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April 2021 Pacific Northwest Weather Obs


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12Z ECMWF shows a very warm weekend and then a little system sneaking in on Monday which actually brings appreciable rain.    Looks like a tenuous set up though... might disappear on future runs.    

 

ecmwf-deterministic-namer-z500_anom-8876800.png

ecmwf-deterministic-namer-precip_6hr_inch-8876800.png

**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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For everywhere wondering/speculating about where I have been, I am very flattered We have been on a road trip to Grand Teton and Yellowstone this week. Took a nice week off before starting a new

Getting married tomorrow so that’s why I’ve not been around a ton of late. Looks like we are about 68F out there and are ready for some much-needed rainfall overnight.

Well I haven't been around in a while. Been a little, erm, preoccupied. Hope everyone's enjoying the sunshine and warmth lately! I'll be in Arizona for the weekend, and hopeful I don't melt!

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The 12Z ECMWF then carves out a ULL with that little system and the pattern by the middle of next week ends up looking very similar to what we have tomorrow and Wednesday.

 

ecmwf-deterministic-namer-z500_anom-9049600.png

**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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12Z EPS also showing a very warm weekend... then that little system early next week and right back to ridging by day 10 like the operational run.

 

 

 

**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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I like the way the ECMWF is going next week.  Decent little shot of cool air.

Death To Warm Anomalies!

 

Winter 2020-21 stats

 

Total Snowfall = 7.0"

Day with 1" or more snow depth = 5

Total Hail = 0.0"

Coldest Low = 23

Lows 32 or below = 55

Highs 32 or below = 2

Lows 20 or below = 0

Highs 40 or below = 5

 

 

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45 minutes ago, MossMan said:

This might be the best April of my lifetime! 

I love it.  As I was explaining to Jesse I found out about Aprils like this being a lot more common in the past many years ago and have been waiting to see one.  Part of the reason I have been so stoked about it.  Most of the really dry Aprils in the past featured unusual shots of cold / dry air like this one.  Super dry Aprils that are a total torch are rare from what I have seen.

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Death To Warm Anomalies!

 

Winter 2020-21 stats

 

Total Snowfall = 7.0"

Day with 1" or more snow depth = 5

Total Hail = 0.0"

Coldest Low = 23

Lows 32 or below = 55

Highs 32 or below = 2

Lows 20 or below = 0

Highs 40 or below = 5

 

 

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12Z EPS... a short cool down for a couple of days in a sea of warmth.    The Midwest stays pretty cold through the entire run.  

 

ecmwf-ensemble-avg-namer-t850_anom_stream-1618228800-1618228800-1619524800-20.gif

**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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Just a spectacular weekend ahead... looks great for getting out on Lake Sammamish.  I did not expect this in April with a Nina.

Screenshot_20210412-130227_Google.jpg

**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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23 minutes ago, snow_wizard said:

I love it.  As I was explaining to Jesse I found out about Aprils like this being a lot more common in the past many years ago and have been waiting to see one.  Part of the reason I have been so stoked about it.  Most of the really dry Aprils in the past featured unusual shots of cold / dry air like this one.  Super dry Aprils that are a total torch are rare from what I have seen.

This has definitely been an interesting April so far. Just 0.39” of rain here so far. One example I can think of for a straight torch April pattern was 2016. Had quite a few days in the 70s and even had a couple upper 80s. This one has been dry but doesn’t look quite as torch like as that one. 

Warm Season Stats

+80s-1

+85s-0

+90s-0

Monthly Rainfall-0.57”

Warm Season Rainfall-1.73”

Warmest high temp-80

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3 minutes ago, TT-SEA said:

Just a spectacular weekend ahead... looks great for getting out on Lake Sammamish.  I did not expect this in April with a Nina.

Screenshot_20210412-130227_Google.jpg

Yeah I’m excited to go camping Thursday and Friday should be in the low 70s for the first time since late September. 

Warm Season Stats

+80s-1

+85s-0

+90s-0

Monthly Rainfall-0.57”

Warm Season Rainfall-1.73”

Warmest high temp-80

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2 hours ago, Phil said:

The fact the GEFS shows it at all at this range is a miracle.

As time goes on, I suspect there will be more of these transient, undercutting systems sandwiched in the sea of ridging, and there’s a chance much of the region could end up with more rainfall during this ridgy cycle than than the recent troughy cycle, even though it’ll be warm/dry a majority of the time.

Similar to what happened in Feb, westerly momentum has been deposited in the tropics. As it is transferred poleward, much like Feb, it will produce the +PNA response and the cold air dump into the Central US (remember that huge arctic blast that froze Texas and clipped the PNW in Feb).

