October 2017 PNW Discussion Thread

[Phil]

Looking back in history, 1974 had 2012 beat for weirdness in Eugene. Saw a freeze on Oct. 7th, but then didn't fall to 31 until Dec. 30th (the current benchmark).

 

This followed a ridiculously torchy September where EUG averaged an 85.1 maximum, more than 2 degrees above second place for the month. This included an 8-day streak of 90 degree heat from 9/18-9/25.

Both 1974/75 and 2012/13 were -ENSO/-QBO, as well. Funny how tiny subtleties in the system state can change the statistical likelihood of certain events.

[Geos]

Starting to rain here. Probably see the convergence zone showing itself fairly soon.

[Kayla]

Not sure if I buy it. Weren't we talking about them looking torchy for much of October just a few weeks ago?

 

I don't think they were ever showing a torchy first half of October. It's been showing a pretty clear high heights signal to end the month for a while now. Just based purely off pattern progression, it will likely end up being the typical late October/November firehouse I would guess which come November usually yields "torching".

[Jesse]

Should be PDX's first sub-60 max of the season today.

[Jesse]

I don't think they were ever showing a torchy first half of October. It's been showing a pretty clear high heights signal to end the month for a while now. Just based purely off pattern progression, it will likely end up being the typical late October/November firehouse I would guess which come November usually yields "torching".

I can definitely imagine a firehose pattern the last 1/3 of the month. Not sure if it will be enough to put a dent in the cold anomalies of the first 2/3, though.

[Kayla]

Up until the end of the run the 12z EPS just continues one deep trough after another. This one is looking pretty noteworthy for mid/late October.

 

[Jesse]

Up until the end of the run the 12z EPS just continues one deep trough after another. This one is looking pretty noteworthy for mid/late October.

 

Screen Shot 2017-10-10 at 2.20.16 PM.png

Must be pretty out of phase with the weeklies.

[Kayla]

Must be pretty out of phase with the weeklies.

 

It's actually just beyond this (21st-22nd) that the ridge begins settling in on the weeklies. So pretty close.

 

[Kayla]

So yeah, Phils progression sounds about right. Chilly, firehose, ridge.

[TT-SEA]

Up until the end of the run the 12z EPS just continues one deep trough after another. This one is looking pretty noteworthy for mid/late October.

 

Screen Shot 2017-10-10 at 2.20.16 PM.png

 

FWIW... the 12Z EPS also starts to transition to ridging right after day 10.   

 

Here is day 10 again:

 

  

 

And here is day 15... that is an unusually large change for the EPS in just 5 days:

 

[Phil]

So yeah, Phils progression sounds about right. Chilly, firehose, ridge.

I'm surprised how well the mix of modest -ENSO/-QBO and expanded warm pool analogs have performed so far. I'd aggregated these analogs pretty much on an experimental basis..not perfect, but didn't expect them to match the progression this well.

 

If this continues, then..cold January?!

 

 

Geopotential height anomalies, by month, depict the coldest weather (relative to average) in October and January, and the warmest weather (relative to average) in September, November and December.

 

September:

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/C6B84B23-1B97-4403-B7BC-D594BD592CEF_zpstsvzlisw.png

 

October:

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/36958577-201D-4C6A-8219-2208138E0A30_zpsd8ynwtqr.png

 

November:

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/8EE3EFC5-6ED5-4BAD-84A8-A3F27466D96B_zpsjefkwzd3.png

 

December:

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/79CC4FD0-B968-4E3E-9EF8-68BBDEB2ED48_zpsx5sy0yyl.png

 

January:

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/A83FB4B8-8FE5-43B3-8C4A-12717D46E0B2_zps4zo0ixmu.png

 

February:

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/6616CCF0-267B-43A2-A348-06F0B545E618_zps3dg0sbbw.png

 

March:

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/9C99B27C-56BD-4693-A488-A7010D64B6F7_zpspwpfzqbh.png

[Phil]

Interesting demonstration of seasonal-scale processes reflected via abrupt flips between quasi-stable modes of operation. Note the multi-month downward trend in the AO, then the regime terminates in a few days once the the Eurasian circulation transitioned far enough away from its summer mode.

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif

[Phil]

The reduced high Arctic seasonality continues.

 

Colder May-August, warmer September-April. Has become more pronounced in recent years.

 

http://ocean.dmi.dk/arctic/plots/meanTarchive/meanT_2017.png

[Front Ranger]

I can definitely imagine a firehose pattern the last 1/3 of the month. Not sure if it will be enough to put a dent in the cold anomalies of the first 2/3, though.

 

And like you pointed out recently, a firehose the second half of October doesn't necessarily mean torching. Despite the fire in the hose.

