January Weather In The PNW 2024 (Part III) - The Warming Shot

[WeatheringLoyalHeights]

This definitely has 12/20/22 vibes based on my location in North Seattle, though it seems more likely this will start as ZR as opposed to the snow we got that time.  I'm consistently in the very lightest gray on the models that show snow for PS, and I know all too well that will likely mean a rain/snow line straddling my house when I watch the radar in real time.

[iFred]

2 minutes ago, SilverFallsAndrew said:

Yeah, I can't help myself. Then I look at the CFS, if nothing there I'll look at seasonal ENSO ensembles. I'm an addict, I need help. 

Looking back, December and January cold waves always seem to have a second shot in February. Additionally, we've seen repeated hints that blocking stays and that we end up in a great position again. I'm confident that we see something that isn't just the garden variety "Looks good for the mountains and that one guy in suburban Vancouver" event in the first two weeks of February.  

[the_convergence_zone]

It's a good day to be watching aircraft temperature data from Sea-Tac: https://a.atmos.washington.edu/marka/tha.cgi?sea

[MR.SNOWMIZER]

5 minutes ago, the_convergence_zone said:

It's a good day to be watching aircraft temperature data from Sea-Tac: https://a.atmos.washington.edu/marka/tha.cgi?sea

Very interesting. 

[LowerGarfield]

1 hour ago, BLI snowman said:

Looks like EUG officially measured 0.7" of snow on Saturday. Of course this was actually sleet, but at least nice to see them recording snowfall there. They are the only airport in Western OR and Western WA besides SEA,  PDX, and MFR that still does.

PAE doesn't?

[SilverFallsAndrew]

Just now, iFred said:

Looking back, December and January cold waves always seem to have a second shot in February. Additionally, we've seen repeated hints that blocking stays and that we end up in a great position again. I'm confident that we see something that isn't just the garden variety "Looks good for the mountains and that one guy in suburban Vancouver" event in the first two weeks of February.  

I think there is a pretty good chance. Pattern is going to take 2-3 weeks to reset and then I think we see a nice shot of something. 

[Phishy Wx]

2 minutes ago, SilverFallsAndrew said:

I think there is a pretty good chance. Pattern is going to take 2-3 weeks to reset and then I think we see a nice shot of something. 

that ol first half of Feb looking better every day

[chinook]

1 hour ago, Frontal Snowsquall said:

NWS Portland thinking the airmass will be cold enough to support 1 inch of snow, I hope they are right! They are also thinking Washington County will be the big winners with the ice storm along with areas near the Gorge, Camas/Troutdale.

 

 

 

 

 

i'm not sure anyone is a winner with an ice storm.   i can support a bust or much less amounts of ice accumulation.  

[bainbridgekid]

5 minutes ago, MR.SNOWMIZER said:

Very interesting. 

Big above freezing layer between 775mb and 940mb currently. Wish it showed DP's though since that's what'll determine evaporative cooling tonight.

 

[The Ms. Anthrop]

 

13 minutes ago, the_convergence_zone said:

It's a good day to be watching aircraft temperature data from Sea-Tac: https://a.atmos.washington.edu/marka/tha.cgi?sea

 

7 minutes ago, MR.SNOWMIZER said:

Very interesting. 

Can either of you help me decipher this a bit? LOL it's a bit advanced for dangerous dilettante level understanding I'm still at.   

[ShawniganLake]

1 hour ago, the_convergence_zone said:

I wouldn't issue anything for Seattle but I'm surprised they haven't issued anything for the lower-elevation areas around Olympia and Tacoma. 

Yea.  It looks like a lot of the I5 corridor will be near or above freezing during the precip.  Likely not a huge icing event that impacts trees and power grids.  But I’m sure there will be very icy sections in low lying areas, especially at the onset of precipitation.  
 

This track does look similar to Dec 20, 2022 but that storm was running into a fresh batch of arctic air across southern BC.  

[the_convergence_zone]

Just now, The Ms. Anthrop said:

 

 

Can either of you help me decipher this a bit? LOL it's a bit advanced for dangerous dilettante level understanding I'm still at.   