This is a very similar progression to that one, as will be the recoil (analogous to the flip to -PNA in March, following Feb cold attacks). Only this time we have the middle latitude -AAM moat propagating poleward which will culminating in the final stratwarm and inception of the summer NAM.

So IMO, the next troughy pattern in May is much likelier to deliver wetter than average conditions to the PNW since the middle latitude spatial AAM regime will have changed as well. 

A visual perspective. Lower amplitude + seasonal shifts, but same theme now in terms of AAM as February.

67DEC688-51D2-4EC3-9977-F33F669E3166.png

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1 minute ago, Rubus Leucodermis said:

58˚F, sunny, and surprisingly windy. High so far: 59˚F. So close…

We’ve only got to 53 here so far...NE winds coming off the sound are keeping us cooler than I expected today. 

Warm Season Stats

+80s-1

+85s-0

+90s-0

Monthly Rainfall-0.57”

Warm Season Rainfall-1.73”

Warmest high temp-80

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Weekly GEFS starting to pick up on the pattern change next month. Pretty much the inverse of the April pattern, with Plains ridging and troughing in the NW and NE.

DEBB94F4-139A-4B1D-BA0D-325E11720957.png

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6 minutes ago, Phil said:

Weekly GEFS starting to pick up on the pattern change next month. Pretty much the inverse of the April pattern, with Plains ridging and troughing in the NW and NE.

DEBB94F4-139A-4B1D-BA0D-325E11720957.png

Not that it really matters... because you picked a single frame at 600 hours.   But in general the GFS  extended shows a trough centered over Alaska in mid-May which could be wet at times but not real cold.

 

gfs-ensemble-extended-all-avg-namer-z500_anom_7day-1123200.png

gfs-ensemble-extended-all-avg-namer-t850_anom_7day-1123200.png

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**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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30 minutes ago, TT-SEA said:

Just a spectacular weekend ahead... looks great for getting out on Lake Sammamish.  I did not expect this in April with a Nina.

Screenshot_20210412-130227_Google.jpg

And it's not a fast cooldown by any means. This is a solid 4-5 days in the 70s. It's still a bit too warm for my liking imo. I prefer we hit 70s when it's June. 

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For anyone that still wants to feel some chill you should go to West Point.  48 at 1 pm with northerlies gusting to 22.  The Sound really keeps them chilly.

Death To Warm Anomalies!

 

Winter 2020-21 stats

 

Total Snowfall = 7.0"

Day with 1" or more snow depth = 5

Total Hail = 0.0"

Coldest Low = 23

Lows 32 or below = 55

Highs 32 or below = 2

Lows 20 or below = 0

Highs 40 or below = 5

 

 

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10 minutes ago, TT-SEA said:

Not that it really matters... because you picked a single frame at 600 hours.   But in general the GFS  extended shows a trough centered over Alaska in mid-May which could be wet at times but not real cold.

 

You’re misinterpreting it a bit. Recognize the spatial pattern and ignore the anomalies (the latter will always be wrong that far in advance).

Here’s an animated gif at the daily resolution. Which can be preferable to a 7-Day mean at that range. Theme is developing offshore ridge and GOA/western trough (and a building 4CH).

 

17BF3880-7D68-4733-9CC6-CB253394FDEF.gif

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2 minutes ago, snow_wizard said:

For anyone that still wants to feel some chill you should go to West Point.  48 at 1 pm with northerlies gusting to 22.  The Sound really keeps them chilly.

Jumping in the Sound would keep you even chillier.     Even in the warmest years... even in the middle of the summer.  👍

**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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2 minutes ago, Phil said:

You’re misinterpreting it a bit. Recognize the spatial pattern and ignore the anomalies.

Here’s an animated gif at the daily resolution. Which can be preferable to a 7-Day mean at that range.

 

17BF3880-7D68-4733-9CC6-CB253394FDEF.gif

Its basically the same thing... I am well aware that its not static.   And of course there will be troughs and rain in May.    But I am not seeing signs of an unusually wet or cold May at this point.    Not yet. 

**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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55 minutes ago, TT-SEA said:

12Z EPS... a short cool down for a couple of days in a sea of warmth.    The Midwest stays pretty cold through the entire run.  

 

ecmwf-ensemble-avg-namer-t850_anom_stream-1618228800-1618228800-1619524800-20.gif

The brief cool down wasn't there a couple of days ago.  The warmth is going to get nibbled away at IMO.  We've seen it numerous times recently.

Death To Warm Anomalies!

