October 2017 PNW Discussion Thread

[BLI snowman]

I could actually buy a milder winter overall with a stronger stand alone arctic airmass or two if anything.

 

One uber cold week in late January. Record mild December (low of 34 at PDX).

[umadbro]

On top of everything else I have liked about the 6 weeks the record or near record warmth the past few days is a feature that almost always leads to cold winters also. The evidence just keeps mounting. Looking at late October / early November record highs for Landsburg we get.

 

1921 - Really good winter

1944 - The only total loser of the bunch

1949 - We all know...

1958 - Good January blast and snow in Feb

1962 - Very cold January

1965 - White Christmas for Seattle and a snowy winter for Seattle.

1970 - Good solid winter for most areas

2006 - Good late November blast and a great January for the Seattle area

2010 - Wicked November blast, wicked late Feb blast, and a near miss huge snowstorm in January.

 

bolded years were cold ENSO

How many were back,to back weak la ninas?

[VancouverIslandSouth]

We could see a situation where an AR may transition to snow before the precip runs out.  Those are fun!

 

December 1996 also featured some chilly weather in the preceding November.

[VancouverIslandSouth]

I think the WRF may be bringing the cold air in too fast, which is pretty common. The 12Z showed 1 to 2 feet of snow across SE Vancouver Island on Friday. In reality, best case scenario is probably 1-2” of wet snow as the moisture pulls off to the south.

 

Looks like it's going to be highly elevation dependent and it's getting lost in resolution there. The 1 1/3 km resolution won't look anything like that. Still I think Friday morning has a decent shot at being snow. The timing is good for snow to start the day, but it will be hard pressed to stick around.

 

Also, looks like you may get your first frost tonight. Even here the winds have died down and the air is much drier. Currently 48F.

[snow_wizard]

I could actually buy a milder winter overall with a stronger stand alone arctic airmass or two if anything.

 

I think this one will have more generalized cold than last winter and not as wet.  IMO everything is aligned more perfectly for a cold winter than any since at least the mid 1980s.  I will say my NPS index strongly indicates at least one major blast so you could be right about that aspect of it.  I'm basically talking about a season where a good number of locations see 100 or more freezing low temperature days.

[Jesse]

I think this one will have more generalized cold than last winter and not as wet. IMO everything is aligned more perfectly for a cold winter than any since at least the mid 1980s. I will say my NPS index strongly indicates at least one major blast so you could be right about that aspect of it. I'm basically talking about a season where a good number of locations see 100 or more freezing low temperature days.

Sounds a lot like last winter.

[snow_wizard]

How many were back,to back weak la ninas?

 

1962.

[snow_wizard]

Sounds a lot like last winter.

 

The cold wasn't THAT persistent last winter.  I'm basically saying every month Nov through Feb decently to downright cold.  1956-57 is another one that comes to mind.

[VancouverIslandSouth]

Sounds a lot like last winter.

 

We never had anything I would consider a "major blast" last year, at least not up here. Otherwise it sounds pretty similar.

[ShawniganLake]

Looks like it's going to be highly elevation dependent and it's getting lost in resolution there. The 1 1/3 km resolution won't look anything like that. Still I think Friday morning has a decent shot at being snow. The timing is good for snow to start the day, but it will be hard pressed to stick around.

 

Also, looks like you may get your first frost tonight. Even here the winds have died down and the air is much drier. Currently 48F.

Yea it might be close if the wind is calm. Sitting at about 43F now. It dropped to 35 here this morning and I did see some frozen puddles, the drier air probably helped. So we had a light frost but not a freeze.

[TigerWoodsLibido]

We never had anything I would consider a "major blast" last year, at least not up here. Otherwise it sounds pretty similar.

 

We had multiple instances here in the Willamette Valley of sub-freezing highs for a prolonged period of several days and numerous snow events.  At least 1 of those was a fairly major blast.

[ShawniganLake]

We had multiple instances here in the Willamette Valley of sub-freezing highs for a prolonged period of several days and numerous snow events. At least 1 of those was a fairly major blast.

