September 2016 Observations and Model Discussion for the Pacific Northwest

[Phil]

So what? Must have said 9/10 as well. Generally correct... getting warm now with no end in sight.

A week ago, there was "no end in sight" regarding the troughing and cool temperatures. Sometimes, it's good to know *why* a pattern is occurring..that way, you might be able to predict when it'll change. Or, sometimes, mother nature gets rebellious and tries something new. Can never be overly certain about things like this. Forecasters consistently end up looking foolish.

[James Jones]

Yes, but it happened last year. No recent Sep has come close. Which goes against the notion that Sep is now more of a summer month than June.

 

Definitely not the case for the PNW overall.

This is kind of like pointing to winter 1933-34 to say that Ninas can be as or more torchy than any Nino - after all, 33-34 is still, to this day, the warmest winter on record for some locations. Technically it's true, but it was such an extreme anomaly that it's not really that useful to talk about it when discussing Ninas vs Ninos (other than as a point of interest), and it doesn't change the fact that on average, Ninas are colder and snowier than Ninos.

[Front Ranger]

So one month undoes 25 years of climatology? Is that what you're saying?

 

Here are the running 1991-2016 averages @ PDX:

 

June - 63.7F

September - 65.1F 

 

No, my point was that June can still outperform September when it comes to summer weather. June 2015 just happened, and until a September comes along that is warmer, that point stands.

 

Why did you start with 1991? I see 1991 had a very warm Sep and very cool June...if you went back to say, 1985, those numbers would look a little different, wouldn't they? Considering June was warmer in 1985 (by a lot), 1986 (by a lot), and 1987. 

 

I trust long term climatology over trends from a couple decades.

 

OLM's long term averages.

 

June: 58.87

Sep: 58.52

[Front Ranger]

You said "ridging returns after the 7th" on August 28th. Unless you changed your prediction afterwards, that was your forecast.

 

I have the screenshot.

 

I have screenshots of those late night texts you sent Tim last weekend after one too many margaritas.

[Phil]

FWIW, early indications are that an anticyclonic wavebreaking event will occur over the NPAC in November, marking winter's initiation for 2016-17..maybe 7-10 days before thanksgiving?

 

Until then...lol.

[TT-SEA]

FWIW, early indications are that an anticyclonic wavebreaking event will occur over the NPAC in November, marking winter's initiation for 2016-17..maybe 7-10 days before thanksgiving?

 

Until then...lol.

 

What does that mean until then?   Warm?

[wx_statman]

Someone tell Front Ranger that 30 year baselines are 1981-2010, 1991-2020, 2001-2030, etc. 

[TT-SEA]

Nice post from Mark tonight...

 

https://fox12weather.wordpress.com/2016/09/09/friday-night-quick-post-2/#comments

 

It’s very obvious now that the 10 day period of cool weather we just went through will not be repeated for at least the next 2 weeks.  There is no sign of record-breaking hot weather, but we are entering a long period of very stable and warm days with comfortably cool nights.  Many would say the next week or so is perfection for September!

[MossMan]

Nice post from Mark tonight...

 

https://fox12weather.wordpress.com/2016/09/09/friday-night-quick-post-2/#comments

 

It’s very obvious now that the 10 day period of cool weather we just went through will not be repeated for at least the next 2 weeks. There is no sign of record-breaking hot weather, but we are entering a long period of very stable and warm days with comfortably cool nights. Many would say the next week or so is perfection for September!

Going to be pure misery for a few members of this forum however.

[TT-SEA]

Going to be pure misery for a few members of this forum however.

 

Nah... I am sure in real life they will be out and enjoying the nice weather too.    And we all know that November will be stormalicious!  

[Trainwreck]

Bravo Mark Nelsen. You have ruined many lives with that post. Lol

[Trainwreck]

And yes Tim, after about 6 weeks from now, the weather will be stormy and wet for the foreseeable future. Hopefully a few snowy days mixed in as well.

[Weather101]

We only get a few snowy days a year if we are lucky. Thats our winter climate, Rain.

[Jesse]

The warm days and cool nights look perfect. Very early Fall-ish.

[Phil]

What does that mean until then? Warm?

I don't know about "warm". After the mid-September warm spell, I think a period of onshore flow is likely as that GOA vortex develops. Probably a period of cool/rainy weather during the second half of September, followed by a retrogression of the GOA vortex towards the Aleutians to start October? That'd probably be another warm pattern, I guess.

