February 2024 Weather in the PNW

[ShawniganLake]

I do lawn and garden maintenance for a living. This isn’t my own lawn but today was the first mowing day of the 2024 season for me. 
 

 

[snow_wizard]

This is how the national map looked as of Feb 4, 1989.  Brrrrr!

[Deweydog]

19 minutes ago, ShawniganLake said:

I do lawn and garden maintenance for a living. This isn’t my own lawn but today was the first mowing day of the 2024 season for me. 
 

 

Fixed!

[snow_wizard]

21 minutes ago, ShawniganLake said:

I do lawn and garden maintenance for a living. This isn’t my own lawn but today was the first mowing day of the 2024 season for me. 
 

 

My lawn looks NOTHING like that.

[iFred]

1 hour ago, Phishy Wx said:

I'm going to try a Cabbage Palmetto in Spokane.  Its the state tree of South Carolina where I grew up

 

You can do it the Emirati way and get it in a large pot, keep it in a greenhouse and actively growing in the winter and roll it out in the summer. You’ll get something beautiful and not the pathetic excuses for a Cretaceous evergreen that I see around the Northwest.

[SilverFallsAndrew]

4 minutes ago, snow_wizard said:

My lawn looks NOTHING like that.

My lawn is pretty green right now. 

[iFred]

26 minutes ago, ShawniganLake said:

I do lawn and garden maintenance for a living. This isn’t my own lawn but today was the first mowing day of the 2024 season for me. 
 

 

Will be doing the late winter prep for the finished half of mine. Kind of excited to have a patch of kid friendly grass adjacent to a larger native plant garden.

[iFred]

1 hour ago, MossMan said:

Sounds like awesome upcoming projects, hope to see pictures this spring/summer! 

I’ll share when we meet up in 2048.

[iFred]

1 hour ago, snow_wizard said:

The Graph Cast digs that trough in a lot more solidly next week than the other models.  It doesn't just move out like the others show either.

Learned how to get both the ICON and GFS initialization points working in the Graphcast. Hoping to have a demo to share by the fall. Some pretty cool high res stuff for our side of the Cascades.

[Phishy Wx]

1 hour ago, snow_wizard said:

Really good post.  I agree that our summers are the absolute best if you want to get stuff done outside.  Just no two ways about it.

The dark and damp days are another thing.  I used to like them MUCH more than I do now.  At least for me the older I get the harder it is to deal with.

except for that sneaky (almost annual) wildfire smoke.  there's always something

[snow_wizard]

11 minutes ago, iFred said:

Learned how to get both the ICON and GFS initialization points working in the Graphcast. Hoping to have a demo to share by the fall. Some pretty cool high res stuff for our side of the Cascades.

I didn't realize that was available.  Noice!  We will have more tools to work with next winter.  We get a little more every year.

[snow_wizard]

6 minutes ago, Phishy Wx said:

except for that sneaky (almost annual) wildfire smoke.  there's always something

That has really been a problem lately for sure.  When I was younger it was very rare.  I'll never forget how bad 2020 was.  Just added to what was already a horrific year in my book.

[Phil]

New Euro weeklies are hardcore porn.

Can we please get this pattern in Jul/Aug? Pretty please?

[the_convergence_zone]

Last spring freeze dates at my location. 

2023 - March 1
2022 - March 10
2021 - March 30 (32.4...borderline...otherwise it would be Feb 14). 

Last one this year was Jan 17, so odds would suggest that I'll get another. Maybe Friday night...

[Phil]

18 minutes ago, iFred said:

Learned how to get both the ICON and GFS initialization points working in the Graphcast. Hoping to have a demo to share by the fall. Some pretty cool high res stuff for our side of the Cascades.

Nice!

[TT-SEA]

4 minutes ago, snow_wizard said:

That has really been a problem lately for sure.  When I was younger it was very rare.  I'll never forget how bad 2020 was.  Just added to what was already a horrific year in my book.

If you were younger in the 1800s or early 1900s you would probably remember thicker smoke than anything you have seen in your life... back when fires burned uncontrolled.    The journals from the 1800s from Fort Snelling in Minnesota talk of thick smoke often in the spring and again in the fall.    Assuming spring smoke was the prairies burning before the green up and the fall smoke being from western forest fires.

[Port Angeles Foothiller]

5 minutes ago, the_convergence_zone said:

Last spring freeze dates at my location. 

2023 - March 1
2022 - March 10
2021 - March 30 (32.4...borderline...otherwise it would be Feb 14). 

