What kind of weather phenomenon am I looking at? (AK wind visualization)

December 14, 2023 10:24 PM

It's a dark and stormy mid-December night and while it's not gale force, the wind is blowing pretty decently outside my home in Southeast Alaska. Wondering what I might expect for the rest of the evening, I pulled up a view of one of my favorite weather visualizers and was pretty intrigued by what appears to be an extremely straight, extremely long front of some sort extending from Baranof Island in the north part of the Alaska panhandle much more than a thousand miles south.

In fact, zooming out, it appears to extend almost as far south in latitude as Baja California does.

It's a huge weather system of some sort but not one for which I have a name.

Can anyone more knowledgeable about weather explain what I'm looking at in these two screen captures?

• Gulf of Alaska wind visualization, 14 December 2023
• Northern Pacific wind visualization, 14 December 2023

posted by Nerd of the North to Science & Nature (4 answers total)

The short answer is that it's a zone where large air masses are meeting and interacting. It helps to looks at a map that marks frontal boundaries that distinguish these air masses, each with it's own temperature, humidity, etc. (like this).
posted by late afternoon dreaming hotel at 11:46 PM on December 14, 2023 [1 favorite]

You can see here that it's a cold front.

Here is an animated wind map showing the relative higher pressure to the east with winds bumping into front and being pushed north.

I can't say there's a name for this.

Also, I believe the map projection on your images is somewhat distorting the 'shape' of the front into a straighter line. Though none of these maps is publishing their projection.
posted by j_curiouser at 12:09 AM on December 15, 2023

Small point of order, that isn't a cold front in the first linked map in the comment above. What's interesting is the progression that took place between the radar image I shared and the one shared above. When I shared an image, there was a stationary front being approached from the east by a warm front. The gap between those two was creating that apparent "wind tunnel" you're referring to. By the time j_curiouser posted another radar image, the warm from caught up to the stationary front and the system evolved into a single occluded front. Although the wind map makes it look like there's some crazy wind wall happening at that occluded front, keep in mind that it's representing trends in wind direction across a two dimensional spherical surface, without capturing any vertical component. In all likelihood, you're seeing cold occlusion in action, in which case the warmer winds coming from the east are approaching the frontal boundary and being redirected to trend vertically (and subsequently enter a different type of dynamic relationship as pressure and temperature drops and the air mass interacts with different zones of the upper atmosphere).

Cool detail to notice!
posted by late afternoon dreaming hotel at 10:13 AM on December 15, 2023 [3 favorites]

Thanks!
posted by j_curiouser at 11:33 AM on December 15, 2023