Nostr notes by Daniel Swain

Okay, folks: The big El Niño update is now out on Weather West! ...

2026-06-11T23:46:26Z

Okay, folks: The big El Niño update is now out on Weather West! This sure looks like it's going to be a dramatic year from a global climate perspective, and there are major implications for extreme events (across California, the U.S. West, & well beyond). https://weatherwest.com/archives/43880

I've got to say that I'm really disappointed in the ...

2026-05-25T17:11:17Z

I've got to say that I'm really disappointed in the recent discourse surrounding the RCP8.5 scenario. The lack of context and understanding is something I expected from the usual suspects, but it's frustrating to see such bad takes from people and outlets who should know better.

Recent strong NWly winds have enhanced upwelling of cold ocean ...

2026-05-23T19:37:53Z

Recent strong NWly winds have enhanced upwelling of cold ocean water along immediate CA coast from Monterey northward, temporarily alleviating near-shore marine heatwave there. But SoCal coastal waters remain very warm, & NorCal ocean warming will likely resume sooner vs later.

It's an honor to be receiving this year's California ...

2026-04-24T18:29:53Z

It's an honor to be receiving this year's California River Award from Friends of the River! I've taken a moment to reflect on the notion of rivers as "integrators of change"--from hydrological and human perspectives--during a period of rapid global change. youtube.com/watch?v=CFm0hyX8BJE&feature=youtu.be

Amid the historic and ongoing record heatwave (which will ...

2026-03-23T15:50:29Z

Amid the historic and ongoing record heatwave (which will continue for at least another week in this region), Colorado River Basin snowpack has unfortunately taken an unprecedented March nosedive. Given the pre-existing water crisis, this is a highly alarming trajectory.

Incredibly, even more locations across U.S. are today ...

2026-03-21T22:07:52Z

Incredibly, even *more* locations across U.S. are today experiencing their warmest March temperatures on record--many by a wide margin, with some even breaking April records. This includes most or all of: AZ, UT, CO, NM, WY, NE, KS, MO, IA, plus portions of many other states. 🫠

Earlier today, I was asked to comment on the current state of ...

2026-03-20T23:32:05Z

Earlier today, I was asked to comment on the current state of American disaster preparedness.

That was already a fraught question, even prior to present chaos, but then I saw today's headlines. 🫠

"Top Disaster Response Official Claims He Teleported to a Waffle House"

Earlier today, I was asked to comment on the current state of ...

2026-03-20T23:28:57Z

Earlier today, I was asked to comment on the current state of disaster preparedness in the United States.

That was already a fraught question, even prior present chaos, but then I saw today's headlines. 🫠

"Top Disaster Response Official Claims He Teleported to a Waffle House"

...And, again today, a huge swath of the continental United ...

2026-03-20T22:04:02Z

...And, again today, a huge swath of the continental United States clear across from the Pacific Coast to Mississippi River is experiencing all-time March monthly record heat. Some locations are so hot that they are actually exceeding *April* all-time record highs. Incredible.

Well, if yesterday's map was ridiculous, I'm running out ...

2026-03-19T23:08:31Z

Well, if yesterday's map was ridiculous, I'm running out of superlatives to characterize today's. Countless locations from Pacific Coast to Great Plains are currently experiencing all-time record March warmth, w/ some locations approaching/exceeding April (or even May) records.

On Friday, Mar 20 at noon Pacific Time, I'll have another ...

2026-03-19T20:01:27Z

On Friday, Mar 20 at noon Pacific Time, I'll have another live virtual office hour to discuss the now record-shattering Western U.S. heatwave. I'll focus on the extraordinary magnitude of warmth so far, plus the snowpack nosedive that has already resulted. https://www.youtube.com/live/p9F5bNduWXY

On Mon, Mar 16 (1pm PT) discuss (live) the astonishing ...

2026-03-15T23:02:03Z

On Mon, Mar 16 (1pm PT) discuss (live) the astonishing meteorological anomalies involved in producing what is very likely to become a record-shattering March heatwave across Western U.S.--including connections to ongoing record rainfall/flooding in Hawaii. https://www.youtube.com/live/6kHJxVavDXk

In fact, this will approach the Jun 2021 PacNW/BC heat event in ...

2026-03-15T22:48:39Z

In reply to nevent1q…teu9
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In fact, this will approach the Jun 2021 PacNW/BC heat event in terms of meteorological anomalousness (though not, fortunately, in terms of absolute surface temperatures. It is still *March*, after all!) Western snowpack, however, will plummet at an unprecedented pace.

The seasonal anomalousness, as well sheer spatial extent, of ...

2026-03-15T22:48:33Z

The seasonal anomalousness, as well sheer spatial extent, of upcoming record-shattering Western U.S. heatwave is genuinely startling. This will be associated with, by far, the strongest ridge ever observed during (at least) any Nov-Mar month. #CAwx #AZwx #NMwx #NVwx #UTwx #COwx

All signs continue to point to an exceptional, long-duration, and ...

