January 03, 2023

The Beauty of an Explosively Developing Cyclone Offshore

 As predicted, a midlatitude cyclone is rapidly developing west of our shores, and the satellite imagery is stunning.

Consider an infrared satellite image taken around 6 PM by the NOAA GOES-West satellite located 35,000 km above the equator (see below).     Whiter clouds are cooler and higher.  

Look close and you can see the swirl of frontal clouds into the low.

A close-up view of the low center shows cold air shower clouds (the mottled elements to the southwest) circling around the low.  (see close-up below).


Even more dramatic perhaps is water vapor satellite imagery that senses water vapor instead of clouds (below).  You can even see dry air circulating into the low from the southwest (darker area).


Another type of beauty is the wind speed forecast for 4 AM PST, with the winds indicated by colors (and wind direction by lines)...see below.  The powerful winds to the south and west of the storm system are evident.... a feature known as the poisonous tail of the storm


Wind speed  (mph) at 4 AM.  Courtesy of WeatherBell, Inc.


As the storm moves off our coast Thursday afternoon (see the forecast for 1 PM below), the huge difference in sea level pressure (higher inland, much lower offshore) will result in our air being accelerated to the ocean.  


Such easterly flow (winds from the east) will be particularly strong on Wednesday night along the western foothills of the Cascades and out the Strait of Juan de Fuca (orange and dark blue are the strongest winds).  Beautiful graphics, but damaging winds and danger are there as well.


And finally, there are the forecast significant wave heights for Thursday morning at 2 AM PST.  Monster waves exceeding 30 feet will reach the northern CA and southern Oregon coasts.  Beautiful but deadly.

The dividing line between science and art is sometimes blurry and this event is a perfect example.  Perhaps someone could start a business selling weather-graphics "art."

My next blog will describe an important societal impact of all the storminess over the eastern Pacific:  the end of the California drought.

18 comments:

  1. The swirling thing in the gulf of Alaska looks almost as big

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  2. Thanks, Cliff! Excited for the easterly wind gusts in North Bend tomorrow.

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    1. Not me. After the recent ice storm and wind storm power outages, I really don't want to lose power again.

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  3. Cliff, can you explain why an area of very low pressure is termed "explosive"? When I hear the term "explosive" I think of very high pressure.

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    1. It comes from 'bomb cyclone' or 'bombogenesis' which is an area of low pressure that drop by 24 millibars (.71") within 24 hours. The term originated at MIT in 1980.

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    2. When a "bomb" "explodes" there is a rapid increase in pressure - the exact opposite of what's happening here. It appears that in this case the terms are used generically to simply imply a "rapid and intense change". Another interpretation I found is that this type of system can spawn storms and high wind, which themselves can cause "bomb like" destruction. It's just an odd and confusing choice of words.

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    3. a rapidly intensifying cyclone is also called explosively deepening. When it deeps at a sufficiently large rate (roughly 24 hPa in 24 hr) it is termed a bomb. That is the terminology that has become accepted....sorry.

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    4. Yes, I noticed that this terminology ("bomb cyclone") seems quite new. It does seem a bit overdramatic. Something that the popular media would invent.

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  4. Boy, the NYT is connecting this with climate change. Poor climate change gets blamed when it shouldn't - crying wolf is not a good strategy.

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    1. Well, to be specific it is UCLA climate scientist Dr. Daniel Swain that is connecting these storms to climate change by referencing increased atmospheric moisture. You can maybe fault the NYT with potentially leading readers with the "is climate change making [atmospheric river] events more extreme?" subheader, but they do quote Dr. Swain as emphasizing the potential for impacts. Basically, to me the article reads that a warmer atmosphere holds more moisture, but how that impacts the likelihood of rapid-succession storms is still not completely understood. The best estimate they provide (in a referenced article) is that the chances for "monthlong statewide storms" goes from 1:50 to 1:30 if average global temps raise by 1.8F based on an article by Huang and Swain. In the end, I don't think the media always gets it right, but I'd argue that the NYT does it's due diligence better than others.

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    2. Daniel Swain has a tendency to provide a certain viewpoint...and the media know it. Midlatitude cyclones are not being enhanced by GW..that is solid. Atmospheric river will intensity as the planet warms...particularly by the end of the century.

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  5. The guy loves weather! Thanks cliff

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  6. Not even your detractors can deny your passion, Cliff. Good on ya!

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  7. Sure hope CA doesn't get hit with the latest forecasts out of the National Weather Service. I don't remember them ever becoming overly alarmed about most upcoming weather events, but today they're really sounding worried for most of the entire state. Widespread flooding, possible washouts of major roads (particularly I - 5) and all kinds of mudslides.

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    1. I believe parts of the state already had by an earlier storm last week if not mistaken.

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  8. Why aren't we getting a piece of the action? Shouldn't we be getting some of the rain?

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  9. There's been some wonderfully warm south-east winds tonight, thanks for explaining why.

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  10. In the wind-speed picture, there is a lot of "wrinkling" to the south of the low. Is this a physical phenomenon, or a measurement or interpolation artifact?

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