It was cold up here but nothing that would quantify as a blast. Lots of weak to moderate Fraser river outflow with 850’s around -7 or -8C or so.

[TigerWoodsLibido]

I think this one will have more generalized cold than last winter and not as wet.  IMO everything is aligned more perfectly for a cold winter than any since at least the mid 1980s.  I will say my NPS index strongly indicates at least one major blast so you could be right about that aspect of it.  I'm basically talking about a season where a good number of locations see 100 or more freezing low temperature days.

 

I'm not sure the Willamette Valley has ever had 100 days with sub-freezing temps in a given winter since records were kept.  I'm sure there have been plenty of those days in a year but even last winter, which was the coldest since I moved here in 1989, only had some 50 days with sub-freezing temps at most.  Now places in Central and Eastern Oregon, absolutely.

[Front Ranger]

Very cold winter in the works.  The incredible lack of low pressure over the NE Pacific for the last several weeks is shown to continue for a long time to come.  Analogs to this suggest a great winter coming.  I'm leaning more toward a winter that features long frequent stretches of cold weather and drier than normal instead of shorter lived and more intense Arctic blasts, although a couple of sharp cold waves are pretty likely.  Winters that would fall into the group of what I'm currently thinking would be ones like 1916-17, 1948-49, 1984-85, 1992-93, etc.  All I know is something is up this season.

 

One caveat to this is the possibility of a wetter winter that would be made up of short lived AR events that could provide significant precip in spite of much of the winter being on the drier side.

 

Last winter fit that bill pretty well through early February.

[Front Ranger]

The only problem with this is that October is actually going to end just a hair above normal temp wise.

 

Not for the region. EDIT: Don't know why the map is only updated through the 27th, but it's not an above normal month.

 

[Deweydog]

When do these troughs begin to be classified as warning shots?

[BLI snowman]

When do these troughs begin to be classified as warning shots?

 

What if this ridge has been the real warning shot?  

[Geos]

Not for the region. EDIT: Don't know why the map is only updated through the 27th, but it's not an above normal month.

 

MonthTDeptWRCC-NW.png

 

No it's not.

If tomorrow's predicted high and low pan out, the month will be -1.6 degrees here.

[ShawniganLake]

GFS looking pretty euroish next week. Southerly flow.

[TT-SEA]

No it's not.

If tomorrow's predicted high and low pan out, the month will be -1.6 degrees here.

 

Where? 

 

SEA is going to end up around +0.5 for October.

 

WFO SEA is going to end up around +0.3

 

Pretty much a normal month.    Biggest departures for the month were -6 and +6 at SEA with the majority of the days within the -2 to +2 range.   Significantly wetter than normal as well. 

[Jbolin]

Where? 

 

SEA is going to end up around +0.5 for October.

 

WFO SEA is going to end up around +0.3

 

Pretty much a normal month.    Biggest departures for the month were -6 and +6 at SEA with the majority of the days within the -2 to +2 range.   Significantly wetter than normal as well. 

Thank you, that's why I said a "hair" in my OP, perhaps I should've clarified when I said (above normal) as it was minuscule at best.

[wx_statman]

FWIW, we're overdue for some legitimate CAA at the mid-levels. 

 

Horse Creek, a favorite RAWS site of mine at 3,400 feet as it sits in the thermal belt during heat ridges and also represents mid-level CAA during the winter, hasn't seen a maximum below 20 since 2/5/2014, when the high was 18. The lowest since were a pair of 21's on January 3 & 4 last winter. 

 

This location hasn't seen a maximum below 15 since 12/15/2008, which had a high of 11. A single digit maximum hasn't happened since 8 degrees on 12/20/1998. 

 

For comparison, the upper level beasts of February 1989 and December 1990 produced maximums of -3 (on 2/3/1989) and 1 (on 12/20/1990). 

[snow_wizard]

Last winter fit that bill pretty well through early February.

 

What do I have to say to get the idea across I think this one will be colder?  I'm not saying it will be the same as last winter.

[Front Ranger]

Where? 

 

SEA is going to end up around +0.5 for October.