[TT-SEA]

I don't know about "warm". After the mid-September warm spell, I think a period of onshore flow is likely as that GOA vortex develops. Probably a period of cool/rainy weather during the second half of September, followed by a retrogression of the GOA vortex towards the Aleutians to start October? That'd probably be another warm pattern, I guess.

 

 

OK.

 

Just wondering what you meant by 'until then... lol'

[snow_wizard]

No, my point was that June can still outperform September when it comes to summer weather. June 2015 just happened, and until a September comes along that is warmer, that point stands.

 

Why did you start with 1991? I see 1991 had a very warm Sep and very cool June...if you went back to say, 1985, those numbers would look a little different, wouldn't they? Considering June was warmer in 1985 (by a lot), 1986 (by a lot), and 1987. 

 

I trust long term climatology over trends from a couple decades.

 

OLM's long term averages.

 

June: 58.87

Sep: 58.52

 

To me June just feels more like a summer month due to higher humidity overall, much longer days, more powerful sun, and all of that.  September (on the whole) is capable of far chillier nights also.

[snow_wizard]

We only get a few snowy days a year if we are lucky. Thats our winter climate, Rain.

 

 

 

Much more true now than it used to be.  No reason we can't go back to better winters at least to some extent. 

[snow_wizard]

Going to be pure misery for a few members of this forum however.

 

I don't even think what he said is necessarily true.  The GFS has been trending cooler the last couple of days.

[snow_wizard]

FWIW, early indications are that an anticyclonic wavebreaking event will occur over the NPAC in November, marking winter's initiation for 2016-17..maybe 7-10 days before thanksgiving?

 

Until then...lol.

 

How can you see that this far out?

[snow_wizard]

September 19th says howdy to Mark Nelson.

 

Obviously a small change could make things really cool around here at that time.

 

 

[snow_wizard]

The WRF is bascially yawning at any potential warmth next week.  I think some expectations are getting unduly high in that regard.

[Phil]

How can you see that this far out?

A combination of analyzing/extrapolating intraseasonal forcings/AAM propagation from the current boundary state, and analoging the aforementioned boundary state directly under similar occurrences.

 

Our background:

 

1) A fairly blatant antecedent tendency for anticyclones to amplify poleward under upper level mass/momentum transport conduits associated w/ +QBO.

 

2) Enhanced off-equator convection and underlying longitudinal gradient bias (ENSO/QBO forcing) that is also spatially evident.

 

Given this, the rest is somewhat easier to extrapolate and/or analog for. The timing/magnitude of the poleward AAM propagation over the Pacific, weak Hadley/Z-cell gradients, weak hemispheric meridional thermal/wind gradient(s), WAFs out of the NWPAC, etc.

[snow_wizard]

Pretty interesting to note the operational GFS, the GFS control model, and a number of ensemble members have been indicating a trough around the 20th the past several runs.  Could be some egg on the face coming for a certain Mark that is often mentioned on here.

[Weather101]

Much more true now than it used to be. No reason we can't go back to better winters at least to some extent.

There's no going back if you want to be real with yourself. Our climate is not good for snow simple as that. Each winter it will rain a lot and have mild temps compared to everyone else who experiences a true winter. We hope to get a cold snap that lasts a week and a overrunning event and then it's over. Or if we are super lucky we get a few days of snow before the warm up and thats our winter. I love snow just as much as you do but I came to understand it is very difficult to get snow around here. Take what you can get.

[snow_wizard]

A combination of analyzing/extrapolating intraseasonal forcings/AAM propagation from the current boundary state, and analoging the aforementioned boundary state directly under similar occurrences.

 

Our background:

 

1) A fairly blatant antecedent tendency for anticyclones to amplify poleward under upper level mass/momentum transport conduits associated w/ +QBO.

 

2) Enhanced off-equator convection and underlying longitudinal gradient bias (ENSO/QBO forcing) that is also spatially evident.

 

Given this, the rest is somewhat easier to extrapolate and/or analog for. The timing/magnitude of the poleward AAM propagation over the Pacific, weak Hadley/Z-cell gradients, weak hemispheric meridional thermal/wind gradient(s), WAFs out of the NWPAC, etc.

 

Do you think we will see some anomalous GOA ridging during October?  My guess is we will at least see one round of it.

[snow_wizard]

There's no going back if you want to be real with yourself. Our climate is not good for snow simple as that. Each winter it will rain a lot and have mild temps compared to everyone else who experiences a true winter. We hope to get a cold snap that lasts a week and a overrunning event and then it's over. Or if we are super lucky we get a few days of snow before the warm up and thats our winter. I love snow just as much as you do but I came to understand it is very difficult to get snow around here. Take what you can get.

