a look at how the “marine layer” of low stratus clouds and fog has completely engulfed the coast and much of Western Washington.

http://www.wrh.noaa.gov/sew/gafd/latest_webafd.html

Now, take a look at how the clouds look 4 hours later.

http://www.atmos.washington.edu/~ovens/wxloop.cgi?vis1km+1

We had a pretty strong marine push last night, and for that I am grateful. It was very hot in my room, and it was nice to have it cool off. Therefore, it has taken some time for the clouds on the coast to “burn off,” and those living on the coast may not even see the sun today. Still, you can see how much it has cleared over the south sound, where the stratus layer was shallower.

So what’s in store for the extended? It looks like we’ll finally resume to a more normal pattern, but not before another couple warm days. Tuesday will straddle on either side of 90 for much of the lowlands, as the onshore flow that morning will be much weaker than today’s. After that, however, we should get into a more typical pattern of highs in the mid-to-upper 70s with clouds in the morning giving way to sunny skies in the afternoon.

However, things look to remain largely dry. Our next shot at rainfall looks to occur next Sunday at the very earliest, and this looks like more of a BB-gun shot than a shot from an UZI.

Valid 02:00 am PDT, Mon 21 Jul 2014 – 165hr Fcst:   http://www.atmos.washington.edu/~ovens/wxloop.cgi?mm5d2_x_pcp3+///3

The CPC (Climate Prediction Center) predicts above normal temperatures and below normal precipitation from now out to two weeks into advance, so long story short, although our warm and sunny pattern may have a few stumbles here and there, we are definitely in the height of summer, and summer isn’t going anywhere for a long time.

Charlie

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