2026-03-13T16:22:34Z

All signs continue to point to an exceptional, long-duration, and record-breaking to (in some cases) record-shattering March heatwave initially centered across U.S. Southwest but expanding to much broader region next week. This is effectively a full-on summer heatwave in March.

The official NOAA stats out this week confirm that winter 2025-26 ...

2026-03-10T18:45:02Z

The official NOAA stats out this week confirm that winter 2025-26 was the warmest on record across a huge portion of the western and central U.S., which has contributed to extremely low mountain snowpack & worsened the CO River crisis. Meanwhile, record March heat is in forecast.

Today's forecast indicated that "large to very large" ...

2026-02-18T00:57:30Z

In reply to nevent1q…q2zq
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Today's forecast indicated that "large to very large" avalanches were "very likely." https://www.sierraavalanchecenter.org/forecasts/avalanche/central-sierra-nevada#/central-sierra-nevada/

The Sierra Avalanche Center discussion reads: "Widespread ...

2026-02-18T00:57:25Z

In reply to nevent1q…2plc
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The Sierra Avalanche Center discussion reads: "Widespread areas of unstable snow & numerous avalanches are expected today, [which could] travel down through treed terrain, often thought of as "safe" during storms. Travel in, near, or below avalanche terrain is not recommended."

There are two factors that led to today's very high risk: 1) ...

2026-02-18T00:57:20Z

In reply to nevent1q…n9pm
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There are two factors that led to today's very high risk: 1) the long dry and record warm spell in recent weeks, which resulted in a weak base snow layer, and 2) very high snowfall rates (multiple inches per hour) during current storm, leading to risk of large slab failures.

A major avalanche in the "high risk" Avalanche Warning ...

2026-02-18T00:57:14Z

A major avalanche in the "high risk" Avalanche Warning zone (per Sierra Avalanche Center) has occurred in the vicinity of Castle Peak, near Truckee. It unfortunately sounds like over a dozen people (skiers) were in the path, and some are still missing. https://www.nbcnews.com/news/us-news/skiers-missing-stranded-avalanche-california-rcna259472

In fact, as of today, many recording sites in broad swath from ...

2026-02-13T20:46:49Z

In reply to nevent1q…24qq
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In fact, as of today, many recording sites in broad swath from PacNorthwest SEward into Great Basin, & central/southern Rockies continue to report record-low SWE. Upcoming snow will help, but will not even come close to ending snow drought (except, possibly, in Sierra Nevada).

This pattern change will bring desperately needed snow to the ...

2026-02-13T20:46:42Z

In reply to nevent1q…3dcy
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This pattern change will bring desperately needed snow to the Mountain West, where overall snowpack remains (as of today) at or near historic record lows (except in a couple of spots, like southern Sierra) due to sustained record warmth this far this season.

Thereafter, it does appear there will be at least a couple of ...

2026-02-13T20:46:36Z

In reply to nevent1q…g6z9
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Thereafter, it does appear there will be at least a couple of additional colder systems to follow, bringing additional beneficial snow accumulations to mountain areas (even at lower elevations than we've seen so far this winter). TBD how long this lasts; ensemble uncertainty.

Mon-Tue next week, a pretty cold and fairly strong system will ...

2026-02-13T20:46:30Z

In reply to nevent1q…fkek
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Mon-Tue next week, a pretty cold and fairly strong system will bring a ~48 hr period of heavy snow to multiple portions of the Mountain West, especially the Sierra Nevada (where multiple feet are likely at peaks). Mountain highway travel will be difficult to impossible.

The first storm of the much-anticipated pattern shift brought ...

2026-02-13T20:46:24Z

The first storm of the much-anticipated pattern shift brought widespread rain to CA, with some modest mountain snowfall in Sierra Nevada and points east. After a couple of quieter days, a sequence of much colder storms will follow (with much larger mountain snowfalls).

Great piece out today in Physics Today on historical origins, ...

2026-02-13T17:46:22Z

Great piece out today in Physics Today on historical origins, contemporary relevance, & fundamental irreplaceability of the National Center for Atmospheric Research, which remains at imminent risk of dismantling for partisan political reasons. https://physicstoday.aip.org/news/what-the-national-center-for-atmospheric-research-means-to-the-atmospheric-sciences

New Weather West update is out now! Some relief, at last, from ...

2026-02-08T23:49:39Z

New Weather West update is out now! Some relief, at last, from recent record warmth and astonishing lack of Mountain West snow in the coming days as cooler/wetter pattern returns. But just how much relief should we expect? Read more: https://weatherwest.com/archives/43706

I've be live on Monday, February 9th at 3pm PT to discuss the ...

2026-02-08T21:55:49Z

I've be live on Monday, February 9th at 3pm PT to discuss the major upcoming change to a much cooler/wetter pattern across the West--including how much this will help bolster presently record-low mountain snowpack in western U.S. Bring your questions! https://www.youtube.com/live/I9tMLfo5Dx0

If you weren't able to attend in person or missed the ...

2026-02-06T20:25:59Z

If you weren't able to attend in person or missed the livestream, a recording of my presentation on "Weather and Water Extremes on a Warming Planet" is now available! Thanks again to the Aquarium of the Pacific for the invitation, and for making this event so accessible!
https://www.youtube.com/watch?v=3HVoFkFTvRQ

This mountain snow in the U.S. West is desperately ...