 

Winter 2020-21 stats

 

Total Snowfall = 7.0"

Day with 1" or more snow depth = 5

Total Hail = 0.0"

Coldest Low = 23

Lows 32 or below = 55

Highs 32 or below = 2

Lows 20 or below = 0

Highs 40 or below = 5

 

 

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Just now, snow_wizard said:

The brief cool down wasn't there a couple of days ago.  The warmth is going to get nibbled away at IMO.  We've seen it numerous times recently.

I'm not buying 80 degrees this April. It will hit mid 70's at best

Dont Believe It GIF by Better Call Saul

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1 minute ago, TT-SEA said:

Its basically the same thing... I am well aware that its not static.   And of course there will be troughs and rain in May.    But I am not seeing signs of an unusually wet or cold May at this point.    Not yet. 

The GOA ridge will likely come back so we will see more NW flow, big diurnal ranges, a few cold shots, and generally delightful weather in all likelihood.  The only thing we don't agree on for it being perfect is I want more cold and you want more warm.  It looks good overall for both of us.

Death To Warm Anomalies!

 

Winter 2020-21 stats

 

Total Snowfall = 7.0"

Day with 1" or more snow depth = 5

Total Hail = 0.0"

Coldest Low = 23

Lows 32 or below = 55

Highs 32 or below = 2

Lows 20 or below = 0

Highs 40 or below = 5

 

 

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7 minutes ago, TT-SEA said:

Its basically the same thing... I am well aware that its not static.   And of course there will be troughs and rain in May.    But I am not seeing signs of an unusually wet or cold May at this point.    Not yet. 

Interesting. What are you looking at to make determinations for the month of May? 

And it’s not the same thing. 😉 Seems to be you’re taking the guidance verbatim instead of picking out the signal in the noise, and its spatial resemblance to climatology (think: EOFs for PNA, TNH, etc).

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1 minute ago, SouthHillFrosty said:

I'm not buying 80 degrees this April. It will hit mid 70's at best

Dont Believe It GIF by Better Call Saul

It's not unheard of to get a one or maybe two day spike where it hits 80 in April.  I know it happened in some places in 1956 which was kind of like this month, and I know it happened in 1984.  Usually a big crash follows in a year like this.

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Death To Warm Anomalies!

 

Winter 2020-21 stats

 

Total Snowfall = 7.0"

Day with 1" or more snow depth = 5

Total Hail = 0.0"

Coldest Low = 23

Lows 32 or below = 55

Highs 32 or below = 2

Lows 20 or below = 0

Highs 40 or below = 5

 

 

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2 hours ago, Phil said:

What exactly are you looking at to make determinations for the month of May? 

And it’s not the same thing. 😉 You’re taking the guidance verbatim instead of picking out the signal in the noise, and its spatial resemblance to climatology.

 

I think we will see troughing in May, but how wet it might be is another question.  As we've recently seen troughs can be pretty dry here.

Death To Warm Anomalies!

 

Winter 2020-21 stats

 

Total Snowfall = 7.0"

Day with 1" or more snow depth = 5

Total Hail = 0.0"

Coldest Low = 23

Lows 32 or below = 55

Highs 32 or below = 2

Lows 20 or below = 0

Highs 40 or below = 5

 

 

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10 minutes ago, TT-SEA said:

Jumping in the Sound would keep you even chillier.     Even in the warmest years... even in the middle of the summer.  👍

You can stay dry and enjoy the chill today. 😀

Death To Warm Anomalies!

 

Winter 2020-21 stats

 

Total Snowfall = 7.0"

Day with 1" or more snow depth = 5

Total Hail = 0.0"

Coldest Low = 23

Lows 32 or below = 55

Highs 32 or below = 2

Lows 20 or below = 0

Highs 40 or below = 5

 

 

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Just now, snow_wizard said:

I think we will see troughing in My, but how wet it might be is another question.  As we've recently seen troughs can be pretty dry here.

My handle on precip departures up there has sucked so far, so take it with a grain of salt, but my hunch is the troughing next month will evolve more favorably for above average rainfall compared to the recent pattern.

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15 minutes ago, snow_wizard said:

The brief cool down wasn't there a couple of days ago.  The warmth is going to get nibbled away at IMO.  We've seen it numerous times recently.

Were you expecting it to stay at 80 degrees for weeks on end in April?    That is a pretty tepid and short-lived cool down.

I also noticed that the EPS control run is much warmer in the long range compared to the 00Z run.   

**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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8 minutes ago, snow_wizard said:

It's not unheard of to get a one or maybe two day spike where it hits 80 in April.  I know it happened in some places in 1956 which was kind of like this month, and I know it happened in 1984.  Usually a big crash follows in a year like this.

Didn't we hit the 80's in March a couple years ago or am I trippin?

