Nostr notes by Daniel Swain

On Wed, Oct 21 at 3pm PT, I'll have a livestream to discuss ...

2026-10-20T18:15:14Z

On Wed, Oct 21 at 3pm PT, I'll have a livestream to discuss the unusually deep early season low pressure system off the CA coast, the rain will bring to much of the state, and its potential to generate severe thunderstorms in unusual places. https://www.youtube.com/live/5Dms27gUhpU

Just did some number crunching using latest (Oct 1) ECMWF ...

2026-10-06T19:57:06Z

Just did some number crunching using latest (Oct 1) ECMWF seasonal data, and I must say that I've never seen such high predictive confidence in a very wet California winter. This is a truly extraordinary forecast amid a record-strength El Niño event. [Thread: please read to end.]

Another very hot October day, especially across coastal central ...

2026-10-04T23:21:54Z

Another very hot October day, especially across coastal central & southern California (where widespread 100s have occurred, again, even near immediate coast) but now also extending farther north into NV, ID, WY, and eastern OR. Anomalous heat continues across the West this week.

Global model ensembles are in strong agreement that a prolonged ...

2026-10-01T00:50:31Z

Global model ensembles are in strong agreement that a prolonged &anomalous nearly West-wide autumn heatwave will develop this week & persist for 10+ days. While some daytime records may be set, this event will be more notable for its persistence & breadth. [Thread]

New Weather West post out this evening! I discuss the hyperactive ...

2026-09-28T02:30:30Z

New Weather West post out this evening! I discuss the hyperactive East and Central Pacific hurricane season, as well as the upcoming heatwave across CA--and also why even a dry & warm autumn tells us essentially nothing about the El Niño winter to come.
https://weatherwest.com/archives/44085

In case you missed it live, this session was recorded and is now ...

2026-09-22T23:54:28Z

In case you missed it live, this session was recorded and is now available! Remarkably, it now appears that Hurricane Polo has likely become the fastest-strengthening East Pacific hurricane on record (from tropical storm to category 5 strength in ~30 hrs)! https://www.youtube.com/watch?v=9uYYzUFoan4

On Thu, Sep 10, at 10am PT I'll offer another major update ...

2026-09-07T22:27:12Z

On Thu, Sep 10, at 10am PT I'll offer another major update regarding El Niño 2026, which is still expected to become strongest on record, summarizing latest observations and forecast updates. I'll also revisit potential California-to-global scale impacts. https://youtube.com/live/2v4k0nbUU1s?feature=share

The ECMWF seasonal ensemble has just updated for September, and ...

2026-09-05T21:37:52Z

The ECMWF seasonal ensemble has just updated for September, and it continues to suggest that a soon record-strength El Niño will exert a very strong tilt in the odds toward wet conditions across the U.S. southern tier, including all of California, the Lower Colorado, and SE U.S.

At last, a clearer forecast re: California and Marie! Marie is ...

2026-09-05T21:22:29Z

At last, a clearer forecast re: California and Marie! Marie is now weakening and will stay well offshore. However, confidence has increased that Marie's remnants will actually have a substantial influence on CA weather for the next 5-6 days! [Thread] #CAwx

Update: The tropical weather feature of great interest--Tropical ...

2026-09-01T22:07:55Z

Update: The tropical weather feature of great interest--Tropical Storm (& soon hurricane) #Marie--has now developed. Marie's track will dictate potential CA impacts over Labor Day; uncertainty remains high, w/significant impacts possible (but direct landfall unlikely). [Thread]

#PlaskettFire is burning intensely on all flanks this evening, ...

2026-08-31T01:41:32Z

#PlaskettFire is burning intensely on all flanks this evening, has now burned to Hwy 1 and possibly to Pacific Ocean, and is likely over 20k acres at this point. Between Plaskett and #TimberFire to north, much of Monterey County coast is now under evacuation warnings or orders.

I'll host a short-notice, "pop-up" livestream TODAY, ...

2026-08-27T21:32:48Z

I'll host a short-notice, "pop-up" livestream TODAY, Aug 27 at 4pm PT to discuss:
1) What is known about the human impacts and geophysical causes of the Himalayan glacier collapse disaster, and
2) Severe humid heatwave/dry t-storms/fire risk in California https://youtube.com/live/m61bKp9NG0U?feature=share

This is a very 2026 map title. 👀 But it also illustrates ...

