The Final Heatwave of the Summer? When does the threat disappear?

 Even with cool temperatures this weekend, the specter of more warmth is on the horizon.

But is this the end of the threat of real warmth in our region?   

Let's start with the forecast.    Another ridge of high pressure will build over the West Coast on Monday and Tuesday, as illustrated by the upper level (500 hPa pressure, about 18,000 ft) map for Tuesday at 5 PM.  The red indicates higher than normal pressure, the blues and purples below normal (troughing.

The latest National Weather Service National Blend of Models temperature forecast for Seattle indicated highs in the upper 80s on Tuesday and Wednesday before an extended cool-off to more seasonal temperatures around 80F.  Importantly, lows will reliably decline into the 50s, ensuring a good night's sleep.

As apparent to all of you, the nights are getting longer, the days shorter, and the strength of the sun's rays is ebbing.   Eventually, we simply won't be able to get into the 80s and 90s anymore.   

But when?  What does climatology tell us?  

To assist in this analysis, let's look at the climatology of temperatures on both sides of the Cascades for late summer and early fall (August 1- November 15, see below).  Each plot below shows the record highs (reds) and lows (cyan) and the average high/low range (brown shade).  I also plotted this year's temperatures (blue bars) and noted the 80, 90, and 100 F levels with dashed lines.

For SeaTac Airport, temperatures have gotten above 90F many times in August and early September, but never after October 1.  Highs above 80F have occurred through mid-October.    

The bottom line, the threat of above 90F in western Washington will be over in a month, with little chance of temperatures exceeding 95F after Sept. 1.

For the Tri-Cities (Pasco shown below), getting above 100F is no big deal in August, but becomes unprecedented after the first week of September.  Reaching into the 90s has occurred many times in September, but become unprecedented in October.  October is a very month in eastern Washington.

The bottom line:  Based on the current forecasts, it appears that after mid-week, there is probably little chance of Seattle exceeding 90F for the rest of the year.  And after Friday, little chance that Richland will exceed 100F for the remainder of 2022. 

Reminder: I will be teaching ATMS Atmospheric Sciences 101 this fall.

Like last year, I am teaching atmospheric sciences 101: a general introduction to weather and climate, this fall. You can learn more about the class on the class website. I talk about everything from the basics of the atmosphere to weather prediction, thunderstorms, hurricanes, and local weather to global warming and climate.

I will be teaching the class in person at the UW, but will also make it available over zoom. Thus, folks can take it remotely.

If you are over 60, you can take the class through the ACCESS program for a very nominal charge (something like $15). Last year I had over 100 folks do so.

If you are a UW student looking to learn about weather or a non-student interested in the topic, I welcome you to join me this fall. My first class is on September 28th.

Have You Been Censored by the Seattle Times?

I have become aware of a serious problem at the Seattle Times:  they have been censoring people who have left comments with a different viewpoint on climate change than theirs, with their actions based on accusations of "climate misinformation."   If you have been censored by the Seattle Times, including removal of comments or locking of accounts, please let me know through email or as a comment on this blog (I will not reveal your identity).

This is a very serious issue and reflects a disturbing attitude at our local newspaper.