2026-02-06T15:48:58Z

In reply to nevent1q…m2av
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This mountain snow in the U.S. West is desperately needed--snowpack has reached record low levels for time of year in many locations & will fall even further behind until early next wk, when there will likely be *some* recovery. TBD just how much; the existing deficits are huge.

In the West, the persistent ridge that has been causing a ...

2026-02-06T15:48:50Z

In reply to nevent1q…9v4y
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In the West, the persistent ridge that has been causing a prolonged dry period will finally shift, with some storms/precipitation returning to both coast & interior. These systems will start out warm, but airmass should eventually cool to near (or even below!) average. Mtn snow!

A much-needed major weather pattern change is finally coming for ...

2026-02-06T15:48:44Z

A much-needed major weather pattern change is finally coming for the continental U.S.! The "Warm West/Cool East" temperature dipole, which has been associated with record Western warmth and extreme Eastern cold/ice/snow, will finally fade in the coming days.

Attention folks in the weather, climate, disaster, wildfire, and ...

2026-01-23T21:57:57Z

Attention folks in the weather, climate, disaster, wildfire, and Earth science communities: NSF has just published a new "Dear Colleague" letter inviting feedback (by Mar 13) on the proposal to dismantle the National Center for Atmospheric Research (NCAR). https://www.nsf.gov/funding/information/dcl-nsf-intent-restructure-critical-weather-infrastructure

The major winter storm and cold outbreak in the central & ...

2026-01-23T18:14:38Z

The major winter storm and cold outbreak in the central & eastern U.S. this weekend will be most notable not for record cold, nor heavy snowfall, but instead for very heavy ice accumulations that will cause widespread/severe electrical infrastructure and travel disruptions.

Mid-January snowpack is at record-low levels across much of the ...

2026-01-22T18:59:28Z

Mid-January snowpack is at record-low levels across much of the American West. Yet it has not been a record dry winter virtually anywhere. So, what's going on? Well, persistent and record-breaking warmth has essentially overwhelmed all other factors. https://www.youtube.com/watch?v=WQDGvZZW6yA

Crowdsourcing: is there anyone at Wordpress/Automattic who could ...

2026-01-20T02:35:06Z

Crowdsourcing: is there anyone at Wordpress/Automattic who could help out this evening with mailing list issue? (Essentially, all outbound links from Jetpack newsletters are broken and my inbox is blowing up. A reminder that there is no "IT team"--it's just me!). Thx!

Fast-moving & destructive wildfires--some burning into ...

2026-01-18T23:37:20Z

Fast-moving & destructive wildfires--some burning into populated areas in/beyond the urban interface--have occurred across many of the Southern Hemisphere's fire prone regions (including Chile & Argentina, South Africa, & SE Australia) over last 3 weeks. https://www.theguardian.com/world/2026/jan/18/chile-president-declares-state-of-catastrophe-as-wildfires-kill

In California, both Dec & Nov-Dec periods were warmest on ...

2026-01-14T03:58:42Z

In reply to nevent1q…9pul
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In California, both Dec & Nov-Dec periods were warmest on record--and by a considerable margin, too. The Central Valley, however, was *not* record warm due to the damp chill associated with weeks-long tule fog episodes (making statewide record all the more remarkable!). #CAwx

The extremely anomalous & in most cases record-breaking ...

2026-01-14T03:58:35Z

In reply to nevent1q…vlvq
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The extremely anomalous & in most cases record-breaking Nov-Dec warmth led to record-low snowpack in many areas. Heavy precipitation bolstered high elevation snowpack in some areas in late Dec despite warmth, but most basins remain far below average snow water equivalent.

Well, it's now official (per NOAA): Dec (and Nov-Dec) 2025 ...

2026-01-14T03:58:26Z

Well, it's now official (per NOAA): Dec (and Nov-Dec) 2025 were the warmest such periods on record for Western U.S. (and also for most individual Western states). It has been an extraordinarily sustained period of winter warmth, and this eerily balmy winter continues into Jan.

On Tue, Jan. 13 at 2pm PT, I'll offer an update re: ongoing ...

2026-01-11T22:38:58Z

On Tue, Jan. 13 at 2pm PT, I'll offer an update re: ongoing efforts to save the NSF National Center for Atmospheric Research from dismantling. In so doing, I'll also reflect on the growing inseparability of weather and climate science and prediction. https://www.youtube.com/live/8T0q_PfJV5g

A large blob of heavy rain is currently moving into NorCal, ...

2026-01-05T21:53:12Z

A large blob of heavy rain is currently moving into NorCal, including in/near SF Bay Area. Given saturated soils, I would expect rapid rises on creeks & smaller rivers. Roadway flooding is also likely, esp. in low-lying coastal areas as tides remain higher than usual. #CAwx

This storm will, once again, start out quite warm with high snow ...

