December 2015 in the Pacific Northwest

[TT-SEA]

I'm beginning to think January has a shot at coming in reasonably chilly this year. I'm not basing that on the CFS, but it is nice to see that model has had a big change of heart for us. I think a combination fake and some real cold later in the month could combine to give us a decently chilly month. I sure am bummed we couldn't manage to come up with some snow going into this long chilly snap coming up.

You say that every single time there is an inversion. Very unlikely you will get real cold after the inversion. You are always rationalizing ahead and it never works out to your plan. That is why you go crazy.

 

And even my snow is going to melt. You had no chance of snow covering the ground during the cold snap even if it had snowed.

[Jesse]

The fact it's "down" to 30 with a few hours now of steady east winds is pretty telling.

We're all screwed.

[MR.SNOWMIZER]

You say that every single time there is an inversion. Very unlikely you will get real cold after the inversion. You are always rationalizing ahead and it never works out to your plan. That is why you go crazy.

And even my snow is going to melt. You had no chance of snow covering the ground during the cold snap even if it had snowed.

Hit a guy when he's down?

[Jesse]

DP down to 31 at PDX.

 

29 at TTD.

[BLI snowman]

DP is down to 30 at Troutdale with a stiff east wind. Hopefully that or cooler/drier can manage to spread across the entire metro by later today.

 

Starting to trickle in there, light SE wind now at PDX with a 39/31 spread. I'll be impressed if we can see widespread td's in the 26-27 range this evening and early tomorrow. That'd indicate a somewhat deeper dry/cool air layer than modeled and indicate a wet bulb zero height right near 1000mb.

[TT-SEA]

Hit a guy when he's down?

Trying to help... he does this to himself.

[Jesse]

Starting to trickle in there, light SE wind now at PDX with a 39/31 spread. I'll be impressed if we can see widespread td's in the 26-27 range this evening and early tomorrow. That'd indicate a somewhat deeper dry/cool air layer than modeled and indicate a wet bulb zero at 1000mb of right near freezing.

DPs in the upper 20s at Troutdale are promising to see.

 

Cool, dry air should continue to advect throughout the area as the day wears on.

[Deweydog]

We're all screwed.

I think there's a lot of people here that struggle mightily in that department.

 

Your elevation should serve you well though if you're on the west side.

[snow_wizard]

Seeing some single digit lows over Central WA this morning with very heavy snow cover in that part of the state.  That should contribue to building a major dome of cold air over the Basin / Central WA next week.  The ECMWF and GFS look very favorable for some impressive low level cold this week.  It begins with some legit cold air after the overruning event very early next week.

 

BTW a friend of mine lives along US 97 about 15 miles north of Ellensburg and reports three feet of snow on the ground.  I was lucky enough to live in that area a couple of winters in the early 1980s and never saw it that deep.

[Jesse]

I think there's a lot of people here that struggle mightily in that department.

 

Your elevation should serve you well though if you're on the west side.

Yeah, I am interested to see how that works out.

We are almost due south of Beaverton.

[BLI snowman]

DPs in the upper 20s at Troutdale are promising to see.

 

Cool, dry air should continue to advect throughout the area as the day wears on.

 

Model output all indicated that, though. TTD's dewpoint seems to drop to about 28 this evening on most of the MOS output the past few days. Anything better today would be encouraging for cooler temps tomorrow morning.

[Jesse]

Model output all indicated that, though. TTD's dewpoint seems to drop to about 28 this evening on most of the MOS output the past few days. Anything better today would be encouraging for cooler temps tomorrow morning.

Yup, I guess it is nice to see considering it is only noon though and easterly flow only looks to increase between now and early tomorrow. Hopefully DPs continue to tick down the next several hours.

[snow_wizard]

As for the longer term, it appears the MJO should enter favorable territory for us again by mid Jan or so.  Every time the MJO has gotten into the 2 through 5 range over the past few months the PNA has tanked pretty good.  With a good AO drop forecast in the near future a -PNA in combination with that could potentially treat us pretty well.  Past history tells us that when the PNA is negative we only need either the AO, NAO, or EPO to be minus to be assured of a good shot at getting an Arctic outbreak.  2007-08 and this past week show us very clearly what happens when only the PNA is minus.  I had 4 consecutive days with snow mixed with rain or wet snow and only got 0.1" out of all of it.  Mid January will be a window of opportunity for us...nothing more nothing less.

 

I'm really tired of Tim trying to make it sound like I have no idea what I'm talking about.

[SilverFallsAndrew]

To bad we won't get some clearing this evening

[MR.SNOWMIZER]

Seeing some single digit lows over Central WA this morning with very heavy snow cover in that part of the state.  That should contribue to building a major dome of cold air over the Basin / Central WA next week.  The ECMWF and GFS look very favorable for some impressive low level cold this week.  It begins with some legit cold air after the overruning event very early next week.

