September 2016 Observations and Model Discussion for the Pacific Northwest

[Jesse]

Seems like a "perfect storm" tomorrow for those interested in cold anomalies. Looks to be a perfectly timed warm front that will allow temps to fall down into the low 50's overnight tonight with the muck beginning around commute time or shortly thereafter.

 

ECWMF says 59º for a high tomorrow. EPS mean sits at 61º. GFS MOS guidance sits 59º.

 

It's actually too bad that the record low, high is only 54º tomorrow.

Yeah, interesting setup. Timing is everything.

 

Today should actually have equally impressive cold anoms with the cooler lows. PDX looks to pull off a -7 or -8.

[luminen]

Is that a flock of birds or just something weird with the photo in front of the cloud?

 

Probably crows. There's always huge flocks of crows flying in the late afternoon and evening here.

[Deweydog]

Nate sure is taking his time with that August PDO number. Clearly he realizes what is on the line.

[snow_wizard]

Looking very likely October starts off below normal.  We're on the right track at least for now.

[Deweydog]

Yikes!

 

PDX up three degrees in the last hour.

[snow_wizard]

The WRF shows tomorrow being downright cool in Seattle.  Only low to mid 50s in the mid afternoon.  Pretty wild temperature swings Sunday through Tuesday.

[snow_wizard]

Yikes!

 

PDX up three degrees in the last hour.

 

We're more than due for a day where SEA owns PDX for minus anomalies.

[Deweydog]

We're more than due for a day where SEA owns PDX for minus anomalies.

We're due for a lot of things.

[Jesse]

We're more than due for a day where SEA owns PDX for minus anomalies.

 

MOS guidance shows a high of 58 tomorrow for PDX.

 

It would surprise me to see lows fall much below 53-54 there, though.

[Jesse]

PDX down three degrees in the last hour!

[PacNW44]

Nate sure is taking his time with that August PDO number. Clearly he realizes what is on the line.

 

The August # is .52

[Deweydog]

The August # is .52

Where'd you find it?

[snow_wizard]

The ECMWF looks a wee bit chilly.

[PacNW44]

Where'd you find it?

 

I received a copy of his email when he issued the # on 9/13, not sure why the UW table hasn't been updated yet.

[Weather101]

54F and rain

[TT-SEA]

Possible windstorm on the 12Z GFS at 240 hours...

 

http://mag.ncep.noaa.gov/data/gfs/12/namer/precip_p03/gfs_namer_240_precip_p03.gif

[stuffradio]

Possible windstorm on the 12Z GFS at 240 hours...

 

http://mag.ncep.noaa.gov/data/gfs/12/namer/precip_p03/gfs_namer_240_precip_p03.gif

Classic windstorm.

[ShawniganLake]

Possible windstorm on the 12Z GFS at 240 hours...

 

http://mag.ncep.noaa.gov/data/gfs/12/namer/precip_p03/gfs_namer_240_precip_p03.gif

Yes please.

[Phil]

Looks like we're going to enter a NPAC vortex pattern during the second week of October. Good news is that it might set up far enough W/SW to allow ridging to continue over AK/NE-PAC.

 

If it does establish farther E/NE, into the upper GOA/Alaska, that's somewhat more problematic given it might be difficult to dislodge, as evidenced by years like 1966, 1975, 2005, 2007, etc.

[stuffradio]

Wow, long range opens up the faucet with more than 5" of rain. Good thing that changes every 6 hours.

 

Phil, 2007 had decent snowstorms here though, so that wouldn't be bad. I don't know how it was further south though.

[Jesse]

Looks like we're going to enter a NPAC vortex pattern during the second week of October. Good news is that it might set up far enough W/SW to allow ridging to continue over AK/NE-PAC.

 

If it does establish farther E/NE, into the upper GOA/Alaska, that's somewhat more problematic given it might be difficult to dislodge, as evidenced by years like 1966, 1975, 2005, 2007, etc.

Do you foresee the mean trough position being over the PNW throughout October?

[ShawniganLake]

Wow, long range opens up the faucet with more than 5" of rain. Good thing that changes every 6 hours.

 

Phil, 2007 had decent snowstorms here though, so that wouldn't be bad. I don't know how it was further south though.

Great, if you lived in the foothills. Frustratingly disappointing for most everyone else.

[Jesse]

The next week is looking pretty cool overall. The upcoming sharp ridge is looking more and more like a short-lived blip on the radar.

