February 2019 Weather Observations and Discussion Part 2

[Deweydog]

Possibly, but I would expect places that maintain DP's in the upper 20's to maximize wet bulb without sacrificing too much of the moisture. Looks like DP's are inching downward towards the mid 20's where the north wind is prevailing.

 

Might want to stop the increasing ambient temps though. If it gets into the mid 40's by sunset, I find it hard to believe temps are going to cool off quick enough when the precip shows up, wet bulb or not.

Surface temps will be fine. It’s the mid level dryness that will prevent anything from accumulating here in the metro area north.

[SilverFallsAndrew]

Right now north of Albany I would predict we see about 6-8 hours of virga before widespread flurries break out between 4a-10a tomorrow morning. 

[FroYoBro]

The temperature refuses to go above 40 here with this strong wind. It has been between 39-40 since 11 am here. Don't think we will see any more warming today. 

[jakeinthevalley]

Medford radar down and many of the tripcheck cams are out of service. Just have to trust the surface obs to track

[TT-SEA]

Andrew's double persona... saying on facebook that enough is enough and spring can't come soon enough!

 

I say that on here AND in real life.      

[Deweydog]

Oh good lord...

[Phil]

A couple questions;

 

How quickly are we to see significant and extended cooling that lasts into the spring and summer if we were to go 80 out of 90 days without spots?

Is it a slam dunk that the Pacific Northwest will see snowy and cold winters if this were to take place?

Cooling as in globally? In the near term, solar forced cooling would be an effect of reduced radiative output rather than the sunspot number, and measuring said cooling might be impossible since year-to-year changes in global temperature due to changes in atmospheric circulation alone (ENSO being one example) have much larger effects on the structure of the energy budget that the 11yr solar cycle. However, if you consider the likelihood that the ENSO/IPWP structure is driven by the 11yr solar cycle (in tandem with other internal components like the QBO/mass circulation/annular modes/off equatorial heat budget/etc) and is a primary systematic conduit to equilibration on a fixed resonance, then the entire equation re: cause/effect becomes muddy since separating external forcing from internal amplification/dampening becomes almost impossible if you’re looking to attribute forcings back to an origin (in time).

 

As for the PNW..low solar statistically increases the chances of cold/snow, because the reduction in both the radiative output and geomagnetic activity, even slightly, promotes changes in upper atmospheric chemistry and thermal gradients (both meridionally [y] and vertically [z]) which affect large scale circulation and wave activity in a manner that promotes more “blocky” type patterns during boreal winter, and possibly in general. This is especially true in the current climate era, which is biased towards a more positive annular mode and broad z-cells in the long run, where-as low solar was less of a necessity during the middle 20th century, when the z-cells were narrow and the annular modes were negative (the climate system was in a multidecadal, structurally self-perpetuating cooling regime at the time, which terminated in the late 1970s).

 

Also, the solar effects on weather patterns/blocking itself is non linear/state dependent..it varies over time. So the answer I’m giving you now might not have applied back in the early Holocene, for instance, when the axial precession/seasonality to eccentricity was inverted).

[jakeinthevalley]

Surface temps will be fine. It’s the mid level dryness that will prevent anything from accumulating here in the metro area north.

Right now I am looking at the N/S cut off of the driest air to determine the moisture eating potential as the plume works it's way NNW.

 

I agree with Andrew that right now Albany north, will be the cut off.

[SilverFallsAndrew]

RGEM is much jucier. Still not impressive, but light snow for about 12-15 hours from Salem-north. 

 

[epiceast]

Tri-Cities is 3.5" away from breaking the February snowfall record from 1916.

Another storm about to rollin as well. Could clinch it.

[jakeinthevalley]

And the PDX NWS just issued Winter Weather Advisory for the valley after 7pm tonight for 1-2" accumulations

[SilverFallsAndrew]

Andrew's double persona... saying on facebook that enough is enough and spring can't come soon enough!

 

I say that on here AND in real life.      

 

Thanks for outing me Tim.

 

I will say it here too. The winter weather has begun to negatively impact my life. It has been a historic and amazing month, but enough is enough I am ready for spring. Some nice wet snow events that melt within a day would be welcome, but so would being able to see my lawn for the first time in a month. 

