June 2017 Observations and Model Discussion for the Pacific Northwest

[Phil]

I would say this will be pretty close.

 

You also said any ridge would crash into retrogression between 6/20 and 6/25.

 

I am just curious what changed?

Glad you asked because I just noticed something today (I've been trying to figure this puzzle out all week). From what I can tell, it has something to do with the convection between 60E and 120E reversing phase by longitude beneath the intraseasonal frequency. With the EASM/Indo convection weakening, there's less exhaust to the Siberia/WPO phase space and a stronger trough over the NPAC given less upstream AAM removal.

 

If it's a true low frequency coupling, it could be early -QBO influence on the static stability integral along/west of the dateline, but the seasonal relationship to ATL/IO has changed since the AMM went positive in 1994, in which case pre-1994 analogs could be problematic.

 

This would explain the apparent preparation for a shift to

WPAC/IPWP-based forcing. This would also imply the ongoing regime is temporary, but above the intraseasonal-scale.

[Jesse]

A second heatwave this month would be pretty noteworthy and solidify a pretty warm month, Phil wrongness notwithstanding.

I couldn't imagine you saying this about a 7+ day cold spell in a million years.

[Phil]

Another note: This is already the fastest-descending -QBO on record (since 1952). At this rate, it will cycle by next summer.

 

I'm going to run a set of analogs, with rapid -QBO transitions under changing boreal summer EHEM phase shifts, and will report the information here when I finish analyzing it.

[Front Ranger]

Did Portland hit 102+ in June all the time before the airport era or something? I never got that vibe.

 

Some examples in the Portland area that have occurred in June or extremely close:

 

103 - Vancouver 1992

104 - Downtown 7/1/1942

103 - Oregon City 2008 and 2006

103 - Late May 1983 in downtown Portland

104 - Troutdale 1992

105 - PDX 7/1/42

[Phil]

This was in regard to retrogression and the return to deep western troughing.

 

The AAM is tanked like you thought.

The tanked AAM was mostly a SH contribution which played onto the tropics. The NH was/is in regime dominated by weak Asian monsoons and Eurasian ridging, which favors NPAC jet extensions. In hindsight, it probably makes sense that this regime would want to persist rather than surrender to a moderate shift in the 10S-near equator tropics.

[Front Ranger]

Nah, seems pretty appropriate for June. The only heatwave on record to produce a reading over 100 was June 2006. The record low of 29 in April is weaker. 

 

In addition to the times the Portland area has hit 103+ in June or very close that I posted, you also have to look at the number of times PDX has hit 100+ before 7/1: 1983, 2016, 1982, 1992, 2006, 2008. That's a lot for only having a record 2 degrees above that, compared to the records of most other months.

[Deweydog]

I couldn't imagine you saying this about a 7+ day cold spell in a million years.

7+ day cold spells typically don't occur during warm months.

 

Weird post.

[Jesse]

7+ day cold spells typically don't occur during warm months.

 

Weird post.

You know how I meant it. Just replace all of the warm stuff with cold and it would turn from a post you would make to a post you would mock.

[Deweydog]

You know how I meant it. Just replace all of the warm stuff with cold and it would turn from a post you would make to a post you would mock.

You're reaching. Cold months result from cold weather. Warm from warm. These are pretty indisputable facts, your angry biases notwithstanding.

[wx_statman]

In addition to the times the Portland area has hit 103+ in June or very close that I posted, you also have to look at the number of times PDX has hit 100+ before 7/1: 1983, 2016, 1982, 1992, 2006, 2008. That's a lot for only having a record 2 degrees above that, compared to the records of most other months.

 

I actually agree that June is a little under-represented by the 102 monthly record at PDX (and especially by the fact that the record was only 100 until 2006). Heat waves like May 1983 and also June 1955 (in the Puget Sound), as well as July 1-2, 1942 demonstrate that there is no reason why June shouldn't be able to produce a top-tier heat wave comparable to anything seen in July or August, i.e. maximums in the 105-107 range at PDX. It's simply a matter of time, and would have been a matter of time even without the aid of a warming climate. 

[Jesse]

You're reaching. Cold months result from cold weather. Warm from warm. These are pretty indisputable facts, your angry biases notwithstanding.

You are being obtuse here.

[Deweydog]

You are being obtuse here.

You're making things up. An obtuse reaction probably isn't too outlandish.

[Jesse]

You're making things up. An obtuse reaction probably isn't too outlandish.

Okie.

[Jesse]

I actually agree that June is a little under-represented by the 102 monthly record at PDX (and especially by the fact that the record was only 100 until 2006). Heat waves like May 1983 and also June 1955 (in the Puget Sound), as well as July 1-2, 1942 demonstrate that there is no reason why June shouldn't be able to produce a top-tier heat wave comparable to anything seen in July or August, i.e. maximums in the 105-107 range at PDX. It's simply a matter of time, and would have been a matter of time even without the aid of a warming climate.

