Part I - January 2020 Weather Discussion for the PNW

[Kayla]

I've found that it is best to look at precip totals along with temp profiles to get an accurate snow accumulation estimate than to rely on the 10:1 ratios or Kuchera ratios on the models.

 

This is especially true for out here where we are looking at 40-50:1 snow ratios. 

[Rubus Leucodermis]

Getting hard to ignore the crazy totals being shown. Last feb showed this and look what happened. Not saying it will but this is the only 2 times i have ever saw these high totals shown over and over. 

 

Last February it was the Euro that was showing such totals. This time it is the GFS. If it was the Euro again, I’d take things more seriously. Also, last February the Euro stuck with that story even as the time frame closed in. We’re still a week out from most of that snow.

[SilverFallsAndrew]

GFS ensembles are about the same through the 16th, a bit warmer after that. Not as many members fall below -10C. Operational seems to be fairly in line with the mean. 

[TT-SEA]

I've found that it is best to look at precip totals along with temp profiles to get an accurate snow accumulation estimate than to rely on the 10:1 ratios or Kuchera ratios on the models.

 

This is especially true for out here where we are looking at 40-50:1 snow ratios. 

 

I do the same... check 850mb temp and precip amounts.    I generally ignore GFS snow maps.   ECMWF is way better.

[Frontal Snowsquall]

[Front Ranger]

Anyone remember how the FV3 performed compared to the old GFS last February? 

 

Not a completely fair comparison to the current GFS, since further enhancements were made to the FV3 later in the year. But still might interesting.

[TacomaWaWx]

Wet morning...up to 0.52" here...1.76 now for January. We're also riding a 7 day rainfall streak currently.

[Frontal Snowsquall]

GFS snowfall maps are almost always overstated... and sometimes dramatically. Particularly over long periods of time.

 

They are almost as useless as the surface temp maps from the GFS.

Yeah, fun to look at for now.

[Kayla]

I do the same... check 850mb temp and precip amounts.    I generally ignore GFS snow maps.   ECMWF is way better.

 

Yeah, the GFS seems to really struggle with snow maps for whatever reason.

 

ECMWF is definitely the way to go and even the NAM once within range. Both of the those models pick up on low level dynamics much better.

[SilverFallsAndrew]

Anyone remember how the FV3 performed compared to the old GFS last February? 

 

Not a completely fair comparison to the current GFS, since further enhancements were made to the FV3 later in the year. But still might interesting.

 

I might go back and take a look at the February thread, but if I recall it was generally colder and more extreme. And had some absolutely ridiculous snow maps. I think it showed Eugene getting 40"+ with that one storm...Of course there were some pretty big storms...

[SilverFallsAndrew]

One of the GFS ensembles drops to -19C. 

[Skagit Weather]

9 am SEA AFD long range:

 

.LONG TERM /THURSDAY THROUGH SUNDAY/...Although the bulk of this
forecast was focused on the impactful near term, there are several
things to note in the long term. The long term period begins on
Thursday, where the local area will be under the influence of NW
flow aloft in the wake of the Oregon shortwave. A weak speed max
is forecast to dive south from W British Columbia and quickly
graze the area. It appears strong enough to enhance shower
activity across the area before it continues south. Snow levels
are rather low, especially across the northern CWA enough to
mention chance of some light rain/snow. Elsewhere in the lowlands,
looks like some chilly rain showers. It should be noted that
overall moisture is not impressive with this quick clipper type
system given its continental influence.

Next organized cold front is on tap for Friday. Given the current
track of this system, looks to be enough Pacific influence to
raise snow levels through the day to 1500-3000 feet. Should make
for another round of rain and mountain snow.

The passage of this system will help build better troughing
across the entire region, with snow levels dropping steadily
through Saturday. Very cold arctic air is noted across BC, with
storm track having the potential to bring some of this cold air
southward. Model guidance is pretty set on colder temperatures
late in the long term (highs 30s and lows 20s for lowlands). At
this time it is unclear if an arctic front will drop south across
western Washington, remain bottled up in BC, or be shoved E of
the Cascades. In addition, it is unclear how much moisture there
would be to work with if an arctic front were to drop south, as
continental polar/arctic airmasses cannot hold much moisture. At
this point the forecast has trended towards colder temps with
decreasing moisture as snow levels drop to the sfc. Will be
important to monitor this forecast in the coming days should
moisture and cold temps appear more significant together.