 

Pretty fun, dynamic pattern we have been in lately.

[Timmy Supercell]

Wow, long range opens up the faucet with more than 5" of rain. Good thing that changes every 6 hours.

 

Phil, 2007 had decent snowstorms here though, so that wouldn't be bad. I don't know how it was further south though.

 

Even the southern Cascades scored in 2007. I know some folks who have been here since the 80's and there were bigger snows in 2007 than the next 8 years. Except this last December was probably bigger locally since we had the most monthly snowfall since the 90's. Probably 10-12 inches on the ground during the Pineapple festival / windstorm in the lowlands. I personally thoroughly enjoyed the warm rains we had and the wind. Almost lost power in Hillsboro during that one.

 

I don't know the exact ins-and-outs but for some reason K-Falls didn't get that much snow in Dec 2008... 

[ShawniganLake]

The next week is looking pretty cool overall. The upcoming sharp ridge is looking more and more like a short-lived blip on the radar.

 

Pretty fun, dynamic pattern we have been in lately.

That's a pretty wicked trough next Saturday on the euro. 850's may drop below 0 with that.

[stuffradio]

It's snowing on some bc highways right now.

 

[ShawniganLake]

It's snowing on some bc highways right now.

 

Is that Pennask summit? That one is way up there. Like pushing 6000' isn't it?

[stuffradio]

Is that Pennask summit? That one is way up there. Like pushing 6000' isn't it?

It is, and around 5500'.

[Jesse]

Today seemed to be an easier jog to 60 than anticipated, down here.

[Deweydog]

Today seemed to be an easier jog to 60 than anticipated, down here.

Windchills are a factor!

[Phil]

Do you foresee the mean trough position being over the PNW throughout October?

I think (at least) through the first 10 days of October, yeah.

 

Thereafter, I'm watching for the development of a North Pacific trough..if we're able to keep it far enough W/SW, NE Pacific ridging may continue, allowing for N/NW flow over the NW US/BC. If it establishes too far E/NE, that opens the door to W/SW flow and/or a Pacific hose job, which would probably be a mild/moist pattern, though I doubt it'd result in a blowtorch.

[BLI snowman]

Today seemed to be an easier jog to 60 than anticipated, down here.

 

Low was 52 at PDX. Pretty difficult to see a

[Phil]

I think (at least) through the first 10 days of October, yeah.

 

Thereafter, I'm watching for the development of a North Pacific trough..if we're able to keep it far enough W/SW, NE Pacific ridging may continue, allowing for N/NW flow over the NW US/BC. If it establishes too far E/NE, that opens the door to W/SW flow and/or a Pacific hose job, which would probably be a mild/moist pattern, though I doubt it'd result in a blowtorch.

For the record, I'm talking about the large scale upper level pattern, not the surface results. I don't yet have a sufficient understanding of the local-scale climate dynamics in play.

 

Definitely figured this out over the summer, as the upper level pattern behaved largely as I anticipated it to, while conditions at the surface wound up slightly warmer than I was thinking, sometimes much warmer.

[Jesse]

Low was 52 at PDX. Pretty difficult to see a

Indeed. Around 60 looking like a good call.

[TT-SEA]

12Z ECMWF is great... basically sunny after today through next Thursday.    Some rain next Friday then clearing from the north on Saturday and then a cool, crisp early October pattern setting up.

 

I prefer that to warm rain for sure.

[James Jones]

It'd be nice if PDX broke their pathetic record low max of 60 on October 1st.

[Phil]

The 12z EPS depicts the ideal scenario regarding the NPAC vortex. Keeps it far enough west to actually constructively interfere w/ the antecedent NEPAC ridge and Siberian High, leading to a bihemispheric "ridge bridge". During winter, this would direct cross-polar flow right into the western US.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/EE8F78B3-EB69-4A96-BB55-9C27A233C7BB_zpsvybvztem.png

[TT-SEA]

SEA popped up to 60 on the last update.

 

WRF last night was too cold... as it often is in these situations.

[Front Ranger]

SEA popped up to 60 on the last update.

 

WRF last night was too cold... as it often is in these situations.

 

The station that matters is still in the mid 50s. All is well.

[TT-SEA]

The station that matters is still in the mid 50s. All is well.

 

 

Ahh... good to know.  

 

Although they might also get some late afternoon clearing and SW winds.