Severe Alaska Storm, Unusual Rain and Low Pressure in Northern California and Dry Northwest. Are they connected?
There’s a lot of weather happening in the eastern Pacific.
First, an unusually strong center of depression, with intense rain and stormy winds, is making landfall in northwestern Alaska (see surface pressure map at 11 a.m. Saturday). A deep center of 963 hPa. This storm evolved from Typhoon Merbok, which experienced extratropical transition: transition from tropical storm to middle storm.
This storm will weaken rapidly today as it moves into the North Pole.
And then there’s the upcoming event in California. By 5 a.m. this morning, a very strong center of low pressure will develop in the western Gulf region and will hover there for several days.
As a result, there will be relatively heavy rainfall in Northern CA, particularly at this time of year: 1-2 inches in some places (total rainfall through Wednesday morning shown below).
Such an event is a very opportune time to reduce the risk of fall bushfires in the region and alleviate the fires burning today. But Washington State will be relatively dry.
Interestingly, the Alaska Low, earlier Hurricane Merbok, and the California lows/rains may all be connected.
The storm moving north interacts with the jet stream in the middle … strong winds moving west to east. Near the jet stream, the storm joined forces with a weaker low pressure area to create a super typhoon that made landfall in Alaska.
The superstorm pushed warm air in front of it, helping to create a stream of high pressure off our coasts, thus helping to create a low-temperature zone in California.
Like pulling a long rope, creating all kinds of waves downstream (see image below).
Let me show you the evolving situation!
This is a higher level map (500 hPa, about 18,000 ft) on Saturday night, with colors indicating a difference from normal (purple and blue mean lower pressure/altitude than normal) , red/orange is above normal – ridges or peaks). You can see a very strong low pressure area approaching Alaska and a high pressure peak east of it.
But as of this morning (Sunday), the low in California has risen and is just as unusual (if not more) than the low in Alaska yesterday. On Sunday, the Alaskan hurricane was rapidly declining.
I could show you more technical diagnostics about the connection, but that would probably be overkill.
There’s a problem with the low temperatures moving south of us….to the north of the low there are winter winds (from the east) and such winds will bring some smoke back temporarily. western Washington (see forecast below for 3 p.m. tomorrow).
Sorry. But most of the smoke will be at high altitudes and our air quality should be good.
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I’ll be speaking in Portland at OMSI about the Great Columbus Day Storm and Modern Weather Technology on September 24 at 10 a.m. (free). Professor Wolf Read of Simon Fraser University will join me. The 60th anniversary of the biggest storm to hit the Southwest in more than a century will take place on October 12.
For more information:
Like last year, I’m teaching atmospheric science 101: a general introduction to weather and climate, this fall. You can learn more about the class on class website. I talk about everything from atmospheric basics to weather prediction, thunderstorms, storms, and local weather to climate and global warming.
I will be teaching the class in person at UW, but will also be delivering it via zoom. So people can get it remotely.
If you are a UW student interested in learning about the weather or a student who is not interested in the subject, I welcome you to join me this fall. My first class was on September 28th.
