August 2016 Observations and Model Discussion for the Pacific Northwest

[TT-SEA]

They weren't the vast majority of the past 2 years or so.

 

They have been a bit more frequent this summer. Baby steps...once the good ol' PDO goes negative again, we'll have rock solid proof the corner has been turned.

Point was more about September... might still end up a warm month despite the first week of the month.

[Jesse]

They weren't the vast majority of the past 2 years or so.

 

They have been a bit more frequent this summer. Baby steps...once the good ol' PDO goes negative again, we'll have rock solid proof the corner has been turned.

 

Even the hot pattern this week has been a pretty decent PDO dropper, with anomalously high pressure remaining offshore.

[Jesse]

I'm guessing it would be like trying to factor in the effects of volcanic cooling after an eruption...only a lot more difficult. 

 

We are due for another big one in the tropics one of these years.

[wx_statman]

We are due for another big one in the tropics one of these years.

 

We did get Pinatubo in '91. Who knows when the next one will be. 

[snow_wizard]

We are due for another big one in the tropics one of these years.

 

Amazingly a lot of scientist think lower solar activity is linked to more volcanism.  I know it sounds like voodoo science, but I have read the long winded explanation and it sounds possible.

[snow_wizard]

Even the hot pattern this week has been a pretty decent PDO dropper, with anomalously high pressure remaining offshore.

 

Indeed.  I'm impressed it has managed to be so warm with that kind of surface pressure over the GOA.

[TT-SEA]

12Z ECMWF is really backing off on the troughing for next week.  Not nearly as deep.  

[snow_wizard]

12z GFS ensembles are pretty solidly cool.

 

No doubt.  The mean line is below normal for 12 straight days.

[Phil]

No hints of a ridgy pattern setting up on any model guidance, as should be expected w/ subsidence along/west of the dateline.

[snow_wizard]

The WRF is quite bullish on cooling tomorrow for the Puget Sound area.  Probably low 70s with a few upper 60s possible.

[Jesse]

Indeed.  I'm impressed it has managed to be so warm with that kind of surface pressure over the GOA.

 

As Matt was saying, it has been a fall like pattern that has "benefitted" from August sun angles.

 

I think this would have been a cool pattern for us even a few months from now.

[TT-SEA]

ECMWF hangs out to troughing longer... despite being less deep.

[Deweydog]

As Matt was saying, it has been a fall like pattern that has "benefitted" from August sun angles.

 

I think this would have been a cool pattern for us even a few months from now.

Pretty much any strong subsidence pattern will be cooler than average about three months from now.

[wx_statman]

Amazingly a lot of scientist think lower solar activity is linked to more volcanism.  I know it sounds like voodoo science, but I have read the long winded explanation and it sounds possible.

 

I've read about that too. There's some thinking out there which correlates the Dalton Minimum with the increased volcanic activity of that era. It wasn't just Tambora, but a number of other major eruptions in the 1805-1815 period and again in the 1830's. 

[TT-SEA]

Pretty much any strong subsidence pattern will be cooler than average about three months from now.

 

Should be obvious.  

 

Many very warm patterns in the summer would be chilly, inversion patterns in the winter.  

[Jesse]

12Z EURO was a great run.

 

Looks primed for another troughy period at day 10.

[TT-SEA]

Here is what I am referring to with the 12Z ECMWF run being less deep in the medium range.

 

12Z run from yesterday for September 1st:

 

http://stream.ecmwf.int/data/atls18/data/data01/scratch/ps2png-atls18-95e2cf679cd58ee9b4db4dd119a05a8d-x_tDFw.png

 

 

12Z run from today for same time:

 

http://stream.ecmwf.int/data/atls17/data/data01/scratch/ps2png-atls17-95e2cf679cd58ee9b4db4dd119a05a8d-PMwOxZ.png

[Jesse]

Pretty much any strong subsidence pattern will be cooler than average about three months from now.

 

I think this would have been cool pattern as early as late October.

[Deweydog]

I think this would have been cool pattern as early as late October.

With heights well into the 580's and good mixing? Not likely.

[Front Ranger]

I think this would have been cool pattern as early as late October.

There's no such thing as a cool pattern any more. Only average.

 

See SEA.

[Jesse]

Model trends today seem to be ruling out PDX experiencing its third consecutive top warm August.

 

Tuesday and Wednesday have trended cooler on both the GFS and the EURO.

