Sunday, January 02, 2011

Jetstream Shifts Bring Powder

We were blessed (!?) with a massive snowfall on Thursday (Dec. 30), followed by some intense cold for a couple of days, which may have worked to keep the crowds down on the ski slopes. Now, though, the weather has cleared and the sun has come out; there should still be some significant powder up there, so optimal conditions for skiing approach.

The storm we got was the continuation of the one that dumped heavy rains and caused flooding in southern California. The storm's track shifted north at our longitude and headed for the upper Midwest.

Trying to understand a little about our fate and what drives it, we are inevitably drawn to examination of the jetstream--the high atmospheric current which circles the northern temperate zones with strong west-to-east currents. It is the north-south movement within the jetstream, though, which causes the aberrations like the current storm.

So would seem to be saying environmental scientist Judah Cohen, who posted an editorial called "Bundle Up: It's Global Warming" in the Times on Christmas, then followed up with a blog/discussion on their Opinionator site. He puts emphasis on fall snowfall in the Siberian hills north of the Himalayas as a driver of a shift in Arctic melting, which is affecting the jetstream path this winter, leading to colder weather and higher snowfall in the Eastern U.S. and in Europe. It is his view that the variable depth of fall snowpack in that region, rather than the oscillation between El Nino/La Nina (sorry, no tildaes) currents in the central Pacific, which is more of a causational factor for season-to-season climate variation.

Re-reading the article, I noticed an interesting additional point he made that I missed the first time: the variation in the jetstream is also vertical. Maybe I don't have it quite right--you should read up on it. Another thing you should do is come here--soon--and ski.

No comments: