May Weather in the Pacific Northwest

[Jesse]

[Phil]

[TT-SEA]

Subtropical storm Alberto has formed. FWIW, previous Mays (non-noñ) w/ names Atlantic storms/-QBO50 are:

 

1954

1959

1970

2007

2012

2016

 

And 1959/1970 are the only solar maximum years. Seems like a solar minimum tendency.

You ruthlessly mocked the GFS for showing this 10 days ago.

[TT-SEA]

I like the evolution on the 12Z GFS.

 

Trough next week and then back to ridging for the weekend.

[Jesse]

You ruthlessly mocked the GFS for showing this 10 days ago.

New posts from you between 9:30 and 10 will always give the old ticker a scare.

 

I figured a 588dm ridge at hour 276 of the 12z GFS was going to be staring me in the face.

[Jesse]

I like the evolution on the 12Z GFS.

 

Trough next week and then back to ridging for the weekend.

There it is!!

[TT-SEA]

There it is!!

Good Lord. Relax.

[Phil]

I like the evolution on the 12Z GFS.

 

Trough next week and then back to ridging for the weekend.

Any return to ridging will probably be brief until forcing leaves the EHEM. Anticyclones will be retrograding quickly enough to keep the ridgy spikes short (~ 2-3 days to complete each cycle).

[Jesse]

Good Lord. Relax.

Joking around. No need to take it personal.

 

Have you checked out those yoga links I sent you yet? I think the deep breathing exercises in particular would really help you get through those low cloud deck days.

[Phil]

We have intraseasonal forcing propagating into the EHEM/Indo-Pacific now. This is the reason for the upcoming troughing/-PNA and temporary demise of the Baffin Bay vortex.

 

 

Once convection reaches the middle of Phase-7 (WPAC) in about 20 days, the pattern will begin to change again, with strong ridging returning a week afterwards (week-4, in this case).

 

The more amplified this intraseasonal forcing gets, the slower it will propagate. A less amplified wave will propagate faster, but it will have less punch.

[Jesse]

We should start a countdown clock for when the troughy period ends.

[Phil]

And when it comes to EHEM forcing, the CMC and UKMET are often the best at handling it.

 

The ECMWF is great with WPAC forcing, and the GFS is best with EPAC/WHEM forcing.

[Phil]

You ruthlessly mocked the GFS for showing this 10 days ago.

No, I mocked it for showing a full blown hurricane strengthening over land.

 

Instead we have a subtropical storm.

[Phil]

We should start a countdown clock for when the troughy period ends.

Pick your poison.

 

Stronger troughing/EHEM forcing now = stronger ridging/WHEM forcing starting in weeks 4/5 and a slower cycle back to EHEM forcing.

 

Weaker troughing/EHEM forcing now = weaker ridging/WHEM forcing starting week 3/4, which will cycle back to the EHEM faster.

[TT-SEA]

Joking around. No need to take it personal.

 

Have you checked out those yoga links I sent you yet? I think the deep breathing exercises in particular would really help you get through those low cloud deck days.

I don't know... it does not seem to work for you so I am skeptical.

[Phil]

The structure of this wave does suggest it might be a higher frequency affair, and the SST gradients across the tropical Pacific are weak enough that a weaker/faster MJO/CCKW wave is probably favored.

 

But we’ve seen these things amplify before, especially with the raised tropopause/-QBO downwelling as we speak.

 

So I don’t know which outcome to expect yet. But it will be fascinating to watch.

[Phil]

This tropical forcing event is also responsible for the upcoming trade wind burst/return of the niña circulation.

 

http://www.atmos.albany.edu/student/ventrice/real_time/timeLon/u.anom.30.5S-5N.gif

[Jesse]

Pick your poison.

 

Stronger troughing/EHEM forcing now = stronger ridging/WHEM forcing starting in weeks 4/5 and a slower cycle back to EHEM forcing.

 

Weaker troughing/EHEM forcing now = weaker ridging/WHEM forcing starting week 3/4, which will cycle back to the EHEM faster.

I would take the first one.

 

We need some deep troughing and decent rain to help prevent another bone dry summer and bad wildfire season. Especially with a hot July-September looking imminent.

[Phil]

Though even with a faster/weaker wave, the GFS projection of VP200 anomalies is almost certainly too fast/weak. Which makes sense, given its WHEM forcing bias.

 

Notice how it tries to throw convection eastward at a rate that is much faster than the current propagation rate.

 

http://www.atmos.albany.edu/student/ventrice/real_time/timeLon/vp.anom.30.5S-5N.gif

[Phil]

So in this case, I would favor the GEPS (CMC ensembles) over the GEFS.

 

Note how the GEFS bifurcates this MJO/CCKW during week2, leaving residual uplift in the IO while propagating the rest of the wave into the WPAC/WHEM, voiding the Indo-Pacific. This is unlikely to occur.

