May 2017 Observations and Model Discussion for the Pacific Northwest

[Jesse]

I have been sneezing and blowing my nose quite a bit the last couple of days. No complaints on the weather though. Pretty much perfect.

I will gladly bleed out my eyes as long as it's warm and the sun is shining.

[richard mann]

(.. cross-reference.)

 

http://theweatherforums.com/index.php/topic/1546-spring-2017-colder-air-mass-movement-and-distribution-projections/?p=241027

[bainbridgekid]

My son said they found spots close to 70 on Sammamish this afternoon when he took the boat out with friends.

Awesome.

 

The combination of a cold Winter followed by such a chilly and rainy Spring had things way cooler than normal till this warm spell, so it's nice to see them recover so quickly.

 

Planning to get out on the water tomorrow and/or Monday.

[Phil]

What it shows in week 2 works for me.

 

http://www.tropicaltidbits.com/analysis/models/gfs/2017052800/gfs_z500aNorm_namer_47.png

That solution is almost certainly incorrect, assuming the convection behaves as modeled, which is by no means guaranteed.

[TT-SEA]

That solution is almost certainly incorrect, assuming the convection behaves as modeled, which is by no means guaranteed.

 

I knew it was impossible before you said it.   You were just talking about the 00Z GFS during week 2 so I checked out what it showed.  

[TT-SEA]

Although the 00Z ECMWF is also showing a ridge starting around day 8 or 9.

 

http://www.tropicaltidbits.com/analysis/models/ecmwf/2017052800/ecmwf_z500aNorm_namer_10.png

[Phil]

I knew it was impossible before you said it. You were just talking about the 00Z GFS during week 2 so I checked out what it showed.

Haha, well I wouldn't say "impossible".

 

Either it's handling the convection incorrectly (which is very possible, the GFS is godawful with convection, even worse than the CMC and JMA), or it's handling the Eurasian wave train incorrectly (which it did throughout last winter, most notably a few days before the early February event).

 

So..flip a coin and pick your favorite model.

[Dave]

Apparently, the aurora can be seen from about Seattle north at the moment if you have a dark enough sky.  

[Brennan]

Also, the CFS/EPS weeklies and GEFS/EPS operational ensembles both depict an anomalous weakening of the Asian monsoonal circulations (relative to climatology) during mid-June, almost to the point of a complete shutdown and return to a winter-like EHEM circulation.

 

If this holds true, the mid/high latitudes experience a very large energy deficit. Could be an interesting setup as we approach the summer solstice.

What does this mean for weather in the Bering Sea this summer? I'm particularly interested in the Bristol bay waters between late June and Mid July.

 

Thanks Phil

[Phil]

What does this mean for weather in the Bering Sea this summer? I'm particularly interested in the Bristol bay waters between late June and Mid July.

 

Thanks Phil

Well, it would (theoretically) lead to a tighter meridional temperature gradient (warmer tropics, colder poles) which is a boundary state that favors a stronger zonal jet stream.

 

Of course, this doesn't factor in intraseasonal influences, which will interfere and affect the wave train/exact latitude of said jet.

[WeatherArchive]

The string of warm nights of the 2013 regime are over. Even during this *heatwave* we have been going at or below

 

  Yesterday morning I sneaked in a 47F and it was chilly!  Today it is 50F for the low however the humidity is at 96 relative so it contrast it doesn't feel that chilly and we don't have the heat on.   Yesterday the humidity got no higher then around 80 relative. 

 

Clouds are starting to form that are blotting the sun out. On church day of course.   Now why couldn't we have had these clouds ALL WEEK! huh? The mornings have been insanely bright like a giant spot light going thru your window but evenings have been perfect on the contrast.

 

Yesterday and the day before was as close to a blue dome sky you will get.  Once in a while I've seen better without the farm haze.

[WeatherArchive]

However, interesting to note the EAWM (East Asian winter monsoon) has been stronger in recent winters, opposite of the EASM (East Asian Summer Monsoon).