But in 140 years of keeping climate records in Portland, (starting downtown) it hasn't happened, for whatever reason. Hard to chock that up to flukish timing, although you do make some good points.

[James Jones]

I actually agree that June is a little under-represented by the 102 monthly record at PDX (and especially by the fact that the record was only 100 until 2006). Heat waves like May 1983 and also June 1955 (in the Puget Sound), as well as July 1-2, 1942 demonstrate that there is no reason why June shouldn't be able to produce a top-tier heat wave comparable to anything seen in July or August, i.e. maximums in the 105-107 range at PDX. It's simply a matter of time, and would have been a matter of time even without the aid of a warming climate. 

 

You and Flatiron bring up some good points. The fact that downtown has hit 103 in May (and 107 on 7/2) is pretty good reason to consider the June record to be weak, though I think it was you who said 5/28/83 is perhaps the most impressive heat event on record for PDX when considering the calendar?

 

I still think April's 29 record low is weaker though.

[Deweydog]

But in 140 years of keeping climate records in Portland, (starting downtown) it hasn't happened, for whatever reason. Hard to chock that up to flukish timing, although you do make some good points.

June is generally a tweener period. We transition from spring heat which tends to really squeeze out maximum adiabatic assistance with deep offshore flow to more four corners, sprawling heat toward the end of the month.

[wx_statman]

But in 140 years of keeping climate records in Portland, (starting downtown) it hasn't happened, for whatever reason. Hard to chock that up to flukish timing, although you do make some good points.

 

I think it is flukey. I don't see any other reasonable explanation for it. It's obviously extremely rare to get a heat wave to produce 105 degree heat in June in the Portland area, but the recurrence rate in a "stationary" climate regime might be something like 1-in-100 years? Totally guessing there. At 140 years, we would obviously be outside of that envelope but still within the realm of climatic variability. With a different roll of the dice, we might have seen three June 105+ events in the last 100 years locally, under the same forcing parameters. Like you said, it just hasn't happened for whatever reason.

[wx_statman]

You and Flatiron bring up some good points. The fact that downtown has hit 103 in May (and 107 on 7/2) is pretty good reason to consider the June record to be weak, though I think it was you who said 5/28/83 is perhaps the most impressive heat event on record for PDX when considering the calendar?

 

I still think April's 29 record low is weaker though.

 

Something like that. I believe I said it was the least-likely heat wave to reoccur for the Portland area as a whole, considering readings such as the 103 downtown and 104 in Oregon City. It's unique in recorded history unlike the September 1988 event, which had a precedent in 1944 (also ~105 degree readings in the valley, i.e. at Battle Ground). 

 

Personally, I think the May 1983 heat wave was a byproduct of the wacked-out jet stream that year. We had a sulfur-loaded atmosphere from the El Chichon eruption in 1982, along with a Super Nino (that transitioned into -ENSO during the course of the year, a transition which is usually good for "unusual" jet stream activity). The jet stream mayhem was demonstrated by the May heat wave (which produced all-time record heat into the Yukon), the roided-out jet stream in July that produced a monthly record of 2.68" at PDX, and the one-of-a-kind national cold wave in December 1983. 

 

Having said all that, it happened in May. Just like 100 happened in downtown Seattle on 6/9/1955, or the 107 in downtown Portland on 7/2/1942. It's a matter of time before PDX breaks through with a 105-107 reading in June, especially in a warming climate....

[Jesse]

June is generally a tweener period. We transition from spring heat which tends to really squeeze out maximum adiabatic assistance with deep offshore flow to more four corners, sprawling heat toward the end of the month.

I was thinking along similar lines.

[Front Ranger]

You and Flatiron bring up some good points. The fact that downtown has hit 103 in May (and 107 on 7/2) is pretty good reason to consider the June record to be weak, though I think it was you who said 5/28/83 is perhaps the most impressive heat event on record for PDX when considering the calendar?

 

I still think April's 29 record low is weaker though.

 

This is probably true. Considering PDX has seen 24 on 3/30 and and 29 as late as 5/1 (both 1954). And 30 on several occasions. 

 

But for record monthly highs, June's 102 is the one that definitely seems lowest hanging to me. Probably followed by March's 80.

[Front Ranger]

June is generally a tweener period. We transition from spring heat which tends to really squeeze out maximum adiabatic assistance with deep offshore flow to more four corners, sprawling heat toward the end of the month.

 

Yeah, and this is the time period that will deliver a 103+ high to PDX probably sooner rather than later. From about the solstice on.

[Jesse]

Pretty much a perfect late June day. Wish I could keep this in a bottle.

[Front Ranger]

Further north, June has underachieved even further. 

