July 2016 Observation and Model Discussion for the Pacific Northwest

[Jesse]

Could be a September payback on the way!

I could definitely envision some sort of anomalous warm spike in early September, especially if this cool period sticks around much of the middle part of summer. I can't really picture September as a whole being a total torch with the building Niña, though.

[TT-SEA]

Could be a September payback on the way!

 

 

Absolutely.

 

Its been fairly troughy since the first week of June with another week to go.  This has a warm September written all over it.  

 

I am fairly certain that the entire pattern will begin the process of retrograding to the north and west after July 10th.    The next trough early next week makes a pass offshore but does not appear to be coming in like the weekend trough.     

 

I am sure Phil will say deep troughing will be parked over us the rest of the summer with only 'very brief' breaks but that will probably not happen.

 

 

http://stream.ecmwf.int/data/atls14/data/data01/scratch/ps2png-atls14-95e2cf679cd58ee9b4db4dd119a05a8d-MfnZzi.png

 

http://stream.ecmwf.int/data/atls13/data/data01/scratch/ps2png-atls13-95e2cf679cd58ee9b4db4dd119a05a8d-GN_xjy.png

 

http://stream.ecmwf.int/data/atls14/data/data01/scratch/ps2png-atls14-95e2cf679cd58ee9b4db4dd119a05a8d-L_wtdC.png

[Phil]

Yes, the trough will come into the PNW. The retrogression of the mass/momentum fluxes will lead to height rises offshore, and downstream troughing over the west.

 

The 11-15 day 00z EPS highlights this beautifully. Basically leads to a return of the current pattern by July 20th.

[Jesse]

Absolutely.

 

Its been fairly troughy since the first week of June with another week to go. This has a warm September written all over it.

 

I am fairly certain that the entire pattern will begin the process of retrograding to the north and west after July 10th. The next trough early next week makes a pass offshore but does not appear to be coming in like the weekend trough.

 

I am sure Phil will say deep troughing will be parked over us the rest of the summer with only 'very brief' breaks but that will probably not happen.

 

 

 

I really fail to understand the line of logic that considers us due for more warmth after less than a month of the first significant cool anomalies in over two years.

 

What about making up for the last 2-3 years of non-stop torching? Are cold anomalies the only thing we are ever forced to make up for?

[TT-SEA]

Yes, the trough will come into the PNW. The retrogression of the mass/momentum fluxes will lead to height rises offshore, and downstream troughing over the west.

The 11-15 day 00z EPS highlights this beautifully. Basically leads to a return of the current pattern by July 20th.

I say it will not happen. We will find out in 2 weeks.

[TT-SEA]

I really fail to understand the line of logic that considers us due for more warmth after less than a month of the first significant cool anomalies in over two years.

What about making up for the last 2-3 years of non-stop torching? Are cold anomalies the only thing we are ever forced to make up for?

We were due for a cool September last year. And it worked out.

[Phil]

I say it will not happen. We will find out in 2 weeks.

Two weeks? You just said "after July 10th". That's 5 days away.

[TT-SEA]

Two weeks? You just said "after July 10th". That's 5 days away,

 

 

I said troughing July 1-10.    I also said July would be hot about 2 months ago.   I backed off that immediately.   But please remind me for the 3,000th time that I said that at one time months ago.   

 

The troughy pattern will be retrograding after July 10th.

 

I said "we will see" about your prediction of the current pattern repeating by 7/20 which is exactly 2 weeks away.

[Phil]

We were due for a cool September last year. And it worked out.

What happened to "persistence"? You're saying that troughing now argues for ridging later, but ridging argues for more ridging based on persistence?

 

Also, you're never "due" for anything, as the occurrence of a given weather pattern has no probabilistic bearing on the occurrence of a future pattern at a given time. This assuming you're treating these pattern variations as randomly occurring.

[TT-SEA]

What happened to "persistence"? You're saying that troughing now argues for ridging later, but ridging argues for more ridging based on persistence?

Also, you're never "due" for anything, as the occurrence of a given weather pattern has no probabilistic bearing on the occurrence of a future pattern at a given time. This assuming you're treating these pattern variations as randomly occurring.

OK.

 

Again... cycles. They are fairly predictable around here. Argue all you want but it generally works as a guide.

[Phil]

I said troughing July 1-10. I also said July would be hot about 2 months ago. I backed off that immediately. But please remind me for the 3,000th time that I said that at one time months ago.

I didn't even mention that comment here? What's up with you?

 

The troughy pattern will be retrograding after July 10th.

Bookmarked.

 

I agree their should be a retrogression, but probably not in the sense you're thinking IMO.

 

I said "we will see" about your prediction of the current pattern repeating by 7/20 which is exactly 2 weeks away.

That was a description of the 00z EPS, though my thoughts are similar, maybe slightly slower? Slow bias again?

[stuffradio]

I really fail to understand the line of logic that considers us due for more warmth after less than a month of the first significant cool anomalies in over two years.

