From the Cliff Mass Weather Blog
Cliff Mass
During the past three days, I have received several calls from media folks asking the same question:
Are storms like this week’s “bomb” cyclone becoming stronger or more frequent due to global warming?
If not, will global warming cause such increases in the future?
The answer to these questions is quite clear: NO.
There is convincing scientific evidence that our region has not seen an increase in such storms and that a warming planet will not bring more meteorological “bombs” into our region.
First Some Terminology
A midlatitude (or extratropical) cyclone is a low-pressure center with winds rotating counterclockwise around it in the northern hemisphere. The strength of the cyclone is generally quantified by the central pressure, although size is also important. Generally, the lower the central pressure, the stronger the cyclone and the more powerful the winds.
As shown by the figure below, cyclones generally form in regions of strong horizontal temperature change….in fact, such temperature contrasts are the fuel of such storms.
Regarding central pressures, garden variety storms in our region have pressures around 990-1000 hPa. Strong storms perhaps 980-990 hPa, and powerful cyclones have pressures of t965-980 hPa, with extreme storms even less.
Tuesday’s storm dropped to an astounding 943 hPa, tying the record for the past 70 years.
Cyclones that rev up particularly rapidly are called “bombs”…..and the media has certainly fallen in love with this term. By definition, bomb cyclones deepen by 24 hPa or more in 24 h. This definition is completely arbitrary. Really just for fun.
Are Local Cyclones Getting Stronger?
The answer is clearly no. There has been no increase in the frequency or intensity of landfilling or near-shore cyclones in our region.
Most of the famous local cyclones occurred during the early to mid-20th century, with the last major landfalling cyclone in 2006 (the Chanukah Eve Storm).
Another way to demonstrate the lack of increase in storms is to plot sea level pressure over time at a point on the Washington Coast (Ocean Shores). As shown below, there is no evidence for an increase in the lowest pressures (say below 980 hPa).
Will Global Warming Increase Strong Windstorms Over the Region?
A group of us at the UW (in association with the UW Climate Impacts Group) did a formal study of this question, funded by Seattle City Light.
We made use of a state-of-science regional climate model driven by an ensemble of Global Climate Models.
This research did not find an increase in extreme winds over the region (we examined several locations). A graphic from the analysis of the extreme wind trends through the end of the century is shown below.
There are good scientific reasons to expect little change in the intensity of midlatitude cyclones over our region.
For example, global warming preferentially warms the Arctic in the lower atmosphere, thus weakening the north-south temperature difference that drives the storms. On the other hand, the temperature change is strengthened aloft, with the result being a wash for the storms.
In summary, natural variability and processes sometimes can come together to produce very intense cyclones like the one we experienced on Tuesday.
We experienced a rare, extreme event and there is no reason to expect that such storms will become more frequent as the planet slowly warms.
Cliff Mass is right on with a Reality Check posting about these storms. I was a sophomore in High School in western Oregon, Columbus Day, 1962 when the famous Columbus Day storm hit. I remember looking up the nearby wooded mountain, seeing paths about a mile wide of trees flying everywhere, teacher moving us students away from the windows (except for my brother and I, both wannabe scientists). How strong was this 1962 storm? Peak wind gust at Neuport, on the Oregon coast, of 138 mph. Lowest central pressure of 960 millibars. What’s new?
Yes, as Prof Cliff Mass posted on his blog when this latest heavy weather event was forming –
Native Americans were quite familiar with such events and they had some colorful stories of their origins: suggesting they were the result of a giant Thunderbird, which lived high in the Olympic Mountains.
[image of Thunderbird totem]
So for centuries (millenia?) before the history-denying climate cranks invented “the climate crisis”, local peoples were experiencing these weather events.
Story tip.
https://www.channelnewsasia.com/sustainability/sustainability-caspian-sea-cop-climate-change-4707106
‘A catastrophe’: Why world’s largest inland water body could disappear and what it says about climate change
Reading deeper into the story it is revealed that the current low level has not dropped to the low levels seen in the 1970s. Further reading reveals the fluctuation of the Caspian Sea level has historical records of highs and lows, which to me suggests some natural cycle may be involved.
The drop in the Caspian Sea levels was caused decades ago when the former Soviet Union diverted much of the water that fed the sea into irrigation projects.
Like the Aral Sea.
Obviously climate changed caused the Caspian Sea phenomenon.
Nothing to see gullible media, move along. Thanks, Cliff for setting the record straight.
I’m on Whidbey Island, and honestly, this was run of the mill for us.
ACE for the Eastern+Central North Pacific basin is only 61% of normal this year according to Dr. Ryan Maue.
https://climatlas.com/tropical/
So the UW experts used a regional climate model based on global climate models? What could go wrong?
At some point, “scientists” who claim that CO2 causes increasingly stronger storms will have to show the mechanism that CO2 possesses that allows minutely increasing amounts to reduce atmospheric pressure.
A cubic meter of air at 20 deg C has only a mere 0.8 grams of CO2 and has a mass of 1.20 kg. That is too little CO2 to have any effect on weather.
‘Another way to demonstrate the lack of increase in storms is to plot sea level pressure over time at a point on the Washington Coast (Ocean Shores). As shown below, there is no evidence for an increase in the lowest pressures (say below 980 hPa).’
That’s what you think. Wait’ll NOAA corrects the data for Time of OBServation bias. You’ll see!
/s
Thank you for putting this straight. I am SO sick of the media hype language (bomb cyclone, atmospheric river) and their over-usage of these terms, clearly to further the CC narrative.
Climate alarmists are certain that a warming atmosphere and ocean will produce more powerful storms. They always get this wrong. It’s the temperature difference and the moisture content (humidity) of the air that are the main drivers of storms. The bigger the difference in temperature and moisture content between two air masses, or an air mass and the land, ocean, or (large) lake under it, the more powerful the storm. If you warm both by the same amount, say 2 ºC, it doesn’t increase the power of the storm. It’s the temperature differential that matters, because the temperature (and atmospheric pressure) differences want to move toward equilibrium. The bigger the difference, the more energy is unleashed to get to a settled state.
Moisture content matters because as moist air rises from thermal convection (heating of the surface), it condenses to form clouds. It releases a lot of energy when it condenses. The greater the heating of the surface and the higher the moisture content, the more energy is released, forming towering cumulus clouds that can develop into thunderstorms. If the moist air rises enough to cool further and undergo another phase change into ice particles, it releases even more energy, forming the most massive cumulonimbus clouds that produce torrential rain, hail, and tornadoes.
It’s not quite as simple as this, because additional factors influence the development of tropical cyclones, typhoons, and hurricanes. But the vastly oversimplified idea that warmer temperatures produce more powerful storms is incorrect.
Thermodynamics 101.
Heat engines, like all engines, derive power from the differential of energy levels. Increase the differential and the engine has more power.
I didn’t get all my wood split and in the shed.
I have three pickup loads of oak (and some fir from last year) still under tarp cover. The tarp is held down by 6 or 8 pieces of of wood. The cyclone winds did not blow the tarp off of the wood. I don’t know why … maybe the god of projected bomb cyclone force winds felt sorry for me.
Seems that bomb cyclone winds are very finnicky.
Very nice Cliff.
Yes…