2026-01-02T17:42:12Z

In reply to nevent1q…zpt0
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This storm will, once again, start out quite warm with high snow levels (above Sierra passes) initially. But colder air will filter in behind the initial cold front, bringing heavy snowfall to more reasonable elevations (and eventually down to 3-4k feet) by early next week. #CAwx

Although the risk looks low overall, a couple of strong to severe ...

2026-01-02T17:42:04Z

In reply to nevent1q…z8aw
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Although the risk looks low overall, a couple of strong to severe thunderstorms could occur in NorCal (mainly in Sac Valley/North Coast to SF Bay region), with weaker t-storms possible elsewhere.

Another winter storm will bring widespread rain and gusty winds ...

2026-01-02T17:41:57Z

Another winter storm will bring widespread rain and gusty winds to much of California this weekend. This one will be focused more on NorCal vs SoCal. Only minor rain/wind impacts are expected--but a notable coastal flood event may occur in SF Bay Area (see my other thread). #CAwx

This wknd's storm is not, by any metric, extreme! (It ...

2026-01-02T17:32:25Z

In reply to nevent1q…529t
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This wknd's storm is not, by any metric, extreme! (It won't even be as strong as last week's.) And astronomical (sun & moon gravity-related) King Tide is typical, as well. But coincidental timing of KT + moderate storm, added atop SLR, will generate a notable coastal flood event.

As NWS Monterey has emphasized, predicted water levels in SF will ...

2026-01-02T17:32:18Z

In reply to nevent1q…p6tp
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As NWS Monterey has emphasized, predicted water levels in SF will be the highest ever observed except for the notable coastal flood events in 1982/3 and 1998. As a result, considerable inundation of low-lying roads, infrastructure, and communities along SF Bay is likely. #CAwx

A moderately strong winter storm this wknd will bring low ...

2026-01-02T17:32:13Z

In reply to nevent1q…eege
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A moderately strong winter storm this wknd will bring low pressure and onshore/southerly winds to the SF Bay region. When combined w/ very high astronomical (King) tides, plus aggregate effect of long-term sea level rise, a 2.5+ feet elevation of SF Bay water levels is expected.

Highest astronomical high tides of year (aka the "King ...

2026-01-02T17:32:05Z

Highest astronomical high tides of year (aka the "King Tides") will occur this weekend in NorCal. But this year, they will coincide w/additional storm surge from nearby low pressure--causing potential for SF Bay Area coastal flooding beyond what we've seen in recent years. #CAwx

SoCal will see, by far, the heaviest rains this week from initial ...

2025-12-30T23:11:55Z

In reply to nevent1q…5x65
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SoCal will see, by far, the heaviest rains this week from initial storm system. And while they won't be as heavy as last week's, they will still be substantial. More importantly, they will again fall with high *intensity,* & may be associated (again) w/torrential downpours. #CAwx

The developing storm is a pretty unusual one, with deep ...

2025-12-30T23:11:48Z

In reply to nevent1q…6gme
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The developing storm is a pretty unusual one, with deep subtropical origins. The parent low pressure has formed quite far south--west of the southern tip of Baja CA! Accordingly, its associated air mass is warm & convectively unstable (w/lots of thunderstorms at present). #CAwx

Yet another major rain event will arrive in Southern CA on NYE ...

2025-12-30T23:11:40Z

Yet another major rain event will arrive in Southern CA on NYE & last into New Year's Day--and it could, once again, bring substantial impacts due to both timing on holiday and preceding exceptionally wet conditions. Peak impact will overlap exactly w/Rose Parade. [Thread] #CAwx

As we head into a new year, I wanted to share this conversation I ...

2025-12-30T21:17:43Z

As we head into a new year, I wanted to share this conversation I had with Muhammad Ittefaq on the big picture surrounding climate change: Where we are now; how much warming we're on track to see; & why it's so important to be honest about where we're headed. https://youtu.be/MOihmtuDFcM?t=0

Tornado Warning inside a Severe Thunderstorm Warning inside a ...

2025-12-24T18:26:06Z

Tornado Warning inside a Severe Thunderstorm Warning inside a Flash Flood Warning in LA County at the moment, if you're wondering how things are going... #CAwx #LArain

One thing that really stands out about this week's California ...

2025-12-24T00:16:56Z

One thing that really stands out about this week's California storms is the highly unusual risk of severe thunderstorms, both overnight Tue Wed and then again late Wed into Thu. Multiple low-topped supercells may generate very strong wind gusts and even a few tornadoes. #CAwx

An even more ridiculously warm day across most of the central and ...

2025-12-22T23:24:57Z

An even more ridiculously warm day across most of the central and western United States, with numerous locations seeing not only calendar date record highs but in many cases all-time December monthly records. Wow. 🫠 #AZwx #NMwx #TWwx #COwx #OKwx #WYwx #KSwx #NEwx #UTwx

Reminder: I'll be going live @ noon Pacific time today to ...

2025-12-22T18:58:45Z

Reminder: I'll be going live @ noon Pacific time today to discuss incoming series of (very?) strong winter storms slated to affect all of CA. Wind risk & flood risk have notched upward vs my blog post yesterday in some spots; I'll discuss in detail. #CAwx https://www.youtube.com/live/m5iMi4MaHf0

Although NorCal flood issues so far have mostly been minor, an ...