 

The weekend is looking cooler than it was a few days ago too. Monday is the only day that has trended warmer.

[TT-SEA]

Scott Sistek table... this August certainly has continued the theme for the past few years.

 

 

[Jesse]

With heights well into the 580's and good mixing? Not likely.

 

I can imagine a highs around 70 lows in the 30s type of setup. Maybe close to average.

[Deweydog]

I can imagine a highs around 70 lows in the 30s type of setup. Maybe close to average.

Hard to call +10 high temperatures cool/cold.

 

PDX is also far more likely at that point to have issues decoupling compared to summertime offshore flow patterns. Frustration.

[wx_statman]

I can imagine a highs around 70 lows in the 30s type of setup. Maybe close to average.

 

Close to average? Anything 70+ in the last week of October and you're pushing historic boundaries at PDX. 

[wx_statman]

Hard to call +10 high temperatures cool/cold.

 

PDX is also far more likely at that point to have issues decoupling compared to summertime offshore flow patterns. Frustration.

 

Very true. This was on full display in early November 2010. 

 

71 on 10/31/1954 is the latest PDX ever managed to get that warm on an east wind.

[Jesse]

Close to average? Anything 70+ in the last week of October and you're pushing historic boundaries at PDX.

Ok, I take it back. Maybe mid-60s? I don't know. We are extrapolating a pattern two months in the future. Not really an exact science.

 

How do you think the current pattern would have played out a few months for now? It's kind of fun to think about.

[wx_statman]

Ok, I take it back. Maybe mid-60s? I don't know. We are extrapolating a pattern two months in the future. Not really an exact science.

 

No, I think you're in the ballpark with 70 degrees. It just wouldn't be average. 

[Deweydog]

Ok, I take it back. Maybe mid-60s? I don't know. We are extrapolating a pattern two months in the future. Not really an exact science.

I think the broad point is that there isn't really any precedence for taking a hot summertime pattern, putting it in late October and making it notably cool. Obviously anomalies will be less pronounced, but it's still warm, relatively speaking. A few weeks later, once the transition to gap winds/inversions is established, that changes.

[Jesse]

I think the broad point is that there isn't really any precedence for taking a hot summertime pattern, putting it in late October and making it notably cool. Obviously anomalies will be less pronounced, but it's still warm, relatively speaking. A few weeks later, once the transition to gap winds/inversions is established, that changes.

 

Fair enough.

[GHweatherChris]

Over achieving here today so far, 87 at my house and Hoquiam is at 84, 4 degrees higher than forecast.

[BLI snowman]

Very true. This was on full display in early November 2010. 

 

71 on 10/31/1954 is the latest PDX ever managed to get that warm on an east wind.

 

Yeah, that's also the point where subtropical airmasses (10/21/2003, 11/6/2006, 11/13/1999) take over as our record high fuel. Late October is very late for warm east winds.

[snow_wizard]

12Z EURO was a great run.

 

Looks primed for another troughy period at day 10.

 

A broad trough carves out over the Western US early in week two.  Really really nice look to it.  It looks like the 4C line comes into WA around day 6 or 7.

[snow_wizard]

With heights well into the 580's and good mixing? Not likely.

 

I think he's referring to the placement of the anomaly centers and offshore amplification right now.  Obviously a pattern with the same look two months from now would have lower heights just seasonally speaking.

[Deweydog]

I think he's referring to the placement of the anomaly centers and offshore amplification right now. Obviously a pattern with the same look two months from now would have lower heights just seasonally speaking.

Not necessarily. We can see heights well into the 580's pretty much any time of year. Late October 2003 featured 600dm heights just offshore prior to the big retrogession at the end of the month.

[Jesse]

Euro ensembles are deeper with the trough next week.

[snow_wizard]

Euro ensembles are deeper with the trough next week.

 

Deeper than the operational?  Impressive.

[Deweydog]

With another 85+ high today, Astoria has now had three in a row. Second time in their history, the other being the August 1981 show.

[Bryant]

Deeper than the operational? Impressive.

http://i.imgur.com/XrRn9FQ.jpg

 

http://i.imgur.com/MHEWv92.jpg

[Deweydog]

I just looked at September 1968 and there was a period of chilly weather around the middle of the month in the PNW. From September 13 to September 22, Seattle had 5 straight days with highs in the 50s and 7 days in that period with highs 60 or lower. For PDX, the average temperature in that 10 day stretch was 61.8.

See... Low sun angles.