It's basically a time-height plot of temperature and wind. This is an aggregation of data from commercial flights approaching and landing at Sea-Tac. Note that the newer times are on the left. And it's in UTC, so the 1617 column is the 9 AM hour. 

One can use it to compare to model data or just watch the trends of that warm layer. 

[MR.SNOWMIZER]

3 minutes ago, The Ms. Anthrop said:

 

 

Can either of you help me decipher this a bit? LOL it's a bit advanced for dangerous dilettante level understanding I'm still at.   

As the plane comes down it is taking temp readings at different altitudes, far left is feet and mb pressure, 925mb is 2500ft and 850 is 4800ft. You want to see the entire air column below or at zero c for snow, However low dewpoints in these areas can cool when precip falls through it. Very touchy forecast. As you get closer to the mountains sometimes there will be cold domes of air trapped that can support snow.

[ShawniganLake]

Thursday night into Friday looks like a better bet for snow along the hood canal and snowmizer than what’s coming tonight. 

[Rubus Leucodermis]

3 minutes ago, MR.SNOWMIZER said:

As the plane comes down it is taking temp readings at different altitudes, far left is feet and mb pressure, 925mb is 2500ft and 850 is 4800ft. You want to see the entire air column below or at zero c for snow, However low dewpoints in these areas can cool when precip falls through it. Very touchy forecast. As you get closer to the mountains sometimes there will be cold domes of air trapped that can support snow.

In fact it is modelled to be too warm aloft for snow here at the onset of the event, but to quickly wet bulb down to freezing or below. It is still quite dry aloft.

[TT-SEA]

12Z ECMWF backing off on freezing rain tonight... just less precip with initial band.   Looks like east wind eats up some of the moisture.

 

[Slushy Inch]

2 minutes ago, TT-SEA said:

12Z ECMWF backing off on freezing rain tonight... just less precip with initial band.   Looks like east wind eats up some of the moisture.

 

Only OP model that has no snow for central  PS

[Randyc321]

Current 925s

 

And the 850s

[TT-SEA]

Just now, Slushy Inch said:

Only OP model that has no snow for central  PS

But the best model for short term surface details.   Just too warm aloft when there is precip.

[MR.SNOWMIZER]

7 minutes ago, ShawniganLake said:

Thursday night into Friday looks like a better bet for snow along the hood canal and snowmizer than what’s coming tonight. 

Yep i got my eye on that, i would like to see the timing change but it has some potential. Tonight is tough for here, it is all about the cold pool and how deep it is. It will for sure snow right along the canal but how far that moves east from there is a hard call. 

[Slushy Inch]

Just now, TT-SEA said:

But the best model for short term surface details.   Just too warm aloft when there is precip.

Dr. No living up to its nickname 

[SilverFallsAndrew]

I'm looking at @Deweydog and @BLI snowman for this one. What would a couple historical comps be for this stretch? This reminds me quite a bit of 2004, but on the other end the temps west of the Cascades have been so impressive. Some kind of hybrid between 2004 and 1968? 

[TT-SEA]

11 minutes ago, ShawniganLake said:

Thursday night into Friday looks like a better bet for snow along the hood canal and snowmizer than what’s coming tonight. 

ECMWF is much warmer aloft with the Thursday system than the system tomorrow.

[Rubus Leucodermis]

6 minutes ago, TT-SEA said:

12Z ECMWF backing off on freezing rain tonight... just less precip with initial band.   Looks like east wind eats up some of the moisture.

 

Seems to be slowly caving to the cooler, snowier consensus of most other models up here.

[MR.SNOWMIZER]

3 minutes ago, Slushy Inch said:

Only OP model that has no snow for central  PS

It is light with precip even in the mountains compared to other models. It is on its own it looks like in the moisture department.

[the_convergence_zone]

5 minutes ago, Slushy Inch said:

Only OP model that has no snow for central  PS

12Z UW-WRF has no snow south of Arlington. Brief period of mixed precipitation to start, then all rain by 10 PM tonight. 

The HRRR has also consistently shown no snow in the central sound, but does show more appreciable freezing rain in the Tacoma-Olympia corridor and over Kitsap. 

