April 2020 Weather discussion for the PNW

[Phil]

Sounds great. I will believe it when I see it of course. This sounds like great material for someone to gloat quote with a smug smiley face a couple weeks from now

Still early, but the signs of that long awaited “cold phase” Pacific/multiyear niña might be showing up. The IPWP structure and PMM are starkly different this year than any of the last seven years. Much more E-IO/Indonesia centered OHC maxima.

[Phil]

OT, but it’s freakin snowing here. Second time this month, after going Feb/Mar without a single flake.

 

To make it crazier, it was 80 degrees yesterday with a dewpoint near 70*F and severe storms. Spring..

[TigerWoodsLibido]

72/32 today.  40F temp swing...awesome!!

[Frontal Snowsquall]

[Frontal Snowsquall]

72/32 today. 40F temp swing...awesome!!

Nice, I hit 39 two straight days last week. Just missed out on the 40 club.

[Timmy Supercell]

65/20, nice spread! 

[TT-SEA]

Historically cold April?

[Phil]

Massive bout of easterlies building right over the IPWP/WPAC. Westerlies over the EPAC and Atlantic.

 

Haven’t seen this in ages. Finally a real sea change?

 

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

[ShawniganLake]

Haven’t seen any 10-15 day eps maps lately

[Jesse]

[TT-SEA]

Haven’t seen any 10-15 day eps maps lately

 

Its been sort of muddled... but there was a more clear zonal flow signal in the long range on the 00Z run.

 

5-10 day:

 

 

10-15 day:

 

[TT-SEA]

The GEFS is not as zonal in the 10-15 day period...

 

[Jesse]

A more active pattern beginning to show up on the long range ensembles.

 

[Jesse]

47 with some drizzle around this morning. First water I’ve seen falling out of the sky in about ten days.

[TT-SEA]

I was expecting some rain here this morning... but the low clouds are already clearing up.  

 

[ShawniganLake]

Clear skies with a low of 40 here this morning

[TT-SEA]

Clear skies with a low of 40 here this morning

 

 

Looks like only got down to 48 here... already up to 52 now.

[Anti Marine Layer]

47 with some drizzle around this morning. First water I’ve seen falling out of the sky in about ten days.

Hooray

[Jesse]

Hooray

 

I bet you aren't even actually excited for me

[TigerWoodsLibido]

52F and cloudy.

[Phil]

The GEFS is not as zonal in the 10-15 day period...

 

Funny, I’ve never seen you post the D10-16 GEFS before. What changed?

[TT-SEA]

Funny, I’ve never seen you post the D10-16 GEFS before. What changed?

 

 

I actually have posted it before.

 

I also have posted many cold EPS maps this year.

 

Settle down troll boy!  

[Omegaraptor]

 

EPO trying to go positive?

[TT-SEA]

9102081C-C123-4B31-A16D-A26A15D4AAC5.png

 

EPO trying to go positive?

 

I am pretty sure a period of zonal flow and more frequent rain is coming... it almost has to come at this point. 

[Frontal Snowsquall]

65/20, nice spread!

Monster spread!

[Frontal Snowsquall]

Its been sort of muddled... but there was a more clear zonal flow signal in the long range on the 00Z run.

 

5-10 day:

 

 

10-15 day:

 

I wouldn't mind seeing some zonal flow. Nothing too major but just to change things up a bit. Then a return to more ridging.

[Phil]

I am pretty sure a period of zonal flow and more frequent rain is coming... it almost has to come at this point.

This post is legit/not trolling.

 

Maybe zonal initially? Seems like a regime that would eventually evolve into a ULL pattern then eventually an Aleutian Ridge/-PNA with cool/dry advection into the PNW region. I’m less sold on the idea of prolonged zonal flow at any point this warm season. Overall the system state looks increasingly crappy for moisture advection into the West as time passes, but I’m getting increasingly confident that the ridge stays offshore this summer and results in more cool/dry NW flow in WA/OR/ID/MT/etc as EHEM forcing has continued to build a low frequency presence and the IPWP has consolidated within the Maritime Continent/E-IO region as an upwelling OKW readies to surface in the central tropical Pacific.

[TT-SEA]

This post is legit/not trolling.