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/56F6FEDC-CA0E-4340-9A70-72DE06D21069_zpsqpnrqfxi.jpg

 

The stronger EAWM = increased WHEM tropical convection and poleward mass transport = -NAM bias. In other words, a stronger EAWM favors increased winter blocking.

 

Weak 1990s EAWM coincided with +NAM, strong EAWM during the 1960s/1970s and mid/late 2000s/early 2010s coincided with a generally -NAM. The EAWM weakened again during the most recent 2012-present period.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/5D7CBEA0-9014-4120-8A31-69CD75B4DE76_zpsxntdjmmn.jpg

Wow! Is that why there was events like the KnickerBrocker type storms?

[WeatherArchive]

Never doubt Phil.   Timing might be off a little bit... but he will get the big picture right most of the time.

In this case a lot bit off but either way night times have been reasonable compared to the string of 60+ lows in the 2013 regime.  I'm happy with that!  

[Phil]

Wow! Is that why there was events like the KnickerBrocker type storms?

The blocking that could result from a strong EAWM/-NAM increases the chances of mid-latitude winter storms, yes.

[Phil]

In this case a lot bit off but either way night times have been reasonable compared to the string of 60+ lows in the 2013 regime. I'm happy with that!

No doubt this pattern has been a challenge for me (and the models too). Honestly, I've been all over the place...so many moving parts right now. Not to mention an extratropical domain that seems almost disconnected from the tropical forcings for the time being.

 

Things should become more coherent with time, but for now the situation remains fluid.

[TT-SEA]

No doubt this pattern has been a challenge for me (and the models too). Honestly, I've been all over the place...so many moving parts right now. Not to mention an extratropical domain that seems almost disconnected from the tropical forcings for the time being.

 

Things should become more coherent with time, but for now the situation remains fluid.

 

So are things changing from 'big time' troughing that will last for 'several weeks'?    

 

Not too happy about that outlook but not doubting the likelihood either.  

[Phil]

So are things changing from 'big time' troughing that will last for 'several weeks'?

I don't think the troughy summer changes, but how we eventually get there most certainly does.

 

I also don't recall using the words "big time".

[Phil]

Also, I'm in Connecticut until Monday night, so until I get back home, I won't have access to all my academic resources and datasets.

 

I'll post a more detailed analysis and update of my thoughts sometime on Tuesday.

[TT-SEA]

I don't think the troughy summer changes, but how we eventually get there most certainly does.

 

I also don't recall using the words "big time".

 

Sorry... you are correct.   You said 'big way'.  My mistake.

 

 

Once that happens, troughing will return in a big way, and will likely last for several weeks following the termination of the wave upon leaving the Pacific.

 

[Phil]

Sorry... you are correct. You said 'big way'. My mistake.

Yeah, I still think that will be the eventual progression. As for when/how that occurs..I'm not as confident as I once was.

 

I'm also busy with friends/family right now, so I haven't looked as deeply at the system as I normally do when forecasting. That shouldn't be an issue for me, though. Or, at least it hasn't been, up to this point.

[TT-SEA]

Yeah, I still think that will be the eventual progression. As for when/how that occurs..I'm not as confident as I once was.

 

I'm also busy with friends/family right now, so I haven't looked as deeply at the system as I normally do when forecasting. That shouldn't be an issue for me, though. Or, at least it hasn't been, up to this point.

 

That's cool... I know how that goes.  

 

BTW - that quote was just from yesterday.

[Phil]

That's cool... I know how that goes.

 

BTW - that quote was just from yesterday.

Yeah, I saw the timestamp on the quote box.

[TT-SEA]

06Z GFS continued the theme of a significant ridge in week 2...

 

http://www.tropicaltidbits.com/analysis/models/gfs/2017052806/gfs_z500aNorm_namer_38.png

[Jesse]

Looks like marine clouds made it up the Columbia to about Longview, and north up the valley to Marion County this morning.

