A Sierra Special!

Map of NWS Watches/Warnings/Advisories as of 5 PM Pacific, 11/19/10

Wanted to discuss what’s about to unfold in the Sierra-Nevada Mountains of California over the next couple of days. Now, the Sierra get rocked every winter…and sometimes they get mind boggling snow amounts. But for some reason, every time it happens, I’m always floored by the numbers and the forecast. The map at the left shows the mess in the West…winter storm warnings for the entire Sierra Crest, mountains around Los Angeles, as well as northern California, Lake Tahoe, Carson City, and Reno. I’d classify this storm as “fun.” Let’s discuss how some of this will unfold.

Here’s one of the best forecasts ever…for the High Sierra (~ 12,000′) , just northwest of Mammoth. That’s 64-88″ of snow. The NAM model has been especially aggressive with this system, bringing extremely high amounts of precip to the Sierra Crest during this event. Here are a few maps..

Saturday Morning

Sunday Morning

Monday Morning

The first wave/cold front pushes through tonight and Saturday morning, dropping a fairly heavy amount of precip (liquid) on the Sierra. The second wave/front swings through Sunday morning, with probably an equal or greater punch. Wave #3 moves through Monday morning and should just be the “insult to injury” system. You have to remember how California is geographically set up. You basically have an 11-13,000′ wall sitting in the middle of the state and this soaks up any moisture on  a westerly wind component, which just allows them to wring everything out in those mountains.

The NAM model is admittedly ridiculously aggressive with QPF totals over 6″ on the northern crest by Monday evening. Using a standard 10:1 ratio of liquid to snow, that’s 60″ or 5 feet. But you would assume the ratios would be much higher so…yeah, you do the math. The GFS is a little more tepid, spitting out 4″ at max over the northern crest and “only” about 2.5-3.5″ liquid in the rest of the Sierra. That still comes out to close to 60″ when you factor in higher ratios. So the Sierra, Tahoe, etc. will get pummeled in this one, with 2-4 feet of snow on average above 8,000′ or so and lesser amounts in the lower high terrain.

We’re not quite done yet, as that Monday storm may be a sneaky one for the Northwest and deliver snow to Seattle or the area around it…and with cold air locked it, snow levels will get awfully low! Then that storm will move into the Rockies and places like Salt Lake City may get pummeled on Tuesday. An interesting start to holiday travel week!

Hitting the Links

Today is the one year anniversary of the debacle known as “Climategate.” Dr. Judith Curry examines if the climate science community has learned anything from it. There are a few good links to some other articles on the issue. Andy Revkin of the New York Times has a recap of what the last year has been like. While I don’t necessarily agree with how this was done, I think Climategate has done more good than bad for the long-term state of the science. It’s put things in perspective and helped curb the “science is settled” crowd to allow us to look at this with a wider focus before making economically destructive decisions. It’s re-opened a two sided debate and brought skeptics to the table. And that’s important for science.

Related: A departing Republican congressman from South Carolina fires a warning shot about dismissing climate change.

Eyjafjallajökull, the Icelandic volcano that messed up travel this summer, is the focus of a new paper in Nature that examines more about what was known about the volcano and what happened.

Today’s edition of the CIMSS Satellite blog shows ice and cold around Hudson Bay.

The Capital Weather Gang examines if the flood control plan being developed for a Flood Wall in Washington, DC is enough to do its job.

And from the photography side, time lapser Tom Lowe is putting together some truly beautiful and amazing scenes from the Southwest into a movie. Check out the site and some previews here. It really is some incredibly beautiful work.

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