September 2025 PNW Discussion

[Meatyorologist]

O/U is 9.5 thunderstorms

[Positive PNA Enjoyoor]

Dropped down to 32 for the fourth time this month, this morning.  Nice autumnal airmass.  

[StormchaserChuck1]

I keep seeing all this stuff on an Aurora Borealis tomorrow night. Any merit?

[Rubus Leucodermis]

7 minutes ago, StormchaserChuck1 said:

I keep seeing all this stuff on an Aurora Borealis tomorrow night. Any merit?

G3 storm, forecast max Kp index of 6. Pretty weak sauce when it comes to lower latitude aurorae. The May 2024 storm was G5 with a Kp of 9, the October storm in that same year was G4–G5 with a Kp of 8.

Plus there will be significant lunar interference this time.

[SpaceRace22]

Our lord and savior CFS has some gifts for us today

[High Desert Mathew]

17 minutes ago, SpaceRace22 said:

Our lord and savior CFS has some gifts for us today

Looks like it’s just doing its standard Nina climo. 

[Positive PNA Enjoyoor]

DR YES!!!1

[Cloud]

Last of the 80s this week (though I’m not buying it yet)? The mid to end week heat is becoming less and less of a factor. At least this side of the mountains and the Sound. 

[Anti Marine Layer]

12 hours ago, Positive PNA enjoyoor said:

Dropped down to 32 for the fourth time this month, this morning.  Nice autumnal airmass.  

This month just started today

[iFred]

Waking up to a low cloud deck, drizzle, and 59° in Everett. Perfect start to the final month of meteorological summer.

[Port Angeles Foothiller]

10 hours ago, StormchaserChuck1 said:

I keep seeing all this stuff on an Aurora Borealis tomorrow night. Any merit?

Yes, there could be a show tonight. It depends on when the CME hits and how strong it is. I’ll have my camera charged.

[KeyPeninsula_Wx]

40 minutes ago, Cloud said:

Last of the 80s this week (though I’m not buying it yet)? The mid to end week heat is becoming less and less of a factor. At least this side of the mountains and the Sound. 

Yeah, forecast is looking cooler than it did towards the end of last week. Looking like mostly low 80s this week instead of a run at some 90s. 

[Phishy Wx]

its over

[Port Angeles Foothiller]

1100 acres fire just East of Mt. Rainer that started just 6 days ago, zero containment. I was told fire season was dead and we would have no fires this side of the mountains. Also, the smoke couldn't possibly be from WA fires... must be coming from the moon. 

[KeyPeninsula_Wx]

Models agree there will be some rain via convection potentially but as always vary being 7 days out roughly. 

[DeepFriedEgg]

48 minutes ago, iFred said:

Waking up to a low cloud deck, drizzle, and 59° in Everett. Perfect start to the final month of meteorological summer.

September is meteorological fall.

[MossMan]

Was an awesome day up at Lake Whatcom yesterday. Had a little lightning just past dusk from a single cloud out in the distance! 

And a light drizzly walk this morning back at home. Fall is here! 
 

At least until this work and school week arrives of course. 

[Front Ranger]

15 hours ago, Positive PNA enjoyoor said:

Dropped down to 32 for the fourth time this month, this morning.  Nice autumnal airmass.  

The fourth time this month already?

[Front Ranger]

The last third of August was amazing here. Had rain on 8 straight days for a total of almost 3", and high temps ranging from the low 70s to the low 80s.

DEN finished the last 10 days of August with no high warmer than 84. Last time that happened was 1987. Also finished as the wettest August on record at the current airport location (which dates back to the mid 1990s), with 4.12".

[Deweydog]

15 hours ago, Positive PNA enjoyoor said:

Dropped down to 32 for the fourth time this month, this morning.  Nice autumnal airmass.  

I’m assuming this means down to 32, up to 33, down to 32, up to 33, down to 32, up to 33, down to 32 this morning? Dynamic!

[VancouverIslandSouth]

59 minutes ago, MossMan said:

Was an awesome day up at Lake Whatcom yesterday. Had a little lightning just past dusk from a single cloud out in the distance! 

And a light drizzly walk this morning back at home. Fall is here! 
 

At least until this work and school week arrives of course. 

I drove through a few thunderstorms between Parksville and Nanaimo last night. They were probably quite visible to anyone near the Strait of Georgia.

[VancouverIslandSouth]

Current SSTs show the 20C mark is nearly up to 47N off the coast:

[KeyPeninsula_Wx]

Euro also showing continued southerly flow like the other models with multiple chances of convection over this week and next week.

Eventually one of these rolls at the dice could work. September historically is a very good time of year for warm core convection. 

