The main purpose of this ongoing blog will be to track planetary 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 Fall Forecast (It Will Be Anomalously Warm.)
Dear Diary. It is now the start of meteorological fall, so once again as we do on this blog, it is time to make a forecast for this season. Summer 2024 had anomalously hot temperatures overall across the lower 48 states and in fact will be pegged as a top twenty warmest since records have been kept since 1895. I think that we will see this warmth continue into this fall due to climate change, although I doubt that we will see the warmest fall on record. Nevertheless, no matter how far above average this fall will be overall, there will be periods of cooler than average conditions for localized areas of the country.
At the very start of fall, it’s time for me to make another attempt at a forecast for average seasonal temperatures in the U.S. This forecast will be very broad and not specific for any one state comprising the continental United States (or lower 48 states).
So how did the forecast work out for Summer 2024? Here is a link to the post for that forecast:
By September 8th the National Center for Environmental Information will finish their climatological assessment for Summer 2024, so our verification is not complete as of August 31st. Let’s do fill in ranking numbers with 1 being the coldest and 130 warmest for a verification for months during 2024, which have already been assessed (130 would be warmest for 2024.):
Here are my two cents for a broad, rough forecast for the U.S. for Fall 2024, which I guarantee to be cooler than this past fall, of course, as the amount of daylight decreases across the Northern Hemisphere. First, I like to look at water temperature anomalies surrounding North America just before the start of a season to get a sense of how much potential anomalous heat can be added to the atmosphere across the continent. Here is what we see:
Some of the most anomalously warm SST’s that I have ever seen encircle North America. This leads me to think that there will be above average temperatures along both the Atlantic and Pacific coasts. As is happening now, cool troughs will impact the Midwest, though:
We do note that the first half of the month will see a refreshing cool spell over the East and South as another heatwave develops across the West:
Here is the National Weather Service forecast for Fall 2024:
I can’t disagree much with this outlook, although we might see above average temperatures across the West Coast due to aforementioned warm SST’s. The coolest temperatures relative to average will probably come from the Midwest as depicted.
Next, we can get another clue looking at prior National Center for Environmental Information ranking and temperature record count data. For this I like to drag out my “Record Scoreboard” (updated through 8/31/2024):
For these data sets all monthly ratios of > 10 to 1 DHMX to DLMN or > 10 to 1 DLMN to DHMX are in bold type. The rankings are for the lower 48 states with the warmest ranking since 1895 of average temperatures being 130 and 1 being the coldest as of 2024. Blue colors represent cold months and red warm. Those months and years with counts close to a 1 to 1 ratio of highs to lows are colored black. Boldly red-, blue-, or purple-colored months, such as January 2020 and June 2021, have ratios of >10 to 1 daily record highs to lows or <1 to 10 daily record highs to lows, and are either historically hot or cold, most of which have made news. All-time record hot or cold ranked months are highlighted in purple. I’ve subtracted Alaska records so we can better compare apples to apples with record totals and rankings for the lower 48 states.
Notice that both December 2023 and February 2024 had a better that 10-1 ratio of DHMX to DLMN record reports. All three spring months saw more daily high max records than low min records. Looking at daily record ratio trends by month, anomalous warmth should continue into the fall with a low probability that one month might see more daily min records than daily max records considering what happened in January 2024.
I’m predicting that all three months of Summer 2024 will be above average with August being the most likely month to see temperatures closer to average and July the warmest. Here is the link to avg. rankings per year for the lower 48 states since 1895:
https://www.ncdc.noaa.gov/cag/national/rankings
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.
Here are all seasons ranked for the last decade:
The last time we had a below average fall season was before 2015. Winter 2023\24 was the warmest in recorded history for the lower 48 state portion of the U.S. An average ranking on the above chart would be 65 as of 2024.
Here is my bottom-line forecast for Fall 2024:
“I think that this fall will be ranked well above average. I’m going to forecast that the Fall 2024 ranking will be around 110 + or – 10, with above average confidence given all of the factors written within this post.“
My forecast for Spring 2024 of a ranking of 110 + or – 10 was 15 rankings too cool, but not too bad considering that the upper end of my forecast was 120, and the verification was 125.
We will see how well my forecast ranking of near 110 for Summer 2024 worked out in a few days.
As of 2024 the top ranking for any month or season would be 130 since climatological rankings for the United States started in the year 1895. Carbon pollution is definitely making below average seasons rarer. As stated, I’m going to guess that Fall 2024 gets ranked at 110 + or – 10, and with above average confidence given all of the factors in this post.
Have a fantastic fall but be weather aware. Despite a slow start, we should see some hurricanes because there is a forecast record active tropical Atlantic season.
Here are more “ETs” recorded from around the planet the last couple of days, their consequences, and some extreme temperature outlooks, as well as any extreme precipitation reports:
Here is More Climate News from Saturday:
(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.)