May Weather in the Pacific Northwest

[ShawniganLake]

Warm

 

[Deweydog]

Wet!!!

[TT-SEA]

Models show a significant c-zone over King County this afternoon.

[Phil]

Baffin Bay vortex split in late May is showing up on all guidance except the GFS/GEFS (typical bias there).

 

The EPS is rushing it somewhat, then prolonging the oblong-baroclinic stage, but it’s coming. Nice visualization here.

 

https://mobile.twitter.com/jhomenuk/status/994238807741476865/photo/1

[TT-SEA]

Although... have to give nature credit for getting the crap out of the way during the week and allowing for a beautiful weekend! 

[Phil]

Since this is the completion of poleward +AAM propagation cycle, rather than poleward -AAM propagation cycle, the pathway of the NAM evolution through the mid-latitudes will be opposite of the one in February.

 

IE: Instead of -PNA/western trough occurring simultaneously with the destruction of the +NAO vortex via cold season style equator-pole coupling, instead the destruction of the +NAO vortex will actually precede the transition to -PNA/western troughing, possibly by a full week.

[VancouverIslandSouth]

Finally getting a bit of rain here this morning; much appreciated with what looks like an extended warm dry stretch coming up. 

[Front Ranger]

Models show a significant c-zone over King County this afternoon.

 

SEA has scored a whopping .03" out of this system so far, so let's hope!

[TT-SEA]

SEA has scored a whopping .03" out of this system so far, so let's hope!

 

No doubt.   

 

Well over an inch of rain here since Sunday and its raining now.     I want SEA to somewhat reflect how wet its been out there this week. 

 

Normally I get about double the rain of SEA.    Its not normally multiplied by more than 30 as it is right now for May.   

[Front Ranger]

No doubt.   

 

Well over an inch of rain here since Sunday and its raining now.     I want SEA to somewhat reflect how wet its been out there this week. 

 

Normally I get about double the rain of SEA.    Its not normally multiplied by more than 30 as it is right now for May.   

 

 

Seems like you've been getting way more than double SEA for a few months at least.

[Jesse]

[Phil]

[TT-SEA]

 

Seems like you've been getting way more than double SEA for a few months at least.

 

I think it was around 2.5 times in April.  

[Phil]

[TT-SEA]

12Z EPS was warm right through day 15 with no end in sight at that time.  

[Phil]

12Z EPS was warm right through day 15 with no end in sight at that time.

There is also a lot of disagreement within the EPS, regarding the exact timing of the high latitude shake-up.

 

Some members flip the high latitudes by May 17th-18th, while others wait until the 24th-25th. Then it will require another week to change the NPAC cell. So middle ground favors ~ May 20th for the NAM flip, then a transition across the NPAC ~ one week later.

 

Though, given the timing uncertainties, it could happen somewhat earlier, or somewhat later. But the potential range of timing is closing somewhat, at least.

[Jesse]

Unless it’s my slow bias talking, I think it might be closer to two weekends. I could be wrong, but I don’t see support for sustained troughing until the end of May. The occasional ULL notwithstanding.

 

The high latitudes flip before the mid-latitudes this time.

I wasn’t counting this weekend. We will be up in Port Townsend so hopefully will avoid the really nasty stuff.

[Phil]

You also gave to admire the meteorology of all this.

 

Big difference between now and D5 on the 12z GFS as the Eurasian anticyclone breaks poleward into the Arctic, which marks the beginning of the NAM reversal.

 

Almost every PNW pattern change begins in Eurasia.

 

Current pattern:

 

 

Day five: Wavebreak ongoing, reversal of NPAC mass gradient developing, which will produce the eventual retrogression, late in the month. Regardless of whether the model sees it correctly or not.

 

[TT-SEA]

I wasn’t counting this weekend. We will be up in Port Townsend so hopefully will avoid the really nasty stuff.

 

GFS MOS has mid to upper 70s this weekend in Seattle.

 

That is some serious NASTY stuff.  

 

I pray its cooler up there for you.   I cannot imagine having to suffer through sunshine and temps in the mid 70s on a May weekend.    Vampires no likey!  

[Farmboy]

Baffin Bay vortex split in late May is showing up on all guidance except the GFS/GEFS (typical bias there).

 

The EPS is rushing it somewhat, then prolonging the oblong-baroclinic stage, but it’s coming. Nice visualization here.

 

https://mobile.twitter.com/jhomenuk/status/994238807741476865/photo/1

 

So, when the shitty weather arrives in late May, any idea as to how long it might be here?  A lot of people with Memorial day plans are really gonna be seriously pissed...

