I don’t want to tell you this, but the model solutions have changed over the last few runs: as a result major cooling will be delayed for several days. Not good.
What has changed, you ask?
Forecasts from a few days ago have a strong low pressure trough moving through on Monday, forcing cooling from offshore (see upper level forecast (500 hPa) given at 5am Wednesday for Monday for Monday. ).
But this morning’s forecast for the same extent and duration is very different, with a hanging bottom/bottom in northern California and a weak approach to the bottom from the west. This is the kind of model that produces a modest cooling step, not the massive cooling we had originally anticipated (and hoped for). The 80s not the 70s.
So, to keep up 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 84 remain warm on Monday, followed by a drop to 70 lower on Thursday.
Pasco in the Columbia Basin will be 111 on Sunday and remain above 100F on Monday and Tuesday before cooling off in the upper 80s.
This is a relatively large change in forecasting very near time – we usually do better than this. But there were hints – strong hints – days before – that there was considerable uncertainty about Monday’s temperature.
One potential tool is a NOAA/NWS aggregation system where the GFS model is run several times, each time slightly differently. This system’s predictions from the following Wednesday are shown below, with the high-resolution forecast (usually first used 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 Sunday, the forecasts are heavily biased … and therefore uncertain.
We (I) need to communicate this better.
Finally, today’s temperature is pretty great. Take a look at some high temperatures in Washington State (below). Low to mid 90s around Puget Sound. 99F in Olympia and about 100F south of the Olympics. Several sites on the lower west slopes of the Cascades hit 100F and it went into the 90s in the mountains. Hiking today will be very brutal.
Eastern WA is all above 100F, with some locations around the Cities seeing temperatures reaching around 110.
In contrast, the 60s are lower along the coast!
Oregon is even worse (see below) – around 100 in the Willamette Valley and some insanely warm temperatures of 112 and up near the Columbia River (I suspect some of these sensors).
And worse still, dew points – the main measure of water vapor content in the atmosphere – are quite high in some locations, such as the western slopes of the Cascades where the dew point reaches 70F.
Now I’m heading to Puget Sound where it shows much better!.
