March Weather in the Pacific Northwest

[Perturbed Member]

EUG is now down to 32F.

[Phil]

So true... seems like these March events make it look easy compared to December events.

Colder Pacific > stronger Sun. Probably.

[Deweydog]

Onshore flow snowfall is where late-February/March definitely has a leg up on mid-winter, at least these days. Any event with offshore or flat gradients and there is obviously no contest compared to late December-January.

 

I can't help but wonder if part of the reason we got more cold onshore snowfall in mid-winter back in the day because the atmosphere/SSTs would cool more quickly than they do now.

Colder air probably did help with snowfall.

[Jesse]

Colder air probably did help with snowfall.

[Phil]

The oceans have a massive thermal capacity hence a massive thermal inertia, which is aided peripherally by both fluid-mechanical and radiative-albedo feedbacks.

 

The NPAC is warmest during the first half of September, and is coldest during the first half of March.

[Jesse]

EUG is now down to 32F.

That is pretty insane for the late afternoon considering we are just a week removed from April.

[Deweydog]

604AC30E-7660-4FE8-9F07-D575DF9C1F27.jpeg

Just trying to help...

[Perturbed Member]

That is pretty insane for the late afternoon considering we are just a week removed from April.

 

Yeah, late March, onshore flow, -5c to -6c 850mb temps doesn't scream snow to low elevations to me but here we are.

 

I was able to get a dusting last night so with a bit more sustained precip maybe a little bit more is possible later tonight?

[Bryant]

The scene here yesterday. Had an inch in total

[SilverFallsAndrew]

High of 37 here. That breaks the record min max of 39 set in 2009.

 

Eugene 41 breaks the record of 45 set in 2009.

 

Salem 42 breaks the record of 44 set in 1917.

 

PDX 46 ties the record set in 1975.

[BLI snowman]

Onshore flow snowfall is where late-February/March definitely has a leg up on mid-winter, at least these days. Any event with offshore or flat gradients and there is obviously no contest compared to late December-January.

 

I can't help but wonder if part of the reason we got more cold onshore snowfall in mid-winter back in the day was because the atmosphere/SSTs would cool more quickly than they do now. 

 

Even in the 1950s, our early/mid-winter snow without offshore flow was almost exclusively accompanied either by a large reservoir of arctic air nearby (i.e. early January 1950 or late January 1954) or an ana-front.

 

Late December 1964 was a nice pattern though. Balls-to-the-wall onshore snow flow for days. Then a repeat the following year. The coast got totally hammered.

[SilverFallsAndrew]

My mother in law lives near the Eugene airport. I know she picked up at least a dusting this afternoon. 

[Jesse]

Even in the 1950s, our early/mid-winter snow without offshore flow was almost exclusively accompanied either by a large reservoir of arctic air nearby (i.e. early January 1950 or late January 1954) or an ana-front.

Sure. But you also had onshore flow snow fests like the early to middle part of January 1969. Hard to imagine onshore flow that cold at that point in the season in recent years.

 

It looks like I missed your edit. I wasn’t aware of the late December 1964 set up either.

[TigerWoodsLibido]

Wow, it's amazing how a marginal setup this late in the season always seems to find "a way" 

 

That very much depends on where you are.  Nothing here for example.  Only other significant March events here I can remember are last March 2017 and 2012.

[Deweydog]

Yeah, late March, onshore flow, -5c to -6c 850mb temps doesn't scream snow to low elevations to me but here we are.

 

I was able to get a dusting last night so with a bit more sustained precip maybe a little bit more is possible later tonight?

This setup is getting help from the column going or trying to go isothermal.

[BLI snowman]

Sure. But you also had onshore flow snow fests like the early to middle part of January 1969. Hard to imagine onshore flow that cold at that point in the season in recent years.

 

It looks like I missed your edit. I wasn’t aware of the late December 1964 set up either.

 

Both the 1964-65 and 1968-69  stretches were fueled by northern jet suppression with a tanked PNA and deep AK trough. We really haven't seen anything comparable in mid-winter since perhaps mid to late January 1996.

[Phil]

The scene here yesterday. Had an inch in total

Nice! Told ya it was just a late bloomer.

[Phil]

Both the 1964-65 and 1968-69 stretches were fueled by northern jet suppression with a tanked PNA and deep AK trough. We really haven't seen anything comparable in mid-winter since perhaps mid to late January 1996.

I don’t think January 1969 had a true Alaska trough. It was mostly a huge -PNA/-NAO combo displacing the TPV into western North America, which happened frequently during the mid-20th century.

 

[BLI snowman]

I don’t think January 1969 had a true Alaska trough. It was mostly a huge -PNA/-NAO combo, which happened frequently during the mid-20th century.

