Weather Blog

Our natural air conditioning, seen from 23,000 miles up

Our natural air conditioning, seen from 23,000 miles up
A look at this visible map of Washington and you can plainly see it's a clear, sunny day around here. But there's also an important clue that shows the heat isn't going to stick around too long… See that little "finger" of clouds along the Oregon coast? That's a layer of fog, but more importantly, it's showing you exactly where our thermal trough is.  First of all, it might do well to read up on what a thermal trough is and how it works. We have a link to that in our Weather FAQ

That will show a hypothetical progression of how a trough works, and how that makes it  get hot around here. But looking at the visible satellite, you can see where our current one is.

Here is the image again, with me superimposing some data (using my *awesome* Photoshop skills!) First, here is the current position of the thermal trough.  (Taken at 1:00 p.m. Tuesday, August 5th.)



Since air flows toward low pressure, On the left/west side of the trough we have the cool, westerly wind, while on the right/east side, we have the hot, easterly wind:



And as a result, here are the current temperatures when this satellite image was taken:



So now that you see where it is, you can watch the script play out.

Here is the link to getting the current satellite image from the University of Washington.

The trough will move north along the coast Tuesday evening and night and that fog bank will follow it north. It will then move inland on Wednesday, eventually starting to cool off the interior by Wednesday night.   And as the clouds pass each city, you'll see their temperature plummet.

For current temperatures, novice users can use this link: http://www.atmos.washington.edu/data/WA_obs.html

More advanced or daring users can use this link: Temperature is under "T" and there is a link at the top of the page to give you a list of each city's weather code. The coastal sites are grouped together and they are the ones to watch plummet late Tuesday or early Wednesday.

Anyway, quite complex, but then, so is your home air conditioner. Oh wait, most of us don't have one of those :)