[TT-SEA]

12Z GFS shows some ridging late next week...

 

[Jesse]

So, when the shitty weather arrives in late May, any idea as to how long it might be here? A lot of people with Memorial day plans are really gonna be seriously pissed...

Seems like you already are.

 

Cool and rainy Memorial days are a PNW tradition.

[TT-SEA]

So, when the shitty weather arrives in late May, any idea as to how long it might be here?  A lot of people with Memorial day plans are really gonna be seriously pissed...

 

Head east!  

 

Always a good option in May and June.    

 

Last year we booked reservations on 3 different weekends including Memorial Day weekend as back-up and cancelled all of them.   

[Jesse]

GFS MOS has mid to upper 70s this weekend in Seattle.

 

That is some serious NASTY stuff.

 

I pray its cooler up there for you. I cannot imagine having to suffer through sunshine and temps in the mid 70s on a May weekend. Vampires no likey!

Sunday looks like it could be 85-90 down here. That’s way too hot for this time of year.

 

It looks like upper 60s to around 70 in Port Townsend which is really nice.

[MossMan]

Wet!

[Farmboy]

Head east!  

 

Always a good option in May and June.    

 

Last year we booked reservations on 3 different weekends including Memorial Day weekend as back-up and cancelled all of them.   

 

Yeah, thinking about maybe Soap Lake/Sun Lakes area....  It should be much nicer there, depending how deep the troughing is....

[Front Ranger]

So, when the shitty weather arrives in late May, any idea as to how long it might be here?  A lot of people with Memorial day plans are really gonna be seriously pissed...

 

3 weeks. 

 

Probably best to start getting pissed about Memorial Day plans now, so it doesn't sneak up on you.

[TT-SEA]

Wet!

Pouring rain and 48 here. January in May!

 

Wish it was the weekend so I could really enjoy this to the fullest.

[Farmboy]

3 weeks. 

 

Probably best to start getting pissed about Memorial Day plans now, so it doesn't sneak up on you.

 

3 weeks.  Baloney... 

[Front Ranger]

Seems like you already are.

 

Cool and rainy Memorial days are a PNW tradition.

 

That tradition has taken a serious hit in recent years. Due...

[Front Ranger]

3 weeks.  Baloney... 

 

It was a reference to Phil's January Arctic blast prediction.

[Jesse]

Pouring rain and 48 here. January in May!

 

Wish it was the weekend so I could really enjoy this to the fullest.

48 degrees and rain is May in May. That’s something you are normally going to see from time to time at your location this time of year.

[Jesse]

Just light showers down here. PDX has only picked up 0.03” today. Wouldn’t surprise me if that is the most they see with this system.

[Front Ranger]

Just light showers down here. PDX has only picked up 0.03” today. Wouldn’t surprise me if that is the most they see with this system.

 

At least they got .09" yesterday.

[Farmboy]

It was a reference to Phil's January Arctic blast prediction.

 

Ok, I get it.  So, we should expect ridging at the end of May/first week of June...

[Thermal Trough]

This weekend is looking spectacular. Finally a weekend with sunny weather. PDX hit 3 straight days of 80+ in late April and this time I think we can pull of 4 straight days. Tuesday will be close. Sunday I think has a 50/50 chance of hitting 90. Probably 87 to 91 for PDX Metro.

[Farmboy]

This weekend is looking spectacular. Finally a weekend with sunny weather. PDX hit 3 straight days of 80+ in late April and this time I think we can pull of 4 straight days. Tuesday will be close. Sunday I think has a 50/50 chance of hitting 90. Probably 87 to 91 for PDX Metro.

 

Local authorities have already sent out an alert to warn all vampires to shelter in place in the nearest coffin with  ample rations of blood at any sign of clearing coming up...  

[TT-SEA]

48 degrees and rain is May in May. That’s something you are normally going to see from time to time at your location this time of year.

 

No sh*t.   

 

Well aware.

 

And that is the reason why I almost never worry about it being too warm or dry here.    The rain and cold always come.   I just appreciate when nature delivers something different.  

[Phil]

So, when the shitty weather arrives in late May, any idea as to how long it might be here? A lot of people with Memorial day plans are really gonna be seriously pissed...

What do you mean by that? Rain? I don’t know what the local precipitation effects will be.

[Phil]

The 12z CMC seems to have a much better handle on the pattern progression than the 12z GFS.

 

The GFS loads the WHEM with much so divergence aloft that it spins a major hurricane off the central American monsoonal gyre, then blows it up over land in Florida.

 

 

https://mobile.twitter.com/splillo/status/994623216198004736