[Cloud]

Latest NOAA CPC. 
Astronomical fall could be on schedule this year.

[High Desert Mathew]

2 minutes ago, Cloud said:

Latest NOAA CPC. 
Astronomical fall could be on schedule this year.

Not if Phil has something to say about it. Dry, dry, dry is all he’s been saying through fall and early winter. We will see. 

[TigerWoodsLibido]

Nice to start a new month. 72F and beautiful out there.

[Phishy Wx]

9 minutes ago, High Desert Mathew said:

Not if Phil has something to say about it. Dry, dry, dry is all he’s been saying through fall and early winter. We will see. 

6 days doesn't make a season

[TT-SEA]

2 hours ago, MossMan said:

Was an awesome day up at Lake Whatcom yesterday. Had a little lightning just past dusk from a single cloud out in the distance! 

And a light drizzly walk this morning back at home. Fall is here! 
 

At least until this work and school week arrives of course. 

We are in Bellingham... yesterday afternoon was pretty nice and it's sunny today.    Mariner layer is stuck farther south... model fail.

[VancouverIslandSouth]

7 hours ago, TT-SEA said:

We are in Bellingham... yesterday afternoon was pretty nice and it's sunny today.    Mariner layer is stuck farther south... model fail.

I had to look that one up, sounds awful:

[DareDuck]

45 minutes ago, High Desert Mathew said:

Not if Phil has something to say about it. Dry, dry, dry is all he’s been saying through fall and early winter. We will see. 

To his credit he did say there would be a 10ish day period that would be cooler then a return to warm and dry. So far that’s looking like a good call. I’m glad this looks like the last truly summer like week. By mid September the lower sun angle and cooler desert nights make things feel less summer-y. 

[Rubus Leucodermis]

5 minutes ago, DareDuck said:

To his credit he did say there would be a 10ish day period that would be cooler then a return to warm and dry. So far that’s looking like a good call. I’m glad this looks like the last truly summer like week. By mid September the lower sun angle and cooler desert nights make things feel like summer-y. 

Records indicate that both Portland and Eugene have been blessed with 90s in October. Premature celebrations seem unwise.

Edit: And ditto for Bend.

[T-Town]

16 minutes ago, VancouverIslandSouth said:

I had to look that one up, sounds awful:

It hangs in all day and then fades away as the playoffs near. 

[TT-SEA]

40 minutes ago, VancouverIslandSouth said:

I had to look that one up, sounds awful:

That just about sums up the last 2 weeks of Mariners baseball.   

[MV_snow]

1 hour ago, TT-SEA said:

We are in Bellingham... yesterday afternoon was pretty nice and it's sunny today.    Mariner layer is stuck farther south... model fail.

I’ve noticed BLI tends to be a good place to escape the marine layer. The downside is they can be brushed more frequently with systems passing by to the north, so I think they have more mid and high clouds than we do in summer.

Latest satellite loop doesn’t look very optimistic for clearing here so the Euro should bust nearly 10 degrees too high IMBY today.

[DareDuck]

1 hour ago, Rubus Leucodermis said:

Records indicate that both Portland and Eugene have been blessed with 90s in October. Premature celebrations seem unwise.

Edit: And ditto for Bend.

For my area it gets pretty hard to get above 90 after 9/20. Even then it’s only for a couple hours with generally better overnight relief. I wouldn’t be surprised with a pretty warm 30 day period around 9/20-10/20. 

[Phil]

8 hours ago, High Desert Mathew said:

Looks like it’s just doing its standard Nina climo. 

Lost track of how many times it showed those crazy patterns last winter. Of course zilch verified.

[MossMan]

3 hours ago, TT-SEA said:

We are in Bellingham... yesterday afternoon was pretty nice and it's sunny today.    Mariner layer is stuck farther south... model fail.

Was a good day to Labor at home. Two of my Cedars were starting to eat the kids play structure, and the other was getting close to touching the house and was starting to swallow the fence and gate. So that was my cloudy day project. 
This tractor has been worth every penny. 

[iFred]

51 minutes ago, MossMan said:

Was a good day to Labor at home. Two of my Cedars were starting to eat the kids play structure, and the other was getting close to touching the house and was starting to swallow the fence and gate. So that was my cloudy day project. 
This tractor has been worth every penny. 

I've been looking into one of these, but for different reasons.

[Phishy Wx]

some interesting analogs

 

[NWbyNW]

The forecast failure for this past weekend is pretty incredible.  They were so off. The black line represents the prediction from the models and the NOAA.  The yellow dots are the actual temps as KSEA.  They were accurate Thursday, but Friday, Saturday, and now Monday have all been way off.