October 2017 PNW Discussion Thread

[TigerWoodsLibido]

MJO is roaring through Phase-6/WPAC right now. Will propagate right across the dateline (phases 7/8), then probably hit a wall as the Niña background state destructively interferes.

 

Still, it will perturb the Niña system for awhile, perhaps even degrading it until convection restarts in the IO/Indo domain.

 

Really hope that doesn't doom our winter.

[Karl Bonner]

My impression about late October / early November, is that it's probably the time of year when the daily standard deviation in temps, is at its lowest.  At least for lowlands east of the Cascades and in the Gorge.  We don't go more than 10-12 degrees above or below average during Halloween season very often.  Inversions are beginning to seriously nerf our sunny warm spells, and the arctic airmasses usually haven't developed enough to get real cold yet.  (There are, of course, the rare exceptions.)

The west side of the Cascades might fare relatively better in these late-season ridges, if they can get a good downslope warming effect.  But even that's far from a guarantee at this time of year.

[Phil]

Really hope that doesn't doom our winter.

It won't.

[Jesse]

PDX in the 40s. Score!!

[Phil]

Super -NAO on the clown range GFS. Result is, not surprisingly, a much colder pattern in the western and central US. If only it was real, lol.

 

#niña-naoclimo

[Phil]

Fun to stare at, though.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/227E106F-25A2-4F63-A3E7-4D7483A30D37_zpsmbmmdodb.png

[Front Ranger]

It's a bit more violent than Seinfeld.

 

But much like that show, it's often a forum about nothing.

[Front Ranger]

Its mostly just because the majority of the posters here are from Washington. Also I was just going to say, you seem to shortchange 92-93 a bit. It was by far the best winter in the Willamette Valley for snow in my lifetime. 

 

Eh, don't know about that. I'd say about 40% of active posters are from OR, 40% from WA, 10% from the Great White North, and 10% from elsewhere.

[Deweydog]

But much like that show, it's often a forum about nothing.

Winter is certainly not nothing.

[snow_wizard]

Pretty big changes on tonight's GFS.  Looks like more ridging tries to build further west.  The impressive thing about all runs is the continued lack of low pressure over the NE Pacific.  This is the time of year that often sets a precedent for winter in that region.  Obviously if we hold onto that theme this winter we will have a fun one!

[snow_wizard]

Really hope that doesn't doom our winter.

 

I think the winter is already set to be good.

[stuffradio]

Pretty big changes on tonight's GFS.  Looks like more ridging tries to build further west.  The impressive thing about all runs is the continued lack of low pressure over the NE Pacific.  This is the time of year that often sets a precedent for winter in that region.  Obviously if we hold onto that theme this winter we will have a fun one!

The LR has a SE ridge too, but it's not very strong yet.

[Phil]

Pretty big changes on tonight's GFS. Looks like more ridging tries to build further west. The impressive thing about all runs is the continued lack of low pressure over the NE Pacific. This is the time of year that often sets a precedent for winter in that region. Obviously if we hold onto that theme this winter we will have a fun one!

The ridging backbuilds due to constructive interference with the downstream wave breaking. In other words, that Hudson Bay vortex was replaced by a giant anticyclone.

 

After this week's wavebreaking event, the stability of the NAO block will probably determine how the pattern progresses, rather than the Pacific.

[stuffradio]

The GFS and GEM completely disagree 240 hours out. The GEM has a mega death ridge through western NA and GFS is pretty troughy.

 

[Phil]

The GFS and GEM completely disagree 240 hours out. The GEM has a mega death ridge through western NA and GFS is pretty troughy.

 

gem_z500aNorm_namer_41.png

gfs_z500aNorm_namer_41.png

Note the differences over the Arctic/Greenland domain.

 

Much like traffic on a highway, when there's a blockage downstream, it affects the flow of traffic upstream. In this case we have a series of NATL wavebreaks that will try to act as such "blockages" on the wavetrain.

 

Stronger, more stable wavebreaks downstream will push the trough anomaly farther southwest. Weaker, more unstable wavebreaks will favor an eastward progression of the trough anomaly.

[Front Ranger]

Winter is certainly not nothing.

 

[snow_wizard]

The GFS and GEM completely disagree 240 hours out. The GEM has a mega death ridge through western NA and GFS is pretty troughy.

 

gem_z500aNorm_namer_41.png

gfs_z500aNorm_namer_41.png

 

Even the GEM shows a lack of low pressure over the NE Pacific though.  That has been the screaming message on every model run.  Huge implications.

[snow_wizard]

Looking at the surface pressure gradients later this month we look well set for an inversion with very weak gradients developing and warm air aloft.

[BLI snowman]

Eh, don't know about that. I'd say about 40% of active posters are from OR, 40% from WA, 10% from the Great White North, and 10% from elsewhere.

