May Weather in the Pacific Northwest

[TT-SEA]

12Z ECMWF looks pretty troughy in a week and about to reload.  

[Front Ranger]

12Z ECMWF looks pretty troughy in a week and about to reload.  

 

Easy to see why the first trough is pretty dry...second may be wetter with it starting further out over the ocean.

[Jesse]

Indeed!

The tables would be turned if we were getting flooding rains and crop killing cold...and I were rooting for more and more. Except that would never happen.

[Front Ranger]

If the 12z Euro verified, a record warm May could possibly be averted in some places.

 

This would, naturally, increase the odds of a record warm July.

[Geos]

First trough

 

 

2nd

 

[TT-SEA]

Easy to see why the first trough is pretty dry...second may be wetter with it starting further out over the ocean.

 

 

Almost no rain for SEA and PDX through next Friday morning on the 12Z ECMWF.

 

Waiting for the last 2 days to finish updating.

[BLI snowman]

Now watch July be an icebox, and August turn into a blast furnace. Lol.

 

August is literally guaranteed a top 5 warm finish every year.

[BLI snowman]

Almost no rain for SEA and PDX through next Friday morning on the 12Z ECMWF.

 

Waiting for the last 2 days to finish updating.

 

It's almost like the ECMWF knows that 2014-17 all had wetter than average finishes at SEA.

[Kayla]

Kind of crazy how quickly that front washes out. Maybe China can help??

[Frontal Snowsquall]

Yes... the troughing for the last couple days of May into the first couple days of June is pretty much a given now. I am just starting to look beyond that to see if we go into a long term troughy pattern as Phil as been predicting.

I'm still thinking the first 2 weeks of June will be troughy but I don't like the general theme I see through the first week of June. A lot can still change though.

[Jesse]

Encouraging to see troughing through day 10 on the 12z Euro. The rainfall amounts it is spitting out are pretty pathetic, though.

 

Quite the southern plains ridge building at day 10. That actually teleconnects well with warm season troughing out here.

[Jesse]

Greenland vortex disappears midway through this run too.

 

#changeisgood

[Phil]

August is literally guaranteed a top 5 warm finish every year.

If we keep the -AMM/retracted IO/ATL Hadley Cell regime going this year, then 1995-2017 will be a thing of the past.

[Geos]

Cloud deck starting to break up in Snohomish County. Getting slight breaks at home too.

 

[Jesse]

The Memorial Day trough trending more progressive/not as hung up has indeed seemed to pave the way for a troughier period, at least in the short to mid-term.

 

It’s a nice feeling to have watched 500mb maps for enough years to start to get a better instinct for this stuff.

[Front Ranger]

To be fair, we've reached the time of year where troughs often aren't nearly as wet as a couple months ago.

[BLI snowman]

To be fair, we've reached the time of year where troughs often aren't nearly as wet as a couple months ago.

 

It's almost like March is wetter than June.

[Phil]

Yes... the troughing for the last couple days of May into the first couple days of June is pretty much a given now. I am just starting to look beyond that to see if we go into a long term troughy pattern as Phil as been predicting.

“Longer term” is subjective. It’s an intraseasonal-scale oscillation in the pattern, not a background state. We’re talking weeks, not months.

 

There isn’t much of a tropical forcing background state this year, despite the recent ridgy stretch (WHEM tropical forcing with the extra-tropical response prolonged by lower frequency poleward +AAM propagation). Future pattern cycles will probably be shorter in duration.

[Frontal Snowsquall]

Per the 12z EURO, Memorial Day looks mostly sunny for PDX. We might be able to make it back into the 80s again.

[TT-SEA]

12Z EPS is warm again by day 9.

 

12Z ECMWF shows about .01 or .02 over the next 10 days at SEA and PDX.     That is really strange.

 

Even out here it only shows about .20

[Jesse]

12Z EPS is warm again by day 9.

 

12Z ECMWF shows about .01 or .02 over the next 10 days at SEA and PDX. That is really strange.

 

Even out here it only shows about .20

Have you been refreshing the EPS page every few minutes for the past hour?

[Phil]

12z EPS is split..about half of the members have a big 500mb trough over the PNW thru D15 with average to below average temperatures, while the other half have a huge western ridge and a deep trough offshore.

 

Though in either case, there would be a re-load.

[TT-SEA]

Have you been refreshing the EPS page every few minutes for the past hour?

 

Just checked... I wait until 1 p.m.

