Monday, March 25, 2019

Aurora Forecast Bust and Dry Western Washington

Well, I have to admit disappointment, both in the lack of auroral activity over Washington on Saturday and the poor forecast by the NOAA Space Weather Center of the Planetary K-index, Kp, which is used to characterize the magnitude of geomagnetic storms.

As noted in my last blog, there was a solar disturbance last Wednesday and the NOAA center predicted that that impacts would be felt on Saturday, with the potential for an evening aurora.

The forecast of Kp made the day before is shown below, with the verification right below.  Values over roughly four suggest a moderate geomagnetic storm that might provoke some decent auroral displays.  The initiation was predicted to occur Saturday morning (18 h is 11 AM).

But what occurred was much less and much later.  The "event" started on Sunday afternoon and was only reach a Kp of 2.

There was some minimal auroral activity Sunday night, but not in our area. 

Well, I suspect that predicting the propagation of particles from the sun to the earth is far more difficult than weather prediction, so I won't be critical of the NOAA folks.  Still disappointed though.

And we are getting some light rain tonight, which is welcome.  The last month has been dry for western Washington, in some places more than 4 inches below normal.  But most of the west has been wetter than normal, particularly around the Bay Area.

As shown in the cumulative one-month rainfall below, Sea Tac Airport received roughly 2.5 inches less than normal (cyan is normal, purple is observed)
But Pasco, in eastern WA, was about right:
The dry conditions in western Washington were very obvious over the weekend when I was busy turning over the soil in my vegetable garden....the soil was quite dry through depth. Sure enough the soil moisture anomaly (difference from normal) for yesterday showed drier than normal soil conditions.  And one good thing about the rain--it should lessen the pollen count a bit.