Update: Excessive Heat Warning Issued, All-Time Records Likely

Thursday was likely the coolest day for the next 10+ days. Below are Thursday’s high temperatures, mainly in the low 80s around the area.

Now, take these temperatures and add 20-25 degrees, and you have Sunday & Monday’s temperatures.

Due to the upcoming heat, the Excessive Heat Watch has been upgraded to an Excessive Heat Warning. This is the highest type of heat alert. 

It is in effect from 2 PM Friday to 1 PM Monday. Excessive heat is very dangerous, and it should be taken seriously. The National Weather Service has done a good job of portraying the dangers of this heat wave.

Below are likely temperatures for the valley and non-valley areas from Friday to Monday. I have compiled these from 5-8 forecasts.

Friday: 

Valley: 88-92°

Non-valley: 86-90°

Saturday:

Valley: 97-103°

Non-valley: 95-100°

Sunday:

Valley: 105-110°

Non-valley: 102-108°

Monday:

Valley: 105-110°

Non-valley: 103-110°

For many residents, these will be the hottest temperatures they’ve experienced here. As you can see, Sunday and Monday will be the hottest days. All time records will likely be broken across the area, especially Seattle southward, where it will be the hottest. Take 2-5 degrees off these temperatures near Puget Sound.

Low temperatures will also be very warm, and the warmest night ever is likely for the Puget Sound area on Sunday night. Expect low temperatures of 65-75° from Friday night to Monday night. This will likely break the all time record high minimum temperature of 71°.

Before we get to all-time records, let’s take a look at NWS Seattle’s probability forecast.

These charts show the high confidence for very hot temperatures in the coming days. Confidence is lowest for Monday, but expect that to verify soon.

Now, a quick look below at daily, monthly, and all-time records for Western Washington. The chart below from NWS Seattle shows records for selected cities.

Many of these records will be broken, some by large margins, during this heat wave.

One notable tidbit: Seattle’s official observing station (Sea-Tac Airport) has a forecast high temperature of over 103°, so Seattle will likely join Portland and Olympia in breaking their all-time record high.

I mentioned in an earlier blog that only 34% of Seattle area homeowners have air conditioning. Because of this, it is good to have some tips on how to keep your house/apartment cool without air conditioning. This informative graphic from NWS Seattle shows some of these tips.

Try your best to stay safe & stay cool! Another good way to look at the risk for heat is from the new NWS HeatRisk product. For the next few blogs, we’ll look at the next day’s HeatRisk. But first, below is an explanation of the HeatRisk scale.

Click here to find HeatRisk for the next 7 days in Western Washington.

Below is the HeatRisk forecast for Friday. Expect a Moderate risk for most of the region.

One more thing…is “relief” in sight? Short answer: relief from extreme temperatures comes by Monday, but temps remain elevated for awhile. Marine air moving in late Monday will drop temperatures to the range of 85-90 degrees, but highs likely remain above 85 degrees through at least July 5th.

Many people in Western Washington consider 85°+ as “warm” weather, so this will be a long-duration and potentially dangerous hot spell. Make sure you are taking every chance to stay cool and stay safe.