Dark days for Seattle

As some of you know, I have my own weather station that I maintain in Seattle.  I post the weather observations online to Weather Underground and the Citizen Weather Observer Program for anyone who is interested in these observations.  But, mostly, the weather station is there for my own personal entertainment and use.  Here's what the station looks like.  It's very poorly positioned--on top of a fence and close to the side of my building, but it's the only place I have...

Yesterday evening I went to check what the temperature had fallen to outside when I noticed that most of the observations on the display were blank. This was puzzling...but looking at the Weather Underground archives it appeared that observations had stopped some time yesterday morning. Here's their time series from my station for yesterday:

You'll notice that the temperature and wind direction flatline several times overnight before going out completely around 9AM.  You'll notice, however, that the barometric pressure observations continued to come in.  It was puzzling until I recalled what the weather had been like for the past several days---overcast and dark.  We have been stuck under clouds for quite some time and, because the outdoor sensor is solar powered, it had been too long since it had a good re-charge and had stopped transmitting.  There is a backup battery in the unit that keeps the station running for a time, but that apparently will run out after some time.  I'll need to replace that battery...

So how dark has it been?  We can turn to another weather station for that answer--the weather station on top of the roof of the Atmospheric Sciences building at the University of Washington.  This weather station has a solar radiation sensor that reports how much shortwave radiation from the sun is reaching the station.  We can add up how much radiation the station received each day to get an idea of how sunny it has been.  Here's a plot of the total amount of solar radiation received each day since the beginning of the year.

Except for January 2nd, the first week or so of the new year was actually very sunny--on January 4th and 5th skies were mostly clear, and you can see that the station received nearly 5000 kilo-Joules per square meter on those days.  You'll notice though that since January 7th, we've been receiving far less--only around 1000 kJ/sq. meter--which is around 1/5 of our maximum possible solar radiation.  No wonder my weather station finally gave up...

Clouds have finally cleared out today, though, and solar radiation is up quite a bit.  Sure enough, this morning my weather station magically kicked back on as it finally had enough power to operate...

Lets hope for more sunny days to come...