 

SEA's record high in June is 7 degrees below its July high (compared to 5 for PDX). At OLM, it's 6 degrees below.

 

The October record lows at both SEA and PDX also standout as weak, though not as much as April.

[Jesse]

Yeah, and this is the time period that will deliver a 103+ high to PDX probably sooner rather than later. From about the solstice on.

Sooner rather than later seems pretty bold though. Almost 80 years of history and it hasn't happened yet. I agree that it could happen down the road at some point, and it is definitely possible from an atmospheric mechanics standpoint. But I see no reason to act like it's imminent.

[Front Ranger]

Sooner rather than later seems pretty bold though. Almost 80 years of history and it hasn't happened yet. I agree that it could happen down the road at some point, and it is definitely possible from an atmospheric mechanics standpoint. But I see no reason to act like it's imminent.

 

Mark already going with triple digits for Sunday...

 

I'm not saying it's "imminent" any more than wxstatman was. We're both basically just saying it's a matter of time, especially in a warming climate. Moreso than most records.

 

To get more specific, by "sooner" I guess I meant it wouldn't surprise me at all to see it fall within 10 years, as opposed to many other records that will probably be later.

[Deweydog]

Sooner rather than later seems pretty bold though. Almost 80 years of history and it hasn't happened yet. I agree that it could happen down the road at some point, and it is definitely possible from an atmospheric mechanics standpoint. But I see no reason to act like it's imminent.

Weren't you the one saying our climate classic "summer starts after July 5th" is becoming less applicable?

 

Doesn't mean anything is imminent unless it's imminent but I'd say a top tier heatwave that happens to occur in late June is more likely to happen in the next decade compared to any other during the last century or two.

[Jesse]

Weren't you the one saying our climate classic "summer starts after July 5th" is becoming less applicable?

 

Doesn't mean anything is imminent unless it's imminent but I'd say a top tier heatwave that happens to occur in late June is more likely to happen in the next decade compared to any other during the last century or two.

Perhaps. Then again according to Phil we will be rapidly descending into an Ice Age by 2020.

[Deweydog]

Perhaps. Then again according to Phil we will be rapidly descending into an Ice Age by 2020.

I prefer to think of it as ascending into cooling.

[TT-SEA]

Pretty much a perfect late June day. Wish I could keep this in a bottle.

 

Looking pretty good for a repeat of the last couple days in the middle of next week.   Maybe even cooler.

 

http://www.tropicaltidbits.com/analysis/models/gfs/2017062200/gfs_z500aNorm_namer_26.png

[luminen]

Today was absolutely perfect weather. Not much more to say really. 

[wx_statman]

Off topic, but this is kinda cool. This image shows annual tree-ring growth from a tree core that was taken out of a Douglas fir in the central Cascades. You can clearly see what looks like the cooling signatures from both the Tambora (1815) and Krakatoa (1883) eruptions. 

 

This tree sprouted in 1772, and you can see the rapid growth in the first few decades. This is typical as the young tree rapidly gains size, and doesn't reflect climatological conditions (at least in the raw growth numbers). However, there are three exceptionally low growth years from 1816-18, before the resumption of fairly rapid "youthful" growth. Then we have another longer period of slow growth from 1883-88, which matches the time frame of global cooling produced by Krakatoa. The slower growth you see in the 20th century is a sign of tree maturation, although you can see what is most likely drought stress in the 1930's and 1940's. 

[BLI snowman]

In addition to the times the Portland area has hit 103+ in June or very close that I posted, you also have to look at the number of times PDX has hit 100+ before 7/1: 1983, 2016, 1982, 1992, 2006, 2008. That's a lot for only having a record 2 degrees above that, compared to the records of most other months.

 

All of our non-strong Nino years where June hit 100+ were followed by goodish winters. Last year kept the streak alive. It's a brilliant correlation.

[BLI snowman]

Off topic, but this is kinda cool. This image shows annual tree-ring growth from a tree core that was taken out of a Douglas fir in the central Cascades. You can clearly see what looks like the cooling signatures from both the Tambora (1815) and Krakatoa (1883) eruptions. 

 

This tree sprouted in 1772, and you can see the rapid growth in the first few decades. This is typical as the young tree rapidly gains size, and doesn't reflect climatological conditions (at least in the raw growth numbers). However, there are three exceptionally low growth years from 1816-18, before the resumption of fairly rapid "youthful" growth. Then we have another longer period of slow growth from 1883-88, which matches the time frame of global cooling produced by Krakatoa. The slower growth you see in the 20th century is a sign of tree maturation, although you can see what is most likely drought stress in the 1930's and 1940's. 

 

Definitely interesting.

 

I do find it quirky how warm a year 1885 was though, in spite of the Krakatoa cooling on a global level. That was actually the warmest year in downtown Portland between 1871 and 1925, before 1926 broke the record. Hell, the 55.7 degree annual mean would be impressively warm even for today's standards.

