'Morning Sunshine

I couldn’t see across the river this morning. Typical winter weather in the Columbia River Basin…cold air, moisture, and the bowl shape that we live in is conducive to fog and clouds getting in here and staying for days. From home I can look at the web cam at KRLD, which is 11 o’clock and a couple of miles from home. They don’t have a ASOS, but KPSC (8 miles to the east and a bit further from the river) is reporting:

KPSC 041453Z 01017G22KT 10SM BKN080 12/01 A2974

krld rwaywindsockbridge

Clearly the KPSC picture is a little different, and the picture on the far right shows the WA DOT traffic cam that is a little closer to that airport. It does show the winds are about what I thought, 15-20 knots. Dewpoint is off–maybe the river is adding the additional cooling and/or moisture that’s keeping the fog on the ground at KRLD. What I still find interesting is the combination of heavy fog and wind–this isn’t what the textbooks tell you is supposed to happen. The windsock at KRLD is standing straight out, and a 15-20 knot wind is supposed to pick that fog up and make it a low stratus layer. But I can’t see 1500 meters across the river, and the visibility at KRLD sucks.

If you’re still reading expecting me to give you an answer, sorry to disappoint. But I can throw in some other confounding observations. On the visible satellite (below, left) you can see the clouds filling the Basin as the sun comes up. From the east. Usually moisture comes into this region from the Pacific Ocean to the west. Low pressure to the southeast is the reason for the easterly winds, and I can only assume that the moisture was brought in here with the front. The other unusual thing is that the Cascade Mountains also form a barrier to low clouds, and if it’s a clear day here and IMC in Seattle, you can often see a north-south line of clouds formed by the terrain holding them to the west. That’s not what’s going on today though. On the IR satellite (right side), the clouds overhead are relatively bright. If I remember correctly, bright clouds on IR indicate colder, high clouds. Fog is low and warm, and doesn’t always stand out on IR. There must be a higher cloud layer obscuring the low fog layer around us.

The take-home from this, for the low-time pilot with little knowledge of real-world weather and a limited understanding of the local weather patterns, is that I might not be a happy camper if I’d planned on scooting over to KRLD this a.m. I’d have launched that way expecting gusty winds based on the KPSC ASOS, but with the winds and 8000 CIG/10 sm VIS reported, I wouldn’t have expected to find IMC (or, at best, MVFR) at KRLD. PIREPS wouldn’t have helped me (none are reporting sky conditions), and the few airports in this region are reporting VFR. If I was coming from the west, I’d have been faced with the decision to press on to KPSC and try to land there, or turn around and head back into the desert. In this case, having that WDOT weather cam at KRLD would have made a huge difference in deciding whether to make the flight or not. I wouldn’t have thought to include a weather cam in my pre-flight planning.

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