Will there be a big windstorm tomorrow night?

 Update Tonight

There is an interesting ultra-local potential twist to this event.... a Hood Canal twist.   The storm is going to rapidly weaken and staff as it makes landfall, with it exact location making a big difference on the localized winds.

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I have gotten over a dozen emails asking about a potential storm.  The amateur sites are going into overdrive talking about the birth of a "monster storm" and other over-the-top descriptions.

So let's examine what the latest model simulations are predicting.

Before I do that, let me note that it was quite windy during the last several hours as a strong trough of low pressure moved through, creating a large north-south pressure difference over western Washington (see model forecast for 7 PM).  The solid lines are isobars of constant sea-level pressure.

This large pressure change produced some serious wind gusts (see max wind today below), reaching an impressive 63 mph at Paine Field in Everett.   Several thousand customers have lost power.

This is an appetizer for the meteorological buffet tomorrow.

Let me show you a series of forecast maps of sea level pressure for tomorrow.  We are close enough in time that this forecast should be reliable.

At 1 PM, an impressive-looking low center, with a central pressure of 982 hPa, is found west of northern Oregon.  For some perspective, this is not even close to the central pressure of the "bomb" cyclone in November (which got down to around 940 hPa).

By 10 PM tomorrow (Monday) night, the low has weakened slightly (to 987 hPa) and has moved towards the central Washington coast.    Very strong pressure difference (and thus winds) along the Oregon coast.

By 4 AM Tuesday, the low has weakened to 996 hPa and is crossing the Olympic Peninsula.

By 7 AM Tuesday, the low had weakened to 1002 hPa and located near Everett.

At 1 PM Tuesday, the low had greatly weakened and was now in NE Washington.

If this forecast is correct, Puget Sound will not see a major blow.  

One thing I have learned about such events is that rapidly weakening lows are rarely big wind producers.  Also, the trajectory of the low is not optimal for strong winds over Puget Sound and NW Washington.  Too far south.

Looking at the highest winds predicted during this event (below), the northern Oregon coast looks like the place to be for a strong blow, with gusts reaching 65 kt.   It's not so exciting over the western WA interior.  Gusts to 30-40 mph perhaps.

But a good forecaster never forgets about uncertainty and the forecast of this storm has varied quite a bit over the past several days.   One way to explore this uncertainty is by looking at ensembles of many forecasts.  

For example, the ensemble of many forecasts for wind at Seattle indicates that most of the solutions are for only modest sustained winds of about 15 kt (12Z/25 is 4 AM on Tuesday, the black line is the average of many forecasts, and winds are at the surface in knots)

In any case, there will be plenty of precipitation, which our region needs.