February 2024 Weather in the PNW

[bainbridgekid]

Widespread overrunning snow Sunday night too on the 00z GFS.

 

[Dave]

Ok. It's time to check in. Is it going to snow in Eugene this weekend? Most models are showing some, but this event will be on the edge of the knife temperature wise. I do have some high hopes to score a slushy inch but it might just stick to the foothills.

[RCola]

6 minutes ago, TT-SEA said:

I have no idea how it will play out over the weekend.   Lots of opportunities and time of day is critical.   The system on the 00Z GFS looks like a good one.    

Looks like early morning on Saturday. If we're being optimistic, timing will speed up and it will be overnight Friday. 

[MR.SNOWMIZER]

This run smashes the hood canal.

[MR.SNOWMIZER]

Good lord 

[TT-SEA]

6 minutes ago, Dave said:

Ok. It's time to check in. Is it going to snow in Eugene this weekend? Most models are showing some, but this event will be on the edge of the knife temperature wise. I do have some high hopes to score a slushy inch but it might just stick to the foothills.

Edge of knife indeed. 

00Z GEM does not show much lowland snow over the next week.    No way to know what will actually happen.

[MR.SNOWMIZER]

Just now, TT-SEA said:

Edge of knife indeed. 

00Z GEM does not show much lowland snow over the next week.    No way to know what will actually happen.

That looks like a little more than it's last run

[TT-SEA]

Raining and 35 here now... no wind yet but it will be here soon.  

[TT-SEA]

1 minute ago, MR.SNOWMIZER said:

That looks like a little more than it's last run

A little more for the Seattle area but really close overall.  

Comparison of 12Z and 00Z runs:

 

[SilverFallsAndrew]

GEM shows massive Pepto here. I’ll take it. 

[MR.SNOWMIZER]

3 minutes ago, SilverFallsAndrew said:

GEM shows massive Pepto here. I’ll take it. 

Same here!!

[Doinko]

8 hours ago, BLI snowman said:

73 in Chicago right now after a low of 55. 

Typical winter!!

Looks like they got hit by some thunderstorms as well. And now they're supposed to see snow tonight with a low of 23!

[SilverFallsAndrew]

Anybody got a gfs snow map?

[Sunriver Snow Zone]

ITS COMING! A FOOT OF SNOW FOR EVERYONE! BUY YOUR DAIRY, BUY YOUR FRUIT, BUY YOUR SNOW SHOVELS AND SNOW BLOWERS, AND PREPARE THIS HISTORIC LATE SEASON SNOW EVENT! WOOOOOOO

 

EDIT: AND TOILET PAPER, AND CANNED FOODS! AND PROPANE! AND BATTERIES! AND GENERATORS!

[bainbridgekid]

1 minute ago, SilverFallsAndrew said:

Anybody got a gfs snow map?

 

[MWG]

Just now, Sunriver Snow Zone said:

ITS COMING! A FOOT OF SNOW FOR EVERYONE! BUY YOUR DAIRY, BUY YOUR FRUIT, BUY YOUR SNOW SHOVELS AND SNOW BLOWERS, AND PREPARE THIS HISTORIC LATE SEASON SNOW EVENT! WOOOOOOO

The toilet paper! Most important item! 

[Snownerd3000]

3 minutes ago, SilverFallsAndrew said:

Anybody got a gfs snow map?

[MR.SNOWMIZER]

The last snow event here was 11.1 ratio. The kuchera isn't always the best map

[MossMan]

9 minutes ago, MWG said:

The toilet paper! Most important item! 

It’s coming! 

[bainbridgekid]

4 minutes ago, MR.SNOWMIZER said:

The last snow event here was 11.1 ratio. The kuchera isn't always the best map

I find when accumulating snow actually happens it tends to be relatively close to 10:1 here. But the 10:1 map way overestimates how often that happens and shows lots of phantom snow that never happens at all.

Kuchera ends up being closer in borderline setups not because the accumulating snow all falls at Kuchera's low ratio but because it eliminates a lot more of the phantom snow.

[SilverFallsAndrew]

Just now, bainbridgekid said:

I find when accumulating snow actually happens it tends to be relatively close to 10:1 here. But the 10:1 map way overestimates how often that happens and shows lots of phantom snow that never happens at all.

Kuchera ends up being closer in borderline setups not because the accumulating snow all falls at Kuchera's low ratio but because it eliminates a lot more of the phantom snow.

It’s almost never 10:1 here. Usually about 6 or 7:1.

[the_convergence_zone]

Yeah it’s never going to be 10:1 when the temperature is 32 or above. Maybe close if it holds at exactly 32 with rapid snow rates and there isn’t much aggregation. Rain gauges undercatch snow so I would suspect a measurement error if someone observed 10:1 at those temperatures. 

The biggest inaccuracies with Kuchera are actually at high snow ratios in the 10-20:1 range because of wind and different crystal habits that accumulate in different ways. I’ve seen ratios as high as 40:1 when there are pristine dendrites and no wind. 

