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Anybody driving tonight or otherwise PLEASE READ THIS THREAD


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I got this from our forecasters here reporting what the weather system is going to do within the next 90 to 150 minutes and wanted to give you guys forewarning. Keep in mind this is from my work so disregard any comments regarding laptops or what have you. This is going to get really REALLY bad tonight with 2 artic fronts moving in back to back and one with temps 20 degrees lower than the first. Our forecasters are very accurate as our production rely's on it. I have seen them peg the weather repeatedly where local weather has been inaccurate. I really don't want to see any of you get hurt tonight or tomorrow from not being aware of what to expect.




We have this system on our radar (quite literally) now and are becoming confident that we know what is going on. We’re now forecasting from observations; model details are clearly lacking.


I’ll save you the meteorological analysis but have to tell you this is one of the most interesting and unique weather situations I’ve ever seen. The arctic air is rushing off Vancouver Island and swinging around the low pressure system that is just starting to move inland across the Chehalis Gap area. While Arctic air coming from this direction is not terribly unusual (it’s the best set up for snow in Seattle if the low was further south), what is unique is that this air is easily cold enough on its own to produce snow at sea-level even though it is moving over water in the 50’s. I’ve never seen that in Portland.


Here are the facts for right now:

1) The arctic boundary has passed Astoria and lies along a line roughly from Astoria to Chehalis.

2) The temperature gradient across the boundary is amazing. It is currently 24 F in Everett, 32F in Chahalis and 40 F in Vancouver, WA

3) Temperatures on the coast are amazing. 23F at Forks in WA, 34F in Hoquiam despite 20 knot winds off the warm ocean, 36 F at Astoria despite 40 knot gusts off the ocean. Snowing showers at all three.

4) Assuming it doesn’t stall the boundary will be passing our area within 90 to 150 minutes depending on where exactly in the metro region you are.

5) There is a band of showers along this boundary and they are all falling as snow. Temperatures in these showers are 32 to 35 F and falling.

6) Within an hour of the boundary passing temperatures will be at or close to freezing and dew points will fall dramatically.

7) There is a second area of moisture behind the front, this is my chief concern – see below.




Here are the facts for tomorrow.

1) It will soon be cold enough for accumulating snow in the valley

2) Tonight will be well below freezing and roads are current very wet

3) It is unclear how much moisture there is behind the cold air and hence how much snow there will be.


So based on these facts:

A) Best case, roads will be slick in the morning commute and lots of extra time or use of public transit should be recommended.

B) Worst case, there will be 2 to 3 inches of snow falling on top of very wet roads which will freeze and compress into a layer of ice making travel not recommended.

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