[epiceast]

Andrew's double persona... saying on facebook that enough is enough and spring can't come soon enough!

 

I say that on here AND in real life.      

Silverton Tim

[Deweydog]

Right now I am looking at the N/S cut off of the driest air to determine the moisture eating potential as the plume works it's way NNW.

 

I agree with Andrew that right now Albany north, will be the cut off.

The best system dynamics are also well to the south so it’s a 1-2 punch.

[TT-SEA]

Just noticed the dewpoint map for Sunday... holy crap that is dry air.

 

[Blizzard777]

EURO showing ridiculous gorge outflow Sunday with a high of 33 at PDX under sunny skies. A balmy 41 down in Salem that day away from the gorge.

The sleeping giant has awoken !!

[Phil]

How strong is the actual correlation between low solar and stronger high latitude blocking? A lot of the stuff I’ve seen seems pretty anecdotal.

It’s actually quite strong, but since the wave structure changes over time regardless, the indices/EOFs we use to *measure* said blocking might not tell us the whole story.

 

For instance, say the structure of the PNA or NAO change slightly over a few centuries (IE: the location, scope, and size of the anomalies changes to some extent, which did happen with the PNA after the 19th century). In that case, the original EOF/index would not capture the variability as well, even if the pattern is just as “blocky”.

 

Which is why I like the annular mode index the best..it’s far from perfect but it best captures the totality of the “blocking” (IE: repetitive and self-reinforcing wave breaking) in the streamflow above the horse latitudes in a given hemisphere.

 

Also, again, the particular effects of solar on the wavetrain do change over time..they’re both nonlinear and state dependent. It’s not an easy question to answer, but the best answer I can give is that there is a clear relationship between the *forward evolution* of the system state and solar forcing..but the nature of that evolution is, well, evolving. Perpetually.

[Jesse]

Thanks for outing me Tim.

 

I will say it here too. The winter weather has begun to negatively impact my life. It has been a historic and amazing month, but enough is enough I am ready for spring. Some nice wet snow events that melt within a day would be welcome, but so would being able to see my lawn for the first time in a month.

Are your sheep still alive?

[SilverFallsAndrew]

The cams that are operational show Medford getting absolutely blasted with snow right now.

[SilverFallsAndrew]

Are your sheep still alive?

 

Yes, but they would probably like to be able to access fresh grass. Been having to spend much more than usual on Alfalfa and grain. 

[Deweydog]

Thanks for outing me Tim.

 

I will say it here too. The winter weather has begun to negatively impact my life. It has been a historic and amazing month, but enough is enough I am ready for spring. Some nice wet snow events that melt within a day would be welcome, but so would being able to see my lawn for the first time in a month.

Can you get on this Jesse?

 

Plan 3E plus a passive aggression upgrade and sugar in the gas tank should suffice.

[FroYoBro]

The cams that are operational show Medford getting absolutely blasted with snow right now.

 

I'm happy to see Ashland getting snow today. They have been in a bad spot this month. 

[SilverFallsAndrew]

GFS shows pretty much nothing with this system tomorrow morning. 

[Jesse]

Can you get on this Jesse?

 

Plan 3E plus a passive aggression upgrade and sugar in the gas tank should suffice.

No I get it. It’s been a crazy stretch for lots of people. You know it’s been pretty historic or at least unusual when winter weather lovers like Kayla and Andrew are screaming “uncle”.

[jakeinthevalley]

The best system dynamics are also well to the south so it’s a 1-2 punch.

There will be enough moisture making it NNW.....eventually

[Deweydog]

There will be enough moisture making it NNW.....eventually

East slope locations against the coast range could do okayish.

[TT-SEA]

If the dewpoint will be at or below zero here by Sunday... maybe I will get to see some of that sublimation action that I hear so much about.   Because the snow will not be turning to water with air that dry.  

[Phil]

It certainly has been for the northern plains/northern Rockies. Not very often you see -15 or greater anomalies over such a large area for a month.

 

30dTDeptUS.png

It’s been the case over North America in general, though it’s been more persistent out West since that -NAM structure downwelled following the SSW.

 

When it was warm in West during the last 10 days of January, that massive Arctic outbreak froze the Midwest and East, which easily compensated for the warmth out there. Then it flipped in February. Still, the theme remained the same: cold dominating over warm across the lower-48.

