This August was a warm month in the Northwest. But how warm? How unusual? And how unusual were the temperatures over the rest of the world during August? Was everyone warmer than normal?
Let me start by showing you a map of the temperature differences from normal (the anomaly from climatology for August) based on satellite observations for roughly the lowest 26,000 ft of the atmosphere.
Yes...one can take the temperature of the earth's atmosphere from space by measuring how much microwave radiation reaches a satellite. Similar technology is used to determine your forehead temperature during COVID temperature checks using the IR part of the spectrum instead.
Note that some places are warmer and and some places colder than normal, with large swaths near normal. Much of this temperature variation is due to waves in the atmosphere, particularly in the midlatitues.
You will notice a center of warmer-than-normal temperatures over southwest Canada...and we get part of that! Cooler than normal over the southeast U.S. and warmer in northern Europe.
But what about near the surface? The National Weather Service uses all weather observations, in concert with their modeling system, to diagnose the temperature difference from normal at a level very close to the surface (1000 hPa pressure, see below).
Now let's telescope to the U.S. using the August temperature differences from normal from the NOAA Climate Prediction Center. Yep... the Northwest is the hotspot of the nation... particularly eastern Oregon, eastern Washington, and northern Idaho/western Montana.
Looking for cooler than normal temperatures? Head to Arizona.
The essential point I want to stress is that temperature differences from normal are NOT uniform over the globe or even voer the U.S. Some areas are warmer than normal and some cooler than normal. Over the past 50 years or so, global warming due to increasing CO2 is slowly warming the planet but does not significantly change the spatial variability, as illustrated above.
Finally, how usual was August, looking at some representative Northwest stations?
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This is somewhat apples vs. oranges. Of course, natural variability will dominate any monthly anomaly, but global warming does have regional variability that acts on top of that. There are ample studies and maps available to show this. Land warms faster than ocean. The Arctic warms faster than low latitudes and there are regional anomalies like south of Greenland, commonly on the order of 1C. This is simply because CO2 isn't the only forcing. There are feedbacks that need to be considered. In addition, 1991-2020 already has some of those regional patterns from global warming baked in. To call 1991-2020 normal in the context of global warming is misleading IMHO. Arizona may be cooler than the 1991-2020 August average, but it is still easily warmer than the 20th century average.
ReplyDeleteAdam...not sure of your point. On a daily, weakly, and even monthly basis synoptic variability created anomalies of differing signs. So one areas heat wave, is colder than normal elsewhere. As you note, on the longer time scales this tends to average out, except for where there are geographically stationary long term trends. I am not calling 1991-2020 normal...that is simply the period used by John Christy to create that graphic. I suspect another period or a longer period would produce the same pattern..which I guess is my point here.
DeleteThere are SO MANY people here on the Cliff Mass page trying to convince us that global-warming is real.
DeleteWHY is no one - no one I can recall - trying to convince us they are not causing it.
Am I violating his guidelines by saying that it all sounds like a lot of "hot air"?
If the problem of global-warming is real then why are people so determined to convince us of that fact but offering us no solutions to cure it?
Always nice to see Olympia charts. Our weather is a little bit different than Seattle. Thank you! I love a chilly August so I can get back to actually working my gardens rather than just being busy watering them. Every July I think of the last chilly August we had in 2011 when the clouds came in early and stayed. That was what I thought Olympia was when I first came here in August of 2000, which was another cool August. That hasn't happened in over a decade. It used to happen more often. I want it to happen more often, everything is still so dry!
ReplyDeleteWhen are our rains coming back? I (and trees!) really need them. I see many cedars, pines and other trees showing clear signs of needing more moisture in the soil.
ReplyDeleteToday! Was raining this evening in Seattle.
DeleteHot August 1969? I read the graph as 1967, which I do remember - my first year in Seattle!
ReplyDeleteI can say from experience...that 23 MAY 1969 saw the temperature in Seattle hit 90 degrees!...It was a harbinger of a very warm summer to come.
DeleteHi cliff- I work on salmon recovery and hoping to complete stream work thru oct 10. What can you see in your magic crystal ball for start of monsoon season?
ReplyDelete“Data from the Southeast Regional Climate Center (SERCC) showed the average temperature nationwide was around 74 degrees, putting it on par with summer 2021 and the 1936 Dust Bowl. Persistent heat waves made 26 cities across the US — including: Newark, NJ; Tampa; Salt Lake City; San Antonio, Texas, and Cheyenne, Wyoming — report their all-time warmest summers.”
ReplyDeleteOf course, lets note that all the other cities did not reach their all-time hottest summer temps.
Professor Mass, I don't remember August 1969 as I was in SE Asia at the time, contending with events other than weather, although my memory is that the monsoon that year began a little late and was below normal in rainfall according to what we were told. When you're sleeping in it the previous and current data seems irrelevant. I DO REMEMBER that August and September 1963 "seemed" abnormally warm to my short number of years experience. Summer seemed to push deep into September that year with warmer than normal temps. I've not taken time to try to verify that, but I presume you could do so with some ease. Memory is so notoriously unreliable in some respects I won't be surprised to learn that events in my 14th year were not as I "believe" they were.
ReplyDelete