August 2017 PNW Discussion Thread

[Kayla]

Not sure if there is much of a signal either way there. But falls where all three months run warm aren't generally followed by great winters.

 

Last year September was cool and October was slightly mild, for the record.

 

Agreed. However, 1990, 1998, 2008, 2016 all had a 3 month warm fall average so it's definitely a noteworthy signal in recent times which is all I was noting several posts ago. 

[wx_statman]

Ironically, 2016 is probably the best match to this year in terms of MEI progression from April to July, at least back to 1950. Don't have to look very far.

[Phil]

Ironically, 2016 is probably the best match to this year in terms of MEI progression from April to July, at least back to 1950. Don't have to look very far.

I think that's where the similarities end, though. We have a weaker sun, opposite QBO, and opposite IOD this year, so IMO the DJF pattern will almost certainly behave differently relative to 2016/17 across the high latitudes and NPAC.

 

What I'm not sure about is whether we go the route of 2007/08, 2011/12, etc, or the route of 1981/82, 1960/61, etc.

[Phil]

[wx_statman]

I think that's where the similarities end, though. We have a weaker sun, opposite QBO, and opposite IOD this year, so IMO the DJF pattern will almost certainly behave differently relative to 2016/17 across the high latitudes and NPAC.

 

What I'm not sure about is whether we go the route of 2007/08, 2011/12, etc, or the route of 1981/82, 1960/61, etc.

 

PDO is significantly lower as well, compared to last year at this time. 

[wx_statman]

I've been looking some more at last winter...turns out 2016-17 had a historically significant (at least with regards to modern observations) disconnect between the ENSO state and the PDO phase. Completely out of sync. The DJF ONI was -0.4, qualifying as cold neutral bordering on a weak Nina. However, the DJF averaged monthly PDO was a whopping +0.88, which is something you might expect in a weak/moderate Nino event. 

 

The last time we saw such a degree of +PDO in conjunction with an ONI as low as -0.4 during DJF was during the 1980s. We had a run of three straight winters from 1983-86 that saw the following ONI/PDO values:

 

1983-84: ONI -0.5; PDO +1.47

1984-85: ONI -0.9; PDO +1.01

1985-86: ONI -0.4; PDO +1.04

 

That streak came at the tail end of a remarkable 8 year run of +ENSO domination that had prevailed since 1976. I've heard the PDO described before as nothing more than a decadal expression of the background ENSO state, since the two coupled oceanic/atmospheric indices are teleconnected. The fact that we were able to maintain such a remarkably positive +PDO despite transitioning to -ENSO conditions in the mid-1980s perhaps lends credence to that idea. 

 

Either way, it's interesting that we had gone more than 30 years without seeing a similar disconnect between ENSO conditions and PDO during boreal winter.

[BLI snowman]

I've been looking some more at last winter...turns out 2016-17 had a historically significant (at least with regards to modern observations) disconnect between the ENSO state and the PDO phase. Completely out of sync. The DJF ONI was -0.4, qualifying as cold neutral bordering on a weak Nina. However, the DJF averaged monthly PDO was a whopping +0.88, which is something you might expect in a weak/moderate Nino event.

 

The last time we saw such a degree of +PDO in conjunction with an ONI as low as -0.4 during DJF was during the 1980s. We had a run of three straight winters from 1983-86 that saw the following ONI/PDO values:

 

1983-84: ONI -0.5; PDO +1.47

1984-85: ONI -0.9; PDO +1.01

1985-86: ONI -0.4; PDO +1.04

 

That streak came at the tail end of a remarkable 8 year run of +ENSO domination that had prevailed since 1976. I've heard the PDO described before as nothing more than a decadal expression of the background ENSO state, since the two coupled oceanic/atmospheric indices are teleconnected. The fact that we were able to maintain such a remarkably positive +PDO despite transitioning to -ENSO conditions in the mid-1980s perhaps lends credence to that idea.

 

Either way, it's interesting that we had gone more than 30 years without seeing a similar disconnect between ENSO conditions and PDO during boreal winter.

All 4 were pretty decent winters. Might be a good thing.

[wx_statman]

All 4 were pretty decent winters. Might be a good thing.

 

That crossed my mind too. 