 

 

The GEPS, on the other hand, maintains the wave-1 regime, propagating the convection into the Indo-Pacific. This has more historical precedent.

 

 

And while these differences appear subtle, they are very consequential as far as mid-latitude wave cycles are concerned.

[Phil]

I would take the first one.

 

We need some deep troughing and decent rain to help prevent another bone dry summer and bad wildfire season. Especially with a hot July-September looking imminent.

July looks like a roast (or at least the first 3 weeks of the month do) but the lower level -QBO/z-cell retraction should be far-enough along by August to prevent a torch, not to mention the favorably-timed intraseasonal tropical forcing by that time. If the -AMM/-AMO cell holds, then there’s a chance for a legitimately cool August and/or September this year. If the +AMM/+AMO cell returns (which would mean a return to the 1996-2017 ITCZ seasonality) then a cool August is less likely.

 

In fact, even 2015 (super-niño) entered into a zonalish, equatorward z-cell regime in Aug/Sep as the -QBO downwelled to the tropopause. And 2016 (the skipped QBO cycle w/ anomalous easterlies @ 50mb emulating another QBO downwell) also flipped cool/zonal in late August/September. Around the same time as 2015.

 

This isn’t a repeat of 2017 or 2014 (downwelling easterlies above westerly shear).

[Phil]

FWIW, it looks like both April and May will finish with +SOIs. In the 1950-present era, yoj have to go back to 1963 to find an example of a niño that developed with +SOI values in both April and May.

 

However, 1968 is an oddball, as it doesn’t meet the specific criteria, but it had tons of +SOI during the summer. A weird year..strong niño in the heart of a -PNA/-NAO decadal cycle, along with a cooling globe at the time.

 

Though, if you count 2014/15 as a niño (debatable) then it meets the criteria too. However, it was a very borderline case in a solar maximum/eastward cycling IPWP regime.

 

Either way, the point stands. Very unlikely to see a niño when both April and May run +SOI averages.

[Jesse]

Great to be seeing 2014 and 2015 showing up as analogs.

[Phil]

In fact, given March 2018 was also +SOI, that eliminates 2014/15 from contention.

 

The only year in the post/WWII era to develop a niño with a +SOI in March, April, and May was 1963/64. And you could lump 1968/69 in there, even though it doesn’t fit the specific criteria (summer was strongly +SOI, even though spring wasn’t).

 

And the circulation today is NOTHING like that of the 1960s. That was the heart of the -NAM era. So IMO, you’d better have a good reason to bet on a niño this year.

[Phil]

Great to be seeing 2014 and 2015 showing up as analogs.

Oh Jesse. Only you could interpret that post as a humping of 2014/15.

[Deweydog]

We should start a countdown clock for when the troughy period ends.

You're gonna manage to worry yourself out of enjoying the upcoming low 500mb heights.

[Jesse]

You're gonna manage to worry yourself out of enjoying the upcoming low 500mb heights.

That was the joke.

[Jesse]

Euro looks great.

[Deweydog]

That was the joke.

Seize the trough! You're gonna be just fine despite a warm up following a cool down.

[Jesse]

Seize the trough! You're gonna be just fine despite a warm up following a cool down.

Shame you never got into the framing business.

 

Well I guess you sort of did...

[Timmy]

Euro looks great.

I should probably take my boat out of the water then. Assuming “great” means rain and cool temps?

[Jesse]

Tim, is there precip on the Euro days 8-10? Looks like a pattern that could produce some.

[Deweydog]

Shame you never got into the framing business.

 

Well I guess you sort of did...

Dude... It's just a joke.

[Jesse]

Dude... It's just a joke.

CALM DOWN MATT

[Farmboy]

Euro looks great.

 

We'll need winter gear?

[Phil]

Tim, is there precip on the Euro days 8-10? Looks like pattern that could produce some.

There is some. Similar to last night’s run.

[Kayla]

Not great for PDX south (similar to previous runs) but it's a little wetter for the SEA area.

 

http://i66.tinypic.com/296eivo.png

[Frontal Snowsquall]

We'll need winter gear?

The 12z EURO shows about 0.2" for you up there in Renton through the next 10 days. Pretty much bone dry down here in the Willamette Valley.

[Front Ranger]

The rains always return in force.    Never a worry here.

 

Not from May to September. That's almost half the year.

[Front Ranger]

No... but the first 2/3rds of April was sure wet.

 

I said at the time that a dry spell was VERY likely coming for my area which usually means dry for everyone.   It was an idea that was dismissed at the time.  

 

Two wet weeks, surrounded by drier than normal weather for weeks on end.

 

Looking back now, the whining becomes even more ridiculous in hindsight.