December 2016 Observations and Model Discussion for the Pacific Northwest

[MossMan]

Puget Sound looks good for some decent CZ/frontal stuff.  You guys deserve it.  

That is the nicest thing you have ever said to us!

[HighlandExperience]

I believe I will end up with about 1 to 3 inches of snow with the initial push this weekend. Would love more but I will take it.

We better go into this with snow on the ground. Remember how painful feb 2014 felt with bone chilling temps and zero snowfall.

[Gradient Keeper]

The snow on the GFS beyond day 10 is... hard to comprehend how much. There is high confidence the block sets up remaining for a long persistence..... so these possibilities we see beyond day 10 I would say are higher than normal due to stable pattern upstream.

[MossMan]

We better go into this with snow on the ground. Remember how painful feb 2014 felt with bone chilling temps and zero snowfall.

I don't remember Feb. 2014 at all...kind of like Dec. 2009...not memorable at all without snow.

[luvssnow_spokane]

We better go into this with snow on the ground. Remember how painful feb 2014 felt with bone chilling temps and zero snowfall.

I believe we will avoid that this time, but I honestly feel if that happened again we would have a lot of pissed off people here. 

[luvssnow_spokane]

I don't remember Feb. 2014 at all...kind of like Dec. 2009...not memorable at all without snow.

Ya same!  There was nothing about either of those. I have a feeling this upcoming event has the potential to be as memorable as 2008 for us.

[ShawniganLake]

I believe we will avoid that this time, but I honestly feel if that happened again we would have a lot of pissed off people here.

The track of that low looks pretty good for the puget sound to get a couple inches. Looks dry for myself. Unless I see some outflow enhancement, I expect to likely go into this snowless.

[Kayla]

Why is it that a certain two members fall quiet when their holy grail model caves??

[snow drift]

My dream is to see a repeat of Jan 13, 1950. Lows that experience cyclogenesis over land are my favorite. Unfortunately, they aren't common in our region.

[BLI snowman]

My dream is to see a repeat of Jan 13 1950. Lows that experience cyclogenesis over land are my favorite. Unfortunately, they aren't common in our region.

 

Long range models have been toying with a similar pattern to the one that produced that.

[Gradient Keeper]

Want more good news?

[Deweydog]

Want more good news?

You're pregnant?

[FroYoBro]

Want more good news?

 

You just saved a bunch of money by switching to Geico? 

[Gradient Keeper]

You're pregnant?

Shockingly, no

 

You just saved a bunch of money by switching to Geico? 

I'm more of a progressive Flo fan...

 

Okay, so

 

12z GEFS Surface Temp anomaly through day 8 incredibly cold, much colder than any other run.

[snow drift]

Long range models have been toying with a similar pattern to the one that produced that.

In late Dec 2010 we had a low bomb out over the Spokane-CdA area. It changed from rain to snow in the morning and dropped a healthy 11 inches by nightfall, where I lived at the time.

[Jesse]

You're pregnant?

I don't know why but I laughed the hardest at that than I have at any post in awhile. It caught me off guard.

[Gradient Keeper]

I don't know why but I laughed the hardest at that than I have at any post in awhile. It caught me off guard.

Always be prepared if Dewey is lurking

[SilverFallsAndrew]

Why is it that a certain two members fall quiet when their holy grail model caves??

 

Maybe because we have jobs...

 

I am thrilled by the GFS...The GEM looks amazing too. Can't wait to check out the WRF!

[Jesse]

Andrew doesn't seem to have much to say about my location?

Not as fun for some when everyone looks to score.

 

Although for me that is the best time. Nothing like the whole region/forum hitting paydirt.

[Heavy Snow]

I just woke up and saw all the post about the 12z GFS and GEM. Thank you to everybody, it makes it easier to just look at all the posts and see what the models look like right away. The 12z UKMET continues to look good. Right now I'm cautiously optimistic, knowing while the models look good we are still a long ways away. I'm hoping we get a solid 12z EURO run.

 

http://img.meteocentre.com/models/ukmet_amer_12/GZ_D5_PN_120_0000.gifhttp://img.meteocentre.com/models/ukmet_amer_12/GZ_D5_PN_144_0000.gif

[Timmy]

I don't know why but I laughed the hardest at that than I have at any post in awhile. It caught me off guard.

I think I am becoming deweys biggest fan.

[Deweydog]

Not as fun for some when everyone looks to score.

 

Although for me that is the best time. Nothing like the whole region/forum hitting paydirt.

Most people's paydirt is only paydirt if the paydirt appears likely to be covered with snow.

[stuffradio]

Most people's paydirt is only paydirt if the paydirt appears likely to be covered with snow.

When can I plant my peas? Jesse wants to know!

[SilverFallsAndrew]

I love it if EUG or SLE score even if I don't. Salem actually did quite a bit better than me on the 14th, I thought that was cool because a big snowstorm like that is unusual there. I have been rooting against PDX since January 1998.

[Timmy]

Why is it that a certain two members fall quiet when their holy grail model caves??

Job, newborn, spent too much time on weather yesterday. Part of me actually wants this thing to fail just so I can be right now. But I'm glad the gfs gave a little and hope it continues to do so. I was never rooting for the gfs, it just made me less optimistic. I'm done responding to people about this "issue" because some people can't understand that.

[SilverFallsAndrew]

This looks like it could be a good event. I hope valley locations can score something at onset. It's going to be tough, but the 12z shows there is a chance. 

[snow drift]

I would love to see this overachieve.

[Timmy]

Not as fun for some when everyone looks to score.

 

Although for me that is the best time. Nothing like the whole region/forum hitting paydirt.

jealous much?

 

I love it, but I feel less need to post and raw raw raw when everyone is doing it. I engage in discussion more when it isn't so one-sided.

