May Weather in the Pacific Northwest

[Deweydog]

RIP Bill Paxton

And Helen Hunt.

[TT-SEA]

A meandering mess of a pattern early next week... and yet looks generally nice at this point. 

 

[Jesse]

A record warm May is starting to look very doable.

 

This sustained high end warmth stuff, punctuated with spikes of well above average warmth, is how we do it. Very reminiscent of the 2014-16 period

[Jesse]

Getting a good soaking rain tonight.

[TT-SEA]

A record warm May is starting to look very doable.

 

This sustained high end warmth stuff, punctuated with spikes of well above average warmth, is how we do it. Very reminiscent of the 2014-16 period

 

 

We are not alone... its been warm across most of the country.   Even warmer to our east.

 

The pattern this winter was so persistently cold across the same region and nature is balancing it out now.    We are just going along for the warm ride.   

 

[Front Ranger]

We are not alone... its been warm across most of the country.   Even warmer to our east.

 

The pattern this winter was so persistently cold across the same region and nature is balancing it out now.    We are just going along for the warm ride.   

 

 

It would take 4 more years of cold anomalies to balance out 2013-17.

 

Sound familiar? 

[Phil]

The system that is moving in now just MIGHT make it all the way to Nevada by Sunday.

 

Every run slows it down more. It might end up sitting over us yet.

 

You could probably keep up with this system with a brisk walking pace.

Looks like I was right about the mid-month ULL.

[TT-SEA]

It would take 4 more years of cold anomalies to balance out 2013-17.

 

Sound familiar? 

 

Yes... 4 years of colder and drier than normal around here would balance out the last 4 years.   I have said that many times.  

[Phil]

[Phil]

It would take 4 more years of cold anomalies to balance out 2013-17.

 

Sound familiar?

It’s a comin’.

[Kayla]

A meandering mess of a pattern early next week... and yet looks generally nice at this point. 

 

 

Cutoff season has arrived!  

[Phil]

This record-breaking +NAO is advecting a huge amount of warm air into the high Arctic (thru the NATL). Still early enough in the spring that it’s just resulting in tons of snowfall, but if the pattern doesn’t change by late May, the ice pack will probably take a hit.

 

Meanwhile, the ice around NE-Canada and Greenland is near record highs in some places. The NW Passage has areas with ice over 13ft deep right now. Baffin Island and Ellesmere Island are over 300% above average in terms of snow depth, and since 2013, many of their glaciers have been growing as a result of this persistent vortex.

[MossMan]

This record-breaking +NAO is advecting a huge amount of warm air into the high Arctic (thru the NATL). Still early enough in the spring that it’s just resulting in tons of snowfall, but if the pattern doesn’t change by late May, the ice pack will probably take a hit.

 

Meanwhile, the ice around NE-Canada and Greenland is near record highs in some places. The NW Passage has areas with ice over 13ft deep right now. Baffin Island and Ellesmere Island are over 300% above average in terms of snow depth, and since 2013, many of their glaciers have been growing as a result of this persistent vortex.

Is this the mini ice age that you talked about years ago?

[Phil]

The 06z GooFuS landfalls a legitimate hurricane into Jacksonville FL in the clown range. Lol, time to terminate this model.

[Phil]

Is this the mini ice age that you talked about years ago?

I would expect a cold episode to feature -NAO/-PNA during the cold season, as they have historically.

 

A warm season vortex in NE Canada might encourage glacial inception if it continued for 50yrs straight, though!

[Phil]

Speaking of which, this is a nice read if you have access.

 

http://adsabs.harvard.edu/abs/2016EGUGA..18..948B

[TT-SEA]

Dumping rain again here over the last hour.

[Phil]

As is this: https://www.google.com/amp/s/www.researchgate.net/publication/222114000_Atmospheric_circulation_patterns_during_glacial_inception_A_possible_candidate/amp

 

Which implies that the ridge west/trough east pattern is naturally favored to increase in frequency as Obliquity declines, over the next ~ 10,000 years.

[MossMan]

Dumping rain again here over the last hour.

Dry up here so far this morning.

[Front Ranger]

Yes... 4 years of colder and drier than normal around here would balance out the last 4 years. I have said that many times.

Yes, but you resisted the notion that the wet 2 weeks of April were nature balancing out the dry Feb/Mar the region saw.

[Front Ranger]

It’s a comin’.

Certain anxious members are skeptical.

[TT-SEA]

Yes, but you resisted the notion that the wet 2 weeks of April were nature balancing out the dry Feb/Mar the region saw.

 

The major stations up here were around half a foot above normal for rainfall for the rainy season from October - April. 

 

Within that period... March was a little drier than normal  And it was offset by one of the wettest Aprils ever.  

 

A wet May is unlikely.   A wet summer is unlikely here as well.  

[Phil]

The QBO is oh-so-close to flipping easterly in the lower levels at/above the tropopause, which would be the first legitimate summer season downwell in 6 years.

