September 2017 PNW Discussion Thread

[Front Ranger]

12z Euro looks very promising for some cooler weather.

 

Record warm September hopes are fading fast.

[TT-SEA]

Record warm September hopes are fading fast.

 

The ECMWF control run and the EPS show the trough later next week now... but the control run is really warm for a good part of the run and the EPS does not show any sustained western troughing.   

[Jesse]

Record warm September hopes are fading fast.

The chilly 79/66 we've seen today so far will definitely put a dent in things!

[Front Ranger]

The chilly 79/66 we've seen today so far will definitely put a dent in things!

 

Watch out for that midnight low!

[Jesse]

The ECMWF control run and the EPS show the trough later next week now... but the control run is really warm for a good part of the run and the EPS does not show any sustained western troughing.

Never heard you talk about the control run until the last few days. EPS was definitely troughy though.

[TT-SEA]

Never heard you talk about the control run until the last few days. EPS was definitely troughy though.

 

I always talk about the control run.   When it agrees well with the ECMWF then its a good sign.   It agrees on the trough later next week.

 

EPS is definitely troughy for a couple days later next week.   But its not troughy overall.    Here is day 10...

 

 

I understand that it goes to climo in the long range... but it does not look troughy for most of the run.

[Front Ranger]

The ECMWF control run and the EPS show the trough later next week now... but the control run is really warm for a good part of the run and the EPS does not show any sustained western troughing.   

 

Ensembles generally look average to a little below from day 6 on, though.

[TT-SEA]

Ensembles generally look average to a little below from day 6 on, though.

 

 

Yes... the trough in one week looks solid now.   

 

And the EPS shows 850mb temps at or above normal again starting on day 9.    

 

Here is day 10... definitely would not say its cool from "day 6 on"

 

[Phil]

The 12z EPS depicts the same split flow/+NAO pattern that's dominated the last several years. That's a warm pattern upon verification, more-so the farther north you go.

 

This regime isn't ready to break down just yet.

[Front Ranger]

Yes... the trough in one week looks solid now.   

 

And the EPS shows 850mb temps at or above normal again starting on day 9.    

 

Here is day 10... definitely would not say its cool from "day 6 on"

 

 

I was referring to GFS ensembles as well.

[BLI snowman]

Yet another GFS run showing a direct hit for Miami. Looking more and more likely that Florida sees a Cat 5 landfall.

[Front Ranger]

The 12z EPS depicts the same split flow/+NAO pattern that's dominated the last several years. That's a warm pattern upon verification, more-so the farther north you go.

 

This regime isn't ready to break down just yet.

 

Ok...but didn't you say just yesterday that the active Atlantic hurricane season was a sign that the regime was breaking down?

[TT-SEA]

Yet another GFS run showing a direct hit for Miami. Looking more and more likely that Florida sees a Cat 5 landfall.

 

The middle of the Everglades might be the best hope.   Worst wind between Naples and Miami.   

 

There is nothing between those cities except for alligators.   Probably too narrow though to spare both coasts.  

[Phil]

D10-15 EPS is the same recent subdecadal pattern we've seen in recent years..+PNA/+NAO and a big ridge over western North America. Man does 2008-2012 feel like an eternity ago.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/49575E53-9FAD-45D1-A816-279FE6B1A614_zpsh8tvjdpw.png

[Phil]

Ok...but didn't you say just yesterday that the active Atlantic hurricane season was a sign that the regime was breaking down?

Preparing to break down, yes. The shifting tropics are a clear precursor in this case.

 

We just need to wait for the Eurasian summer circulation (monsoonal) to be replaced by the winter circulation (Siberian high) for the conduits to waveguide perturbation to open and flip the PNA. This starts in late September, usually.

[wx_statman]

We've definitely seen some sort of shift this year. The progression regionally has been more akin to what we saw from the 1950s-80s, as opposed to the three decades since.

[BLI snowman]

Probably a severe thunderstorm now in the OR Cascades. You don't see 74dbz too often.

[Dave]

Probably a severe thunderstorm now in the OR Cascades. You don't see 74dbz too often.

https://twitter.com/NWSPortland/status/905918724355612672

 

Edit:  Hmm.  Not sure how to embed tweet.  Golf ball hail reported in Oakridge.

[BLI snowman]

https://twitter.com/NWSPortland/status/905918724355612672

 

Edit:  Hmm.  Not sure how to embed tweet.  Golf ball hail reported in Oakridge.

 

And I see there's a warning now.

 

Too bad all that will die over NW OR before getting into the valleys 

[Jesse]

That band of thunderstorms looks to be making a bee line for the Portland area. Would be nice if it held together.