[Deweydog]

No I get it. It’s been a crazy stretch for lots of people. You know it’s been pretty historic or at least unusual when winter weather lovers like Kayla and Andrew are screaming “uncle”.

Eh. When you live at 1,600 feet on the west slopes of the Cascades or in Montana you should know this is gonna happen from time to time.

[Phil]

2F2D9865-6074-4893-8254-0FB392A9224A.png

Not surprised in the slightest.

[MossMan]

Just noticed the dewpoint map for Sunday... holy crap that is dry air.

 

Looks like my area has the highest DP’s! Winter cancel.

[Jesse]

It’s actually quite strong, but since the wave structure changes over time regardless, the indices/EOFs we use to *measure* said blocking might not tell us the whole story.

 

For instance, say the structure of the PNA or NAO change slightly over a few centuries (IE: the location, scope, and size of the anomalies changes to some extent, which did happen with the PNA after the 19th century). In that case, the original EOF/index would not capture the variability as well, even if the pattern is just as “blocky”.

 

Which is why I like the annular mode index the best..it’s far from perfect but it best captures the totality of the “blocking” (IE: repetitive and self-reinforcing wave breaking) in the streamflow above the horse latitudes in a given hemisphere.

 

Also, again, the particular effects of solar on the wavetrain do change over time..they’re both nonlinear and state dependent. It’s not an easy question to answer, but the best answer I can give is that there is a clear relationship between the *forward evolution* of the system state and solar forcing..but the nature of that evolution is, well, evolving. Perpetually.

 

Thanks for the explanation. So yeah it's pretty complex and non-linear, as I would have guessed. It seems like a lot of people use low solar as kind of a carte blanche with "It will make weather type x which I also happen to prefer soooo much more likely!" type reasoning. Enough certainty exists around it where it can be pretty much anything you want it to be with enough stretching.

[jakeinthevalley]

East slope locations against the coast range could do okayish.

We also have a few 1000' ridges of hills in the Salem area that tend to enhance precip rates coming from that direction. I have seen it before, as I am smack dab in the middle of one.

 

Not the cold damming of the coast range, but kinda orographic and providing a little extra lift

[TT-SEA]

Did a google search... snow sublimation happens best when its sunny, windy, and the air is really dry.  

 

Check, check, and check early next week.   Sublimate away! 

[epiceast]

Did a google search... snow sublimation happens best when its sunny, windy, and the air is really dry.  

 

Check, check, and check early next week.   Sublimate away! 

Doesn't your snow already have a crust on it, so all of that is moot?

[Deweydog]

We also have a few 1000' ridges of hills in the Salem area that tend to enhance precip rates coming from that direction. I have seen it before, as I am smack dab in the middle of one.

 

Not the cold damming of the coast range, but kinda orographic and providing a little extra lift

Makes sense.

[TT-SEA]

Doesn't your snow already have a crust on it, so all of that is moot?

It does at night... but its quite soft right now during the day.

[Blizzard777]

NE winds gusting to 18 here in Federal Way and dew point has crashed to 11*

Feel like I’m back in Troutdale !!!

Chilly sunshine 42.7

[Jesse]

Eh. When you live at 1,600 feet on the west slopes of the Cascades or in Montana you should know this is gonna happen from time to time.

 

I agree with this too. But it doesn't mean people aren't going to complain a little when it does.

[SilverFallsAndrew]

No I get it. It’s been a crazy stretch for lots of people. You know it’s been pretty historic or at least unusual when winter weather lovers like Kayla and Andrew are screaming “uncle”.

 

I am lucky this happened in February and not December or January, when this pattern would have delivered even colder temps, snow/water ratios would have been higher, meaning deeper snow and with less or no melting in between events. This pattern in January would lead to January 1950/1969 type events. I would not be able to handle those kinds of situations, I thought I would be able to because I went through some really huge storms back in 2012, but those melted quickly and were relatively mild systems. The sustained cold and snow cover present challenges. I had 21 days of snow cover in January 2017, but my max depth never got over 10" and my daughter had not been born yet. So in short, the silver lining is I now have a pretty good list of things I need to do to prepare for this kind of streak of winter weather in the future, and to be able to truly be able to enjoy it comfortably.