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8 minutes ago, snow_wizard said:

You can stay dry and enjoy the chill today. 😀

60 degrees and totally calm here... does not feel too chilly in my backyard today.    In fact it feels quite warm out there.  👍

**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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1 minute ago, SouthHillFrosty said:

Didn't we hit the 80's in March a couple years ago or am I trippin?

It hit 80 here in March of 2019... when there was still snow on the ground from the February blizzard.     It was strange to see the trees leafing out with snowbanks still hanging around in the shaded areas.  

**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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9 minutes ago, Phil said:

Should be noted the latest EPS weeklies align likewise, projecting a transition to -PNA/GOA trough next month.

A GOA trough would make the most sense.   Even years like 1951 had frequent rainy periods in May before it turned bone dry again for June through most of September.  

**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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8 minutes ago, TT-SEA said:

A GOA trough would make the most sense.   Even years like 1951 had frequent rainy periods in May before it turned bone dry again for June through most of September.  

Hard to know what precip departures will look like up there this summer. This isn’t a clear cut case like 2019 where moist advection was favored to be stronger.

August and September have a clearer warm/dry signal in the analog series, but June and July have a cool/moist signal on the west side of the cascades, which I assume is indicative of heavy marine influence. Which would make sense with the anticyclone offshore.

But how that averages out (assuming that’s what actually happens) isn’t something I can answer. Even if I somehow knew exactly what the 500mb would do.

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Just now, Phil said:

Hard to know what precip departures will look like up there this summer. This isn’t a clear cut case like 2019 where moist advection was favored to be stronger.

August and September have a clearer warm/dry signal in the analog series, but June and July have a cool/moist signal on the west side of the cascades, which I assume is indicative of heavy marine influence. Which would make sense with the anticyclone offshore. 

I could be totally wrong... but this does not feel like its going to be a gloomy, marine layer summer.   

**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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3 minutes ago, Phil said:

Hard to know what precip departures will look like up there this summer. This isn’t a clear cut case like 2019 where moist advection was favored to be stronger.

August and September have a clearer warm/dry signal in the analog series, but June and July have a cool/moist signal on the west side of the cascades, which I assume is indicative of heavy marine influence. Which would make sense with the anticyclone offshore.

But how that averages out (assuming that’s what actually happens) isn’t something I can answer. Even if I somehow knew exactly what the 500mb would do.

I'm feeling a wet May and a wet August.

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2 minutes ago, TT-SEA said:

I could be totally wrong... but this does not feel like its going to be a gloomy, marine layer summer.   

Based on what, specifically? I’d be interested to know.

I guess I’ll put you in the warm/dry summer camp, then?

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1 minute ago, Phil said:

Based on what, specifically? I’d be interested to know.

I guess I’ll put you in the warm/dry summer camp, then?

No idea... just a feeling.   I am probably wrong.  

**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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1 minute ago, BLI snowman said:

I'm feeling a wet May and a wet August.

Interesting. I guess how it all comes together in that area would be something you locals have a better grasp of.

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9 minutes ago, Phil said:

Hard to know what precip departures will look like up there this summer. This isn’t a clear cut case like 2019 where moist advection was favored to be stronger.

August and September have a clearer warm/dry signal in the analog series, but June and July have a cool/moist signal on the west side of the cascades, which I assume is indicative of heavy marine influence. Which would make sense with the anticyclone offshore.

But how that averages out (assuming that’s what actually happens) isn’t something I can answer. Even if I somehow knew exactly what the 500mb would do.

A coolish/dampish June seems like a good bet.  Average/slightly warm July and a slightly warm August.  Of course this is based on old school 1981-2010 stuff...

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My preferences can beat up your preferences’ dad.

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2 minutes ago, Phil said:

Interesting. I guess how it all comes together in that area would be something you locals have a better grasp of.

Been about 8 years since our last reasonably wet May and 17 years since our last reasonably wet August. Feels like time and this current dry trend will almost certainly reverse at some point before summer.

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Hard to bet against warmth with a potent MJO like this traversing the Pacific (at this time of year).

Can see it will be awhile before it reaches the Indian Ocean. Until then, mean state will be warm/+PNA.

 

034EB76B-C13F-4F4D-BEAB-FA5A910B82D3.gif

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I think it’s worth noting 2008 had a similar intraseasonal event, just centered ~ 3 weeks later than this year. 

The pattern match is uncanny.

58EC7553-9800-4D2E-85EC-9BBDCEA555B6.png

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And the month that preceded the intraseasonal event in May 2008 also resembles the pattern we’re coming out of now.

 

8458CAD6-FE1E-47B1-B9DA-09F7B9B1AD72.png

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