 

Today should be a few degrees cooler than yesterday.

[TT-SEA]

And the 12Z GFS went the opposite way. Lots of model swings for being the quiet time of the year.

[TT-SEA]

And wow does it crash on Tuesday... NAM MOS shows cloudy and 60 that day.

[Phil]

And the 12Z GFS went the opposite way. Lots of model swings for being the quiet time of the year.

I'm being honest when I say this might be the most complicated, inherently unstable system state I've ever seen during the warm season.

 

You know it's a tough one when model skill scores approach coin flip territory.

[Jesse]

I'm being honest when I say this might be the most complicated, inherently unstable system state I've ever seen during the warm season.

 

You know it's a tough one when model skill scores approach coin flip territory.

That's a bold statement. It is definitely unusual to see this much flip flopping even in the short to mid range this time of year, though.

[Phil]

That's a bold statement. It is definitely unusual to see this much flip flopping even in the short to mid range this time of year, though.

Probably some recency bias on my part, though did say "during the warm season" for a reason.

 

I've definitely seen worse during the cold season.

[Jesse]

Probably some recency bias on my part, though did say "during the warm season" for a reason.

 

I've definitely seen worse during the cold season.

Feels like the summer background state is trying to find its legs right now.

[Phil]

Feels like the summer background state is trying to find its legs right now.

Yeah, pretty much this. It's been a prolonged, unstable seasonal transition this year, and that looks to continue.

[Jesse]

Interesting how we've been only a couple hundred miles removed from cold anomalies the past few weeks. I didn't realize how chilly the mountain west has been. Definitely no early season four corners high showing up just yet.

 

[Jesse]

Yeah, pretty much this. It's been a prolonged, unstable seasonal transition this year, and that looks to continue.

Once the atmosphere finds a way to plant a big, fat ridge over us it will probably decide to call it good.

[Phil]

Once the atmosphere finds a way to plant a big, fat ridge over Phil's house, it will probably decide to call it good.

fyp

[Jesse]

Pretty ridiculous ensemble spread on the 12z in the mid range and beyond. At least we know highs will be somewhere between 62 and 100 in the latter half of next week.

[Kayla]

Interesting how we've been only a couple hundred miles removed from cold anomalies the past few weeks. I didn't realize how chilly the mountain west has been. Definitely no early season four corners high showing up just yet.

 

IMG_2123.PNG

 

Yeah it's definitely been below average out this way this month. I know Phil was talking about the trough axis reaching this area roughly around the first week of June but it seems like it has already set up shop here.  We've been stuck in the 50's and 60's here while the western lowlands have been experiencing plenty of 80's to 90º days it seems.

 

Looking forward to the ridge axis shifting a little further east this week giving us some more summer like temps in the 70's to near 80º until we return to below average temps once again late week.

[Phil]

Yeah it's definitely been below average out this way this month. I know Phil was talking about the trough axis reaching this area roughly around the first week of June but it seems like it has already set up shop here. We've been stuck in the 50's and 60's here while the western lowlands have been experiencing plenty of 80's to 90º days it seems.

 

Looking forward to the ridge axis shifting a little further east this week giving us some more summer like temps in the 70's to near 80º until we return to below average temps once again late week.

I think in the end, the trough axis will retrograde westward after the off-equator WPAC forcing terminates. I was thinking it would happen during the first week of June but there's a chance it could occur up to a week later than I was originally thinking.

[TT-SEA]

All the models turned very troughy in 7-10 day period this morning.    Ridging just disappeared.  

[Jesse]

All the models turned very troughy in 7-10 day period this morning. Ridging just disappeared.

If you don't like what the Euro shows in the long range, just wait another 12 hours! I'm sure it will dramatically change again.

[SilverFallsAndrew]

Bit of a marine push last night and this morning. SLE running 12 degrees behind yesterday.