Sunday, February 22, 2009


Well, it looks like we will have a break in the weather tomorrow morning and afternoon, but later in the day the next system will start moving in (see the satellite picture). You see that swirling cloud mass off of California? That's it.
I show these picture a a word of explanation. This is an infrared satellite image taken by a geostationary satellite 35000 km above the surface. We get these pictures every 15 minutes. These satellite look at the earth in wavelength that the atmosphere is transparent (an atmospheric "window" in the biz). Basically, it is measuring temperatures...white indicates cool and dark indicates warm. Since temperature generally decreases with height, these images can tell us how how clouds are. And infrared pictures are available 24-h a day, unlike the visible imagery. These satellite pictures are the reasons why we always know where the big storms are now..compared to 50 years ago. In fact, the first weather satellite was launched in 1960...TIROS 1.
One of the major things I teach my students is how to be expert interpreters of such imagery...a key skill of a meteorologist. Humans are really excellent at pattern recognition, so after a few classes they gain quite a bit of skill. A frustration at time is to watch the occasional inexperienced TV weathercaster who points at the wrong thing on these images...generally one of the weekend folks. But I better stop before I get into trouble!

PS: Remember the KIRO TV weather special tomorrow night at 7 PM on the big December storm! I taped a segment on the coastal radar for it...we will see whether it made the cut.

1 comment:

andycottle said...

I will be sure and watch that episode tomorrow! Should be good and see what really happened in 2007.

As far as tomorrow goes, perhaps another day of sun breaks/ clouds. Kinda like today. Maybe even just as warm as I see the WRF-GFS for tomorrow shows 925mb temps at about +8c with S-SW flow and S-SE surface flow over central sound. And for it`s worth, it also shows highs in the upper 50 to perhaps lower 60`s.

I had a high of 61 today, so maybe another day in the 60`s for me? We`ll see! :o)