April 2026 Weather In The PNW

BLI snowman · April 1

Speaking of ENSO, officially 2025-26 was the 2nd consecutive neutral winter for the ONI. Came up a bit short once again of the low end weak Niña classification.

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php

Good riddance to that base state. We've just been circling the drain the last year plus largely stuck in a pukish purgatory.

Phil · April 1

26 minutes ago, SeattleMarineLayerFan said:

Trash IPWP, -QBO, weak La Nina... Not a good combo.

Technically next winter can do "better" (it's a matter of inches anyways). But it won't be good unless we pull Feb 2019 level luck again.

+QBO/strong Niño is the worst possible combination in the PNW and for arctic air anywhere in the lower-48, FWIW.

Notable analogs: 57/58, 69/70, 82/83, 86/87, 91/92, 02/03, 15/16. The epitome of +EPO/NPAC megatrough monsters. They are at least stormier up there vs endless +TNH ridgefest years but you can forget about any kind of meaningful cold.

Also, strong Niño/+QBO has a very difficult time snapping back to Niña the following winter due to destructive interference inhibiting off-equator convection at crucial stages in the seasonal cycle.

Almost always the result is an ENSO neutral/low amp of some variety. The one exception is 70/71 probably because it followed a second year Niño which had a drained IPWP/thermocline primed for upwelling. All the other cases post-WWII failed to transition to Niña the subsequent winter.

BLI snowman · April 1

2 minutes ago, Phil said:

+QBO/strong Niño is the worst possible combination in the PNW and for arctic air anywhere in the lower-48, FWIW.

Notable analogs: 57/58, 69/70, 82/83, 86/87, 91/92, 02/03, 15/16. The epitome of +EPO/NPAC megatrough monsters.

They are at least stormier up there vs endless +TNH ridgefest years but forget about any kind of meaningful cold.

Strong Niño is very unlikely based on historic climo and where the subsurface anomalies are heading into spring.

CFS spaghetti is pretty meaningless at this stage. I'm thinking a lowish end moderate event is probably the cap for next winter.

StormchaserChuck1 · April 1

4 minutes ago, BLI snowman said:

Strong Niño is very unlikely based on historic climo and where the subsurface anomalies are heading into spring.

Subsurface is about as warm as it gets right now. TAO/Triton will probably pop the +5c mark tomorrow, I've never seen it that high in the western subsurface before.

Phil · April 1

14 minutes ago, BLI snowman said:

Strong Niño is very unlikely based on historic climo and where the subsurface anomalies are heading into spring.

CFS spaghetti is pretty meaningless at this stage. I'm thinking a lowish end moderate event is probably the cap for next winter.

I think high end moderate or strong is doable. However I agree the structure of the off-equator IPWP likely caps the amplitude of this event well beneath super niño threshold.

We are at the proper stage of the solar/IPWP vacillation cycle where you generally see the healthy Niño response and transition to +PMM/+PDO for several years (which doesn’t align with a healthy Niña in 27/28, nor does a likely -QBO). That is the case regardless of whether the Niño is moderate or strong+ (see 02/03).

If anything you can think of the Niño as a consequence of/response to the intradecadal restructuring of the IPWP/general circulation shift as opposed to the other way around. The PMM/PDO is already flipping in response to said change in background circulation.

BLI snowman · April 1

10 minutes ago, StormchaserChuck1 said:

Subsurface is about as warm as it gets right now. TAO/Triton will probably pop the +5c mark tomorrow, I've never seen it that high in the western subsurface before.

The upper ocean heat anomaly hasn't looked terribly impressive compared to past strong Niños at this juncture.

The return interval for another strong Niño is also historically 5-6+ years. It would be unprecedented to have another completely independent strong Niño event in 3 years time. Not counting multi-year events like 1939-40/1940-41.

StormchaserChuck1 · April 1

1 hour ago, BLI snowman said:

The upper ocean heat anomaly hasn't looked terribly impressive compared to past strong Niños at this juncture.

The return interval for another strong Niño is also historically 5-6+ years. It would be unprecedented to have another completely independent strong Niño event in 3 years time.

This ranks up there with before Moderate-Strong Nino's

3-21-2024.png.b5e7c362f3ba0543b5d4994da4c53726.png

The so short for a 2nd Strong Nino isn't correct, imo because we don't have many examples. In the limited dataset, there are a lot of instances of Moderate+ Nina's repeating in 2 years time.

StormchaserChuck1 · April 1

Phoenix broke it's March monthly temp record by +6.5F. Its March would have been the 2nd warmest April all time.

DJFM average was +4.2 over number 2

MossMan · April 1

32 minutes ago, Phil said:

+QBO/strong Niño is the worst possible combination in the PNW and for arctic air anywhere in the lower-48, FWIW.

