December 2015 in the Pacific Northwest

[TT-SEA]

Nah. Look at history. You don't have to wait for the PV to break up for the PNW to get cold/snow. In fact, it's often the wave breakers leading up to the PV destruction (or not) that causes Arctic outbreaks in the PNW.

 

Don't take it from me, Phil has mentioned this several times.

 

 

OK.   We will see.   Until the ECMWF shows something within 10 days... I will not be holding out any hope.

[BLI snowman]

 

Back on the weather front, this will not be the warmest December on record for the U.S. Even with very little high latitude blocking, warm anomalies across the country are going to take a big hit over the next 5-6 days. And it's looking increasingly likely that the next 7-10+ days will be quite cool across the West.

 

Might be some wishful thinking there camp. No meaningful cold anomalies across the vast majority of the lower 48 in the next week. Followed by a good likelihood for a huge Eastern ridge during Christmas week, with more Pacific air infiltrating the country.

[Front Ranger]

Snow down to the valley floor in southern OR this morning. My dad sent me this pic from their front yard in Myrtle Creek.

 

 

[Front Ranger]

Might be some wishful thinking there camp. No meaningful cold anomalies across the vast majority of the lower 48 in the next week. Followed by a good likelihood for a huge Eastern ridge during Christmas week, with more Pacific air infiltrating the country.

 

12z Euro through day 5. If this went through day 6, the eastern half turns much cooler. 

 

 

[Timmy]

Wet rain/snow mix up here now

[BLI snowman]

12z Euro through day 5. If this went through day 6, the eastern half turns much cooler. 

 

get_orig_img.png

 

We've had a great head start for a record warm month with the +EPO/+AO combination, and that warmth looks to continue almost unabated for the East. The West finally cools off this week but it's not going to make much of a serious dent in the widespread +5 to +10 departures thus far.

 

Either way it's way too early to feel confident about a national record, but it certainly fair to say that it looks like a pretty reasonable possibility at this point. 

[Front Ranger]

We've had a great head start for a record warm month with the +EPO/+AO combination, and that warmth looks to continue almost unabated for the East. The West finally cools off this week but it's not going to make much of a serious dent in the widespread +5 to +10 departures thus far.

 

Sure it will. A lot of anomalies will be cut in half or more in 4-5 days.

[snow_wizard]

Significant improvement on the 12z ECMWF ensemble in the to 8 to 12 day period.  Sharper + anoms over the NW GOA and sharper - anoms over the NW.

[snow_wizard]

Snow down to the valley floor in southern OR this morning. My dad sent me this pic from their front yard in Myrtle Creek.

 

FullSizeRender_7.jpg

 

What's the elevation there?

[snow_wizard]

Sure it will. A lot of anomalies will be cut in half or more in 4-5 days.

 

Especially with Wednesday progged to be so much chillier than earlier thought.  WRF says highs in the upper 30s on both Tuesday and Wednesday now.

[BLI snowman]

Sure it will. A lot of anomalies will be cut in half or more in 4-5 days.

 

On the West Coast or in the Plains? Wouldn't count on it. Maybe a few places in the Rockies. It still looks rather mild for what's getting to be the coldest time of the year. Then zonal flow makes a comeback around the 20th. 

[snow_wizard]

Huge improvement on the ECMWF ensemble between Christmas and New Years over the 0z run.   This might be something.  I have to post the graphics for that very sparingly and I already posted some ECMWF ensemble graphics earlier today, but it's considerably better.

 

Another great run for the ECMWF ensemble control model also.  Cold enough for snow at times during the 8 to 15 day period.  Besides that it has Arctic air starting to move down through BC.

[Phil]

I think something a lot of people have missed is the 12z GFS is considerably colder for Wednesday now that it was on previous runs. Pretty interesting to see that kind of change in such a short time frame. The change is strongly reflected in the WRF. We will have freezing low temps this week. The WRF strongly hints at some Hood Canal and North Interior snowfall this week.