[MR.SNOWMIZER]

I might go back and take a look at the February thread, but if I recall it was generally colder and more extreme. And had some absolutely ridiculous snow maps. I think it showed Eugene getting 40"+ with that one storm...Of course there were some pretty big storms...

It was very close for my snow amounts. 

[Jesse]

12z ensembles looking great.

[MR.SNOWMIZER]

You know things are looking good when jim makes a post in the morning on a weekday.

[kokaneekidz]

Appears MOSSMAN will be the first to receive the goods//

Would be surprised if this actually accumulates in the lowlands outside of maybe the convergence zone, but shows temperatures will be right on the edge. Most of the sea level stuff falls early Thursday morning.

 

9620snow.gif

[AJ1013]

Ensemble mean looks good. Can anyone point me to a site that allows one to view each individual ensemble run? 

[Omegaraptor]

GEFS mean high/lo temps for KBLI, KSEA, and KPDX.

 

 

 

 

How are snow ensembles looking?

 

Glad to see some ice days (subfreezing highs) in there. Haven't had one in a long time.

[Blizzard777]

Current time zone

45*

Moderate rain

.47 for the day

rain rate .14 in/hr

a bit breezy 

 

we now return you to your winter model riding 

[Frontal Snowsquall]

GEFS mean high/lo temps for KBLI, KSEA, and KPDX.

 

 

 

Solid cold!

[MossMan]

You know things are looking good when jim makes a post in the morning on a weekday.

I thought the exact same thing when I saw his post!

[Blizzard777]

GFS snowfall maps are almost always overstated... and sometimes dramatically.   Particularly over long periods of time.

 

They are almost as useless as the surface temp maps from the GFS.

Hope the programming folks are all over this bug, issue or whatever causes it to give inaccurate data such as this.

[OysterPrintout]

PDX snowfall ensemble is of the real go big or go home variety 

[Frontal Snowsquall]

PDX snowfall ensemble is of the real go big or go home variety

Thanks for sharing!

[BLI snowman]

PDX snowfall ensemble is of the real go big or go home variety 

 

 

p18 is evil. 

[Esquimalt]

PDX snowfall ensemble is of the real go big or go home variety

Could you please post those for yyj?

[Blizzard777]

p18 is evil. 

Reality lol

[Frontal Snowsquall]

[OysterPrintout]

Could you please post those for yyj?

 

[Rubus Leucodermis]

p18 is evil. 

 

Seems to be one of the least snowy runs in general. It has the second-lowest snow total at KBLI.

 

Correction: more like fourth-lowest, but still a low outlier.

[SilverFallsAndrew]

Really nice slug of moisture moving through the valley. 

[Blizzard777]

EURO time! ❄☃

I will join you as you have them in the correct order

 

edit: my prayer symbol disappeared!  Don’t understand why these character sometimes print and sometimes don’t for me....oh well

it’s  there in Spirit  

[TacomaWaWx]

Rainy and breezy here in Tacoma. We're only 6 days in and January should surpass November's pathetic 1.83" rainfall total shortly.

[Front Ranger]

Comparing the 12z Euro for 2 days out compared to the same time frame 5 days ago, nice to see how much better things are turning out.

 

 

[Deweydog]

[Blizzard777]

Rainy and breezy here in Tacoma. We're only 6 days in and January should surpass November's pathetic 1.83" rainfall total shortly.

So nice to see this pattern change!  Hoping this is only the beginning of some really active fun weather!

wet.....then cold, snow......AR......Wind event....back to snow.......cold and so on

[Front Ranger]

Euro looks a bit more stronger with block and shortwave is a little deeper and further south down the coast compared to yesterday's 12z.

[Blizzard777]

 

You make it look so easy!

[Deweydog]

Euro looks a bit more stronger with block and shortwave is a little deeper and further south down the coast compared to yesterday's 12z.

Warmer so far.

[MR.SNOWMIZER]

You make it look so easy!

That is what a good Lawyer does.