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!.

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