 

BTW my basic prediction still stands. Cold and snow sometime between now and erly Jan. Earlier GFS runs had simply jumped the gun a bit. The 0z ECMWF ensemble was notably colder than previous runs and the control on that model looked very much like the 12z GFS late in the month. The models appear to making a move after a few days of frustratingly close, but no cigar solutions.

I'm not impressed. Need to either get rid of that Aleutian High or develop a solid Eurasian high, both of which promote wave-1 activity in the stratosphere via GWD/RWP. If we can tilt/weaken the PV, I could see something in the January 1-10 range.

 

However, if we fail to do so, then we're stuck with the +EPO/+NAM regime until the mid/late January flip to a -NAM, which will benefit the Eastern Half of the nation but not you guys.

[Front Ranger]

On the West Coast or in the Plains? Wouldn't count on it. Maybe a few places in the Rockies. It still looks rather mild for what's getting to be the coldest time of the year. Then zonal flow makes a comeback around the 20th. 

 

The entire West.

[Front Ranger]

What's the elevation there?

 

About 700' or so.

[SilverFallsAndrew]

What's the elevation there?

 

Myrtle Creek, Oregon has an elevation of 660'. Southern Oregon valleys are generally higher than the Willamette Valley, however, because they are further south and generally have no offshore influence (i.e. gorge) they generally average a bit warmer wintertime temperatures, and about the same if not less snow. 

[SilverFallsAndrew]

Looks like a potential atmospheric river event for SW Oregon/N CA later this week. These are 24 hour totals.Flooding on the Chetco.

 

http://mag.ncep.noaa.gov/data/gfs/18/gfs_namer_102_precip_p24.gif

[Front Ranger]

Myrtle Creek, Oregon has an elevation of 660'. Southern Oregon valleys are generally higher than the Willamette Valley, however, because they are further south and generally have no offshore influence (i.e. gorge) they generally average a bit warmer wintertime temperatures, and about the same if not less snow. 

 

That must be right by the creek. My parents are about a mile from there and just over 700'. 

 

According to the locals, they only see accumulating snow in that valley about every other year on average.

[snow_wizard]

Myrtle Creek, Oregon has an elevation of 660'. Southern Oregon valleys are generally higher than the Willamette Valley, however, because they are further south and generally have no offshore influence (i.e. gorge) they generally average a bit warmer wintertime temperatures, and about the same if not less snow. 

 

Pretty amazing they pulled off snow with the numbers we have today.  No reason there couldn't be surprises elsewhere in the coming days.

[snow_wizard]

That must be right by the creek. My parents are about a mile from there and just over 700'. 

 

According to the locals, they only see accumulating snow in that valley about every other year on average.

 

It would sure be nice if the Puget Sound region could pull off a surprise snow sometime.  It has been terribly frustrating up here the past few years.

[snow_wizard]

It's going to be interesting if the ECMWF ensemble mean begins to see support from the operational over the next few runs.  I'm not kidding when I say the 12z is way better than the 0z.

[BLI snowman]

The entire West.

 

Like in the PNW, where we will be lucky to see any daily departures below -4 or -5  in the next week and will probably see another mild storm train by next weekend?

[Front Ranger]

Like in the PNW, where we will be lucky to see any daily departures below -4 or -5  in the next week and will probably see another mild storm train by next weekend?

 

I said anomalies will be cut in half or more the next 4-5 days. Too soon to say for the extended.

[High Desert Mat]

Snow wizard, post the euro ensembles please. Would love to see what you're talking about.

[TT-SEA]

Wondering if this c-zone slipping south will bring some wet snow to my house this evening.

 

Just dumping snow at the pass right now.   

 

38 and drizzle here.

[MossMan]

That was about an hour of heavy rain up here, just starting to let up now.

[Bryant]

Wondering if this c-zone slipping south will bring some wet snow to my house this evening.

