January Weather In the PNW

[Gradient Keeper]

Day 10 heading the right direction much like the GFS, GEM. It's OUR turn! Colder runs ahead

 

http://maps1.pivotalweather.com/maps/models/ecmwf/2018012400/240/500h_anom.na.png

[Gradient Keeper]

00z CMCE is quite good! Here is day 10-11

http://maps3.pivotalweather.com/maps/models/cmce/2018012400/258/500h_anom.na.png

 

Here is the loop> http://www.pivotalweather.com/model.php?m=cmce&p=500h_anom&rh=2018012400&fh=loop&r=na&dpdt=

[Deweydog]

Maybe.

 

Might join forces with the ridge to the south and become a full latitude monster.

 

Extremely unlikely.

[Jesse]

Extremely unlikely.

Bob and Doug McKenzie seem sold on the idea.

[snow_wizard]

The Canadian ensemble is on board for some fun.  Some of these members are crazy cold.

 

 

[Phil]

I’m having a difficult time figuring out what would force a full-blown retrogression in the middle of a jet extension upstream. Sort of a head scratcher.

 

Not that it matters what I think, at this point.

[Deweydog]

Bob and Doug McKenzie seem sold on the idea.

I wouldn't go that far, still quite a bit of undercutting. Any "merging" looks coincidental to me. Hard to find many instances of a massive, closed block just floating around up there and happening into a position where it merges with a fairly progressive mid latitude ridge and they marry into a true full latitude block.

[Gradient Keeper]

I’m having a difficult time figuring out what would force a full-blown retrogression in the middle of a jet extension upstream. Sort of a head scratcher.

 

Not that it matters what I think, at this point.

The coming tanked -EPO along with -PNA. DONE DEAL

 

--

18z NAM (Friday) in 60 hours 31 minutes

[wx_statman]

I wouldn't go that far, still quite a bit of undercutting. Any "merging" looks coincidental to me. Hard to find many instances of a massive, closed block just floating around up there and happening into a position where it merges with a fairly progressive mid latitude ridge and they marry into a true full latitude block.

 

Feb 1995 basically did that. But it was a real fluke. 

[Phil]

The coming tanked -EPO along with -PNA. DONE DEAL

 

--

18z NAM (Friday) in 60 hours 31 minutes

l don’t want to get into an hours-long PNA debate again.

 

Remember, though, that these indices don’t drive the pattern..they only reflect it. I don’t know what will happen this time, but I certainly don’t think this is anything close to a “done deal”. I’m still on the skeptical side, if anything.

[Jesse]

I wouldn't go that far, still quite a bit of undercutting. Any "merging" looks coincidental to me. Hard to find many instances of a massive, closed block just floating around up there and happening into a position where it merges with a fairly progressive mid latitude ridge and they marry into a true full latitude block.

Ah, we are putting our serious face on.

 

It definitely is not a likely progression.

[Phil]

FWIW, we haven’t had a single -NAO month during DJF in five years. That’s a new record.

[Deweydog]

Feb 1995 basically did that. But it was a real fluke.

The Pacific was essentially shut down in the days leading up to it, leading up to a pretty classic retrogression. In this case they seem to be like two global warming ships passing in the night.

[snow_wizard]

I’m having a difficult time figuring out what would force a full-blown retrogression in the middle of a jet extension upstream. Sort of a head scratcher.

 

Not that it matters what I think, at this point.

 

It appears the low that settles in NW of Hawaii is the key.  All models agree on that feature.

[Frontal Snowsquall]

00z CMCE is quite good! Here is day 10-11

http://maps3.pivotalweather.com/maps/models/cmce/2018012400/258/500h_anom.na.png

 

Here is the loop> http://www.pivotalweather.com/model.php?m=cmce&p=500h_anom&rh=2018012400&fh=loop&r=na&dpdt=

What's been missing this winter is that we haven't had much positive tilt to any troughs. The 00z CMCE shows some nice positive tilt and this should drive the Arctic air down to us. Now we need the GFS and EURO to show this.

[snow_wizard]

Ah, we are putting our serious face on.

 

It definitely is not a likely progression.

 

It sure looks like the models like the idea of it though.  One of my indicators is in play now...that being sub 1000mb pressure over Darwin.  Don't ask me why, but that figures into some nice cold waves for us.  I have actually thought the models have to change in our favor based on the tropics.  I'm dying to see how this is going to work out.

[snow_wizard]

What's been missing this winter is that we haven't had much positive tilt to any troughs. The 00z CMCE shows some nice positive tilt and this should drive the Arctic air down to us. Now we need the GFS and EURO to show this.

 

The GFS operational did.

[wx_statman]

The Pacific was essentially shut down in the days leading up to it, leading up to a pretty classic retrogression. In this case they seem to be like two global warming ships passing in the night.

 

It looked somewhat similar to me, compared to maps being shown tonight. I don't doubt what you're saying though.

 

Either way, Feb 1995 was one of the least likely events we'll ever see w/regard to background forcing. Interrupting a full-blown Nino torch in February. Not supposed to happen. I'm pretty sure you have to go back to mid-Feb 1900 for a precedent. 