Last one this year was Jan 17, so odds would suggest that I'll get another. Maybe Friday night...

LMAO. I had a freeze mid June last year. 

[Phil]

2 hours ago, snow_wizard said:

Wowzers!  I think Phil is going to have to concede on this.  It's a big enough deal that we don't even have to score at the very beginning of it.  We could be looking at a quick hit, then cold in the East, then a retrogression.

Tim is saying this is like 2016, but that year had a +QBO, and this is minus.

FWIW, I never said I was against a SSW happening. I said there was no indication of a SSW from guidance at the time (and what you were originally calling a SSW actually wasn’t). Keep in mind not a single piece of guidance indicated a wind reversal this time last week.

Obviously the picture *has* changed since then. The +PNA/Aleutian low is effectively driving vertical wave activity into the stratosphere, producing a wave-1 response from the PV (and a possible SSW at some point).

So the odds of a blocky F/M/A are increasing. El Niño pattern over the Pacific probably delivers the majority of the cold to other regions, but that doesn’t preclude a couple cold shots west of the Rockies as we head into March.

[snow_wizard]

No doubt this thing next week has potential to be an interesting quick hitter at least.  Massive run to run change on the 18z GFS vs 12z.

[snow_wizard]

3 minutes ago, Phil said:

FWIW, I never said I was against it. I said there was no indication of a SSW from guidance at the time (and what you were originally calling a SSW actually wasn’t).

Obviously the picture has changed since then. The +PNA/Aleutian low is effectively driving vertical wave activity into the stratosphere, producing a wave-1 response from the PV (and a possible SSW at some point).

I just had a hunch it would evolve like it did.  It will be interesting to see what effect it has on the actual weather.

[Phil]

1 hour ago, High Desert Mat? said:

Full wind reversal?

That would be, yes. A solid one at that.

If we have a second SSW this winter, that would be 7 SSW events in the last 7 winters. Basically unprecedented.

Not looking forward to when the other shoe drops.  

[Port Angeles Foothiller]

18z shows a overrunning event on the 15th. I would get shadowed, but looks like seattle could score some wet snow. 

[Phil]

1 minute ago, snow_wizard said:

I just had a hunch it would evolve like it did.  It will be interesting to see what effect it has on the actual weather.

+PNA/Aleutian Low is the most effective pattern to precede a SSW due to how it augments +WAFz thru the NPAC. It just wasn’t clear the upcoming +PNA/AL would be that intense (though now it is evident will be).

The majority of +1 sigma +PNA/AL (& over 80% of +2 sigma cases) result in a W1 response and subsequent SSW. So it is consistent, at least.

[Phishy Wx]

5 minutes ago, Phil said:

That would be, yes. A solid one at that.

If we have a second SSW this winter, that would be 7 SSW events in the last 7 winters. Basically unprecedented.

Not looking forward to when the other shoe drops.  

could thinning/less sea ice in the arctic (relative to long term average) be driving them more frequently?  I feel like this is climate change driven to some degree

[Phil]

15 minutes ago, Phishy Wx said:

could thinning sea ice in the arctic (relative to long term average) be driving them more frequently?  I feel like this is climate change driven to some degree

If it is climate change driven, it’s not from sea ice. Wave activity fluxes that drive SSW events arise via large scale dynamics connecting the tropics and mid-latitudes.

It’s more likely due to a combination of increasing O^3/improving BDC since the 1990s, the glut of H2O from the Hunga Tonga eruption, and internal intradecadal variability in the NPAC/NH general circulation that has favored more pronounced WAFz.

Recall we had very frequent SSWEs in the 1950s/60s (and likely 1940s as well) but they began lessening in frequency in the mid-1970s when onwards, with relatively few SSWEs from the mid-1990s to the middle 2000s (we went 8 years without a single SSW during that timeframe).

Their frequency began to increase again in the mid/late 2000s (starting with the big one in 08/09). That trend appears to be continuing still.

[iFred]

3 minutes ago, Phishy Wx said:

could thinning/less sea ice in the arctic (relative to long term average) be driving them more frequently?  I feel like this is climate change driven to some degree

Shorter wave lengths lead to a more turbulent polar jet, leading to a delay in sub arctic sea ice, which allows lows to build a little stronger, which then allow for warmer air to go a bit further north, leading to a weaker jet, allowing for the polar vortex more opportunities to be dislodged when one of these areas of pressure meander north, which means that dislodged PV jumps the tracks, allowing for the first cracks into the upper end of the troposphere, which then allows for a flood of warmer air, and bam, a PV split. Then the fight to homeostasis occurs as the air cools again, at a quicker clip later in the season as the surface is perfect for radiative cooling.