 

The point I was making is it used to be much easier and there's no reason to think we can't go back at least partway to that kind of thing.  Keep in mind some places in the Midwest had an historic cold winter just a couple of years ago.  If they are capable of an historic cold winter then anywhere should be capable of it.  We have had some great winters you know.  There is something of a cycle where anomalous cold winters alternate between the Western US and the Eastern US.  Even places in the West that normally have very cold winters have seen extreme mildness in recent years.

 

I totally get where you are coming from though.  Recent years have been an utter embarrassment. 

[Phil]

Do you think we will see some anomalous GOA ridging during October? My guess is we will at least see one round of it.

Yeah, I think so. I suspect after the GOA vortex retrogrades westward towards the Aleutians/WPO domain, the downstream ridge over the western US will amplify and then retrograde N/W into the GOA and/or EPO domain.

 

Could be one of those bifurcated EPO/WPO scenarios.

[Phil]

As far these analogs are concerned, no matter how I tweak things, I'm continuing obtain a strong signal for NPAC blocking in November, and a heavy round of high latitude blocking in January (though the location/orientation of the January blocking is all over the place). It's interesting.

[snow_wizard]

Yeah, I think so. I suspect after the GOA vortex retrogrades westward towards the Aleutians/WPO domain, the downstream ridge over the western US will amplify and then retrograde N/W into the GOA and/or EPO domain.

 

Could be one of those bifurcated EPO/WPO scenarios.

 

How about that wild trade wind burst that's about to hit?  I'm really liking how that has developed the last few days.

[Phil]

How about that wild trade wind burst that's about to hit? I'm really liking how that has developed the last few days.

Yeah, it's a strong one. Should boost thermocline tilt somewhat, especially given the divergence progged around 120W.

[snow_wizard]

As far these analogs are concerned, no matter how I tweak things, I'm continuing obtain a strong signal for NPAC blocking in November, and a heavy round of high latitude blocking in January (though the location/orientation of the January blocking is all over the place). It's interesting.

 

I saw the same thing on the maps available on the Tropical Tidbits site.  Quite frankly it worries me because getting hit early has seemed to be our MO lately.  Admittedly this year has some differences though. 

[Phil]

I saw the same thing on the maps available on the Tropical Tidbits site. Quite frankly it worries me because getting hit early has seemed to be our MO lately. Admittedly this year has some differences though.

I suspect this'll be a winter with frequent fluctuation(s) in the longwave pattern, rather than a winter where a dominant pattern sets up around New Years and persists until March. I'm not worried about a "one and done" winter for you, as I anticipate there'll be plenty of a opportunities to go around.

 

This is just my preliminary opinion, though. I've been wrong before.

[snow_wizard]

The temp is dropping fast again tonight.  Another low well below 50 on the way.  Looks like we have finally turned the corner on the low temps.

[ShawniganLake]

Pretty interesting to note the operational GFS, the GFS control model, and a number of ensemble members have been indicating a trough around the 20th the past several runs. Could be some egg on the face coming for a certain Mark that is often mentioned on here.

I am not sure that Marks post was really setting himself up for egg on his face. A 10 day cool period is not upcoming in the next 2 weeks. Should be a week or so of warm days and cool nights, even if that trough shows up around the 20th. That's really all he said

[snow_wizard]

I suspect this'll be a winter with frequent fluctuation(s) in the longwave pattern, rather than a winter where a dominant pattern sets up around New Years and persists until March. I'm not worried about a "one and done" winter for you, as I anticipate there'll be plenty of a opportunities to go around.

 

This is just my preliminary opinion, though. I've been wrong before.

 

I like this kind of talk!

[snow_wizard]

I am not sure that Marks post was really setting himself up for egg on his face. A 10 day cool period is not upcoming in the next 2 weeks. Should be a week or so of warm days and cool nights, even if that trough shows up around the 20th. That's really all he said

 

It looked to me like he was saying the next two weeks would be all warm.

[TT-SEA]

I am not sure that Marks post was really setting himself up for egg on his face. A 10 day cool period is not upcoming in the next 2 weeks. Should be a week or so of warm days and cool nights, even if that trough shows up around the 20th. That's really all he said

 

 

Jim finds it really annoying when people make confident claims.     

[TT-SEA]

00Z ECMWF has mid 80s at SEA and mid 90s at PDX later next week... like the 12Z run.

[TT-SEA]

00Z ECMWF still looking great at day 10... same with the 00Z Canadian.