[TT-SEA]

00Z ECMWF operational and control runs watered down the heat for next weekend and beyond.   Looks like the EPS is quite a bit warmer and more ridgy in that time frame.  

[BLI snowman]

Pretty much end to end torching on the 12z.

[Phil]

I've been looking some more at last winter...turns out 2016-17 had a historically significant (at least with regards to modern observations) disconnect between the ENSO state and the PDO phase. Completely out of sync. The DJF ONI was -0.4, qualifying as cold neutral bordering on a weak Nina. However, the DJF averaged monthly PDO was a whopping +0.88, which is something you might expect in a weak/moderate Nino event.

 

The last time we saw such a degree of +PDO in conjunction with an ONI as low as -0.4 during DJF was during the 1980s. We had a run of three straight winters from 1983-86 that saw the following ONI/PDO values:

 

1983-84: ONI -0.5; PDO +1.47

1984-85: ONI -0.9; PDO +1.01

1985-86: ONI -0.4; PDO +1.04

 

That streak came at the tail end of a remarkable 8 year run of +ENSO domination that had prevailed since 1976. I've heard the PDO described before as nothing more than a decadal expression of the background ENSO state, since the two coupled oceanic/atmospheric indices are teleconnected. The fact that we were able to maintain such a remarkably positive +PDO despite transitioning to -ENSO conditions in the mid-1980s perhaps lends credence to that idea.

 

Either way, it's interesting that we had gone more than 30 years without seeing a similar disconnect between ENSO conditions and PDO during boreal winter.

Yeah, ENSO/PDO/PNA are a part the same mechanical "equilibration" system, which includes the NAM/SAM. From a multidecadal perspective, the boreal winter -NAM/-SAM circulation(s) constructively teleconnect to -ENSO/-PDO, and visa versa. The opposite holds true on millennial timescales but that's another topic altogether.

 

It's no coincidence that -PDO/-PNA/-NAM winters cluster in multiyear stretches with -PDO/-PNA dominance. It's also no coincidence that the flip to +NAM (starting in boreal winter 2011/12) was followed by the flip to +PDO/+PNA one year later, and it's no coividehcd that the last several years have featured huge +NAM/+NAO circulations during DJF.

 

- The 1950s to 1970s were predominantly -NAM/-PNA/-PDO

- The 1980s & 1990s were predominantly +NAM/+PNA/+PDO

- The late 2000s & early 2010s were mostly -NAM/-PNA/-PDO

- The 2013-present period is mostly +NAM/+PNA/+PDO

 

The leading variable is in fact the boreal winter NAO, which is a solid long term statistical predictor of the PDO and global temperature tendency years in the future.

 

- The abrupt flip to +NAO in the 1910s was followed by an transition to +PDO a few years later. The +NAO continued through the 1920s/1930s and began to decline in the 1940s.

 

- The steady decline in the NAO during the 1940s was followed by a flip to -PDO. The NAO continued to decline into the late 1960s and remained in its multidecadal negative state until the middle 1970s, during that multi-year super niña.

 

- The flip to +NAO in the mid/late 1970s corresponds to the "great Pacific climate shift" to +PDO thereafter. The +NAO continued until the early 2000s, peaking from the late 1980s to middle 1990s, in the heart of the +PDO era.

 

- The decline in the NAO during the early/mid 2000s was followed by a flip to -PDO during the mid/late 2000s. The late 2000s and early 2010s were largely -PDO/-NAO.

 

- The most recent example being the flip to +NAO, starting in winter 2011/12 (to present), was followed by the flip to +PDO a year later. Winter 2014/15 had one of the most prolific +NAOs ever recorded for DJF.

[Jesse]

Pretty much end to end torching on the 12z.

Figured we'd pay for July being merely slightly above average.

[Phil]

See how the cold season NAO trend/tendency appears to lead the PDO tendency by 2-5 years, for the most part. Amplitude is another story, though.

 

[Jesse]

Nice day! (in Madras)

[Deweydog]

We had a high cloud eclipse here. Totality was a good couple hours.

[wx_statman]

Currently experiencing an Earth eclipse. Started at 8:09 pm and is expected to continue until 6:19 am. 

[Jesse]

Wow, and here I wasted all this time and money to see a total solar eclipse in about four hours, and it only lasts two minutes. Jealous guys!!!