 

BTW a friend of mine lives along US 97 about 15 miles north of Ellensburg and reports three feet of snow on the ground.  I was lucky enough to live in that area a couple of winters in the early 1980s and never saw it that deep.

Must have alot of elevation.

[Jesse]

Must have alot of elevation.

The area around Liberty/Blewett Pass is between 2-4,000'.

[snow_wizard]

Hit a guy when he's down?

 

He's famous for it.  Speculating about possible chances for cold and snow is about the only thing that can keep a cold weather fan sane around here sometimes.  I have never said anything about being sure the second half of January will be cold.

[snow_wizard]

Must have alot of elevation.

 

2500 or so.  He lives on a hill a few hundred feet above the Liberty Cafe if you know where that is.

[MR.SNOWMIZER]

2500 right there.  He lives on a few hundred feet above the Liberty Cafe if you know where that is.

I used to ride snowmobile there alot. Cool area.

[ShawniganLake]

As for the longer term, it appears the MJO should enter favorable territory for us again by mid Jan or so.  Every time the MJO has gotten into the 2 through 5 range over the past few months the PNA has tanked pretty good.  With a good AO drop forecast in the near future a -PNA in combination with that could potentially treat us pretty well.  Past history tells us that when the PNA is negative we only need either the AO, NAO, or EPO to be minus to be assured of a good shot at getting an Arctic outbreak.  2007-08 and this past week show us very clearly what happens when only the PNA is minus.  I had 4 consecutive days with snow mixed with rain or wet snow and only got 0.1" out of all of it.  Mid January will be a window of opportunity for us...nothing more nothing less.

 

I'm really tired of Tim trying to make it sound like I have no idea what I'm talking about.

Do you have any examples of Januaries where we have seen an inversion period transition into an arctic outbreak within a week or so?

[TT-SEA]

As for the longer term, it appears the MJO should enter favorable territory for us again by mid Jan or so. Every time the MJO has gotten into the 2 through 5 range over the past few months the PNA has tanked pretty good. With a good AO drop forecast in the near future a -PNA in combination with that could potentially treat us pretty well. Past history tells us that when the PNA is negative we only need either the AO, NAO, or EPO to be minus to be assured of a good shot at getting an Arctic outbreak. 2007-08 and this past week show us very clearly what happens when only the PNA is minus. I had 4 consecutive days with snow mixed with rain or wet snow and only got 0.1" out of all of it. Mid January will be a window of opportunity for us...nothing more nothing less.

 

I'm really tired of Tim trying to make it sound like I have no idea what I'm talking about.

You build things up way too much and only see what you want to see and then get way too down when it does not work out.

[MR.SNOWMIZER]

Jim its a well known fact your one of the most knowledgeable people on the forum. I look forward to your analysis as do most of us on here I'm sure.

[BLI snowman]

Do you have any examples of Januaries where we have seen an inversion period transition into an arctic outbreak within a week or so?

 

Happened to some extent as recently as January 2009. Fake cold midmonth that morphed rather seamlessly into an upper level event around the 26th.

 

If you look at many of the brutally cold months like January 1949 and January 1957, that eastside cold pool was integral in preserving our cold temperatures. A lot of the cold in those years was rather low level based.

[SilverFallsAndrew]

Little bit of north wind here. That bodes fairly well I would think...

[snow_wizard]

Do you have any examples of Januaries where we have seen an inversion period transition into an arctic outbreak within a week or so?

 

1985 is the most extreme example in recent times.  1984-85 had a classic mix of real cold and low level / fake cold.  We transitioned from an inversion for most of the first three weeks of the month to deeper cold late month and then snow with an Arctic outbreak around Feb 1.

[stuffradio]

Jan 2009 was awesome for Sun and cold lovers alike.

[Jesse]

Happened to some extent as recently as January 2009. Fake cold midmonth that morphed rather seamlessly into an upper level event around the 26th.

 

If you look at many of the brutally cold months like January 1949 and January 1957, that eastside cold pool was integral in preserving our cold temperatures. A lot of the cold in those years was rather low level based.

That's something that a lot of people here overlook. Much maligned "fake" cold generally has played a large role in our coldest months, historically. Even in January 1930 and 1950, the temps brought about by monster cold airmasses in the upper levels were supplemented by loads of low level cold in between.

 

It's unusual for significant cold in the upper levels (

[TT-SEA]

Not sure if I will have snow tomorrow or not... the pass is at 24 right now which is a good sign and obviously its colder to the east of that.   With an established cold pool...it can stay cold and snowy here for a long time in the absence of strong onshore flow.    Many times there is a dramatic line right at the Hwy 18 exit on I-90... going down the hill into North Bend it suddenly turns snowy and cold while its raining to the west and even at Tiger Mountain which is higher than my location.  

 

Weak systems like tomorrow can be great here... spreads solid precip in but there is no scouring of the cold air.    

[BLI snowman]

That's something that a lot of people here overlook. Much maligned "fake" cold generally has played a large role in our coldest months, historically. Even in January 1930 and 1950, the temps brought about by monster cold airmasses in the upper levels were supplemented by loads of low level cold in between.

