Thursday, February 6, 2014

Oregon Snow

I am writing this blog at 34,000 feet somewhere over NW Nebraska, as I return from the annual meeting of the American Meteorological Society in Atlanta.  Quite interesting to compare the Atlanta snow disaster last week to the kind of events we get west of the Cascades (and there are similarities!)

In my blog of Tuesday, I noted the potential for snow over northern Oregon...and the model forecast was correct--if anything it underplayed it a bit. 1-6 inches of snow has fallen over portions of western Oregon and over southwest Washington as far north as Longview as well.  Some VERY light snow has even gotten as far north as south Sound.

Here is the 6:30 PM radar image, you can see the heavier amounts around Portland/Vancouver...this area is lifting out to the east-northeast, so Seattle should not see anything.


This morning's WRF model forecast (started from data at 4 AM) was pretty reasonable...here is the 24 h amount ending 4 AM on Friday.  Some totals up to 8-10 inches...and this may prove to be quite accurate.

Why is the precipitation going south of most of Washington State?  Because the jet stream is directed south of us into Oregon and northern California.   (see map at 500 hPa, around 18000ft)

This is all extraordinarily good news, because the result will be substantial precipitation for our parched neighbors.  Here is the 72hr precipitation forecast for the 72h ending on Sunday at 4 PM.  Wow! Huge amounts (5-10+ inches) onthe Sierra Nevada and coastal range of CA.  Plenty in the central and southern Oregon Cascades.  Folks..this is going to really help the California water situation.  Western Washington is forecast to be dry.   Seahawks win, Seattle avoids Snowmaggedon--the gods are clearly with us.  Next Big Bertha will start working.


In fact, next week the models indicated are that California is about to be hit by a series of atmospheric rivers--currents of large amounts of moisture streaming out of the subtropics--that should continue the precipitation for quite a while.  Here is a sample of the moisture associated with the atmospheric river forecast to occur on Saturday at 4 PM.

The Golden State is about to turn green.

Want to see what the Portland area is like...here is picture taken by Steve Pierce at his house in Vancouver Washington...he is AMS Chapter president in Portland.


Finally, here is an interesting tidbit.  Atlanta has a lot in common with Seattle regarding snow problems.  They have lots of hills.  Significant snow is rare. They are generally warm enough so that the subsoils are fairly warm...which tends to melt snow into slush...then if it turns cold..they get ice.
And their mayor is in big trouble. 




13 comments:

immamatrace said...

I'm seeing a few tiny flakes here in Bonney Lake, Wa, any chance we'll see more than that? It's quite cloudy out there and I would love a good dumping. And a three day weekend! I love the snow!

Ansel said...

But when we finally do get precip- and we will eventually- with all this cold air, doesn't it almost have to start as snow?

If it doesn't my guess is- no snow this year at sea-level...

Josh said...

Bummer :-(

David B. said...

I beg to differ on it being "good news" to miss out on all the snow. If it's going to get cold, I'd just as soon see it get pretty and white.

immamatrace: I've seen the flakes here on Bainbridge Island, too. They're in the NWS forecast ("30 percent chance of snow before 11pm"). No, they're not supposed to amount to anything much, a dusting at most. Sorry.

rsumpter said...

oh no, is that what they call a 'pineapple express' that's going to hit central california?

Barb Shillinger said...

23 degrees here in Aberdeen at 11:30 pm. Looks like Grays Harbor is right on the edge of the "snowline," so, as usual, we'll have to wait and see. Is is SPRING yet???!!

Colleen said...

I'm with those who are bummed on the lack of snow. Very jealous of those farther south! So seriously tired of frigid temps, non-stop Fraser outflow winds ~ and nothing but dry ground to show for it. Boo, hiss!

Ryan said...

Spots here on the north Oregon Coast reporting up to 9 inches of snow from yesterday's snowfall (Manzanita, Wheeler etc). That's pretty remarkable!

Sra Mac said...

We are in northwest Bend, OR and its been snowing like gangbusters since yesterday -- light, fluffy powder and temps in the 20's. Perfect.

Michael Hammond said...

There is snow on the ground here in Tumwater, looks like less than an inch though. Temperature is around 18-20 degrees F.

Sulla said...

Looks like it will soon be time to post on how rare back-to-back winters of little to no snow are in the Northwest. This winter doesn't even know how to rain right.

Trevor said...

Ugh. Why does Portland get all the fun? So jealous. I guess I should be grateful for the 1 in. this morning in south bellingham.

Ben Green said...

Tonight's GFS and WRFGFS show some warm advection tomorrow evening/night, but model agreement is horrible.

This is important to note for those of us who remember the warm advection that caused the ice storm (seattle south)/snow storm (North of Seattle/Kitsap Pen) in 2012....it was not well forecasted either.
We will see.