[Rubus Leucodermis]

1 minute ago, MR.SNOWMIZER said:

It is light with precip even in the mountains compared to other models. It is on its own it looks like in the moisture department.

Also been a warm outlier up this way.

[Slushy Inch]

2 minutes ago, the_convergence_zone said:

12Z UW-WRF has no snow south of Arlington. Brief period of mixed precipitation to start, then all rain by 10 PM tonight. 

ahh at least it’s just the uw-wrf

[Skagit Weather]

9 minutes ago, TT-SEA said:

12Z ECMWF backing off on freezing rain tonight... just less precip with initial band.   Looks like east wind eats up some of the moisture.

 

Shifted another 5 miles south with the snow though. Gives me about 2" now instead of less than 0.5".

[SpaceRace22]

Had a low of 8 degrees here this morning and everything is still completely covered in snow with almost 0 melting since Saturday. It's been so still that even the tree branches are still caked in it. Without a doubt the longest I have seen snow on the ground in the lowlands without any significant melting.

[The Ms. Anthrop]

22 minutes ago, the_convergence_zone said:

It's basically a time-height plot of temperature and wind. This is an aggregation of data from commercial flights approaching and landing at Sea-Tac. Note that the newer times are on the left. And it's in UTC, so the 1617 column is the 9 AM hour. 

One can use it to compare to model data or just watch the trends of that warm layer. 

 

19 minutes ago, MR.SNOWMIZER said:

As the plane comes down it is taking temp readings at different altitudes, far left is feet and mb pressure, 925mb is 2500ft and 850 is 4800ft. You want to see the entire air column below or at zero c for snow, However low dewpoints in these areas can cool when precip falls through it. Very touchy forecast. As you get closer to the mountains sometimes there will be cold domes of air trapped that can support snow.

Thank you both for the explanations, they are super helpful! 

[TT-SEA]

Based on the 12Z ECMWF... I am not really expecting much here.   Some light freezing rain tonight with marginal temps and probably not much if any snow.

[Slushy Inch]

Euro is initializing with warmer upper temps than the rest, odd.

[ShawniganLake]

7 minutes ago, TT-SEA said:

ECMWF is much warmer aloft with the Thursday system than the system tomorrow.

Aren’t 850s below 0 ahead of Thursday’s system. SE flow usually holds that in place along the east slopes of the olympics. Similar to my location. Both systems are showing 6”+ here.  While SE flow will scour out the BC lower mainland Thursday, the cold will likely hang in a little longer over here. 

[Front Ranger]

Southern system looks to be coming in further south than models were projecting 1-2 days ago.

[MossMan]

Just now, Slushy Inch said:

Euro is initializing with with warmer upper temps, odd.

Something is up with that model. I’m going with the GFS and GEM. 

[MossMan]

10 minutes ago, the_convergence_zone said:

12Z UW-WRF has no snow south of Arlington. Brief period of mixed precipitation to start, then all rain by 10 PM tonight. 

The HRRR has also consistently shown no snow in the central sound, but does show more appreciable freezing rain in the Tacoma-Olympia corridor and over Kitsap. 

Are you able to post that Cliff Mass Map? 

[the_convergence_zone]

3 minutes ago, TT-SEA said:

Based on the 12Z ECMWF... I am not really expecting much here.   Some light freezing rain tonight with marginal temps and probably not much if any snow.

The three most reliable models for this type of situation -- ECMWF, HRRR, and UW-WRF -- all show next to nothing south of Arlington. And there's currently a 5,000 ft deep layer of above-freezing air above us plus the entire day of additional warming ahead of us. 

Quick, better find some obscure Canadian model that paints a better narrative! 

[the_convergence_zone]

2 minutes ago, MossMan said:

Are you able to post that Cliff Mass Map? 

My work computer blocks image posting LOL.

https://a.atmos.washington.edu/~ovens/wxloop.cgi?wrfd3_ww_snowacc+///3

[Rubus Leucodermis]

4 minutes ago, MossMan said:

Something is up with that model. I’m going with the GFS and GEM. 

I’ve thrown out the GFS, too, for the opposite reason. Going with GEM, HRDPS, and NAM 3km on this one.