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.