 

Maybe zonal initially? Seems like a regime that would eventually evolve into a ULL pattern then eventually an Aleutian Ridge/-PNA with cool/dry advection into the PNW region. I’m less sold on the idea of prolonged zonal flow at any point this warm season. Overall the system state looks increasingly crappy for moisture advection into the West as time passes, but I’m getting increasingly confident that the ridge stays offshore this summer and results in more cool/dry NW flow in WA/OR/ID/MT/etc as EHEM forcing has continued to build a low frequency presence and the IPWP has consolidated within the Maritime Continent/E-IO region as an upwelling OKW readies to surface in the central tropical Pacific.

 

 

I always appreciate your serious analysis posts.

[Phil]

Earlier in the year I was less confident the ridge would establish offshore and thought there was a good chance it would be over the west coast, but the E-IO/Indo-Pacific OHC spike in conjunction with the upwelling wave and invigorated NPAC E-bndry current/lowered PMM has me thinking otherwise now.

 

Sucks for CA drought and rain in general but nice way to avoid blowtorches. More like the “cold phase” type drought patterns that wrecked the SW US in 2011 and 2012 with the weak jet/large 4CH that roasted the inland West but spared the immediate coast.

[Jesse]

This post is legit/not trolling.

 

Maybe zonal initially? Seems like a regime that would eventually evolve into a ULL pattern then eventually an Aleutian Ridge/-PNA with cool/dry advection into the PNW region. I’m less sold on the idea of prolonged zonal flow at any point this warm season. Overall the system state looks increasingly crappy for moisture advection into the West as time passes, but I’m getting increasingly confident that the ridge stays offshore this summer and results in more cool/dry NW flow in WA/OR/ID/MT/etc as EHEM forcing has continued to build a low frequency presence and the IPWP has consolidated within the Maritime Continent/E-IO region as an upwelling OKW readies to surface in the central tropical Pacific.

By this time of year, troughing is our best bet for getting significant precip. Rarely happens with higher than average heights between now and sometime in late September. So I will take my chances with a troughy pattern.

 

The moisture advection you are thinking of probably has more to do with the SW monsoon, which tends to be more robust during less troughy summers in the west.

[Dave]

If I hear one more lawnmower, I'm gonna kick a puppy.

[Jesse]

Still overcast and 52 here, with some spots of drizzle around. Feels great outside today after the endless sunshine and very dry air. I enjoyed that too but a change of pace is always welcome.

[El_Nina]

Can't believe we're gonna be kicking the rain can down the road even longer. Looked like it might've started to rain this Sunday, then it was Monday and now it's Wednesday.

Gonna be a remarkably dry April folks, never seen anything like it. Look at my 12" rainfall deficit over here. Big month.

[Jesse]

Can't believe we're gonna be kicking the rain can down the road even longer. Looked like it might've started to rain this Sunday, then it was Monday and now it's Wednesday.

Gonna be a remarkably dry April folks, never seen anything like it. Look at my 12" rainfall deficit over here. Big month.

Yeah, definitely discouraging to see the rain for early next week keep getting put off. But my gut feeling is that some sort of pattern change is coming. Models are typically too quick with those and that’s why we are seeing the delays right now.

 

At least the weekend is now looking cooler and cloudier than it did a couple days ago.

[Omegaraptor]

Combine the dry April, the dry summer forecast, and our typical new December 1 start to wet season and we should be good for another sub 30” year.

[Jesse]

Combine the dry April, the dry summer forecast, and our typical new December 1 start to wet season and we should be good for another sub 30” year.

There’s the Omegaposts I know and love!

[Timmy Supercell]

Monster spread!

 

For this time of year I agree. I usually see those kinds of spreads in the Fall. Oct/Nov, and sometimes in September.

[Timmy Supercell]

If I hear one more lawnmower, I'm gonna kick a puppy.

 

Like your profile picture

[TT-SEA]

Its been sort of muddled... but there was a more clear zonal flow signal in the long range on the 00Z run.

 

 

10-15 day:

 

 

 

12Z EPS is a little less zonal in that period...

 

[Phil]

12Z EPS is a little less zonal in that period...

 

You can see where it’s going, though, with the negatively tilted ridge axis off CA and building -NAM (haven’t seen that in awhile during late April/May).