December 2016 Observations and Model Discussion for the Pacific Northwest

[MossMan]

Would sure be fun to watch some snow falling at Centurylink on Sunday evening!

[MossMan]

Had my coldest high temp today of the season so far...43 degrees! Currently 41.

[Heavy Snow]

Good KING EURO run. Still lots of things up in the air but we should have a clearer picture in the coming days. Goodnight everybody.

[Gradient Keeper]

Considering how many warning shots, kill shots, flu shots, wrist shots, money shots, desk pops and aftershocks we're in for, people probably should pace themselves.

The Other Guys

[Gradient Keeper]

It would be nice to see some solid model agreement and continuity among GFS, GEM, ECMWF after day 4-5....Timing of precip, how the arctic trough digs, how the Kona Low, cut-off is handled, how the southeast US ridge builds, they all change run to run. No consistency. I guess the pattern is too complex for that.

[Gradient Keeper]

Day 10 get a little interesting....

 

http://maps1.pivotalweather.com/maps/models/ecmwf/2016120200/240/500h_anom.na.png

[Skagit Weather]

Still time for that to change! Perhaps a brand new trend starting with the 6z!!

Skagit Weather and Winterdog...thoughts on accumulations in our area?

 

The last couple winters have turned me from an optimist to a realist in regards to accumulation in my area. I think it's very likely that imby temperatures will be too warm on Sunday until the precipitation cuts off. You seem to get snow sometimes with the first arrival of the cold so I wouldn't be surprised if you get a quick inch of slop. I could see that weak Monday low shown bringing maybe another inch (more widespread around the North Sound), but as usual we will likely stay pretty dry.

 

I have no idea what to think for the overrunning event. Generally, up here I am shafted by the rain shadow and by the time the precipitation arrives (if it does) it almost always falls as rain. Even with some of the best overrunning events we have had I have barely managed more than 3" because I don't have the precip rates. However, I think you tend to do better with overrunning events and would not be surprised if much of the area (especially those under the Fraser influence) gets at least a few inches before switching over to rain.

 

Summary: I would be extremely surprised if you come out of this with less than 2-3" and it could be much more.

[VancouverIslandSouth]

The models are all handling the amount of precip differently. GFS much better scenario for whatcom county compared to the GEM which leaves everyone up north dry

 

The GFS, ECMWF and GEM all show the low in roughly the same spot on Monday. I can tell you based off numerous experiences any model that has a low in that position and has SE Vancouver Island completely dry in the face of arctic outflow is out to lunch in terms of precipitation. It's probably a resolution thing. Monday, as it's shown in tonight's runs is looking very promising, but the biggest winners will be favored upslope localized areas.

[Jesse]

[Gradient Keeper]

Wow... 00z GEPS 850mb/surface temp anomaly quite a bit colder than 12z... GEM wants to make this a snowy, memorable event.....

[HighlandExperience]

Best I got.

I'd be happy if we can squeeze an inch out of this. Not sure.

[Gradient Keeper]

00z ensembles looking good. Still some room for the airmass next week to get a little colder in the home stretch. Then the ensemble mean near or below average beyond that with some fairly cold members scattered in.

Yep agreed. I like how the mean temp is down to 0c when the precip arrives down from +2c previous run. Long range could change turn colder.

[Bryant]

Best I got.

Yuck... especially compared to previous runs

[Gradient Keeper]

Colder, snowier runs ahead! 

 

.......

I never said when, BUT..... yeah, well it covers my ***

 

GEM leads the way on this one.

 

 

6z in 2 hours 6 minutes

[snow_wizard]

CFS continues to look cold late Dec / early Jan on most runs.

[Perturbed Member]

Hmm Mark has a new forecast

http://lmgcorporate.com/kptv/weather/ibs_web_7-day.jpg

 

 

As per his comments, at least as of this afternoon he didn't think widespread snow Monday would be possible but he is on the fence because of all the models insisting on an inch or two.

[Perturbed Member]

PDX NWS

 

Post frontal showers behind a departing shortwave
will continue to bring snow to the Cascades and Foothills, with snow
levels lowering to around 1000 ft on Monday. Models continue to show
snow levels lowering below 500 ft on Tuesday as another cold
shortwave moves across the region. This is the good news for those
looking for valley snow. The bad news is that limited moisture and
cold air filling in through the Gorge may act to decrease the snow
potential. 