 

 

Yeah, I should have specified SE Alaska trough. Juneau had its coldest month on record. Understandably their weather is often relevant for us down here.

[FroYoBro]

Wow, the radar actually looks pretty good.

[SilverFallsAndrew]

Dumping snow up here again over the past hour. 

[SilverFallsAndrew]

They are measuring snow in the mountains of SW Oregon in the feet this evening. Great news because that area has had terrible snowpack to this point. 

[FroYoBro]

Getting darker here. 

[Jesse]

PDX still holding at 42-43. It’s 40 here. Precip rates would definitely need to pick up for us to see anything tonight.

 

The radar does look somewhat promising, though.

[SilverFallsAndrew]

PDX still holding at 42-43. It’s 40 here. Precip rates would definitely need to pick up for us to see anything tonight.

 

The radar does look somewhat promising, though.

 

PDX still holding at 42-43. It’s 40 here. Precip rates would definitely need to pick up for us to see anything tonight.

 

The radar does look somewhat promising, though.

 

Quite a bit of precip downstream on the Medford radar too...

[Phil]

Yeah, I should have specified SE Alaska trough. Juneau had its coldest month on record. Understandably their weather is often relevant for us down here.

Ah, gotcha. FWIW, I think it’s amazing how frequently that pattern recurred from the mid-1950s to the early-1970s.

 

There was a 5 year stretch from from 1964-69 (the heart of the -PDO/-AMO/global cooling period) where all of the winters had almost the exact same pattern. The ENSO state didn’t even matter (strong/super Niños in 1965/66 and 1968/69, Niñas in 1964/65, 1967/68, etc). Every winter had the same blocking pattern(s).

 

Here’s five year stretch:

 

 

 

 

 

[SilverFallsAndrew]

-11 departure day for EUG today.

[TT-SEA]

-11 departure day for EUG today.

 

49/34 at SEA... good for a -5 depature.

 

47/34 here.    A raw morning turned into a very pleasant and partly sunny afternoon.   

 

Good bet that tomorrow morning is a wintry scene here.

[Phil]

Even outside that stretch, the vast majority of winters between the early/mid 1950s and early/mid 1970s featured that same pattern. It was so consistent.

 

It started breaking down quickly in the early 1970s, first into an anti-phased regime (Pacific/Atlantic in opposing states, no dual blocks) from 1971-76, which produced the Indo/west-Pacific heat uptake that culminated in the Great Pacific climate shift in 1976/77.

[Phil]

Watch climate change in action.

 

Flip from cool globe/-NAM to warm globe/+NAM happens in just 20 years.

 

1976-80:

 

 

 

1981-85:

 

 

 

1986-1990:

 

 

 

1991-95

 

[snow_wizard]

The GFS really likes the idea of a significant cold shot in early April.  The ECMWF made a small move toward it today.  I like what I'm seeing overall.

[snow_wizard]

Watch climate change in action.

 

Flip from cool globe/-NAM to warm globe/+NAM happens in just 20 years.

 

1976-80:

 

 

 

1981-85:

 

 

 

1986-1990:

 

 

 

1991-95

 

 

Incredible how the step by step progression shows up in 5 year blocks like that!

[snow_wizard]

Wow!  SEA actually had a spike down to 34 at 11am today with some snowfall.  They actually beat my low by 1 degree which is an extreme rarity.  

[MossMan]

Dynamic afternoon!

[snow_wizard]

The NAM WRF is very interesting for late tonight and tomorrow morning.  A surface low tracks over central and eastern WA which puts the Puget Sound region is a cold backwash situation with significant precip tomorrow morning.  I'll be interested to see if GFS follows suit.

[HighlandExperience]

The NAM WRF is very interesting for late tonight and tomorrow morning. A surface low tracks over central and eastern WA which puts the Puget Sound region is a cold backwash situation with significant precip tomorrow morning. I'll be interested to see if GFS follows suit.

Looks like we get precip during the coldest period of time. Maybe some surprises in store!

[snow_wizard]

-11 departure day for EUG today.

 

Pretty crazy.  SEA only managed a -6 in spite of the late morning 34.

[The Swamp]

I'm watching the pressure falls near Darwin to see where we go from here.

 

It hailed today at my house nearly damaging my daffodils and tulips.

[snow_wizard]

Looks like we get precip during the coldest period of time. Maybe some surprises in store!

 

At face value the NAM WRF would be snowy for us.  We know this air mass is cold enough since some places had snow this morning.

[snow_wizard]

I'm watching the pressure falls near Darwin to see where we go from here.

 

It hailed today at my house nearly damaging my daffodils and tulips.

 

This almost sounds like an insult.