 

Just a few months away!

 

[Phil]

The major stations up here were around half a foot above normal for rainfall for the rainy season from October - April.

 

Within that period... March was a little drier than normal And it was offset by one of the wettest Aprils ever.

 

A wet May is unlikely. A wet summer is unlikely here as well.

You’re way over-due for a wet summer. Don’t be surprised if/when it happens. Watch August this year.

[TT-SEA]

You’re way over-due for a wet summer. Don’t be surprised if/when it happens. Watch August this year.

 

Yeah... I could see August being wet this year if MJJ are dry.  

 

August of 2015 was one of wettest ever but the rain came in bunches.   It was a very sunny and warm month overall... and extremely wet.  

[Phil]

Certain anxious members are skeptical.

All good (and bad) things must come to an end at some point. The western mega-torch will be no exception.

 

We torched almost perpetually from 1997 to 2002, minus some legit (but short lived) cold shots in 2000/01. The blast furnace continued into the summer of 2002, then, after 6 years of torching, the switch flipped with an MJO wave, and it was just..over. Like the flip of a switch, or the snap of a finger. Poof.

 

Won’t be long until blue colors cover the PNW weather maps again.

[TT-SEA]

Here are the summer (JJA) precip departures from normal for SEA over the 2013-17 period:

 

2013  -0.60

2014  +0.06

2015  +0.35

2016   -0.59

2017   -1.71

 

It has not exactly been incredibly dry in the JJA period at SEA over the last 5 years.    Only 2017 stands out and that was after the wettest rainy season in history when SEA was running over 12 inches above normal going into the summer.     The negative departure in JJA did not even come close to offsetting the positive departure last year.

[Phil]

Given how insanely warm biased the NMME forecasts generally are, I’m surprised there is blue anywhere. It looks like it’s leaning towards the mega-vortex solution, which is present on ~ 30% of the seasonal EPS members.

 

Legit -AMO/cold Canadian Arctic pattern, with the coldest anomalies around Baffin Island yet again.

 

[Front Ranger]

The major stations up here were around half a foot above normal for rainfall for the rainy season from October - April. 

 

Within that period... March was a little drier than normal  And it was offset by one of the wettest Aprils ever. 

 

Feb/Mar was drier than normal for the vast majority of the region. Both months were well below normal for SEA, OLM, and PDX.

 

If you can use the logic that the warmth now is offsetting the cool weather of the previous months, then there is no reason you should have disagreed with the idea that those very wet two weeks in April were offsetting the drier than normal weather of the previous couple months. But you did. 

[Front Ranger]

Yeah... I could see August being wet this year if MJJ are dry.  

 

August of 2015 was one of wettest ever but the rain came in bunches.   It was a very sunny and warm month overall... and extremely wet.  

 

This is also the same line of reasoning I have used with you talking about the 2013-17 period. Very wet, but with the rain highly concentrated in certain months, with most months actually featuring near or below normal precip.

[TT-SEA]

Feb/Mar was drier than normal for the vast majority of the region. Both months were well below normal for SEA, OLM, and PDX.

 

If you can use the logic that the warmth now is offsetting the cool weather of the previous months, then there is no reason you should have disagreed with the idea that those very wet two weeks in April were offsetting the drier than normal weather of the previous couple months. But you did. 

 

I thought we might finally be entering a drier regime back in March.   February was very wet just to the north and east of Seattle.   

 

April blew that idea away.     

 

By the end of April... SEA was 3 inches above normal for 2018 and over 6 inches above normal for the rainy season.     So its been wet overall... which has been the case for the 2014-17 period as well.

[Phil]

Here are JJA combined precip departures from normal for SEA over the 2013-17 period:

 

2013 -0.60

2014 +0.06

2015 +0.35

2016 -0.59

2017 -1.71

 

It has not exactly been incredibly dry in the JJA period at SEA over the last 5 years. Only 2017 stands out and that was after the wettest rainy season in history when SEA was running over 12 inches above normal going into the summer. The negative departure in JJA did not even come close to offsetting the positive departure last year.

The two wettest summers combined (+0.41) don’t even match the weakest single-year dry anomaly (-0.59). And FWIW, all six of those JJAs were warmer than average.

 

So, you are way overdue for a cool/wet summer, if anything. I suspect there’ll be quite a correction towards that type of regime, and it’s probably not far off, either.

[TT-SEA]

The two wettest summers combined (+0.41) don’t even match the weakest single-year dry anomaly (-0.59). And FWIW, all six of those JJAs were warmer than average.

 

So, you are way overdue for a cool/wet summer, if anything. I suspect there’ll be quite a correction towards that type of regime, and it’s probably not far off, either.

 

I would agree that we are due for a cooler summer... and probably a wetter than average summer as well.   

 

But we are also due for some drier years and that is clearly not happening yet either.   