[MR.SNOWMIZER]

Cliff mass is going all out for a good amoint of snow. I think he is hitting the bottle again.

[Perturbed Member]

http://maps3.pivotalweather.com/maps/models/ggem/2016120200/108/sn10_acc.us_nw.png

 

00z GDPS snow totals for Tuesday. 

 

 

Through the end of the run

http://maps3.pivotalweather.com/maps/models/ggem/2016120200/240/sn10_acc.us_nw.png

 

 

No clue how good this model is.

[Skagit Weather]

Cliff mass is going all out for a good amoint of snow. I think he is hitting the bottle again.

 

Yeah, like others have said it seems out of character. His post from Tuesday was much more hesitant. It almost seems like he is putting too much emphasis on his probabilistic forecasting methods. Even if "all the models show at least 3 inches by the end of the period" that still does not mean it is set in stone. With this sort of set up, one day and a few slightly warmer model runs later, and half those models show zero snow.

[Bryant]

 

 

00z GDPS snow totals for Tuesday. 

 

 

Through the end of the run

 

 

 

No clue how good this model is.

 

 

That's the GEM 

[Perturbed Member]

That's the GEM 

 

Ah, I was wondering that since it had a Canadian flag on it. Good to know.

 

GEM looks nice for WA Thursday. Seems to warm the air aloft at PDX really fast. Pretty much goes straight to sleet and ZR.

 

26F there with a cold east wind at the surface as precip arrives

 

http://maps3.pivotalweather.com/maps/models/ggem/2016120200/162/sfct.us_nw.png

 

 

 

850mb about to go above freezing at the same time

 

http://maps3.pivotalweather.com/maps/models/ggem/2016120200/162/850th.us_nw.png

 

 

Quite the ice storm, should be interesting to see how this plays out.

[Bryant]

Ah, I was wondering that since it had a Canadian flag on it. Good to know.

 

GEM looks nice for WA Thursday. Seems to warm the air aloft at PDX really fast. Pretty much goes straight to sleet and ZR.

 

26F there with a cold east wind at the surface 

 

 

 

 

 

850mb about to go above freezing at the same time

 

 

 

 

Quite the ice storm, should be interesting to see how this plays out.

 

 

Shows potential during the overrunning event, but sure would be a bummer to miss out completely on Sun-Mon like the GEM depicts.

[Perturbed Member]

Shows potential during the overrunning event, but sure would be a bummer to miss out completely on Sun-Mon like the GEM depicts.

 

 

Yeah, at least the other models aren't quite as stingy with precip with that Monday low as the GEM for northern WA.

[Perturbed Member]

In case anyone cares, the 06z NAM is a bit faster with the cold at least at hour 60.

[Gradient Keeper]

6z Day 2 ... Slightly different Block/Kona Low configuration. It is sitting directly under the right axis. Need it to back

 

http://maps1.pivotalweather.com/maps/models/gfs/2016120206/048/500h_anom.na.png

[Gradient Keeper]

Nope. D**n Kona/Cut-off is shoving both the block and offshore ridge towards us.

[Gradient Keeper]

Worst run by far in many days. As soon as I saw the Kona Low right under the block pushing northeast I knew it was bad. We need that Kona west-southwest side of the block or just not existing at all. I hope it's not a trend, and it might not be. Another run, another entirely different 500mb progression.

[Bryant]

6z brings a bit more moisture into northern regions, with 3-4" from Whatcom to Snohomish county. Mossman, you're in a good spot it appears, as multiple runs have shown your location doing well. 6z has precip pushing in Monday morning at 12z / 10:00am and hanging around until evening.

 

Map valid through Tuesday afternoon

[Perturbed Member]

6z brings a bit more moisture into northern regions, with 3-4" around whatcom and skagit county. Mossman, you're in a good spot it appears, as multiple runs have shown your location doing well. 6z has precip pushing in Monday morning at 12z / 10:00am and hanging around until evening.

 

Map valid through Tuesday afternoon

 

Are these supposed to show the same thing? The whole run looks quite bad for PDX from what I can see.

 

http://maps1.pivotalweather.com/maps/models/gfs/2016120206/114/sn10_acc.us_nw.png

[Gradient Keeper]

There is no chance for any snow in PDX or any lowlands on this run. The flow is much more onshore aloft, the warm push would be strong. No chance. Probably not even east side of PDX where a -12mb PDX-DLS gradient pulls in cold air.... Onto 12z and let's hope they don't follow suit. If so it's probably "Game over" for any snow for us lowlanders.