[Front Ranger]

FWIW. Years with similar, developing -ENSO.

 

 

2017 is certainly following the similar ENSO template so far this month. Long way to go, though.

 

[WeatherMonster]

Me smells lotsa Arctic blasts!

[stuffradio]

And like you pointed out recently, a firehose the second half of October doesn't necessarily mean torching. Despite the fire in the hose.

What comes first, the fire or the hose?

 

It's a beautifully sunny afternoon after receiving .20" of rain today

[Geos]

Pouring buckets here. Temp slide down to 46.

[TT-SEA]

Pouring buckets here. Temp slide down to 46.

 

Wow... fairly sunny here and dry for the last couple hours.  

 

SEA is at 57 now and 56 here.

[Geos]

Wow... fairly sunny here and dry for the last couple hours.  

 

SEA is at 57 now and 56 here.

 

Not a full blown CZ, but it was pretty impressive for about 15 minutes. Heaviest cell heading over Bothell and Woodinville now.

I didn't see too much sun here today. There was a little early this morning and then it was dark and gloomy the rest of the day.

[TT-SEA]

Not a full blown CZ, but it was pretty impressive for about 15 minutes. Heaviest cell heading over Bothell and Woodinville now.

I didn't see too much sun here today. There was a little early this morning and then it was dark and gloomy the rest of the day.

 

Most of western WA is fairly sunny now except for the c-zone area. 

[Geos]

Most of western WA is fairly sunny now except for the c-zone area. 

 

I noticed the lighter skies to the south. 

[TT-SEA]

I noticed the lighter skies to the south. 

 

Good view of the c-zone on the Space Needle cam:

 

[Deweydog]

I saw a woolly bear caterpillar today and its coat looked anomalously thick!

[Geos]

Got home and I had hail... I think, dotting the yard.

 

[TT-SEA]

I saw a woolly bear caterpillar today and its coat looked anomalously thick!

 

There seems to be an unusual number of them around here this year... my daughter collected 11 of them the other night.   She did let them go.   

[BLI snowman]

I saw a woolly bear caterpillar today and its coat looked anomalously thick!

It's going to be a cold winter last year!!

[Deweydog]

It's going to be a cold winter last year!!

We were definitely due for a cold January this winter last year!

[seattleweatherguy]

Not a full blown CZ, but it was pretty impressive for about 15 minutes. Heaviest cell heading over Bothell and Woodinville now.

I didn't see too much sun here today. There was a little early this morning and then it was dark and gloomy the rest of the day.

Heard it here was wondering what happened

[wx_statman]

57/43 @ PDX. Not bad. 

[Front Ranger]

I saw a woolly bear caterpillar today and its coat looked anomalously thick!

 

He's gonna be regretting that during the upcoming November torch!

[Front Ranger]

57/43 @ PDX. Not bad. 

 

Didn't have a high that cold until 10/30 last year, 11/3 in 2015, and 10/24 in 2014. 

[Dave]

What's crazy is that after those early freezes, they went until Dec 15th without falling to 31. 

 

Yesterday's 31 is also the earliest there since 10/6/2009, fwiw. 

i think that was around the time that Bend got 6 inches of snow, which is pretty miraculous for that time of year.  My google fu is having trouble digging up any info on that event though.

[snow_wizard]

The temp has plunged to 28 at Hurricane Ridge already.  That is cold for this time of year!

[wx_statman]

Didn't have a high that cold until 10/30 last year, 11/3 in 2015, and 10/24 in 2014. 

 

We were due.

[wx_statman]

i think that was around the time that Bend got 6 inches of snow, which is pretty miraculous for that time of year.  My google fu is having trouble digging up any info on that event though.

 

Yeah, early October 2009. Crazy pattern progression. Mitchell got 7" of snow on the 4th officially, a little over a week after temps were in the mid 90's in that area.

[Geos]

Received 0.37" of rain today so far. Starting to rain again here.

 

Only hit 53 here today too.

[Front Ranger]

We were due.

 

Indeed. I think the regime has finally, actually shifted.

 

PDO index the past couple months, while still barely positive, was the lowest since Nov/Dec 2013. 

[VancouverIslandSouth]

The temp has plunged to 28 at Hurricane Ridge already.  That is cold for this time of year!

 

This afternoon had the feeling of conditions we typically get prior to an Arctic blast. Sunny but cool/dry onshore winds and low level convection coming down into the Juan de Fuca. If there was an actual blast following it wouldn't be uncommon to wake up to snow falling as the outflow starts creeping in.

[VancouverIslandSouth]

Indeed. I think the regime has finally, actually shifted.

 

PDO index the past couple months, while still barely positive, was the lowest since Nov/Dec 2013.