Extreme Temperature Diary- Monday November 30th, 2020/ Main Topic: A Saffir-Simpson Type Scale For Cold Waves

The main purpose of this ongoing blog will be to track United States extreme or record temperatures related to climate change. Any reports I see of ETs will be listed below the main topic of the day. I’ll refer to extreme or record temperatures as ETs (not extraterrestrials).😉

Main Topic: A Saffir-Simpson Type Scale For Cold Waves

Dear Diary. Yesterday I let my readers know that the first significant cold wave for the U.S. South would penetrate deep into the Southeast starting today. Over the summer we started naming and ranking heat waves, establishing criteria for doing so:

Extreme Temperature Diary- Thursday July 2nd, 2020/ Main Topic: Introducing A Saffir-Simpson Type Scale For Heat Waves – Guy On Climate

So, fair is fair, especially in the world of science. It’s now time to introduce a scale for cold waves similar to that of my proposal for heat waves. After all, global warming has not extinguished dangerous cold weather phenomena yet.

Today going into Tuesday we have a good example of a minor “CAT 1” event. We don’t have an Arctic outbreak, with chilly conditions mainly being generated from a cold system aloft. Most readings this afternoon are above freezing south and east of the Great Lakes, but gusty winds being generated from a Midwestern storm system are sending wind chills below freezing:

Advisories for snow are out for eastern parts of the Midwest this morning. Here we see freeze warnings out for much of the Gulf Coast:

Wind advisories are colored brown.

Unlike heat waves, where we sometimes see drought or “anti-storms,” cold waves likely will be accompanied by associated named Weather Channel winter storms. “Winter Storm Dane” is the latest TWC incarnation, which encompasses the midwestern National Weather Surface watches and warnings shown on the above advisory map. Most people won’t need to bundle up too much to stay safe from this CAT1 cold wave. I would propose that cold outbreaks also be named for TWC winter storms if they coincide to get a quick reference to the public.

Sometimes we can get a cold outbreak without a winter storm, though. In those cases of mainly Arctic outbreaks, we could name the cold outbreaks Alpha 2020, Beta 2020, Gamma 2020, etc.

Also, cold outbreaks can remain long after a winter storm has left the scene and can feed into the next system. In those cases the cold outbreak name should continued to be referred to. A fresh reinforcing cold outbreak behind a subsequent storm should get the new storm system’s TWC name, but only if the cold wave gets up to major CAT 3 strength.

A CAT 2 cold wave would be of medium strength but would not be historic in nature. These would have some Arctic air entrainment, with fairly widespread NWS wind chill advisories, and large areas of below average temperatures at least the size of Texas. In all cases, departure from average over a given area needs to be taken into account. We would not see significant numbers of cold record temperature reports from CAT 2’s.

We’ve already seen a “historic” CAT 3 cold wave very early in the season during the last week of October:

During that week thousands of cold records were set across the Rockies and western Plains. Many places, such as Denver, experienced sharp, life threatening drops in temperature as the first Arctic air of the system rapidly penetrated into the area.

A CAT4 cold wave would be even more historic and dangerous. Usually these encompass most of the nation. Wind chills would need to go below 0°F across at least one large section of the country about the size of Texas to meet criteria. Numerous monthly and all-time records would also need to be threatened to meet criteria.

And finally we have the top dog of the scale, CAT5. During this day and age of global warming these might already be extinct animals. The historic cold outbreak of February 1899 here in the U.S. would be a good example of a CAT5. Read about that here:


So, do we have a CAT1 “Cold Wave Dane” on our hands ATTM? In my opinion no. Assigning cold wave names, in my opinion, should only be reserved for historic CAT3 outbreaks or worse much like CAT3 heatwaves. Like heatwaves, these can go up or down in ranking depending upon the synoptic weather situation.

Perhaps you disagree with this assessment. That’s fine, keeping in mind the best way to communicate weather threats to the public. It’s been my experience that named systems of any sort register with the public better than those not named. The great Louisiana Flood of 2016, which was not named, is just one example that did not get nearly as much press compared with named tropical storms that have had much less adverse effects. Maybe you would prefer that all cold waves regardless of rank get names. Let’s debate this in the coming weeks over winter as we inevitably see some life threatening chill penetrate the nation.

Here is more climate and weather news from Monday:

(As usual, this will be a fluid post in which more information gets added during the day as it crosses my radar, crediting all who have put it on-line. Items will be archived on this site for posterity. In most instances click on the pictures of each tweet to see each article. The most noteworthy items will be listed first.)

Now here are some of today’s articles and notes on the horrid COVID-19 pandemic:

(If you like these posts and my work please contribute via the PayPal widget, which has recently been added to this site. Thanks in advance for any support.) 

Guy Walton “The Climate Guy”

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