Significant Aurora Possible Tonight

Update:

The situation does not look as favorable now.  The clouds have made it up to central Puget Sound (see below) and the DSCOVR satellite is not picking up the expected influx of particles.   

Not as skillful as weather prediction! 

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Folks in the northern half of Washington State may well see an impressive auroral display tonight.

A major Coronal Mass Ejection (CME) on the solar surface has resulted in a flux of particles moving into the earth's magnetic field.

A measure of the disturbance of the earth's magnetic field is Kp:  auroral activity moving southward into our area generally requires Kp of 5 or more.   The estimated value right now is 6.

And the predicted peak value is 7 between 8 and 11 PM tonight (see below)

The weather tonight should be relatively clear in northern WA state and southern BC (see visible image below), but some cloud debris from thunderstorms/showers now in northern Oregon may mess up viewing the southern part of WA state.

Here is an "expert tip" to help you decide whether to head outside in the dark.  

The DSCOVR satellite is between us and the sun and measures a variety of parameters that provide a 49-minute "heads up" for major auroral activity.   You can view this on the excellent space weather live website.   A sample is below.

Keep your eye on the second panel (plasma density).  If it goes up into the dark oranges or reds, then it will be worth a trip outside.  In the yellows right now (4 PM).

When and where to watch?

We are lucky that nighttime is expanding now, but it won't be dark enough to see an aurora until astronomical twilight (about 10:20 PM)--- two hours after sunset.

You need a dark location looking north.   My recommendation in Seattle: go to Magnuson Park and climb to the top of the kite hill.  Nice view north down Lake Washington.  The park closes at 11:30 PM.  If enough of us go, it should be safe enough.