 

It's unusual for significant cold in the upper levels (

 

Indeed, although 1950 was in fact a little more freakish in that the PV resided fairly close to us for an extended period and the upper level patterns did support extreme cold for a majority of that run. That monthly PNA of -4.39 in January 1950 is probably something we won't see repeated in our lifetimes, honestly. 

[TT-SEA]

Although the MM5 says it will not snow here tomorrow.   And it showed 3 feet of snow for me this week so it tends to over-estimate just a little bit!  

 

http://www.atmos.washington.edu/mm5rt/data/current_gfs/images_d4/ww_msnow24.36.0000.gif

[snow_wizard]

Interesting to see Jan 1985 is a top analog right for the pattern progged at days 8 and 11 in spite of that being a La Nina.  Another one that catches my is December 1976...another one where we went directly from an overhead ridge to an Arctic intrusion a bit later on.

 

There are a number of odd things going with this Nino such as the current MJO wave making a strong showing regions 4 and 5 and an SOI average for the last 4 days +19.65.  An SOI like that with this ENSO should be impossible, but it is happening.  We have a shot at the warmest anomalies remaining over the NC and NE parts of the country in January after those areas receive some relief from the warmth early in the month.  All just speculation right now though.

[Phil]

Jim its a well known fact your one of the most knowledgeable people on the forum. I look forward to your analysis as do most of us on here I'm sure.

Agreed, Jim really knows his stuff. I don't always agree with him, but when he feels strongly about something, I always take notice.

[Jesse]

Indeed, although 1950 was in fact a little more freakish in that the PV resided fairly close to us for an extended period and the upper level patterns did support extreme cold for a majority of that run. That monthly PNA of -4.39 in January 1950 is probably something we won't see repeated in our lifetimes, honestly.

Who knows...

 

But yeah, 1950 probably isn't the best example. That is one of the most freakish anomalies in our period of modern record as far as sustained cold in the upper levels goes. Still, I'm sure "fake" cold helped pad the anomalies to some small degree.

[Perturbed Member]

Model output all indicated that, though. TTD's dewpoint seems to drop to about 28 this evening on most of the MOS output the past few days. Anything better today would be encouraging for cooler temps tomorrow morning.

 

Just starting to feel the effects of the offshore flow here on the west end now. HIO dp at 32 from 34 in the last hour. Mostly following what the models showed so far.

[BLI snowman]

Although the MM5 says it will not snow here tomorrow.   And it showed 3 feet of snow for me this week so it tends to over-estimate just a little bit!  

 

http://www.atmos.washington.edu/mm5rt/data/current_gfs/images_d4/ww_msnow24.36.0000.gif

 

Or it's just wrong a lot. Like the NAM. 

[snow_wizard]

Indeed, although 1950 was in fact a little more freakish in that the PV resided fairly close to us for an extended period and the upper level patterns did support extreme cold for a majority of that run. That monthly PNA of -4.39 in January 1950 is probably something we won't see repeated in our lifetimes, honestly. 

 

Jan 1950 and Jan 1909 were a couple of cases where extreme -PNA was enough to do the job.  Very rare though.

 

An interesting fact about Jan 1969 is minus PNA in combination with very low NAO is what delivered the goods that month.  If the PNA is minus low AO or low NAO can be our friend big time.

[MossMan]

Indeed, although 1950 was in fact a little more freakish in that the PV resided fairly close to us for an extended period and the upper level patterns did support extreme cold for a majority of that run. That monthly PNA of -4.39 in January 1950 is probably something we won't see repeated in our lifetimes, honestly.

Was there ever an event that was similar as far as duration and overall setup in recorded history? Late 1800's? Wasn't there some epicness around 1917? I really would want nothing more than to experience a 1950 type event. My grandparents were so lucky!!

[snow_wizard]

Who knows...

 

But yeah, 1950 probably isn't the best example. That is one of the most freakish anomalies in our period of modern record as far as sustained cold in the upper levels goes. Still, I'm sure "fake" cold helped pad the anomalies to some small degree.

 

I think I read somewhere the monthly average positive height anomaly over the GOA / Aleutians in Jan 1950 was the single most extreme 500mb monthly anomaly observed anywhere on Earth during the 20th century.  Pretty wild.

[BLI snowman]

Who knows...

 

But yeah, 1950 probably isn't the best example. That is one of the most freakish anomalies in our period of modern record as far as sustained cold in the upper levels goes. Still, I'm sure "fake" cold helped pad the anomalies to some small degree.

 

Mostly with the late month event. The Columbia Basin cold pool was off the charts at the end of January 1950. This sh*t was pretty stupidly ridiculous

 

http://www.wunderground.com/history/airport/KDLS/1950/1/31/DailyHistory.html

[MR.SNOWMIZER]

Even the high resolution is not backing off on snow. Currently 35 degrees here with no wind .