Wednesday, December 14, 2016

Hard Freeze Will Soon Hit West of the Cascade Crest

You think it has been colder than normal?  It has been.  But even colder air will descend over the region by this weekend, dropping temperatures below 20F for a number of western Washington locations.   And lots of below-zero temperatures east of the Cascade crest.

We are talking about the coldest temperatures in 3-5 years for many locations.  A hard freeze capable of damaging plants and freezing some exposed pipes.

And then there will be snow tomorrow over Oregon, the southern Cascades, southwest Washington, and much of eastern Washington.  

Let's "warm up" by starting with the low temperatures on Tuesday (below). Upper 20s and 30s over western Washington, teens in the mountains, and single digits of NE Washington.  A few negative temperatures in some cold pockets, generally in valleys.  Before long you will be thinking of these temperatures as subtropical.

One way to show you the changes are with forecast maps of sea level pressure (solid lines) and 925 hPa (around 2500 ft) temperatures (colors).  Blues are very cold and purples you don't want to know about.

Currently, cold air is found east of the Cascade crest with cool air over NW Washington.
 By Friday morning at 4 AM, the air has cooled and extended over all of Oregon.

 Four AM on Saturday, the entire region is locked in the ice box, with very cold air pushing into CA and Nevada.

The latest European Center ensemble  and high resolution temperature forecasts suggest the HIGHS at Sea Tac airport will remain in the upper 20s on Saturday and the lows in the lower 20s.


Weather.com, which uses sophisticated statistics on top of combining a number of major weather models,  projects a high of 33 and a low of 21 on Friday.


Sea-Tac is NOT a cold spot and teens will be prevalent away from the water and particularly in low-lying locations.  Protect your pets, plants, and hoses.

And did a say something about snow?  Yes, I did!  A low pressure center will move across southern Oregon tomorrow, producing a shield of snow that will move across Oregon and SE Washington.

Here is the 24 h snow total ending 4 AM Thursday.  Eastern Oregon really gets it, with the eastern slopes of the Oregon Cascades BURIED with several feet of snow.  Folks around Mt. Batchelor will be smiling.  Portland may get a small piece of this, as might Yakima and the Tri-Cities.

But there is a bright light in all this.  Expect plenty of sun with the cold temperatures and believe it or not, sunset times are now getting later.  4:17 PM today and by Monday it will be 4:19 PM.  Unfortunately, it will still be getting darker in the morning until the winter solstice.

15 comments:

Unknown said...

Strong east winds and blowing snow for the past hour+ here in North Portland. 28 degrees and getting white.

richard583 said...

Kinda of similar to a "June Gloom" as I see it. Mainly having to do with the level and—relative—depth of cold more consolidated, held (holding.?) to the northern mid-latitudes, main Eastern Pacific and the West.

Unknown said...

It's been snowing and blowing in north pdx for a couple hours now; very wintry here about a mile from the Columbia River.

Bob said...

Technically, it will be "getting darker in the morning" until early January.

Scott K. said...

Is there not even a slight chance that wet system comes farther north and west? With recent forecasters grasping at anything that resembles snow in the puget sound region, I'm surprised this isn't happening again.

This kind of has me on edge, a lot of our extreme weather (big wind storms, big snow events) happen when not predicted.

Elston Hill said...

I believe it will continue to get dark later and later in the morning for a full week after solstice.

Ansel said...

Cliff do you care to comment on the asymmetry of Western Washington's annual temperature profile? Unlike other parts of the country, we have only about a five-month period from the annual maximum (end of July) to the annual minimum (about New Year's Day). This followed by a (slow) seven-month warm-up.

Whereas, in the east, for example, and over most of the country it is a nearly symmetrical curve, with a maximum about July 22 and a minimum about January 22.

David Chuljian said...

It won't be getting lighter in the mornings until the 31st. Solstice is merely the shortest overall day. It will be about Jan 3rd before the sun rises earlier

Aloha Rider said...

"Unfortunately, it will still be getting darker in the morning until the winter solstice."

Actually, the latest sunrise in Seattle is January 1st, not the winter solstice.

lhsouthern said...

We are getting a decent snowfall here in Chehalis@ 9:30pm 2 inches.

Unknown said...

About 2 inches in Vancouver. It seems to have stopped now. Started at about 1:45.

Scott K. said...

My instincts proved right again. We got more snow in N. Auburn last night than any of the previous snow predictions during the last couple weeks.

It continues to snow this morning at least as far north as Bellevue as of 10:30am

Mark said...

Forecast max and min temp for Barrow, AK today is +21F and +13 with light snow or about 26 to 30F above normal.

http://forecast.weather.gov/MapClick.php?lat=71.29057570200052&lon=-156.78871632799974&site=all&smap=1#.WFL6ZLkzWCg

Normal max/min for Barrow on Dec 15 are -5F and -17F.

By next week, our current cold streak will end.

windlover said...

Snow flurries all day today, and still flurrying at 6:00 p.m. Thursday in Eatonville...yet not even a little blip of moisture on the radar over our area....really weird! But I'm not complaining....just puzzled...

p206.1981 said...

In Seattle nothing remarkable or out of the ordinary has happened compared with normal December winter weather. I'm aware other locations are colder such as Vancouver BC in the upper teens F right now. In fact, Seattle's been well above the extreme traditional December cold experienced at times in years past, such as occasionally dipping below 20F at night, or not thawing during the day for three days in a row. As a matter of fact, even Seattle used to hit sub-15F from time to time. My Washingtonia palm tree that hasn't even skipped a beat with this so called cold weather.