[bainbridgekid]

5 minutes ago, the_convergence_zone said:

Yeah it’s never going to be 10:1 when the temperature is 32 or above. Maybe close if it holds at exactly 32 with rapid snow rates and there isn’t much aggregation. Rain gauges undercatch snow so I would suspect a measurement error if someone observed 10:1 at those temperatures. 

The biggest inaccuracies with Kuchera are actually at high snow ratios in the 10-20:1 range because of wind and different crystal habits that accumulate in different ways. I’ve seen ratios as high as 40:1 when there are pristine dendrites and no wind. 

Not sure your first sentence is true if the DP remains below freezing. I've seen relatively dry snow fall with zero melting while the temp is 33 plenty of times if the air starts out fairly dry in evaporative cooling events. 

Forecasting snow amounts is so fascinatingly difficult because there are so many factors to nail down (exact temp and humidity through the air column and exact location and strength of every band of snow.)  Crazy how much harder that is to forecast than rain.

[TT-SEA]

2 minutes ago, bainbridgekid said:

Not sure your first sentence is true if the DP remains below freezing. I've seen relatively dry snow fall with zero melting while the temp is 33 plenty of times if the air starts out fairly dry in evaporative cooling events. 

Forecasting snow amounts is so fascinatingly difficult because there are so many factors to nail down (exact temp and humidity through the air column and exact location and strength of every band of snow.)  Crazy how much harder that is to forecast than rain.

It was snowing pretty hard here this afternoon... if you didn't look at the ground you would think it was piling up fast.  But it never accumulated and it was around 33 at the time.   On a different day that would have accumulated.   Must have been something different in the air column above.    Fascinating stuff. 

[MR.SNOWMIZER]

Here she is. One of the most powerful flashlights in the world. Fan cooled,  100k lumens!! This is about 1/2 charged its normally even brighter.  The charger is at cabin. 

[Deweydog]

1 minute ago, MR.SNOWMIZER said:

Here she is. One of the most powerful flashlights in the world. Fan cooled,  100k lumens!! This is about 1/2 charged its normally even brighter.  The charger is at cabin. 

That’s sexy AF.

[Meatyorologist]

1 minute ago, Deweydog said:

That’s sexy AF.

Can't bring you anywhere!

[bainbridgekid]

1 minute ago, TT-SEA said:

It was snowing pretty hard here this afternoon... if you didn't look at the ground you would think it was piling up fast.  But it never accumulated and it was around 33 at the time.   On a different day that would have accumulated.   Must have been something different in the air column above.    Fascinating stuff. 

And in the opposite direction snow immediately started sticking even to roads here yesterday afternoon while the temp was still 38 degrees because the upper levels were very cold (850mb temps near -9) and snow was heavy and a bit groupely. Flakes must have been well below freezing till the lowest 1,000 feet or so.

[Meatyorologist]

Really hard not to get excited looking at weather models tonight. Lots of small mesoscale oportunities with very high jackpot potential. This next trough will be in rarified territory due to its cold nature alongside its negative tilt, allowing for moisture as well. Fun times ahead.

[MossMan]

39/30 on the day. Currently 37. 

[MWG]

NWS Medford calling 10 to 20% chance of snow at the coast. Is it Friday yet?? Curious how all this plays out! 

[MR.SNOWMIZER]

3 minutes ago, Meatyorologist said:

Really hard not to get excited looking at weather models tonight. Lots of small mesoscale oportunities with very high jackpot potential. This next trough will be in rarified territory due to its cold nature alongside its negative tilt, allowing for moisture as well. Fun times ahead.

It looks like the angle will be just right so that the Olympics will not be blocking anything this time for the sound.

[bainbridgekid]

WRF drops the hammer Friday night. Widespread 3-5" East of Puget Sound in Snohomish and King Counties. This would require perfectly threading the needle for both timing and strength of that band but nice to see the top end potential.

 

[bainbridgekid]

And that first map doesn't include this other snow Thursday night. The timing on these maps don't overlap.

 

[bainbridgekid]

Total snow combining the Thursday night and Friday night events. Fascinating cutoff between the West and East side of Puget Sound. Can't say I've ever seen that happen before.

 

[Front Ranger]

This upcoming pattern seems reminiscent of March 2002. With some 2012 thrown in.

[SnowWillarrive]

2 minutes ago, bainbridgekid said:

Total snow combining the Thursday night and Friday night events. Fascinating cutoff between the West and East side of Puget Sound. Can't say I've ever seen that happen before.

 

I’m praying this is real 

[MR.SNOWMIZER]

6 minutes ago, bainbridgekid said:

Total snow combining the Thursday night and Friday night events. Fascinating cutoff between the West and East side of Puget Sound. Can't say I've ever seen that happen before.

 

It's bizarre. This model did some strange stuff like this last event. This isn't what the gfs shows so I'm not sure where this is coming from?

[Sunriver Snow Zone]

WRF-GFS for Oregon. HOLYYY SHIIT!

[GHweatherChris]

The snow maps are wrong, they show very little IMBY, throw them out, let's try again tomorrow.

Edited February 28 by GHweatherChris