Notable analogs: 57/58, 69/70, 82/83, 86/87, 91/92, 02/03, 15/16. The epitome of +EPO/NPAC megatrough monsters. They are at least stormier up there vs endless +TNH ridgefest years but you can forget about any kind of meaningful cold.

Also, strong Niño/+QBO has a very difficult time snapping back to Niña the following winter due to destructive interference inhibiting off-equator convection at crucial stages in the seasonal cycle.

Almost always the result is an ENSO neutral/low amp of some variety. The one exception is 70/71 probably because it followed a second year Niño which had a drained IPWP/thermocline primed for upwelling. All the other cases post-WWII failed to transition to Niña the subsequent winter.

If we have to suffer though the bull crap we endured this last winter…Everyone including you should have to suffer as well!

Phil · April 1

15 minutes ago, BLI snowman said:

The upper ocean heat anomaly hasn't looked terribly impressive compared to past strong Niños at this juncture.

The return interval for another strong Niño is also historically 5-6+ years. It would be unprecedented to have another completely independent strong Niño event in 3 years time. Not counting multi-year events like 1939-40/1940-41.

I’d argue our period of record is too short to say this confidently.

- Until 86/87 & 87/88 it was unprecedented for a Niño to span two seasonal cycles without attenuating during boreal summer.

- Until 2016 it was unprecedented for the QBO to skip a heartbeat, metaphorically speaking.

- It was unprecedented to go 13+ years without a single trimonthly ONI below -0.8 until 1956/57 -1969/70.

A lot of things are “unprecedented” in a limited sample of data. Until they aren’t.

Doom Buster · April 1

4 hours ago, T-Town said:

The judges would have also accepted:

There's a lot of weather-related songs on this show.

DTF_St_Louis_miniseries_poster.png.07ffacce71d0f2ba9dfe8879da6ef087.png

Doom Buster · April 1

34 minutes ago, Phil said:

I’d argue our period of record is too short to say this confidently.

- Until 86/87 & 87/88 it was unprecedented for a Niño to span two seasonal cycles without attenuating during boreal summer.

- Until 2016 it was unprecedented for the QBO to skip a heartbeat, metaphorically speaking.

- It was unprecedented to go 13+ years without a single trimonthly ONI below -0.8 until 1956/57 -1969/70.

A lot of things are “unprecedented” in a limited sample of data. Until they aren’t.

Using stats from almost 40 years ago kinda dilutes your point, though. There's been a lot more data since then.

Doom Buster · April 1

EUG on pace for 15" of rain this month.

Phil · April 1

11 minutes ago, Front Ranger said:

Using stats from almost 40 years ago kinda dilutes your point, though. There's been a lot more data since then.

Huh? The point is it had no “precedent” before (and has none since). Who knows how long the return period is for such an occurrence? We don’t know because we only have ~75 years of solid data, which is barely a snapshot in this context.

Strong Niños occurring within 3 years of each other is easily within the limits of ocean-atmosphere physics. We know they’ve occurred 4 years apart, mere decades ago. Two events occurring 3 years apart would have a longer return period, yes. However, I’ll wager you it has occurred dozens of times over the last millennium.

StormchaserChuck1 · April 1

46 minutes ago, Phil said:

I’d argue our period of record is too short to say this confidently.

- Until 86/87 & 87/88 it was unprecedented for a Niño to span two seasonal cycles without attenuating during boreal summer.

- Until 2016 it was unprecedented for the QBO to skip a heartbeat, metaphorically speaking.

- It was unprecedented to go 13+ years without a single trimonthly ONI below -0.8 until 1956/57 -1969/70.

A lot of things are “unprecedented” in a limited sample of data. Until they aren’t.

I don't see any reason why one can't occur 3 years later. Actually, over like a thousand years I think there is +correlation year-to-year of ENSO events (warm ENSO would favor at like 50.1% warm ENSO the following year). I think the Nina snapback that has been so strong this century is a bit of anomaly in the much longer term

Phil · April 1

StormchaserChuck1 · April 1

Nino 4 is already in Weak Nino range, +0.511

This is way ahead of other later in the year >+1.2 El Nino's.. only 2015 and 1997 were greater for the month of April.

April 1957 -0.06

April 1963 -0.34

April 1965 -0.92

April 1968 -0.46

April 1972 +0.11

April 1982 +0.33

April 1986 -0.34

April 1987 +0.08

April 1991 +0.34

April 1994 +0.11

April 1997 +0.59

April 2002 +0.41

April 2009 -0.26

April 2015 +0.98

April 2023 +0.13

Early in the Spring Nino 4 is a loading pattern for Nino 3.4 as we progress later on.