 

Same warm signal in the 10-15 day period.   Really starts warming up on day 8.

 

[Jesse]

12z EPS is split..about half of the members have a big 500mb trough over the PNW thru D15 with average to below average temperatures, while the other half have a huge western ridge and a deep trough offshore.

 

Though in either case, there would be a re-load.

Thank you for giving information that is actually useful, beyond an orange splattered map.

[MossMan]

Sun peeks and a breeze while eating lunch on my deck. Oh I so love living 3 minutes from work!

[Phil]

12z EPS is split..about half of the members have a big 500mb trough over the PNW thru D15 with average to below average temperatures, while the other half have a huge western ridge and a deep trough offshore.

 

Though in either case, there would be a re-load.

The control run is in the warm camp, FWIW.

 

But when you look at how it gets there, you have to be somewhat skeptical. The wavetrain is anchored and retrograding, then it devolves into a chaotic mess despite being in a state of dispersion.

 

There are no examples of such a progression in the 500mb reanalysis for 1948-present, or at least none that I can see.

[Jesse]

Here is day 9 on the 12z EPS. Weak troughy signal.

 

[TT-SEA]

Thank you for giving information that is actually useful, beyond an orange splattered map.

 

 

The is the ensemble mean... pretty strong signal there Jesse.  

 

By useful... you mean less stressful for you.   

[Phil]

The is the ensemble mean... pretty strong signal there Jesse.

 

By useful... you mean less stressful for you.

The ensemble mean doesn’t always reflect the ensemble spread, however.

 

You often have cases where a minority of the ensemble members depict an amplified solution, and it skews the mean that way despite the majority of members depicting something different.

[TT-SEA]

Here is day 9 on the 12z EPS. Weak troughy signal.

 

BDD671BA-C49B-4C4B-81BD-A4FBCA6339CA.png

 

 

EPS ensemble mean for that day.  I see cold air on there... to our east.

 

   

[Jesse]

Day 10 500mb mean. Looks like a situation where there is a lot of spread, like Phil mentioned. Not really a strong signal either way.

 

[TT-SEA]

The ensemble mean doesn’t always reflect the ensemble spread, however.

 

You often have cases where a minority of the ensemble members depict an amplified solution, and it skews the mean that way despite the majority of members depicting something different.

 

And yet is been basically correct over the last 6 weeks.

 

There has been just one below normal day at SEA since April 18th... and that was a -1 departure on 4/28.

[Jesse]

EPS ensemble mean for that day. I see cold air on there... to our east.

Not sure how well those anomaly maps couple with the actual pattern depicted in that case. Since when would 570dm heights and onshore flow in early June give us 850mb anomalies of 5-10F?

 

That’s why I think the mean heights map is a much better way to go when deciphering the EPS.

[TT-SEA]

Day 10 500mb mean. Looks like a situation where there is a lot of spread, like Phil mentioned. Not really a strong signal either way.

 

20CFCDE8-532D-4E07-AF71-966AE6F3697E.png

 

This feels exactly like the rationalization that you accuse me of all the time.  

[TT-SEA]

Not sure how well those maps couple with the actual pattern depicted in that case. Since when would 570dm heights and onshore flow in early June give us 850mb anomalies of 5-10F?

 

That’s why I think the mean heights map is a much better way to go when deciphering the EPS.

 

I disagree.   I think the 850mb temperature mean is very useful as well.   

[Phil]

And personally speaking, I haven’t been very impressed with the EPS lately.

 

It completely missed this upcoming pattern swing. There was lots of spread, but it had the same issue with the “vocal minority” of super warm/ridgy members skewing the mean in the warm direction.

[Jesse]

This feels exactly like the rationalization that you accuse me of all the time.

Yes, we all know you make this stuff very personal.

[TT-SEA]

Yes, we all know you make this stuff very personal.

 

 

You literally do that all the time.  

[Jesse]

I disagree. I think the 850mb temperature mean is very useful as well.

Maps that show orange for patterns that aren’t necessarily above average are certainly useful if you are trying to push a narrative.

[TT-SEA]

And personally speaking, I haven’t been very impressed with the EPS lately.

 

It completely missed this upcoming pattern swing. There was lots of spread, but it had the same issue with the “vocal minority” of super warm/ridgy members skewing the mean in the warm direction.

 

I agree.   Its been showing warm for the most part out here for the last 6 weeks.   It has missed all of the cold troughs and cold anomalies we had over that time span.