[Phil]

Perhaps. Then again according to Phil we will be rapidly descending into an Ice Age by 2020.

Still trying to figure out where this rumor originated.

 

Geologically speaking? Yeah, I guess so. It'll take several hundred, if not a thousand years, though.

[Phil]

Off topic, but this is kinda cool. This image shows annual tree-ring growth from a tree core that was taken out of a Douglas fir in the central Cascades. You can clearly see what looks like the cooling signatures from both the Tambora (1815) and Krakatoa (1883) eruptions.

 

This tree sprouted in 1772, and you can see the rapid growth in the first few decades. This is typical as the young tree rapidly gains size, and doesn't reflect climatological conditions (at least in the raw growth numbers). However, there are three exceptionally low growth years from 1816-18, before the resumption of fairly rapid "youthful" growth. Then we have another longer period of slow growth from 1883-88, which matches the time frame of global cooling produced by Krakatoa. The slower growth you see in the 20th century is a sign of tree maturation, although you can see what is most likely drought stress in the 1930's and 1940's.

Fascinating. Always tough to isolate rainfall influence from temperature/seasonality influence, as well.

[wx_statman]

Definitely interesting.

 

I do find it quirky how warm a year 1885 was though, in spite of the Krakatoa cooling on a global level. That was actually the warmest year in downtown Portland between 1871 and 1925, before 1926 broke the record. Hell, the 55.7 degree annual mean would be impressively warm even for today's standards.

 

Very dry July & August in 1885...I'm guessing the tree was responding to the dry conditions more than anything else that year?

 

1885 was kind of an oddball here. My guess is that the persistently ridgy pattern was at least in part fueled by the perturbed atmospheric state post-Krakatoa. That would also explain the 94 degrees on May 5th downtown. It takes a pretty wildly anomalous ridge to produce that kind of warmth, when the background climate was about 3F cooler than today in the PNW. That ridge crashed hard as well. Havre, MT recorded their latest-ever 18 degree minimum two days later (5/7/1885). 

[Phil]

Definitely interesting.

 

I do find it quirky how warm a year 1885 was though, in spite of the Krakatoa cooling on a global level. That was actually the warmest year in downtown Portland between 1871 and 1925, before 1926 broke the record. Hell, the 55.7 degree annual mean would be impressively warm even for today's standards.

Proxies worldwide show a period of rapid warming in the 19th century, following the Dalton minimum, possibly exceeding the warming rate observed from 1910 to 1940 and 1976 to 2006, though that's hard to confirm for various reasons. The only faster period of warming in the proxy aggregate(s) (in the "modern" era) was right after the LIA, between 1700 and 1800.

 

Edit: 19th, not 17th. Ugh.

[wx_statman]

Fascinating. Always tough to isolate rainfall influence from temperature/seasonality influence, as well.

 

Absolutely. The reason I have access to the raw data is because I'm prepping for a study that I'll be doing @ PSU this summer. Hopefully something I'll publish eventually. We're going to try to isolate the snowpack/SWE signal in the central OR Cascades from Douglas fir core samples. Apparently this is something that can be done when analyzing the latewood and earlywood growth separately...a season-specific precipitation signal can emerge. The idea is to extend the snowpack data timeseries beyond what we have via instrumental records. It will be a challenge! 

[BLI snowman]

Very dry July & August in 1885...I'm guessing the tree was responding to the dry conditions more than anything else that year?

 

1885 was kind of an oddball here. My guess is that the persistently ridgy pattern was at least in part fueled by the perturbed atmospheric state post-Krakatoa. That would also explain the 94 degrees on May 5th downtown. It takes a pretty wildly anomalous ridge to produce that kind of warmth, when the background climate was about 3F cooler than today in the PNW. That ridge crashed hard as well. Havre, MT recorded their latest-ever 18 degree minimum two days later (5/7/1885). 

 

It was a weak ENSO year too, so presumably not a lot of tropical forcing to generate extreme persistence like that. But yeah, after the epic midwinter, things went into torch mode and never looked back. Portland's minimum temp between January 27 and December 10 was 32, and we had possibly the ridgiest early spring on record with just 0.01" of precip from March 11 to April 10!

[Phil]

Absolutely. The reason I have access to the raw data is because I'm prepping for a study that I'll be doing @ PSU this summer. Hopefully something I'll publish eventually. We're going to try to isolate the snowpack/SWE signal in the central OR Cascades from Douglas fir core samples. Apparently this is something that can be done when analyzing the latewood and earlywood growth separately...a season-specific precipitation signal can emerge. The idea is to extend the snowpack data timeseries beyond what we have via instrumental records. It will be a challenge!

Awesome! I definitely look forward to your results on this one. It would be so much easier for everybody if all trees responded the same to temperature and precipitation changes, lol.