Monday, July 8, 2019

Heat and Smoke

As I'm sure all readers are fully aware, an extraordinarily intense heat wave has been occurring across much of southern Alaska in the past week, and longstanding temperature records have been falling left and right.   Here's a quick summary that Rick Thoman posted yesterday:


 

There's far too much to comment on, but the remarkable July 4 heat in Anchorage may be the most astonishing statistic: the previous all-time record for the city's official climate site was only 85°F.

Dense smoke from wildfires has held temperatures down in some parts of the interior, including Fairbanks, but many locations in western and southern Alaska are well up into the 80s today.  Particularly striking to me is the 87°F currently being reported from Noatak in the northwest - above the Arctic Circle - and 92°F earlier today at the high-quality CRN station to the southeast of Ruby.


Here's an annotated true-color satellite image, courtesy of Rick Thoman and UAF:



Click on the image below for a higher resolution version:


 As bad as the smoke is at the moment in Fairbanks, this summer has a long way to go to equal the awful summer of 2004 in terms of duration and choking density of smoke - see the chart below, showing data from the Fairbanks airport ASOS instrument.  Here's hoping that 2004 remains an outlier.


8 comments:

  1. Nice write-up. More smoke here in Haines than in a long time. Two days fairly thick (2-3 mi vis much of the day). And the warmth was a topic of conversation, though we get it now and then. The chart at the top seems to say that the 90F on the 6th was a record high for July. My search reveals 6 other 90F readings in past Julys plus a 92, a 94 and a 98. The last two are suspect highs from 1975 & 1976 respectively, but it seems likely that even if they were a little "hot" that they were pretty good bet for at least 90. Juneau had 90 and 84 on or close to the dates. This year it was 82 in Juneau on the 6th, 83 on the 5th etc.

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    1. Thanks for the comment, Jim. I'll do some digging and try to get to the bottom of it. A quick look at what I believe is the official Haines record shows 90F in July 1934 and 1936, and as high as 92F (but possibly dubious) in July 1915. I'm not seeing anything higher than that in any month.

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  2. Richard, I use the ACIS2 system primarily to get my data, plus I have checked the scanned coop forms for some of these records and found that they at least are not keying mistakes. There are a suspicious number of really warm temperatures from 1975-78 which I'm trying to figure out. So far there is little corroboration although there were few stations nearby to compare (no other stations in this valley that I've found and no Skagway). Some more distant stations like Juneau and Sitka offer some support. On the other hand the very warm summer of 1915 has lots of support nearby (Klukwan 25 miles inland which is typically 5 or more degrees warmer in summer recorded 99F on July 28) and regional and basically the eastern half of AK was extremely warm that summer (100F in Fort Yukon, 97 in Gulkana, etc). Also, in a biography of Haines pioneer Charlie Anway, that summer was described as very warm and dry, with multiple large wildfires in the are that came close to burning down the town.

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    1. Thanks very much for the additional details. I completely agree on the support for widespread heat in 1915; it would be a very interesting study to look at what happened that summer.

      GHCN-Daily, which is the top source for ACIS, has no data for Haines from 1954 to 1997, so I'm wondering if somehow data from another location made it into the ACIS history for those years. Stranger things have happened.

      Thanks again.

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  3. See PM2.5 smoke over Alaska:

    https://earth.nullschool.net/#current/particulates/surface/level/overlay=pm2.5/orthographic=-147.50,65.28,3000/loc=150.000,-35.832

    Gary

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  4. Interesting that a lot of the records we are breaking now were set back in the 70s and before that in the 30s. Fifty year cycles...give or take?

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    1. Yes there are multi-decadal (and longer) climate cycles involving the oceans, but there are many different time scales involved and it's not easy to piece together the various influences. Also, many all-time records are being broken, and obviously in those cases there's no precedent in the century or so of modern climate data.

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