 

Just dumping snow at the pass right now.

 

38 and drizzle here.

It won't, no need to worry

[TT-SEA]

It won't, no need to worry

 

Probably won't happen.    Not worried.   Did not think about it until looking at the radar more closely.   

[Guest Winterdog]

The 18Z sure was a winner. Looking at the 2m temps, Sea hits 31F on the 23rd and that is the only freezing temp shown for Sea on the entire run.

[snow_wizard]

Snow wizard, post the euro ensembles please. Would love to see what you're talking about.

 

I have to do it sparingly.  I'm really not supposed to at all.  Let's just say there is good potential during the 8 to 15 day period right now.  Even the 18z GFS shows lowland snow as per the snowfall maps on Weatherbell.  One window around hour 102 and the other around day 9.  There will be some pretty good low level cold in place on Wednesday so something when the first moisture arrives after that could produce snow for some.

 

At this point though the period from 22nd through 28th looks really interesting.

[snow_wizard]

The 18Z sure was a winner. Looking at the 2m temps, Sea hits 31F on the 23rd and that is the only freezing temp shown for Sea on the entire run.

 

Wednesday morning looks pretty likely to freeze to me.  Way better than you are making it out to be.

[TT-SEA]

37.2 and falling as very large c-zone moves south just about to reach my location.   History tells me it will snow here in this situation... easier than the air mass would indicate.

[snow_wizard]

I'm not sure how some could see this as not good.

 

 

[MossMan]

37.2 and falling as very large c-zone moves south just about to reach my location. History tells me it will snow here in this situation... easier than the air mass would indicate.

There were reports of chunky rain around Camano and also the Oso area, even I noticed some lumps in the heavy PSCZ a bit ago so I have a feeling you might get a little something.

[MossMan]

I'm not sure how some could see this as not good.

Wow! I thought the 18z was a streaming pile??? I guess everyone sees things a little different when looking at the models.

[SilverFallsAndrew]

I thought the 18z was improved in the mid-range and a pooper scooper in the long range. 

[Guest Winterdog]

Wednesday morning looks pretty likely to freeze to me.  Way better than you are making it out to be.

It's just rinse and repeat. We may get some wet snow or a mixture in some areas just before Christmas but it is not looking like anything cold is going to take place. I'm not trying to be negative but I don't know how you can spin the 18Z as a good run. Yeah, it's better than most of last year and there is some promise with the ridge placement but so far it just looks uninspiring.

[Guest Winterdog]

snow_wizard, on 13 Dec 2015 - 3:47 PM, said:

Wednesday morning looks pretty likely to freeze to me.  Way better than you are making it out to be.

I hope it does. I will not like it if Seattle goes the whole month of December without a freeze. The 2m temps are not accurate I know but they are usually too cold in cold events. I'm just saying the 18Z shows only one freezing temp on the whole run. These last few posts make me feel like I'm channeling Tim.

[SilverFallsAndrew]

PDX closing in on another day of 0.25" precip.

[luvssnow_spokane]

It's just rinse and repeat. We may get some wet snow or a mixture in some areas just before Christmas but it is not looking like anything cold is going to take place. I'm not trying to be negative but I don't know how you can spin the 18Z as a good run. Yeah, it's better than most of last year and there is some promise with the ridge placement but so far it just looks uninspiring.

I do not see you as being negative at all. In fact you are being level-headed and honest in my view. We tend to have some who can swing wildly, either way. In fact I think we all can from time to time, but that being said I feel your view is realistic at this point. Personally, I feel if we see anything it will be quick, short, wet slop that may satisfy some as a winter "score" and others it may not. I do not see anything as being much more than that at this point based on models, averages, and the current global setup.

 

 Will it be 100% accurate? Who knows ... but in the end I think it is a fair assessment. BUT as my tag says "Epic is always possible...!"  and I hope it is. Heck, a white Christmas would be amazing!!!