BLI snowman · April 1

1 hour ago, Phil said:

I’d argue our period of record is too short to say this confidently.

- Until 86/87 & 87/88 it was unprecedented for a Niño to span two seasonal cycles without attenuating during boreal summer.

- Until 2016 it was unprecedented for the QBO to skip a heartbeat, metaphorically speaking.

- It was unprecedented to go 13+ years without a single trimonthly ONI below -0.8 until 1956/57 -1969/70.

A lot of things are “unprecedented” in a limited sample of data. Until they aren’t.

I get your point but I'd argue our ENSO record stretches back a century or so now. That's now a pretty reasonable sample size.

It gets murkier before that and you could make the case that we had some short return strong Niño events at the turn of the 20th century (1896-97, 1899-00, 1902-03) but it's a little harder IMO to really be able to compare and identify the nuances of the pre-1930s ENSO events to today's data set outside of the obvious top tier ones like the 1877-78 Niño or the 1889-90 Niña.

Phil · April 1

28 minutes ago, StormchaserChuck1 said:

I don't see any reason why one can't occur 3 years later. Actually, over like a thousand years I think there is +correlation year-to-year of ENSO events (warm ENSO would favor at like 50.1% warm ENSO the following year). I think the Nina snapback that has been so strong this century is a bit of anomaly in the much longer term

Interesting you mention that. The -ENSO tendency is common in warm(ing) climate regimes such as this one, as we now know from ocean proxies dated to the Roman and Medieval Warm Periods as well. The tendency towards a broad/poleward Hadley Cell descending branch/strong 4CH (SW US Heat/Drought) is also characteristic of such a -ENSO/-PMM biased low frequency state (oft-hand referred to as the “enhanced state” in literature), which likely explains the multi-century megadroughts during both climate periods.

The MWP terminated in two stages, following a shift in the structure of the IPWP and seasonal character of the ENSO dipole, defined by a relaxation of the zonal temperature gradient over the equatorial Pacific and a slackening of the trade winds/walker cell on balance, indicative of a more +ENSO tendency. This coincided with a substantial moistening across SW North America and likely the expulsion/drawdown of stored oceanic heat into the atmosphere/space over the span of many decades to centuries. A minor and largely unforced reorganization of the planetary heat budget, all things considered, but more than enough to trigger a broader multicentury climate shift.

BLI snowman · April 1

11 minutes ago, StormchaserChuck1 said:

Nino 4 is already in Weak Nino range, +0.511

This is way ahead of other later in the year >+1.2 El Nino's.. only 2015 and 1997 were greater for the month of April.

April 1957 -0.06

April 1963 -0.34

April 1965 -0.92

April 1968 -0.46

April 1972 +0.11

April 1982 +0.33

April 1986 -0.34

April 1987 +0.08

April 1991 +0.34

April 1994 +0.11

April 1997 +0.59

April 2002 +0.41

April 2009 -0.26

April 2015 +0.98

April 2023 +0.13

Early in the Spring Nino 4 is a loading pattern for Nino 3.4 as we progress later on.

CDAS data still doesn't align with the CPC. Different baselines I'm assuming.

CPC data has Niño 4 at +0.2c as of 3/30. Much lower than the CDAS index.

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

Phil · April 1

21 minutes ago, StormchaserChuck1 said:

Nino 4 is already in Weak Nino range, +0.511

This is way ahead of other later in the year >+1.2 El Nino's.. only 2015 and 1997 were greater for the month of April.

April 1957 -0.06

April 1963 -0.34

April 1965 -0.92

April 1968 -0.46

April 1972 +0.11

April 1982 +0.33

April 1986 -0.34

April 1987 +0.08

April 1991 +0.34

April 1994 +0.11

April 1997 +0.59

April 2002 +0.41

April 2009 -0.26

April 2015 +0.98

April 2023 +0.13

Early in the Spring Nino 4 is a loading pattern for Nino 3.4 as we progress later on.

It’s definitely a loading pattern in Niños that develop from the WPAC. But for events that evolve from the EPAC (72/73, 23/24, etc) I don’t believe it is nearly as predictive.

For instance, you will find it is much more predictive following the 1976 pacific climate shift, which also marked a shift to almost entirely WPAC/null emergent events (until 23/24, which was the first EPAC emergent event since 72/73).

During the 1950s/60s the character of developing niños was much different, with very few Niños emerging from the WPAC. Niño-4 was much less relevant in the statistical sense during that era.

Eugene-5SW · April 1

51 minutes ago, Front Ranger said:

EUG on pace for 15" of rain this month.

Seems solid. Would like to see a teensy bit more ensemble support.

