July 30, 2022

The Big Cooling is Weakened and Delayed. And some amazing temperatures today.

 I hate to tell you this, but the model solutions have shifted during the past several runs:  the result is that the major cooling will be delayed for several days.  Not good.

What has changed you ask?

 The forecasts from a few days ago had a sharp trough of low pressure moving through on Monday, forcing cooling from off the ocean (see the upper-level (500 hPa) forecast made Wednesday afternoon for Monday at 5 AM).

But this morning's forecast for the same level and time is very different, with the trough/low hanging off northern California and a weak trough approach from the west.  This is the kind of pattern that produces a modest step down of cooling, not the large cooling we originally predicted (and hoped for).  80s not 70s.

So to update with the bad news, here are the latest NOAA/NWS National Blend of Models (NBM) predictions for Seattle and Pasco.

For Seattle, 91F tomorrow and a still warm 84 for Monday, followed by a slide down into the lower 70s by Thursday.

Pasco in the Columbia Basin will be 111 on Sunday and still over 100F on Monday and Tuesday before the cooling into the upper 80s.

This is a relatively large change in forecast so close in time--we generally do better than this.  But there were hints--strong hints--days ago--that there was considerable uncertainty about Monday's temperatures.

A potential tool is the NOAA/NWS ensemble system in which the GFS model is run many times, each slightly differently.  The prediction of this system from Wednesday after is shown below, with the high-resolution forecast (which is normally used first by forecasters) indicated by the blue line.  For the first few days, all the forecasts were on the same page, giving us confidence in the (warm) forecasts,.  But starting on Sunday the forecasts had a lot of diferences...and thus uncertainty.

We (I) need to communicate this information better.

Finally, the temperatures today were pretty amazing.   Take a look at some of the high temps in Washington State (below).  Low to mid 90s around Puget Sound.  99F in Olympia and around 100F to the south of the Olympics.  Some locations on the lower wester slopes of the Cascades hit 100F and it got into the 90s in the mountains.  Hiking would have been brutal today.

Eastern WA was all above 100F, with some locations around the Tri-Cities getting to around 110.

In contrast, the lower 60s along the coast!

Oregon was even worse (see below)--around 100 in the Willamette Valley and some crazy warm temperatures of 112 and more near the Columbia River (I suspect some of these sensors).

And to make it all worse, the dew points--a prime measure of water vapor content in the atmosphere--were quite high in some locations, such as the western slopes of the Cascades where dew points hit 70F

I am heading to Puget Sound now where it show be much cooler!.


  1. We drove Hwy 84 along the Columbia today from Portland to Biggs, from 11 am-12:30 pm and our car thermometer (which seems to read a few degrees too hot) was reading 98-101. As soon as we crossed the river going into Washington, the reading climbed to 104.
    I console myself by thinking about how hot it has been with equally high humidity for weeks and weeks where my daughter lives in South Texas.

  2. Mid 70’s for highs…high 60’s for lows…San Diego!

  3. Hot as it's been, I'm still pretty happy to finally be having some summer after what really has been an extraordinarily wet year here at the foot of Mt Baker. It has been sultry for the last six days, true (from 7/26): 88.7, 96.8, 93.2, 95.4, 96.8, and 94.1 F. But LOWS have been coming down (from 7/26): 58.5, 60.4, 60.6, 59.4, 56.3, 52.5 F. I like that trend; the lows make it tolerable. The wild birds seem much happier this morning than they did a few days ago.

    It is - after all - summer. I was starting to wonder if we'd have a summer at all. 'Getting tons done. Some farmers are only now getting their first cutting of hay(!).

  4. "We (I) need to communicate this information better."

    In comparison with other public agencies i think you-all do pretty well. (then again some of us are fixated on actually reading useful resources like: https://a.atmos.washington.edu/data/disc_report.html )

    Conveying levels of uncertainty to the public ...well, *educating*, the public on levels of uncertainty: that's the challenge! I don't know, maybe come up with an emoji set of increasingly shrugged shoulders? -sigh-

  5. Thanks for the update. I was puzzled when the forecast for Monday suddenly jumped into the 80s, when I'd been so looking forward to a good cooldown.

  6. I had noticed that the heatwave kept extending by a day, then a day, then a day, but it was always low to mid 90's, then drop into the 80's before dropping into the 70's, but it always show it eventually rebounding to the low to mid 80's. and then extend out a good ways and today, it didn't change for a change, well, maybe a degree or two here and there, but essentially the same since I think yesterday.

    Yesterday morning, around 10-10:30, I went out to mow the front yard of mostly dandelions but the grass got cut too but the grass is not growing as readily as it had before July anyway and noted the humidity and temps I believe still in the mid to upper 80's and got the front quickly mowed and was hot and sweaty by the time it was finished.

    Today was not so bad, though I went out a bit earlier and got the back done. Will be glad to have it be pleasant for a change, even for a few days before we rise back into the 80's.


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