 

55% WA, 30% OR, 15% BC. 

[Phil]

55% WA, 30% OR, 15% BC.

Flatiron/Me/Black Hole/Kayla/Andie/Luminen/etc contribute something like 40% of the posts here..I think?

[SilverFallsAndrew]

A seasonal 41 this morning. Long range starting to look okay.

[Timmy]

Flatiron/Me/Black Hole/Kayla/Andie/Luminen/etc contribute something like 40% of the posts here..I think?

He said “active poster” %, not post %.

[Jesse]

He said “active poster” %, not post %.

Hot take!!

[Front Ranger]

55% WA, 30% OR, 15% BC. 

 

Could be, technically. Although I think Portland metro people in Vancouver and such associate more with OR posters than Puget Sounders. I think the split is pretty even between Portland metro south, and Washingtonians north of there.

[TigerWoodsLibido]

And only a handful south of PDX metro. SFA and myself. There's others but they escape me at the moment. Anybody from south valley like Corvallis or Eugene here?

[Jesse]

And only a handful south of PDX metro. SFA and myself. There's others but they escape me at the moment. Anybody from south valley like Corvallis or Eugene here?

There’s a poster named Eujunga who is sometimes in Eugene, but spends the rest of the time in Tujunga, CA I believe. There is a poster down there named Dolt as well. We also have Perturburance, who lives in Corvallis, but he doesn’t post much. DareDuck is originally from Eugene but is now in Bend. I feel like there could be some other occasional Eugene posters besides Eujunga and Dolt though.

[Front Ranger]

There’s a poster named Eujunga who is sometimes in Eugene, but spends the rest of the time in Tujunga, CA I believe. We also have Perturburance, who lives in Corvallis, but he doesn’t post much. DareDuck is originally from Eugene but is now in Bend. I feel like there are some other occasional Eugene posters besides Eujunga though.

Dolt.

[TT-SEA]

Beautiful morning... on Monday of course. 

 

[wx_statman]

Noticed on the way in to downtown the Willamette is noticeably higher than last week.

[SilverFallsAndrew]

Noticed on the way in to downtown the Willamette is noticeably higher than last week.

 

I'd say...

 

[Front Ranger]

With only a slight chance of showers for some areas on Wednesday, today marks the start of what may turn out to be one of the more lengthy dry spells this time of year for the PNW. Things could always change, of course, but model consensus is strong right now for things remaining dry for at least the next 10 days.

[ShawniganLake]

Looks like Shawnigan Lake is running approx -1.5F for the month to date. Considering our daily averages are down to 55/41, it’s going to take some very chilly mornings during this upcoming dry spell to hold that negative departure thru the 31st.

[SilverFallsAndrew]

With only a slight chance of showers for some areas on Wednesday, today marks the start of what may turn out to be one of the more lengthy dry spells this time of year for the PNW. Things could always change, of course, but model consensus is strong right now for things remaining dry for at least the next 10 days.

 

I don't expect anymore meaningful rainfall this month. 

 

Currently at 8.90", average here for the month total is 6.20" so it will end up above average for the month. 2016 and 2012 were wetter in October here. 

[Timmy]

Noticed on the way in to downtown the Willamette is noticeably higher than last week.

Probably because of all the rain.

[Front Ranger]

I don't expect anymore meaningful rainfall this month. 

 

Currently at 8.90", average here for the month total is 6.20" so it will end up above average for the month. 2016 and 2012 were wetter in October here. 

 

Not many Octobers that produced this much rain across the region, but only 9-10 days of meaningful rainfall. 

 

1994 is probably the most extreme example. 21 dry days at PDX, yet a monthly rain total of 8.41"...thanks mainly to three days with 2.3"+ rainfall towards the end of the month.

[TigerWoodsLibido]

Things maybe cooling a bit in the clown range? You wonder if this ridge is just going to be persistent through the winter?

[TT-SEA]

Things maybe cooling a bit in the clown range? You wonder if this ridge is just going to be persistent through the winter?

 

 

No.   

[ShawniganLake]

Things maybe cooling a bit in the clown range? You wonder if this ridge is just going to be persistent through the winter?

It’s October 23rd

[SilverFallsAndrew]

Things maybe cooling a bit in the clown range? You wonder if this ridge is just going to be persistent through the winter?

 

It won't be. And it probably won't be as persistent as things look now... 

[Jesse]

Looks like Shawnigan Lake is running approx -1.5F for the month to date. Considering our daily averages are down to 55/41, it’s going to take some very chilly mornings during this upcoming dry spell to hold that negative departure thru the 31st.

That’s crazy. It’s interesting how the coldest anomalies have been focused to the south so often in recent years.