[Deweydog]

Sprinkles incoming?????

[Deweydog]

Nice to see the inversion breaking up a bit this afternoon.

[Phil]

We've definitely seen some sort of shift this year. The progression regionally has been more akin to what we saw from the 1950s-80s, as opposed to the three decades since.

I agree, and I'd even extend this line of thinking across the high latitudes and into the tropics. The SIOD/EPAC both reversed signs within a span of a few months this summer, which is a pretty rapid shift by tropical standards.

 

Part of this is your typical response to decreasing solar, which we also saw back in 2006-2010.

[Perturbed Member]

Latest HRRR shows that band holding as it passes PDX metro and drops some decent (badly needed) precip over the gorge.

[luminen]

not sure if posted here yet but Brett Anderson posted a fall forecast for Canada. He's calling for above normal temps and above normal precip in the PNW. Hopefully that leads to another killer winter...maybe even better than last? I would absolutely love some temps below 15F...

 

https://www.accuweather.com/en/weather-blogs/anderson/canada-fall-2017-outlook/70002654

[epiceast]

How do we relate this first football game to what matters, weather?

[wx_statman]

The path at landfall for Irma could be very similar to "Hurricane King" in October 1950. The eye of that one tracked directly over Miami, bringing 122 mph sustained winds to the Miami Weather Bureau Office. 

[Geos]

The path at landfall for Irma could be very similar to "Hurricane King" in October 1950. The eye of that one tracked directly over Miami, bringing 122 mph sustained winds to the Miami Weather Bureau Office. 

 

That's about the oddest paths I've seen.

[Jesse]

not sure if posted here yet but Brett Anderson posted a fall forecast for Canada. He's calling for above normal temps and above normal precip in the PNW. Hopefully that leads to another killer winter...maybe even better than last? I would absolutely love some temps below 15F...

 

https://www.accuweather.com/en/weather-blogs/anderson/canada-fall-2017-outlook/70002654

Ugh, enough with the above normal temps.

 

Although if I remember correctly, Brett called for above normal Dec-Feb temps for PNW in his outlook for last winter. So take that for what it's worth. I don't think I've ever seen a cool seasonal outlook for us from him.

[Jesse]

Precip is just falling apart at Portland's doorstep. Too bad.

 

The good news is that fire areas in the Gorge appear to be getting a decent soaking.

[wx_statman]

That's about the oddest paths I've seen.

 

Might have something to do with the whacked-out NH jet stream that month. That was also one of the wettest Octobers on record for the PNW. 

[wx_statman]

Precip is just falling apart at Portland's doorstep. Too bad.

 

The good news is that fire areas in the Gorge appear to be getting a decent soaking.

 

Rain band literally split around Portland. I'm sitting at PSU and there hasn't been a drop. 

 

Tillamook about to get a good soaking. 

[TT-SEA]

00Z NAM basically misses Florida as Irma curves to the NE at the last minute.   A huge eastward shift compared to its 12Z run.

 

[Phil]

August NH snowcover extent was the highest since 1998.

 

Not bad.

[VancouverIslandSouth]

Some smokey rain here in Victoria this evening, large drops but nothing measurable yet. Today felt a lot warmer than yesterday as well, it'll be nice to have the smoke gone.

[luminen]

Precip is just falling apart at Portland's doorstep. Too bad.

 

The good news is that fire areas in the Gorge appear to be getting a decent soaking.

 

Portland probably has the most frustrating climate I've ever lived in, even more so than southern California.

[Front Ranger]

00Z NAM basically misses Florida as Irma curves to the NE at the last minute.   A huge eastward shift compared to its 12Z run.

 

 

FWIW, the NAM is terrible with tropical systems.

[VancouverIslandSouth]

Portland probably has the most frustrating climate I've ever lived in, even more so than southern California.

 

Ever lived in Victoria?

[snow_wizard]

Ugh, enough with the above normal temps.

 

Although if I remember correctly, Brett called for above normal Dec-Feb temps for PNW in his outlook for last winter. So take that for what it's worth. I don't think I've ever seen a cool seasonal outlook for us from him.

 

With a full blown Nina taking hold now it's nearly inevitable below normal temps will be coming soon enough.  I'm very surprised how fast the Nina has developed and how strong it is now forecast to get.  The fact we have 3 hurricanes over the Atlantic and none over the Pacific shows how rapidly the atmosphere is reacting to the colder ENSO.  I'm betting on a solid cold period somewhere in the late Sept to mid Oct period.

[Deweydog]

PDX running above average for temperatures so far this month. Below average for precipitation.