Doom Buster · April 1

47 minutes ago, StormchaserChuck1 said:

I don't see any reason why one can't occur 3 years later. Actually, over like a thousand years I think there is +correlation year-to-year of ENSO events (warm ENSO would favor at like 50.1% warm ENSO the following year). I think the Nina snapback that has been so strong this century is a bit of anomaly in the much longer term

And no one said that. But as you know and often do yourself, it doesn't hurt to look at history and the available data for such things.

KeyPeninsula_Wx · April 1

Still raining but just 0.40” so far today. Little less than what was shown on the models today. This coupled with the fact that the models are very dry following today leads me to believe this will likely be a drier than normal April.

StormchaserChuck1 · April 1

34 minutes ago, Phil said:

It’s definitely a loading pattern in Niños that develop from the WPAC. But for events that evolve from the EPAC (72/73, 23/24, etc) I don’t believe it is nearly as predictive.

Yeah, for the majority of Nino 3.4 based Nino's. 72/73 and 23/24 were east-based

T-Town · April 1

11 minutes ago, KeyPeninsula_Wx said:

Still raining but just 0.40” so far today. Little less than what was shown on the models today. This coupled with the fact that the models are very dry following today leads me to believe this will likely be a drier than normal April.

.65 here. I wasn’t really paying attention so pleasantly surprised at that total. But yeah looks pretty dry going forward.

Tanis Leach · April 1

I have unconfirmed reports of rotation SE of Oregon City. Can anyone back this up?

I don't trust the source FTR, but radar could back their claim.

KeyPeninsula_Wx · April 2

1 minute ago, T-Town said:

.65 here. I wasn’t really paying attention so pleasantly surprised at that total. But yeah looks pretty dry going forward.

If I had to guess the next few months will be warmer and drier than normal overall…but we will see. Having a pretty dry first half of April makes it tough to get back up to normal in the second half.

StormchaserChuck1 · April 2

Actually there is historically El Nino tendency +3-5 years after a Strong Nino (2:1 Nino vs Nina).

DeepFriedEgg · April 2

2 hours ago, StormchaserChuck1 said:

Phoenix broke it's March monthly temp record by +6.5F. Its March would have been the 2nd warmest April all time.

DJFM average was +4.2 over number 2

Insanity. Even with subtracting 2F for UHI.

BLI snowman · April 2

56 minutes ago, StormchaserChuck1 said:

Actually there is historically El Nino tendency +3-5 years after a Strong Nino (2:1 Nino vs Nina).

The question is about another strong Nino vs. a weaker event. I don't think anyone questions that there will be a Nino of some sort this year.

SeattleSmokeLayerFan · April 2

All good things come to an end. On different time scales.

In the short term, the rain is over. Luckily the next sight of rain isn't too far off... Just a week out for some showers and maybe t-storms east of the Cascades.

In the long term, our favorable -PDO regime is coming to a close..could be several decades until we return.

StormchaserChuck1 · April 2

4 minutes ago, BLI snowman said:

The question is about another strong Nino vs. a weaker event. I don't think anyone questions that there will be a Nino of some sort this year.

El Nino potential ranges from weak to strong. We are working with limited data.

MossMan · April 2

.43” so far on the day.

SeattleSmokeLayerFan · April 2

3 hours ago, Phil said:

+QBO/strong Niño is the worst possible combination in the PNW and for arctic air anywhere in the lower-48, FWIW.

Notable analogs: 57/58, 69/70, 82/83, 86/87, 91/92, 02/03, 15/16. The epitome of +EPO/NPAC megatrough monsters. They are at least stormier up there vs endless +TNH ridgefest years but you can forget about any kind of meaningful cold.

Also, strong Niño/+QBO has a very difficult time snapping back to Niña the following winter due to destructive interference inhibiting off-equator convection at crucial stages in the seasonal cycle.

Almost always the result is an ENSO neutral/low amp of some variety. The one exception is 70/71 probably because it followed a second year Niño which had a drained IPWP/thermocline primed for upwelling. All the other cases post-WWII failed to transition to Niña the subsequent winter.

In the PNW lowlands, we get so little snow it really doesn't matter. It just takes one event to define the whole winter. Even the worst winters could randomly deliver in a single day, and you wouldn't even know. Anafronts and convergence zones can drop snow even with non-arctic setups that don't even look remotely close to good at the 500mb level.

The entirety of an El Nino +QBO can be absolutely horrendous, but it just takes one week to change everything.

The same thing happened this winter for Seattle. Randomly got snow in March, despite the pattern still remaining largely miserable.

2018-2019 was more of the same. Winter was garbage but quickly turned around towards the end.

The only good configuration in the PNW is La Nina and +QBO, for more consistent cold and locked in average or above average snowfall. Everything else is a wild card when your average snowfall is literally 4-6 inches.