This is my layman understanding of it. Now if you will excuse me, the NOAA MPs are pounding loudly at my door. If I am not seen again, tell my wife and son that I loved them as much as I loved sub 500mb heights pooling over the Puget Sound.

 

[iFred]

4 minutes ago, Phil said:

I doubt that, but if it is climate change driven, it’s not from sea ice. Wave activity fluxes that drive SSW events arise via large scale dynamics connecting the tropics and mid-latitudes.

[iFred]

35 minutes ago, the_convergence_zone said:

Last spring freeze dates at my location. 

2023 - March 1
2022 - March 10
2021 - March 30 (32.4...borderline...otherwise it would be Feb 14). 

Last one this year was Jan 17, so odds would suggest that I'll get another. Maybe Friday night...

As long as we dont get below 28º or are back above freezing in 12 hours, the ground should hopefully still be good for planting and prepping.

[Phil]

Hints of the springtime GFS bias to GOA ULLs has been showing up the last few days. Lots of backwards tracking cutoffs in the medium/long range lately.

If heartstrings haven’t been pulled to their breaking point yet this winter, they will be soon! 

[Phil]

21 minutes ago, iFred said:

Shorter wave lengths lead to a more turbulent polar jet, leading to a delay in sub arctic sea ice, which allows lows to build a little stronger, which then allow for warmer air to go a bit further north, leading to a weaker jet, allowing for the polar vortex more opportunities to be dislodged when one of these areas of pressure meander north, which means that dislodged PV jumps the tracks, allowing for the first cracks into the upper end of the troposphere, which then allows for a flood of warmer air, and bam, a PV split. Then the fight to homeostasis occurs as the air cools again, at a quicker clip later in the season as the surface is perfect for radiative cooling.

This is my layman understanding of it. Now if you will excuse me, the NOAA MPs are pounding loudly at my door. If I am not seen again, tell my wife and son that I loved them as much as I loved sub 500mb heights pooling over the Puget Sound.

 

It’s not that simple, because weaker zonal winds also translate to weaker wave activity fluxes.

The trend since the 1970s has actually been towards a more positive state of the northern annular mode (+AO). The increase in SSW frequency is likely related to increases in stratospheric ozone and internal variability in general circulation. But if there’s a better explanation out there I’m open to it.

[Phishy Wx]

yeah it's done to well done

[Sunriver Snow Zone]

40 minutes ago, the_convergence_zone said:

Last spring freeze dates at my location. 

2023 - March 1
2022 - March 10
2021 - March 30 (32.4...borderline...otherwise it would be Feb 14). 

Last one this year was Jan 17, so odds would suggest that I'll get another. Maybe Friday night...

My last subfreezing low was June 22nd for the 2022-2023 season. Not really sure when the limit is for a last freeze, because I also had 32.0 low in late July and also early July, but I guess 32.0 doesn't count as subfreezing, it's just freezing.

 

At what point of the year can it not be a "last freeze" anymore?

[Phil]

16 minutes ago, iFred said:

If the intensity of the Okhotsk Sea low were correlated to ice extent there (or showed any trend consistent with climate change signals) I would be more interested.

[RentonHill]

51 minutes ago, Phil said:

That would be, yes. A solid one at that.

If we have a second SSW this winter, that would be 7 SSW events in the last 7 winters. Basically unprecedented.

Not looking forward to when the other shoe drops.  

Wouldnt this be a final warming? 

[Cascadia_Wx]

Great day to catch up on the gardening forum!

[Sunriver Snow Zone]

Pretty decent 18z, a lot of snow for the mountains, 18ish inches for me, and some wet snow for the Washington lowland. We desperately need more mountain snow.

[Phil]

1 minute ago, RentonHill said:

Wouldnt this be a final warming? 

If there is no subsequent recovery to cyclonic/westerly winds, then yes it would be considered a dynamic final warming (essentially a SSW but late enough in the season that there is no time for the vortex to recover before solar radiative warming precludes its formation).

[Phil]

Clown range goofus wants to nuke the PV from existence. This has to be overkill, would be another top-5 wind reversal.  

[snow_wizard]

Now this is what we want.

[snow_wizard]

1 hour ago, Phil said:

That would be, yes. A solid one at that.

If we have a second SSW this winter, that would be 7 SSW events in the last 7 winters. Basically unprecedented.

Not looking forward to when the other shoe drops.  

Lets hope it doesn't