2025-12-22T01:22:06Z

Although NorCal flood issues so far have mostly been minor, an exception is near Redding in northern Sac Valley. A narrow but persistent & stationary band of torrential downpours associated w/convergence zone has resulted in significant & still-escalating flash flooding. #CAwx

I'll host a "lunch hour" livestream on Mon, Dec 22 ...

2025-12-21T23:44:58Z

I'll host a "lunch hour" livestream on Mon, Dec 22 (noon PT) discuss the inbound series of strong winter storms in California, including the exceptionally warm initial airmass, SoCal flood risk, and eventual return of Sierra snow (yes, finally!). #CAwx https://www.youtube.com/live/m5iMi4MaHf0

Update: very active weather week to come in CA! First, a ...

2025-12-21T02:39:33Z

Update: very active weather week to come in CA! First, a persistent and very warm atmospheric river will remain draped over NorCal, continuing to generate rain--and snow levels in the Sierra will rise yet further, above 8k-9k feet. SoCal stays warm/dry through Tue. [Thread] #CAwx

Next Tue/Wed storm could be a fairly high-impact event as ...

2025-12-18T20:13:54Z

In reply to nevent1q…w2sg
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Next Tue/Wed storm could be a fairly high-impact event as it's looking pretty strong (with high rain rates, stronger winds, possible t-storms) and it will also coincide with peak of holiday travel period. Road and air travel delays are likely. More details this weekend!

One key point is that the initial days of this CA pattern shift ...

2025-12-18T20:13:48Z

In reply to nevent1q…hc2g
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One key point is that the initial days of this CA pattern shift will involve a very anomalously warm airmass--and there will be essentially no snow at all even in the higher mountains until Tue/Wed next week. Record low snowpack will persist, or become even lower, in meantime.

Impacts: in PacNW, renewed/additional flooding/landslides quite ...

2025-12-18T20:13:42Z

In reply to nevent1q…aeq4
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Impacts: in PacNW, renewed/additional flooding/landslides quite possible. CA flood risk looks generally minor through early next wk with modest rain rates (despite large cumulative volume). Greater flood risk could occur next Tue/Wes as more intense storm moves ashore (TBD!).

By the middle of next week, a more "dramatic" storm is ...

2025-12-18T20:13:37Z

In reply to nevent1q…rtcj
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By the middle of next week, a more "dramatic" storm is likely in California as a deepening surface low connects with/atmospheric river--likely generating heavy rain/strong winds. While it will start out warm, snow levels will drop to 6k ft or below behind the front (finally!!).

In NorCal, a prolonged period of light to moderate (and ...

2025-12-18T20:13:29Z

In reply to nevent1q…80zu
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In NorCal, a prolonged period of light to moderate (and occasionally heavy, in the mountains) rain will occur over next few days as a very persistent & warm atmospheric river stalls overhead. Snow levels will generally be above 7k-8k feet, so even Sierra passes will see rain.

Another very active weather period for Pacific Coast will occur ...

2025-12-18T20:13:21Z

Another very active weather period for Pacific Coast will occur over the next 10 days, with very moist storms and a persistent (atmospheric river-associated) moisture transport corridor bringing copious rain progressively farther south into California by early next week. [Thread]

Here in Boulder, power is still out due to combination of ...

2025-12-18T18:42:51Z

Here in Boulder, power is still out due to combination of pre-emptive shut-offs to prevent wildfire ignitions & damage from 90-100 mph wind gusts yesterday, & a similar event is inbound again Fri. I'm doing the best I can amid limited connectivity; thanks for your patience!

In case you missed it live, a full recording of my rapid-response ...

2025-12-17T18:49:43Z

In case you missed it live, a full recording of my rapid-response livestream regarding news surrounding the proposed imminent and sudden dismantling of the National Center for Atmospheric Research (NCAR) is now available. https://youtu.be/FTKW68RqdkE

Unbelievable. This would be a terrible blow to American science, ...

2025-12-17T03:28:08Z

Unbelievable. This would be a terrible blow to American science, writ large. It would decimate not only climate research, but also the kind of weather, wildfire, and disaster research that has underpinned half a century of progress in prediction, early warning, and increased resilience. https://www.usatoday.com/story/news/politics/2025/12/16/trump-dismantle-national-center-atmospheric-research-climate/87798771007

Although ongoing atmospheric river in PacNW is focused farther ...

2025-12-15T20:22:33Z

Although ongoing atmospheric river in PacNW is focused farther north vs last wk, w/somewhat less heavy rain in WA state, cumulative stress from days of high flows/saturated soils are now manifesting, w/landslides & now NWS Flash Flood Warning for levee failure near Renton. #WAwx

New Weather West post: As warm atmospheric rivers slide gradually ...

2025-12-15T00:08:15Z

New Weather West post: As warm atmospheric rivers slide gradually southward along Pacific Coast, a return to rain and end to tule fog in NorCal later this week–but don’t expect much mountain snow (at least initially). https://weatherwest.com/archives/43624

The fact that parts of Washington are seeing record-breaking ...

