People talk to me about the weather....and several have told me that the winds this summer have been unusual.
Last night, I gave a talk at a local paragliding club, and many of their members thought that northerly winds (from the north) were stronger and more frequent during the past month around central Puget Sound.
And tonight I discussed the issue with one of the leaders of Sand Point Sail on Lake Washington. He was also convinced that the northerly winds were stronger than normal this year.
Surely, we have had a drier-than-normal late spring and early summer in western Washington: have the winds been unusual as well, and if so, why?
This blog will reveal the answer.
The tool I will use is called a wind rose, which shows the frequency of winds by direction and speed range.
Consider the wind rose at Seattle Tacoma Airport for June 1 to July 16. The wind speed ranges for each direction are color-coded. The distance from the center tells you the frequency. Winds from the north occurred a bit over 15% of the time. Southwesterly was also a popular direction.
We can compare the wind rose from this year (again June 1- July 16) to the average wind rose for the same days of the year, but based on the climatological record over decades (1948-2025).
It is shown below.
They were right! The normal situation is to have less frequent northerly winds and more frequent southwesterly winds.
Considering the wind roses at Paine Field, Everett, in the North Sound, for the same late spring/early summer period (below), we note way less southerly winds this year than normal, but stronger northerly winds.
Western winds dominated this year from June 1 through today. Almost no winds from the east for the last 1.5 months.
I think I can answer that. Below is the difference from normal of sea level pressure for the same period (June 1-mid July).
Higher than normal sea level pressure to the west and north of our region. This will tend to cause stronger than normal northerly winds and drier than normal conditions.
There is no reason to expect that this pattern has anything to do with global warming.
How do I know this?
Because climate models driven by increasing CO2 and methane do not produce this pattern.
I have carefully examined the climate model runs and my group has been running regional climate simulations as well.
Living in the South End of Tacoma I see this in the SEATAC airport traffic patterns over the years (with of course the 3rd runway issue). When the winds are from the north I have lots of inbound lights overhead and this seems to be increasing (could be due to changes of air traffic control rules) starting about 10 years ago. The Emirates Air flight 1-2PM is very noticeable (Dreamliner ER - that plane is big, connecting to all over Africa and Asia over the pole). I think this is more that just the past year. Maybe SEA tower might have data for a student project.
ReplyDeleteLiving in Shoreline, I too notice the air traffic patterns. Winds out of the North mean things are quiet over heard. Winds from the South mean things are noisy over head. Definitely been a quiet summer.
DeleteHey Cliff, Is that anomalous high pressure, both the extent and duration, potentially leading to another blob (marine heat wave) like we had 10 years ago?
ReplyDeleteThank you for including Hoquiam and the coast in this discussion. The lack of winds from the east this summer has contributed to what has been a cooler summer so far out there. For things to get particularly hot out there (upper 80s and 90s), easterly winds do seem to be a necessary ingreident. Without them, 60s and 70s prevail. Even the odd summertime high in the upper 50s once you get out to Ocean Shores.
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