Meteorological Summer is Over… But Summer-Like Weather Continues

Blue skies on full display from my yard 🙂 (9/1/20)

Although “traditional” or astronomical summer doesn’t end until September 22 (when fall begins), meteorological summer has officially ended. Meteorological summer spans the months of June through August.

Meteorological seasons were created to help aid in keeping consistent climatological data that could accurately be compared from year to year (there’s some variation in astronomical seasons). More can be read on this topic here.

Below is a snapshot of temperatures for the months of June through August. The highest temperature recorded for the summer at Paine Field occurred on August 16, with a temperature reaching 100 degrees! This was only the second time a triple-digit temperature has been recorded at Paine Field, with the first coming on July 29, 2009. August 16 was also when we had some thunderstorms in the area 🙂 ⛈ Two high temperature records were broken: June 23 with 77 degrees and August 16 with 100 degrees.

Figure 1: Temperature snapshot for meteorological summer at KPAE (2020)
Figure 2: Accumulated precipitation for June through August at KPAE

In terms of precipitation (shown above), we ended just slightly below average, with 3.55 inches compared to the average 4.05 inches. 2020 actually ended at number 10 in terms of the most precipitation during a meteorological summer! I’m not complaining ¯\_(ツ)_/¯

For fall lovers like me, the goal is in sight… but we aren’t quite there yet. We still have a stretch of summer-like weather to contend with.

Figure 3: GFS Ensemble temperature forecast for KPAE

The GFS ensemble members average near 80 degrees for the next several days at KPAE (ensemble averages tend to be more skillful than individual members). After that, it shows a spike in temperatures on Wednesday and Thursday of next week, with high temperatures in the mid-to-upper-80s. This still has time to change as it is still a ways away, but it’s worth keeping an eye on.

However, other models like the Euro do not go as warm as the GFS does. Take a peak at the Euro ensemble daily high/low temperature forecast:

Figure 4: Euro daily high/low temperature for KPAE

This still shows a spike in temperatures next Tuesday through Thursday, but not nearly as warm as the GFS.

But regardless of exactly how high temperatures get in the greater Everett area, it will still be warm. A ridge of high pressure setting up shop over the area will help contribute to the heat.

It is also possible that a thermal trough develops, which is responsible for most of our heat waves.

The great Cliff Mass describes this phenomenon in an old blog post found here. Here is an excerpt from it:

A lobe of high pressure extends inland of us, forcing offshore flow.   This offshore (easterly) flow starts over the heated interior of the continent and then gets even warmer when it sinks down the western slopes of the Cascades.   The result is that a tongue of warm air extends northwestward out of the southwest–generally northward from the interior valley of CA or the intermountain West—towards our region.   Each day it moves farther northward and strengthens.  And since warm air is less dense, a pressure trough (area of low pressure) extends northward with the warm air. 

As already mentioned, models disagree on exactly how warm it will get over the next several days. But I think it’s safe to say that it’ll still feel like summer for awhile–in terms of both temperature and dryness.

Figure 5: GFS ensemble for 24 hour precipitation at KPAE

None of the GFS ensemble members show a drop of rain until late next week, and even then, it’s a small amount. The Euro shows a mostly dry next several days, as well. Good news for those who never want summer to end. Take advantage of it while you can! It won’t last forever 😉

Sunny and Dry This Week… But Please Stay Home

This week, for the first time in forever (or so it seems), it should be dry and the sun should be out at times for much of Western Washington. But that doesn’t mean you should be going out to public parks and beaches to enjoy it.

The last time it got super nice, people flocked to parks and beaches, hardly taking any consideration for social distancing. Exhibit A:

Figure 1: Tweet originally found here

Please, for the sake of those around you (especially the most vulnerable), don’t do this. If you go outdoors, do not congregate in places with a lot of people (yes, that includes certain hiking trails). Try to stick with walks and bike rides around the neighborhood, always maintaining distance from others.

Okay, rant over (sorry about that).

It will be tempting at times to want to go out to these public places, though. Take a look at the daily temperatures at Paine Field in Everett according to the GFS (i.e. American) ensemble.

Figure 2: Temperature GFS Ensemble for KPAE

Much of the week will see highs in the mid-to-upper 50s, while the low 60s are possible by the end of the week. For native Washingtonians like me, that is almost t-shirt weather. The European model doesn’t show temperatures quite as warm, but are still in the mid-to-upper 50s. Temperatures closer to Seattle and Sea-Tac look to be a touch warmer than Everett, as shown below.

Figure 3: Temperature GFS Ensemble for KSEA

Not only is it supposed to be warmer, but it’s also supposed to be dry. Take a look at this:

Figure 4: 24-Hour Precipitation GFS Ensemble for KPAE
Figure 5: 24-Hour Precipitation GFS Ensemble for KSEA

All of the above GFS ensemble members are not showing the chance of rain until Saturday… BUT, there’s still plenty of time for that to change in the coming days.

Even though it’ll be warmer and dry, it won’t be 100% sunny the whole week. Expect to see some cloudy to partly cloudy skies at times; but don’t worry–we should definitely see our fair share of sun. There will be plenty of opportunities to go outside for a walk or bike ride–again, keeping your distance from others!

This week, it’ll finally start to feel more like Spring after a stretch of below-normal temperatures. In this time of uncertainty, I know it will lift the moods of many people. Just like the sun always eventually comes out, even after the darkest of days, we will eventually get through this.

In the meantime, I hope you stay safe and healthy.