2025-12-12T00:32:12Z

The fact that parts of Washington are seeing record-breaking flooding this week is not surprising given that 1) many locations saw record 24hr precipitation (well above 100yr ARI) & 2) near-record temperatures *simultaneously* (no snow in mtns, so all precip became runoff). #WAwx

Mid-PM temps within a few hundred feet of sea level in Central ...

2025-12-11T22:47:20Z

In reply to nevent1q…mtuw
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Mid-PM temps within a few hundred feet of sea level in Central Valley (low 40s F) quickly rise to (low 70s F) just 2,000ft up in surrounding slopes. That's an inversion magnitude of ~30F/2,000ft! Amazingly, airmass atop fog layer is *record warm* despite damp chill right at sfc.

Central California is currently experiencing one of the most ...

2025-12-11T22:47:14Z

Central California is currently experiencing one of the most remarkable temperature inversions I've ever seen in this part of the world. The Central Valley remains miserably damp & chilly under dense fog layer, but it's balmily warm & sunny just 2,000ft up nearby mountain slopes!

An incredible weather day across the West! Co-occurring ...

2025-12-10T22:51:59Z

An incredible weather day across the West! Co-occurring w/long-duration & extremely moist #AtmosphericRiver bringing widespread/locally record flooding in PacNW is record-warm airmass region-wide (yet, meanwhile, CA's Central Valley remains damp & cold under dense tule fog).

This flood event will also extend into NW Oregon and SW British ...

2025-12-10T02:40:44Z

In reply to nevent1q…9t56
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This flood event will also extend into NW Oregon and SW British Columbia, though WA will likely be worst-hit. Major impacts and significant inundation/damage is possible, as are significant landslides. Additional warm rain on horizon through late Dec. #WAwx #BCstorm #ORwx [3/3]

On Wednesday, widespread heavy rain & very high snow levels ...

2025-12-10T02:40:38Z

In reply to nevent1q…2rmw
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On Wednesday, widespread heavy rain & very high snow levels (7,000-9,000 feet) will cause enormous runoff into already swollen rivers. Widespread moderate to major flood is likely, with some rivers expected to experience *record* flooding (esp. Skagit & Snohomish). #WAwx [2/3]

Widespread significant river flooding has already developed ...

2025-12-10T02:40:31Z

Widespread significant river flooding has already developed across western Washington as a series of extremely warm & moist #AtmosphericRivers move slowly across the region. This flooding will further worsen tomorrow as strongest part of AR moves ashore. #WAwx [1/3]

I'll be offering a dual-purpose "rapid response" ...

2025-12-08T18:59:16Z

I'll be offering a dual-purpose "rapid response" livestream today (1pm PT) focused on EPA's recent scrubbing of climate info from its website, & also the developing major flood event in Pacific Northwest stemming from very warm atmospheric river event(s). https://www.youtube.com/live/FQqkkggQ2qc

None of this is, unfortunately, surprising in the present ...

2025-12-08T17:51:37Z

In reply to nevent1q…ugy7
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None of this is, unfortunately, surprising in the present American moment. But it is still profoundly alarming that the primary regulatory body for environmental protection and pollution control in this country is now actively ignoring scientific evidence. This will end poorly.

To be clear: the new, near-exclusive emphasis on natural causes ...

2025-12-08T17:51:31Z

In reply to nevent1q…slag
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To be clear: the new, near-exclusive emphasis on natural causes of climate change on the U.S. EPA's website is now completely out of synch with all available evidence demonstrating overwhelming human influence on contemporary warming trends.

Additionally, it appears that all of EPA's previously ...

2025-12-08T17:51:26Z

In reply to nevent1q…alsn
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Additionally, it appears that all of EPA's previously extensive "indicators of climate change" pages have been scrubbed entirely. The pages no longer exist; there are numerous dead links on the current/live EPA site, and no indication they have been moved to a new URL.

This can be confirmed using the Wayback Machine's last ...

2025-12-08T17:51:20Z

In reply to nevent1q…3uh3
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This can be confirmed using the Wayback Machine's last snapshot (from Oct 8, 2025). At some point between Oct 8 & Dec 8, major changes were made to this and other EPA climate change content. Information has either been removed completely or "adjusted" to emphasize natural causes.

It appears that the U.S. Environmental Protection Agency (EPA) ...

2025-12-08T17:51:13Z

It appears that the U.S. Environmental Protection Agency (EPA) has, within the past week, scrubbed a large amount of climate change content from its official website, as well as *removed human-caused warming* from the discussion on its "causes of climate change" page.

New post: Under resilient ridge, prolonged tule fog episode ...

2025-12-06T23:46:19Z

New post: Under resilient ridge, prolonged tule fog episode brings cold & damp weather to Central Valley but anomalously warm/dry weather elsewhere. Plus, update on what turned out to be record-wet autumn in some spots & PacNW flood risk this wk. elsewhere.https://weatherwest.com/archives/43605

Then, on Thu, Dec 4 @ 2pm PT, I'll offer a global #climate ...