[WeatherArchive]

Didn't we have a partial solar in the 90s? I remember everyone being upset that it was cloudy and I think it rained.  I believe it happened in the rainy months and all it did was make it a bit darker then usual such as street lights coming on when they shouldn't but other then that it was no big deal.  I remember as a kid that it was a bit disappointing. 

[TT-SEA]

8-21-17 dawns sunny across most of the region.   

 

 

 

If you want a fascinating read... check out the adventures of James Gilliss who traveled across the country to view the total eclipse of July 18, 1860 in the Puget Sound region.   Seattle only had 188 residents back then... and they no idea what to expect in terms of weather.  And the eclipse was just after dawn.   He got soooooo lucky in the end.  

 

http://komonews.com/weather/scotts-weather-blog/even-astronomers-viewing-seattles-1860-eclipse-were-flummoxed-by-zany-weather-patterns

[BLI snowman]

Temp dropped about 4 degrees here during the eclipse.

[TT-SEA]

The 12Z GFS is really warm for the rest of the run after our brief trough on Thursday.

[TT-SEA]

Click 'Play' and watch this eclipse race across the country.   That is so cool.

 

http://weather.cod.edu/satrad/exper/?parms=northwest-02-48-0

[Phil]

Stuck in rain/wind here on the GA coast. Guess I'll have to wait until 2024.

[Phil]

Not even a solar eclipse can stop the steam bath.

 

http://www.wrh.noaa.gov/zoa/getobext.php?sid=KDCA

[TT-SEA]

My sons are stuck in bumper-to-bumper traffic near Salem now... heading northbound.

 

They still say it was totally worth it and an incredible experience.  

[Chewbacca Defense]

Click 'Play' and watch this eclipse race across the country.   That is so cool.

 

http://weather.cod.edu/satrad/exper/?parms=northwest-02-48-0

I'm not sure what is more fascinating to watch, the eclipse shadow moving across the country or that boiling mass of clouds over South Dakota!

[TT-SEA]

I'm not sure what is more fascinating to watch, the eclipse shadow moving across the country or that boiling mass of clouds over South Dakota!

I was thinking the same thing... that thing looks nasty!

[ShawniganLake]

Some of the worst fire areas in BC received some rain this weekend. Our property at Watch Lake has seen the evacuation order reduced to an alert.

 

Total area burned so far is just over 3,000,000 acres.

[Timmy]

I was only in the 98% but it was way cooler than expected. A lot of time with strange light. Good day!

[Phil]

Got pretty creepy here in SE GA. Sun semi-poked out of the clouds just in time and everything was basked in a full orange glow.

[Phil]

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/623FF87B-87B5-4922-8649-30B673CB6429_zpstozjvfkc.jpg

[Dave]

I watched the eclipse from a beautiful park in the metropolis of Waterloo.  It was spectacular.  Hardly any traffic getting there or coming back.  I'll never forget it.  

[FroYoBro]

It was pretty neat. 

[ShawniganLake]

90% eclipse is totally underwhelming. If I didn't watch the news I probably wouldn't have even noticed it happened. I would trade it for a couple inches of snow.

[TT-SEA]

90% eclipse is totally underwhelming. If I didn't watch the news I probably wouldn't have even noticed it happened. I would trade it for a couple inches of snow.

 

Yeah... it was really interesting watching the live coverage from Salem.   It looked very bright right before totality.   I am sure it looked unusual there but on the TV it looked like a normal sunny day.   Then it went completely dark... and then it looked bright and normal again in a couple minutes.   

 

For an eclipse... totality is the only way to go.    The light was noticeably strange here for a totally sunny day for maybe 30 minutes but it was not dramatic.   Amazing that 8% of normal sunlight is still very bright.   

[Deweydog]

Got dusky here. Kinda.

[TT-SEA]

Looks like my kids and their friends bailed on traffic and went hiking at Silver Falls.  

[TT-SEA]

12Z ECMWF is quite warm for the next 15 days with the exception of the little trough on Thursday.  

[Tenochtitlan]

It was pretty cool seeing shadows that cast the image of the partial eclipse all over buildings and sidewalks. 

[Jesse]

Probably one of the most spectacular examples of natural phenomena I've ever seen this morning. Definitely one of those things everyone should see at least once in their lives.