[Deweydog]

What's been missing this winter is that we haven't had much positive tilt to any troughs. The 00z CMCE shows some nice positive tilt and this should drive the Arctic air down to us. Now we need the GFS and EURO to show this.

What is shown there is almost a carbon copy of the close call leading up to Christmas. We have an overdevoloped block over AK with a dirty ridge axis to the south preventing any westward digging.

[Deweydog]

It looked somewhat similar to me, compared to maps being shown tonight. I don't doubt what you're saying though.

 

Either way, Feb 1995 was one of the least likely events we'll ever see w/regard to background forcing. Interrupting a full-blown Nino torch in February. Not supposed to happen. I'm pretty sure you have to go back to mid-Feb 1900 for a precedent.

Definitely a rogue one. Maybe this winter is finally the payback for that badass.

[snow_wizard]

With the current situation it's amazing to think a few details of how the pieces come together could be the difference between a very cold February and one that is a complete flop.  If the good pattern happens it could easily lock in long enough to give us a couple of solid cold shots.

[Phil]

It appears the low that settles in NW of Hawaii is the key. All models agree on that feature.

That’s just one piece in the giant puzzle, though. I’ve spent the last 30 minutes laying in bed, looping the streamfunction and height anomalies over and over again..and while I can see why the retrogression happens on some of the guidance, it’s super convoluted.

 

#ThreadingTheNeedle

[Frontal Snowsquall]

What is shown there is almost a carbon copy of the close call leading up to Christmas. We have an overdevoloped block over AK with a dirty ridge axis to the south preventing any westward digging.

Yeah that too. Some of the problems this winter has been that the block becomes too top heavy.

[Deweydog]

With the current situation it's amazing to think a few details of how the pieces come together could be the difference between a very cold February and one that is a complete flop. If the good pattern happens it could easily lock in long enough to give us a couple of solid cold shots.

Could lead to a really hot and cloudy summer too.

 

#dewforsomehighdewpoints

[wx_statman]

Definitely a rogue one. Maybe this winter is finally the payback for that badass.

 

No, payback was 2000-01. This current payback is for last winter. 

[BLI snowman]

It looked somewhat similar to me, compared to maps being shown tonight. I don't doubt what you're saying though.

 

Either way, Feb 1995 was one of the least likely events we'll ever see w/regard to background forcing. Interrupting a full-blown Nino torch in February. Not supposed to happen. I'm pretty sure you have to go back to mid-Feb 1900 for a precedent. 

 

March 1906 was pretty crazy as well. Huge torchy ridge retrograded into one of the more freakish arctic airmasses on record for us, after a mild, strong Nino winter. Then ridging quickly returned and lead into one of the great April torches.

 

Vancouver went from 72/37 on March 9 to 30/22 on March 12. Nutso stuff.

[TT-SEA]

00Z EPS at day 10...

 

 

[Deweydog]

No, payback was 2000-01. This current payback is for last winter.

It's making the bellyaching they did in the BG School District when scheduling this year. They ended up settling on building in six snow days for this year back in May. Pretty much sealed the deal.

[Deweydog]

00Z EPS at day 10...

 

 

EXTREME!!!

[Phil]

This is one heck of an MJO wave. Still looks to avoid phases 8-3 until after February 10th. So still 2+ weeks left with decent tropical forcing.

 

 

[TT-SEA]

EXTREME!!!

I think that is actually a full latitude block.

 

I still sense retrogression!

[TT-SEA]

Control run still going nuts in the 10-15 day period as well.

[Deweydog]

I think that is actually a full latitude block.

 

I still sense retrogression!

With a 20+ dm north/south gradient from the offshore waters to Anchorage?

[TT-SEA]

With a 20+ dm north/south gradient from the offshore waters to Anchorage?

Debbie Downer.

[wx_statman]

March 1906 was pretty crazy as well. Huge torchy ridge retrograded into one of the more freakish arctic airmasses on record for us, after a mild, strong Nino winter. Then ridging quickly returned and lead into one of the great April torches.

 

Vancouver went from 72/37 on March 9 to 30/22 on March 12. Nutso stuff.

 

Yeah, definitely a crazy one.

 

Late March 1914 is another good example of a Nino torch having a hiccup. Some places in western WA went from highs near 80 to 40's/30's with snow in the air in the span of a few days. 

[wx_statman]

It's making the bellyaching they did in the BG School District when scheduling this year. They ended up settling on building in six snow days for this year back in May. Pretty much sealed the deal.

 

Classic overreaction!

[Deweydog]

Classic overreaction!

Nine days last year, which was unprecedented for the district by almost double.

[Jesse]

Could lead to a really hot and cloudy summer too.

 

#dewforsomehighdewpoints

6th consecutive and coming off of a La Niña? Getting into some pretty unlikely territory.

[Phil]

I think the control run brings the actual PV (tropospheric vortex coupled to the stratospheric one) into southern Canada by day 14. Have to check the strat plots when they come out, but it looks like it.

[Deweydog]

Easterlies making a comeback!!!