2025-12-01T23:05:40Z

In reply to nevent1q…vfvd
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Then, on Thu, Dec 4 @ 2pm PT, I'll offer a global #climate update. I'll discuss the likely upcoming transition from La Niña to El Niño conditions, recent global temperature trends, impacts, & implications. I'll also be taking questions live! #CAwx [2/2] https://www.youtube.com/live/XP4Nx--2gMg

I'll be hosting two separate livestreams this week, each ...

2025-12-01T23:05:35Z

I'll be hosting *two* separate livestreams this week, each w/different focus. First, join me on Tue, Dec 2 @ 4pm PT for a CA weather update. I'll discuss the recent tule fog/stratus episode & what appears to be a pretty long dry spell into Dec. #CAwx [1/2] https://www.youtube.com/live/P-FTpZdpNOA

Another day, another solid overcast throughout nearly entirety of ...

2025-11-30T22:28:28Z

Another day, another solid overcast throughout nearly entirety of CA's Central Valley. However, as some have noted, as this event has persisted the density of actual fog has been diminished near the surface because temps actually aren't cold enough! "Tule stratus," perhaps? #CAwx

For the most part, it's looking like a mostly dry and warm ...

2025-11-29T18:40:26Z

For the most part, it's looking like a mostly dry and warm start to December across much of the Southwest including much of California--with the major exception of the Central Valley, where a cold/damp tule fog layer may persist for a while yet. [Thread]

Quite a metaphor. 👀 "The blaze [sent] panicked delegates ...

2025-11-20T19:36:39Z

Quite a metaphor. 👀

"The blaze [sent] panicked delegates racing to evacuate...rain from a torrential downpour leaked into the meeting spaces...There were complaints about food shortages, & the air-conditioning struggled to keep up with the high heat..."

https://www.nytimes.com/2025/11/20/climate/fire-cop30-belem-climate.html

An active weather pattern will continue this week across ...

2025-11-17T16:53:33Z

An active weather pattern will continue this week across California, with widespread moderate rainfall. Some local flooding issues could occur in areas that saw heavier rain last week, but overall concern is low. #CAwx

I recorded a short video op-ed to help cut through the noise ...

2025-11-14T16:56:20Z

I recorded a short video op-ed to help cut through the noise surrounding the ongoing COP30 climate conference. In short: now is not the time to scale back our efforts to address climate change--quite the opposite, as the intensifying consequences have never been clearer. https://www.youtube.com/watch?v=wksV7vvQWq8

#PackFire is now 1000+ acres and wind driven. Although it may ...

2025-11-13T21:52:35Z

In reply to nevent1q…h3nv
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#PackFire is now 1000+ acres and wind driven. Although it may seem counterintuitive, fast wind-driven fires do occur on Sierra lee side prior to cold frontal passages in fall/winter as strong & dry downslope winds (induced by mountain rain shadow) precede precip. #CAwx #CAfire

Despite heavy precip across much of California today (including ...

2025-11-13T21:52:30Z

Despite heavy precip across much of California today (including on the Sierra West slope/crest), the dry downslope wind-driven #PackFIie has broken out on Sierra east (lee) side & is actively burning along Hwy 395 corridor, threatening some structures near Lake Crowley. #CAfire

I'll keep a close eye on the weekend SoCal storm to see if it ...

2025-11-13T03:51:04Z

In reply to nevent1q…gws4
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I'll keep a close eye on the weekend SoCal storm to see if it gets "upgraded" any further (in terms of potential flood risk). Given two recent very warm (even hot!) and dry weeks in SoCal, this will represent a rather dramatic shift from recent weather conditions.

In fact, much of the SoCal coastal plain could see 2-4+ inches ...

2025-11-13T03:50:59Z

In reply to nevent1q…vek9
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In fact, much of the SoCal coastal plain could see 2-4+ inches between Thu & Mon. That is pretty impressive for a Nov storm in this part of the state! In fact, at least localized flash flooding (esp. near recent wildfire zones & in other susceptible spots) is certainly possible.

Fri into Sat, a secondary low pressure system will spin up off ...

2025-11-13T03:50:51Z

In reply to nevent1q…ukn6
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Fri into Sat, a secondary low pressure system will spin up off coast of SoCal, entraining deep subtropical moisture. This storm now looks more impressive than previously indicated, & the slow-moving moisture plume could generate heavy rain + isolated t-storms for much of weekend.

Overnight tonight into Thursday morning, a fairly strong and ...

2025-11-13T03:50:27Z

In reply to nevent1q…ym6m
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Overnight tonight into Thursday morning, a fairly strong and moist cold front (and associated atmospheric river) will move across Northern California. A relatively brief period of heavy rain is likely, along with gusty winds and isolated thunderstorms. Sierra snow levels >8k ft.

A pair of notable storms will bring widespread & in some ...

2025-11-13T03:50:19Z

A pair of notable storms will bring widespread & in some cases heavy rain along w/locally stronger wind gusts and isolated thunderstorms through this weekend. Snow levels will be very high, esp. initially, due to warm airmass, & SoCal will actually see more rain vs NorCal! #CAwx

I do try my best to review more than I publish, and think I have ...