 

What about making up for the last 2-3 years of non-stop torching? Are cold anomalies the only thing we are ever forced to make up for?

I wish we could make up for it by getting lots of snow

[Jesse]

We were due for a cool September last year. And it worked out.

Last September was average. A nice respite, but merely an average month in a sea of torching.

 

We are still overdue for a legitimately cool one. I think 2007 was the last time that happened.

[Jesse]

What happened to "persistence"? You're saying that troughing now argues for ridging later, but ridging argues for more ridging based on persistence?

 

Also, you're never "due" for anything, as the occurrence of a given weather pattern has no probabilistic bearing on the occurrence of a future pattern at a given time. This assuming you're treating these pattern variations as randomly occurring.

We will be due for a warm September after all of the cool mid-summer weather we will not be seeing since it is going to turn warm again very soon.

 

It makes sense if you don't think about it.

[TT-SEA]

Last September was average. A nice respite, but merely an average month in a sea of torching.

 

We are still overdue for a legitimately cool one. I think 2007 was the last time that happened.

 

 

This no longer feels like the year it will happen.     I think you know that as well but would rather just make sarcastic comments about how nature is out to screw you.

 

I would gladly take a wall-to-wall warm July and a cool September.      

[Jesse]

This no longer feels like the year it will happen. I think you know that as well but would rather just make sarcastic comments about how nature is out to screw you.

 

I would gladly take a wall-to-wall warm July and a cool September.

September is two months away. And while I don't think it necessarily be wall to wall cool, a cool one is not out of the question at this point. Hard telling. It's not like a coolish mid-summer (which we certainly won't be seeing!) invariably leads to a torchy September.

[TT-SEA]

September is two months away. And while I don't think it necessarily be wall to wall cool, a cool one is not out of the question at this point. Hard telling. It's not like a coolish mid-summer (which we certainly won't be seeing!) invariably leads to a torchy September.

 

 

OK.

 

Whatever helps you sleep at night.     

[Phil]

OK.

 

Again... cycles. They are fairly predictable around here. Argue all you want but it generally works as a guide.

I'm honestly curious here.

 

Developing La Niña summers almost always feature ridging offshore over the NPAC/Aleutians, troughing over the western USA, and heat/ridging over the central/eastern US in the J/A/S averages. There are very few exceptions to this, in fact it's probably the most consistent seasonal pattern progression I'm aware of. This is the very definition of "persistence".

 

So, given this fact, what (specifically) causes you to think differently? Because I can find no reason to ignore such a strong, coherent systematic relationship in favor of a few outlying years like 1998.

[Deweydog]

What happened to "persistence"? You're saying that troughing now argues for ridging later, but ridging argues for more ridging based on persistence?

 

Also, you're never "due" for anything, as the occurrence of a given weather pattern has no probabilistic bearing on the occurrence of a future pattern at a given time. This assuming you're treating these pattern variations as randomly occurring.

Due is just a euphemism for pattern variability with local knowledge. If we are in a persistence pattern of west coast troughing during the heart of the warm season, which at least looks like a possibility at this point, there is an increased likelihood we'll see that pattern reverse for a period of time in early fall. It's not universal, but it's a fairly common dynamic.

[Jesse]

OK.

 

Whatever helps you sleep at night.

We don't really know what will happen at this point. I realize that probably sounds pretty outlandish to the king of pseudo-certainty.

[Phil]

Due is just a euphemism for pattern variability with local knowledge. If we are in a persistence pattern of west coast troughing during the heart of the warm season, which at least looks like a possibility at this point, there is an increased likelihood we'll see that pattern reverse for a period of time in early fall. It's not universal, but it's a fairly common dynamic.

Then why can't I find this supposed "dynamic" in any of the data I look at? The correlation I see is opposite, with Septembers following cool Julys averaging cooler than Septembers following warm Julys.

[GobBluth]

Absolutely.

 

Its been fairly troughy since the first week of June with another week to go.  This has a warm September written all over it.  

 

I am fairly certain that the entire pattern will begin the process of retrograding to the north and west after July 10th.    The next trough early next week makes a pass offshore but does not appear to be coming in like the weekend trough.     

 

I am sure Phil will say deep troughing will be parked over us the rest of the summer with only 'very brief' breaks but that will probably not happen.

 

 

http://stream.ecmwf.int/data/atls14/data/data01/scratch/ps2png-atls14-95e2cf679cd58ee9b4db4dd119a05a8d-MfnZzi.png

 

http://stream.ecmwf.int/data/atls13/data/data01/scratch/ps2png-atls13-95e2cf679cd58ee9b4db4dd119a05a8d-GN_xjy.png

 

http://stream.ecmwf.int/data/atls14/data/data01/scratch/ps2png-atls14-95e2cf679cd58ee9b4db4dd119a05a8d-L_wtdC.png

Logic dictates that as the NW heads into the warmest segment of the year - July 20-August 10, that the temps will be slightly warmer than now, even in a non-ridgy pattern. I'm not seeing much support for a heat blast, which you've implied over and over the NW is due for.

