CHANGES ON THE HORIZON

The majority of our weather comes from the west and today if you looked to the west you could see it coming. I took this picture around noon. Notice how the sky is sort of split in two. There was blue on the top part and white below. It made a pretty clear line in the sky.



The orange dot on the satellite image is about where I took the picture in Kirkland. It is looking across lake Washington at the city of Seattle. I drew an orange line on the satellite image where I believe to be the front edge of the clouds in the previous picture. The thin clouds to the east of the orange line are also visible in the previous picture.



Some of the thin clouds were thick enough to produce a halo around the sun. As expected the rest of the clouds moved in later in the day consuming the blue sky. These clouds are ahead of a weak weather system that is expected to bring Seattle at least a little bit of rain Wednesday.

ON THE WATER… Calm but warm

I was on a sailboat today shooting a segment that will air in June on KING5. It allowed me a great vantage point for watching the sky.



It was a perfect lazy day for these sea lions. Notice how calm the water looks. The glassy appearance indicates that it was a bit too calm to give the sails a workout but it was still nice just to be out there.

Overhead there was a nice halo around the sun. A halo forms when sunlight is refracted through the ice crystals that make up these high clouds.

It was a bit hazy on the horizon but there is still nothing like seeing Mt. Rainier from the water.

I hope you enjoyed this weekend as much as I did because we are heading back to more typical spring weather this week.

CONTRAILS A sign of change

It seems our spring time weather changes as fast as the jet planes flying overhead. In fact, we can look to the contrails produced by those jets as a signal for coming changes in our weather.

First it is important to understand what exactly contrails are. They form when water vapor is emitted as a byproduct from a jet engine. The water vapor condenses in the cold air and forms a cloud (made of ice crystals). Most contrails form in the upper levels of the atmosphere, above about 25,000 feet (more than 10,000 feet higher than Mt. Rainer).

If the atmosphere is dry then the cloud will dissipate quickly, or a contrail will not form at all. If there is a lot of moisture in the atmosphere then the contrail will last much longer. So the longer it lasts, the higher the humidity.

Increasing moisture in the upper levels of the atmosphere is usually a sign of an incoming weather system. I took these pictures during the early afternoon, notice the blue skies. By dinner time the skies were totally white and the front was just offshore with rain falling at the coast.



Another sign we have increasing moisture in the upper levels is when we see a halo or ring around the sun. In this case you can make out a faint rainbow at the base of the ring with contrails below.