[TT-SEA]

Precip departures at SEA:

 

2014   +9.65

2015   +5.98

2016   +6.33

2017   +9.02

 

And 2018 is at +2.43 right now.

 

We are clearly due for some drier years up here or 'normal' does not mean anything.  

[Front Ranger]

Here are the summer (JJA) precip departures from normal for SEA over the 2013-17 period:

 

2013  -0.60

2014  +0.06

2015  +0.35

2016   -0.59

2017   -1.71

 

It has not exactly been incredibly dry in the JJA period at SEA over the last 5 years.    Only 2017 stands out and that was after the wettest rainy season in history when SEA was running over 12 inches above normal going into the summer.     The negative departure in JJA did not even come close to offsetting the positive departure last year.

 

However, if you look at the May-Sep warm season overall, there have been a lot of exceptionally dry months in that period.

 

July 2013: no rain at all

June 2014: .73", half the normal amount

May 2015: .58" top 5 driest May

June 2015: .23"#4 driest June on record (driest May/June on record)

July 2015: .09" (driest MJJ on record)

Sep 2015: .83" less than half of normal

May 2016: .94" about half of normal

August 2016: .17" top 10 driest, way below normal

July 2017: no rain at all

August 2017: .02" third driest on record

 

It's been an exceptional period for exceptionally dry warm season months, especially July, with 3 of the past 5 featuring under .10" of rain and two of those with no rain at all.

[TT-SEA]

However, if you look at the May-Sep warm season overall, there have been a lot of exceptionally dry months in that period.

 

July 2013: no rain at all

June 2014: .73", half the normal amount

May 2015: .58" top 5 driest May

June 2015: .23"#4 driest June on record (driest May/June on record)

July 2015: .09" (driest MJJ on record)

Sep 2015: .83" less than half of normal

May 2016: .94" about half of normal

August 2016: .17" top 10 driest, way below normal

July 2017: no rain at all

August 2017: .02" third driest on record

 

It's been an exceptional period for exceptionally dry warm season months, especially July, with 3 of the past 5 featuring under .10" of rain and two of those with no rain at all.

 

Last summer was exceptionally dry.   But the rainy season was exceptionally wet.   And 2017 was exceptionally wet.    We had favorable timing for a dry period over the summer.  

 

The difference between no rain at all and above normal rainfall in July can be very small.   One or two days can swing it from no rain at all to being a very wet month.  

 

Monthly rainfall stats in the summer are not that meaningful.   Its really the persistence of rainy days in the summer that tell the tale of summer.    Years like 1983 and 1993 are at one end of the spectrum and 2017 is on the other end.     Ironically... 1983 and 1993 were the top analogs going into the summer of 2017.   

[Phil]

Rainy springs don’t always lead to dry summers. Only under certain conditions is such a progression favored.

[Phil]

The warm pool discharge (OKW) continues. It’s evident in the OHC anomalies for the upper 300m. Also, the warm subtropical EPAC/+PMM is quite shallow, apparently.

 

The cold subtropical NATL and IO are also relatively new to the scene. Opposite was the case from 1995-2016.

 

[Front Ranger]

I thought we might finally be entering a drier regime back in March.   February was very wet just to the north and east of Seattle.   

 

April blew that idea away.     

 

By the end of April... SEA was 3 inches above normal for 2018 and over 6 inches above normal for the rainy season.     So its been wet overall... which has been the case for the 2014-17 period as well.

 

Eh, it depends on how you look at it, which time periods. If you look at the past year, the region has definitely moved in a drier direction than previous years, and even with the wet April, the past 90 days show a similar trend.

 

 

 

If you want to look at it month by month for the past year at SEA:

 

May 2017: Wetter than normal

June 2017: Normal

July 2017: Drier than normal

August 2017: Drier than normal

Sep 2017: Drier than normal

Oct 2017: Wetter than normal

Nov 2017: Wetter than normal

Dec 2017: Drier than normal

Jan 2018: Wetter than normal

Feb 2018: Drier than normal

Mar 2018: Drier than normal

Apr 2018: Wetter than normal

 

5/12 months wetter than normal.

[Front Ranger]

This is also the same line of reasoning I have used with you talking about the 2013-17 period. Very wet, but with the rain highly concentrated in certain months, with most months actually featuring near or below normal precip.

 

 

Last summer was exceptionally dry.   But the rainy season was exceptionally wet.   And 2017 was exceptionally wet.    We had favorable timing for a dry period over the summer.  

 

The difference between no rain at all and above normal rainfall in July can be very small.   One or two days can swing it from no rain at all to being a very wet month.  

 

Monthly rainfall stats in the summer are not that meaningful.   Its really the persistence of rainy days in the summer that tell the tale of summer.    Years like 1983 and 1993 are at one end of the spectrum and 2017 is on the other end.     Ironically... 1983 and 1993 were the top analogs going into the summer of 2017.