[Bryant]

Are these supposed to show the same thing? The whole run looks quite bad for PDX from what I can see.

 

 

I'm not sure if Pivitol uses the same snow ratio calculations as tropical tidbits. It's all just for fun anyways because the snow totals are a craps shoot

[MossMan]

There is no chance for any snow in PDX or any lowlands on this run. The flow is much more onshore aloft, the warm push would be strong. No chance. Probably not even east side of PDX where a -12mb PDX-DLS gradient pulls in cold air.... Onto 12z and let's hope they don't follow suit. If so it's probably "Game over" for any snow for us lowlanders.

Are you just talking Oregon? The map that Bryant posted shows snow in my location still.

[Gradient Keeper]

Are you just talking Oregon? The map that Bryant posted shows snow in my location still.

I don't know about western Washington. I think places 500-1000'+ should see something.

 

I do have some crummy news. Well, that's not good. 6z GEFS 850mb/surface temp anomaly quite a bit warmer than 00z..... We'll have a better picture when the 850mb Ensembles are out in 12 minutes or so.

[SilverFallsAndrew]

Yeah wow the 06z was terrible. Not even a good run for my location at 1600' almost to warm even for me. Would be pretty cruel if the models took it all away at this late stage in the game. 

[Gradient Keeper]

Yeah wow the 06z was terrible. Not even a good run for my location at 1600' almost to warm even for me. Would be pretty cruel if the models took it all away at this late stage in the game. 

Good morning. Yeah, it would. I also realize 12z runs could bring the cold right back. I expect it too. The 00z GFS Op/GEFS, ECMWF Op/EPS, and GEM Op/GEPS were good. GEPS was the coldest yet. If it doesn't happen it will be a bummer, but it is what it is. It's just not that important.

[westcoastexpat]

CFS continues to look cold late Dec / early Jan on most runs.

 

Euro weeklies and CFS sub monthlies and monthlies all favoring a west coast torch in January, so I'm really hoping we get hit around the new year -- who knows how long we'll have to wait for a reload.

[westcoastexpat]

Looks like a possible flurry storm next week if we have enough moisture...best chance is probably with the last few dying showers on Monday morning. The transition event still looks pretty Gorge-centric to me with an outside shot of a mix at the onset of precip. Feel WAA will be quite strong with this system precluding snow in Portland unless the center remains south of us.

 

Areas above 1500' should see a good snowfall...several inches or more.

 

The post heard around the world.

 

Kind of a shame that an employed meteorologist in Oregon can't take a stab at a forecast for PDX in the medium range without getting destroyed for his "pessimism"... There are seriously nearly two pages of posts ripping that post to shreds like a mob of rabid, snow starved villagers with torches. "Hang that bloody heretic!"

 

I'd take Chris' analysis over the "I have a feeling the models are going to trend snowier"/"I have a sneaking suspicion the dry pocket is going to moisten"/"Even in a borderline scenario, my gut is telling me that it's going to start and stay as snow despite the models" analyses. I definitely want my doctor to stop chemo because he has a "gut feeling" the cancer will stop spreading.

 

I don't necessarily agree with Chris' forecast, but it's kind of outrageous that a met can't post a preliminary forecast without being told that they are "not accomplishing anything" -- I think posting a forecast with an analysis to back it up is accomplishing more than the "my palm is itchy so it's gonna snow!!!" posts, which set people up for heartbreak.

[Phil]

Euro weeklies and CFS sub monthlies and monthlies all favoring a west coast torch in January, so I'm really hoping we get hit around the new year -- who knows how long we'll have to wait for a reload.

Just saw the new weeklies..eww. Blowtorches most of the nation through January under a raging +EPO. That's definitely not something you'd expect in a weak -ENSO/+QBO. In fact, since 1950, no such pattern has occurred in January during a weak Niña/+QBO winter.

[westcoastexpat]

Just saw the new weeklies..eww. Blowtorches most of the nation through January under a raging +EPO. That's definitely not something you'd expect in a weak -ENSO/+QBO. In fact, since 1950, no such pattern has occurred in January during a weak Niña/+QBO winter.

Yup. It looks like November.

 

Simlar to a lot of the fall analogs I posted which all had cold December and return to nationwide warmth in January and February