 

WFO SEA is going to end up around +0.3

 

Pretty much a normal month.    Biggest departures for the month were -6 and +6 at SEA with the majority of the days within the -2 to +2 range.   Significantly wetter than normal as well. 

 

Always a great reflection of the region.

[snow_wizard]

FWIW, we're overdue for some legitimate CAA at the mid-levels. 

 

Horse Creek, a favorite RAWS site of mine at 3,400 feet as it sits in the thermal belt during heat ridges and also represents mid-level CAA during the winter, hasn't seen a maximum below 20 since 2/5/2014, when the high was 18. The lowest since were a pair of 21's on January 3 & 4 last winter. 

 

This location hasn't seen a maximum below 15 since 12/15/2008, which had a high of 11. A single digit maximum hasn't happened since 8 degrees on 12/20/1998. 

 

For comparison, the upper level beasts of February 1989 and December 1990 produced maximums of -3 (on 2/3/1989) and 1 (on 12/20/1990). 

 

Very interesting stats.  No question we are due for a big one.

[snow_wizard]

The 0z GFS looks like the coldest run yet.  It keeps the low closer to the coast and swings it in faster.  Still no end to the anomalous high pressure over the GOA.

 

The WRF spits out afternoon temps in the 30s for Seattle on Saturday.

[Front Ranger]

What do I have to say to get the idea across I think this one will be colder?  I'm not saying it will be the same as last winter.

 

I hear you. But what you described was pretty similar to last winter, December through early February. That period had consistent cold, and was drier than normal. There's a reason like three different people pointed that out.

 

Beyond that...devil's in the details.

[luvssnow_spokane]

Not physically possible.

It would be as unlikely as one person killing dozens of people with an automatic weapon on the 32nd floor of a Vegas hotel.

Too soon...

[snow_wizard]

I hear you. But what you described was pretty similar to last winter, December through early February. That period had consistent cold, and was drier than normal. There's a reason like three different people pointed that out.

 

Beyond that...devil's in the details.

 

I think the monthly averages will be colder.

 

Already down to 40 here tonight.

[snow_wizard]

Coldest GFS ensemble yet...it bottoms out at -7 over Seattle.

 

Hats off to the ECMWF ensemble on this event.  It had this nailed a while back.

[TT-SEA]

Always a great reflection of the region.

 

Added WFO SEA to corroborate.   About the same.  

[stuffradio]

I hear you. But what you described was pretty similar to last winter, December through early February. That period had consistent cold, and was drier than normal. There's a reason like three different people pointed that out.

 

Beyond that...devil's in the details.

There was a "thaw" in January for us for a couple weeks last year, and then activity picked back up again in February.

[Front Ranger]

There was a "thaw" in January for us for a couple weeks last year, and then activity picked back up again in February.

 

Sure. But at OLM for instance, December still ended up -3.0 and January ended up -4.6. February -1.4. 24 highs below 40. That's consistent cold.

[Front Ranger]

Added WFO SEA to corroborate.   About the same.  

 

For the overall region, it will end up more below normal than above.

[snow_wizard]

There was a "thaw" in January for us for a couple weeks last year, and then activity picked back up again in February.

 

We are still extremely overdue for a really cold January.  Chances are very elevated it could happen this winter.

[Front Ranger]

I think the monthly averages will be colder.

 

Already down to 40 here tonight.

 

Every month DJF? Bold. 

[James Jones]

Sure. But at OLM for instance, December still ended up -3.0 and January ended up -4.6. February -1.4. 24 highs below 40. That's consistent cold.

 

It was extremely impressive at PDX as well. Could be decades before we see another DJF this cold in the Portland area.

[TT-SEA]

00Z ECMWF cut the Bellingham snow total in half... 4 inches instead of 8 inches like 12Z run showed.

 

Not much for anyone else... including my area.

[snow_wizard]

For the overall region, it will end up more below normal than above.

 

My average will end up around 49.8 and normal is 51.1

[snow_wizard]

Every month DJF? Bold. 

 

It will be a colder tri monthly average.  It's so obvious the table is set for this winter I can't believe others don't see it.