Friday March 20th… Dear Diary. 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: U.S. Average Temperature Spring Forecast
This nation and world is facing two big existential threats as we start this new season, the COVID-19 outbreak and the climate crisis. As I’ve stated in the last few weeks the climate crisis will be with us long after the world tackles and survives the coronavirus crisis. I’ll have many new articles posted concerning COVID-19 at the end of what will seem like, at this point, a minor facet of the climate crisis, seasonal weather forecasting for the United States. For those interested in weather and climate trends the following may prove interesting, though.
Welcome to boreal spring everyone, or the three months that are March through May. Meteorologically and on climate summaries spring is considered to start on March 1st instead of when the solstice occurs on the 19th, which was yesterday. So how will boreal Spring 2020 stack up compared to long term temperature averages across the United States? Will we continue to see the climate crisis signature of warmer than average conditions? Let’s try to make a forecast as usual at the start of a new season.
So how did the forecast work out for Winter 2020? Here is the post for that forecast:
Earlier this month the National Center for Environmental Information completed their assessment for Winter 2019/20, so let’s fill in their ranking numbers with 1 being the coldest and 125 warmest for a verification:
The winter was at near record warm levels across the CONUS coming in at 120th coolest or sixth warmest for average temperatures, which is eye opening.
February turned out to be the warmest month.
Overall this winter turned out to be well above average and warmer than on recent winters this decade looking at the ranking of 120 from 2020. My forecast of a ranking of 80 + or -20 was too cool.
Why? Because a strong positive Arctic oscillation developed in December and lasted all season. It is very hard to predict AO trends.
O.k. Now that we have established that our forecast was too cool but half decent for the last season let’s use the same techniques to forecast temperature rankings for this spring, keeping in mind some cold monkey wrenches that the atmosphere can still throw at forecasters despite our warming world.
First, let’s look at current water temperatures anomalies surrounding North America:
Around North America we see an interesting SST pattern. For a change it was colder than average in Alaska this winter, leading to below average surface water temperatures across the Gulf of Alaska. This cold water has moved southward such that some of it lies off the West Coast. We are already seeing a tendency during March for cold weather systems to dig or develop in the West and eject into the eastern half of the U.S. Also, warmer than average SST’s across the Gulf of Mexico and Atlantic are adding a continuation of warm conditions across the southern and eastern states from the winter. This pattern on all accounts will probably continue into April and May and also, unfortunately, lead to a very stormy spring in the Plains and Midwest.
In the Pacific we also don’t have an El Nino or a La Nino with ENSO in neutral phase. ENSO should not be a factor for warmth or chill in the U.S. this spring, remaining in neutral conditiond.
Second, I like to look at the strength of the Hudson Bay low or polar vortex at the start of any season:
As of today it is non-existent over Hudson Bay due to the continuation of a positive AO. Yet another cold storm lies over the West. Such a patter, if it continues, will lead to average or below average conditions in the West and above average temperatures for the southeastern half of the country.
Here is the National Weather Service forecast for Spring 2020, which I agree with except that it may be too toasty in the Southwest:
As we have seen though, a warm March can sometimes lead to a very cool April, so the NWS “best guess” forecast may not work out during spring.
Overall, Spring 2020 will probably verify above average looking at trends from the rest of the planet.
Last, we can get another clue looking at prior ranking and temperature record count data. For this I like to drag out that “Record Scoreboard” (updated through 3/15/2019):
Again, here we see clues that winter remained warm for all three months, which were colored red. In fact, January was colored in bold red because it had a greater than ten to one ratio of daily record high maxes to low minimums.
March has started out above average or “red” with many record reports coming into the National Center for Environmental Information system.
I expect a slight cooling trend through May. May could be the coolest of the three months, relative average temperature wise, but all three months of spring should see an above average ranking of more than 62.5.
Not all seasons in the near future will see above average temperatures, but seasonal forecasters are beginning to”chuck it,” discounting colder than average scenarios due to carbon pollution.
Again, here are all seasons ranked for this decade:
Here is my bottom line forecast for Spring 2020:
“I think that this winter will be ranked near that of the last four. Carbon pollution is definitely making below average seasons more rare. I’m going to guess that the Spring 2020 ranking will be around 100 + or – 10, with near average confidence given all of the factors in this post.” (Note that my forecast was on the too cool side by 20 ranking numbers for this winter.)
Notice that the past three of the past four springs had a ranking at or above 100, but that of 2019 was the coldest relative to averages. The big El Nino of 2015/16 really spiked global temperatures as well as those for the U.S. From Fall 2018 through most of 2019 U.S. averages have gotten considerably lower than the torrid levels of 2016, though. Will increased global heat once again be a catalyst, helping to produce another “heat spell” or two during the middle of the spring for the United States? We will see.
As of 2020 the top ranking for any month or season would be 126 since climatological rankings for the United States started in the year 1895. I think that this spring will be ranked at least as high as 80. Carbon pollution is definitely making below average seasons more rare. As stated, I’m going to guess that the spring of 2020 ranking will be around 100 + or – 10, but with average confidence given all of the factors in this post.
We will see how this forecast pans out around June 10th.
Now, here are some of todays articles on the coronavirus:
Here is more climate and weather news from Friday:
(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.)
Here is another “ET” from Alaska:
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Guy Walton “The Climate Guy”