[TT-SEA]

Logic dictates that as the NW heads into the warmest segment of the year - July 20-August 10, that the temps will be slightly warmer than now, even in a non-ridgy pattern. I'm not seeing much support for a heat blast, which you've implied over and over the NW is due for.

I never said hot and ridgy. In fact, I went out of my way to say that I am not saying hot and ridgy. But this significant troughing will end.

[Phil]

Looks like the 12z Canadian is following the 00z EPS. Builds heights offshore in the extended range, and basically repeats the current pattern after day 8. Maybe a bit fast, but we're starting to see more agreement regarding this general progression.

[Deweydog]

Then why can't I find this supposed "dynamic" in any of the data I look at? The correlation I see is opposite, with Septembers following cool Julys averaging cooler than Septembers following warm Julys.

I dunno. I just know that there are many occasions where a persistently cool pattern during mid summer has a tendency to be followed by a spike as fall wavelengths begin to set in.

[Jesse]

I dunno. I just know that there are many occasions where a persistently cool pattern during mid summer has a tendency to be followed by a spike as fall wavelengths begin to set in.

I think a spike in the first half of September is a good bet this year.

[BLI snowman]

Then why can't I find this supposed "dynamic" in any of the data I look at? The correlation I see is opposite, with Septembers following cool Julys averaging cooler than Septembers following warm Julys.

 

In recent decades it's been very difficult to follow a cool July up with a troughy September. 2012, 2011, 1999, 1993, 1989... all of these cool Julys (which is most of the recentish ones) were followed by ridgy/warm Septembers.

 

The last really troughy July/September combo was probably 1986, and we had a near record hot August sandwiched in between that year. 

[BLI snowman]

I never said hot and ridgy. In fact, I went out of my way to say that I am not saying hot and ridgy. But this significant troughing will end.

 

We won't see 554dm heights the entire rest of the month of July? 

 

Really putting yourself out there with that one.

[Jesse]

12z GFS ensembles coming into agreement on another troughy period around the 20th.

 

[Jesse]

We won't see 554dm heights the entire rest of the month of July?

 

Really putting yourself out there with that one.

What kind of rainfall totals are you thinking for SW Wa Thu-Sun?

[TT-SEA]

We won't see 554dm heights the entire rest of the month of July? 

 

Really putting yourself out there with that one.

Phil said a pattern repeat.

[Phil]

In recent decades it's been very difficult to follow a cool July up with a troughy September. 2012, 2011, 1999, 1993, 1989... all of these cool Julys (which is most of the recentish ones) were followed by ridgy/warm Septembers.

 

The last really troughy July/September combo was probably 1986, and we had a near record hot August sandwiched in between that year.

Thanks, I'll eliminate years before 1980 and see what happens. Maybe it's a more recent phenomenon.

[BLI snowman]

What kind of rainfall totals are you thinking for SW Wa Thu-Sun?

 

Prefrontal precip on Thursday, then the upper level core of the trough looks likely to come ashore on Saturday or early Sunday, maybe 1/3" and some stratiform precip with all of that. 

 

Otherwise our typical hit/miss popcorn should be the rule of thumb. Probably another 1/4" on average for most.

 

I'd guess PDX ends up with around 0.60" altogether. Not bad for July but not exactly recordbreaking. 

[Phil]

Phil said a pattern repeat.

Stop putting words in my mouth. Even if I were predicting an exact "pattern repeat" (which I'm actually not), that's a general statement regarding the configuration of streamflow and circulation. It says nothing about how extreme or "anomalous" this said configuration would be.

 

As for what I'm predicting, while I anticipate a similar pattern during mid/late July, I believe the trough will be centered farther east than the upcoming weekend trough, with a higher wavenumber over the NPAC.

[stuffradio]

6Z GEFS has an anomaly of -15 for Walla Walla for the 11th.

[Phil]

12z ECMWF depicts a classic warm season retrogression. Ridge builds offshore, downstream troughing follows over the west. This is very typical behavior in developing La Niña summers, and fits the analog aggregate quite well.

[stuffradio]

Both 6-10 and 8-14 day outlooks on CPC have below normal odds over the PNW. The 6-10 is wetter than normal and the 8-14 is drier than normal.

[Jesse]

12z ECMWF depicts a classic warm season retrogression. Ridge builds offshore, downstream troughing follows over the west. This is very typical behavior in developing La Niña summers, and fits the analog aggregate quite well.

Indeed. Euro ensemble mean matches this run overall. If anything the ensemble mean is a little troughier in the long range.

[Jesse]

Nice day!

[Front Ranger]

Due is just a euphemism for pattern variability with local knowledge. If we are in a persistence pattern of west coast troughing during the heart of the warm season, which at least looks like a possibility at this point, there is an increased likelihood we'll see that pattern reverse for a period of time in early fall. It's not universal, but it's a fairly common dynamic.

Some stats would be cool.