[Gradient Keeper]

❄ ❄ Happy Holidays ❄ ❄

12z GEFS

Surface Temp anomaly

HR 132-240

Coldest yet by far. Look for 850mb Ensembles to improve in the 5-10 day range.

 

Animated Gif - http://imgur.com/dZaaz0J

[BLI snowman]

WRF shows a rain to snow transition on Sunday morning. Maybe a quick inch.

[SilverFallsAndrew]

Job, newborn, spent too much time on weather yesterday. Part of me actually wants this thing to fail just so I can be right now. But I'm glad the gfs gave a little and hope it continues to do so. I was never rooting for the gfs, it just made me less optimistic. I'm done responding to people about this "issue" because some people can't understand that.

 

Yeah no need to defend yourself. 

 

I never even said this was going to fail, just said we shouldn't discount models because we don't like them. People are so defensive because deep down they are worried it will bust. The good news is things look on track for at least some cold weather. And could be decent snow above 1000'. 

[Gradient Keeper]

12z WRF

10 PM Sunday

Here she comes!

 

http://www.atmos.washington.edu/wrfrt/data/2016122812/images_d2/slp.114.0000.gif

[Gradient Keeper]

Interesting snippet from NWS Seattle morning AFD:

 

And that is where the headaches begin. ECMWF and GFS

fall out of lockstep for Saturday and Sunday...which given the

incoming colder air and the precip associated with the incoming

system...results in a fair number of possibilities for the New Years

Eve/Day timeframe. ECMWF is more progressive and colder with the

system...but overall less precip while the GFS has more precip...is

slower and slightly less cold. Given trends in both

models...currently more inclined to lean toward the GFS

solution...which would start the event as rain on New Years Eve then

changing over to snow during the early morning of New Years Day.

This sort of timing actually takes the edge off of the greater

precip amounts of the GFS...placing the bulk of precip more during

the rain phase...but should rain end up being too much too

fast...that could actually help the chances for transition to snow

earlier. If that sounds like hedging or indecisiveness...welcome to

the fun of trying to forecast snow. As touched on briefly before

laying out the scenarios...inclined to lean toward GFS due to its

more consistent progs. But even with GFS`s own difficulty in guiding

in regards to transition times...as it seems to be an hour or two

off using the previous instance as a mental milepost...inclined to

side with later timings. Definitely too early to suggest

amounts...but current thinking is to pare back a little bit on

inherited forecast...bringing lowland snow amounts more in the 1 to

1.5 inch range. Will make final decision on that with 12z run.

I can tell this was made before 12z because Sat-Sun both models are now in agreement literally mirroring each other

[SilverFallsAndrew]

12z WRF

10 PM Sunday

Here she comes!

 

http://www.atmos.washington.edu/wrfrt/data/2016122812/images_d2/slp.114.0000.gif

 

Confidence is starting to grow that Monday will be a solidly cold day...

[MossMan]

48hr snow totals from 12z WRF aren't too shabby. 2-4 inches for EPSL. I'll take it.

 

Also grabbed the map for 1AM Sunday. Nice CZ look. If we can get a CZ going, those can be extremely unpredictable.

 

http://www.atmos.washington.edu/wrfrt/data/2016122812/images_d2/ww_snow48.120.0000.gif

 

 

http://www.atmos.washington.edu/wrfrt/data/2016122812/images_d2/ww_snow3.93.0000.gif

I am ok with that map!

[Deweydog]

Confidence is starting to grow that Monday will be a solidly cold day...

[MossMan]

I can tell this was made before 12z because Sat-Sun both models are now in agreement literally mirroring each other

The forecaster even mentioned that...

 

Area Forecast Discussion

National Weather Service Seattle WA

930 AM PST Wed Dec 28 2016

 

.LONG TERM...And that is where the headaches begin. ECMWF and GFS

fall out of lockstep for Saturday and Sunday...which given the

incoming colder air and the precip associated with the incoming

system...results in a fair number of possibilities for the New Years

Eve/Day timeframe. ECMWF is more progressive and colder with the

system...but overall less precip while the GFS has more precip...is

slower and slightly less cold. Given trends in both

models...currently more inclined to lean toward the GFS

solution...which would start the event as rain on New Years Eve then

changing over to snow during the early morning of New Years Day.

This sort of timing actually takes the edge off of the greater

precip amounts of the GFS...placing the bulk of precip more during

the rain phase...but should rain end up being too much too

fast...that could actually help the chances for transition to snow

earlier. If that sounds like hedging or indecisiveness...welcome to

the fun of trying to forecast snow. As touched on briefly before

laying out the scenarios...inclined to lean toward GFS due to its

more consistent progs. But even with GFS`s own difficulty in guiding

in regards to transition times...as it seems to be an hour or two

off using the previous instance as a mental milepost...inclined to

side with later timings. Definitely too early to suggest

amounts...but current thinking is to pare back a little bit on

inherited forecast...bringing lowland snow amounts more in the 1 to

1.5 inch range. Will make final decision on that with 12z run.

 

Behind all of that hullabaloo...models re-align for cold and dry

conditions over W WA...with sub-freezing afternoon highs for the

first half of next week. SMR 

[BLI snowman]

Confidence is starting to grow that Monday will be a solidly cold day...

 

Could even see a freeze if things break just right.

[SilverFallsAndrew]

Big time ensemble improvement.

[Gradient Keeper]

❄ ❄ Happy Holidays ❄ ❄
12z GFS 850mb Ensembles
Portland, Seattle, Yakima, Vancouver BC

 

DRAMATIC improvement! WOW
Mean temps: PDX -11c, Seattle -13c, Yakima -17c, Vancouver BC -13c

This is quickly turning into a prolonged, significant blast and cold snap!