2025-11-12T03:38:12Z

In reply to nevent1q…jkl6
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I do try my best to review more than I publish, and think I have a pretty good track record of doing so! But the now-continuous bombardment is overwhelming. Even logging in/registering w/an ever increasing number of journal portals even to formally decline is now time-consuming!

Nostr notes by Daniel Swain

Okay, folks: The big El Niño update is now out on Weather West! ...

I've got to say that I'm really disappointed in the ...

Recent strong NWly winds have enhanced upwelling of cold ocean ...

It's an honor to be receiving this year's California ...

Amid the historic and ongoing record heatwave (which will ...

Incredibly, even *more* locations across U.S. are today ...

Earlier today, I was asked to comment on the current state of ...

Earlier today, I was asked to comment on the current state of ...

...And, again today, a huge swath of the continental United ...

Well, if yesterday's map was ridiculous, I'm running out ...

On Friday, Mar 20 at noon Pacific Time, I'll have another ...

On Mon, Mar 16 (1pm PT) discuss (live) the astonishing ...

In fact, this will approach the Jun 2021 PacNW/BC heat event in ...

The seasonal anomalousness, as well sheer spatial extent, of ...

All signs continue to point to an exceptional, long-duration, and ...

The official NOAA stats out this week confirm that winter 2025-26 ...

Today's forecast indicated that "large to very large" ...

The Sierra Avalanche Center discussion reads: "Widespread ...

There are two factors that led to today's very high risk: 1) ...

A major avalanche in the "high risk" Avalanche Warning ...

In fact, as of today, many recording sites in broad swath from ...

This pattern change will bring desperately needed snow to the ...

Thereafter, it does appear there will be at least a couple of ...

Mon-Tue next week, a pretty cold and fairly strong system will ...

The first storm of the much-anticipated pattern shift brought ...

Great piece out today in Physics Today on historical origins, ...

New Weather West update is out now! Some relief, at last, from ...

I've be live on Monday, February 9th at 3pm PT to discuss the ...

If you weren't able to attend in person or missed the ...

This mountain snow in the U.S. West is desperately ...

In the West, the persistent ridge that has been causing a ...

A much-needed major weather pattern change is finally coming for ...

Attention folks in the weather, climate, disaster, wildfire, and ...

The major winter storm and cold outbreak in the central & ...

Mid-January snowpack is at record-low levels across much of the ...

Crowdsourcing: is there anyone at Wordpress/Automattic who could ...

Fast-moving & destructive wildfires--some burning into ...

In California, both Dec & Nov-Dec periods were warmest on ...

The extremely anomalous & in most cases record-breaking ...

Well, it's now official (per NOAA): Dec (and Nov-Dec) 2025 ...

On Tue, Jan. 13 at 2pm PT, I'll offer an update re: ongoing ...

A large blob of heavy rain is currently moving into NorCal, ...

This storm will, once again, start out quite warm with high snow ...

Although the risk looks low overall, a couple of strong to severe ...

Another winter storm will bring widespread rain and gusty winds ...

This wknd's storm is not, by any metric, extreme! (It ...

As NWS Monterey has emphasized, predicted water levels in SF will ...

A moderately strong winter storm this wknd will bring low ...

Highest astronomical high tides of year (aka the "King ...

SoCal will see, by far, the heaviest rains this week from initial ...

The developing storm is a pretty unusual one, with deep ...

Yet another major rain event will arrive in Southern CA on NYE ...

As we head into a new year, I wanted to share this conversation I ...

Tornado Warning inside a Severe Thunderstorm Warning inside a ...

One thing that really stands out about this week's California ...

An even more ridiculously warm day across most of the central and ...

Reminder: I'll be going live @ noon Pacific time today to ...

Although NorCal flood issues so far have mostly been minor, an ...

I'll host a "lunch hour" livestream on Mon, Dec 22 ...

Update: very active weather week to come in CA! First, a ...

Next Tue/Wed storm could be a fairly high-impact event as ...

One key point is that the initial days of this CA pattern shift ...

Impacts: in PacNW, renewed/additional flooding/landslides quite ...

By the middle of next week, a more "dramatic" storm is ...

In NorCal, a prolonged period of light to moderate (and ...

Another very active weather period for Pacific Coast will occur ...

Here in Boulder, power is still out due to combination of ...

In case you missed it live, a full recording of my rapid-response ...

Unbelievable. This would be a terrible blow to American science, ...

Although ongoing atmospheric river in PacNW is focused farther ...

New Weather West post: As warm atmospheric rivers slide gradually ...

The fact that parts of Washington are seeing record-breaking ...

Mid-PM temps within a few hundred feet of sea level in Central ...

Central California is currently experiencing one of the most ...

An incredible weather day across the West! Co-occurring ...

This flood event will also extend into NW Oregon and SW British ...

On Wednesday, widespread heavy rain & very high snow levels ...

Widespread significant river flooding has already developed ...

I'll be offering a dual-purpose "rapid response" ...

Incredibly, even more locations across U.S. are today ...

I'll be hosting two separate livestreams this week, each ...