2026-08-15T04:20:14Z

This is a very 2026 map title. 👀

But it also illustrates importantance of circumspection when considering potential failure modes that can interact and cause seemingly implausible cascading consequences in complex systems (such as record heat, jellyfish swarms, & power grids).

I've been talking a lot about the disastrous recent loss of ...

2026-08-13T23:01:49Z

I've been talking a lot about the disastrous recent loss of American institutional capacity regarding climate science. But today, I'd like to announce something we've been working on, quietly, in the meantime to offer a lifeline to some of those affected. [Thread]

My commentary on Marshall et al 2026's climate change rapid ...

2026-08-11T18:37:32Z

My commentary on Marshall et al 2026's climate change rapid attribution study on severe Western U.S. snow drought, which developed during record-warm 2026 winter & has contributed to widespread drought & wildfire-related impacts since, is now out. [Thread] https://www.pnas.org/doi/10.1073/pnas.2620765123

In case you missed it, my latest livestream update on the very ...

2026-08-10T21:59:58Z

In case you missed it, my latest livestream update on the very strong developing #El Niño event was recorded & is now available. In it, I focus on current observations, just-released new forecasts for fall and winter, and California to global implications. https://youtu.be/0THLEMorMDI

I'm seeing headlines, "citing" me, to effect of ...

2026-08-08T20:13:31Z

I'm seeing headlines, "citing" me, to effect of "California braces for wettest winter ever."

To be clear: I have not claimed any such thing!

Record strength El Niño? Quite possibly! But while that does shift odds in favor of wet winter, that's a far cry from "wettest ever."

The #GannFire, burning upslope in the Central Sierra foothills ...

2026-08-04T20:30:31Z

The #GannFire, burning upslope in the Central Sierra foothills west of Angels Camp, is gaining a bit of a foothold despite the lack of extreme fire weather conditions at the moment (though it is quite hot and dry), and has forced some expanding evacuations. Why? #CAwx #CAfire

A dangerous wind shift (visible on radar imagery) has just ...

2026-08-02T03:44:37Z

A dangerous wind shift (visible on radar imagery) has just occurred in #Spokane, WA, where major wildfire disaster is currently unfolding. Three separate major fires (circled) near or within city limits have already caused major structure loss & chaotic, expanding evacs. #WAwx

In addition to the potential unfolding WUI wildfire disaster in ...

2026-08-01T23:33:59Z

In addition to the potential unfolding WUI wildfire disaster in Spokane, WA, numerous other large & fast-moving fires (existing & new) are blowing up under extremely critical fire weather conditions & severe drought conditions from eastern slopes of Cascades eastward into ID/MT.

Remarkable amount of fire on the ground, and smoke in the air, ...

2026-07-31T01:30:54Z

Remarkable amount of fire on the ground, and smoke in the air, this evening. In this satellite snapshot, numerous large fires (red thermal detections) and smoke plumes stretch from Great Basin northward into British Columbia; fire weather conditions will worsen this weekend.

If the latest FIRIS perimeter for #WoodsideFire is accurate, this ...

2026-07-31T01:03:56Z

If the latest FIRIS perimeter for #WoodsideFire is accurate, this would be one of the stranger fire footprints & trajectories I've seen. Under strong NWly winds parallel to coastline, it appears fire has spotted *over oceanic coves* & into downwind forest...twice!! Whoa.

New post out on Weather West on the upcoming intense, ...

2026-07-29T01:26:54Z

New post out on Weather West on the upcoming intense, double-peaked heatwave event in the Pacific Southwest. What are the (indirect) links to Hurricane Genevieve? (Substantial.) And also: will California see an uptick in wildfire activity? (Probably yes.) https://weatherwest.com/archives/43959

An intense and long-duration heatwave now appears likely by late ...

2026-07-27T18:32:07Z

An intense and long-duration heatwave now appears likely by late Jul/early Aug for SW U.S., including California. Extreme heat is likely in hottest inland deserts, and a potentially dangerous combination of heat & elevated humidity may develop in SoCal. More to come. #CAwx #AZwx

In recent weeks, there has been a remarkable surge in large, ...

2026-07-27T03:06:37Z

In recent weeks, there has been a remarkable surge in large, intense, fast-moving, and unfortunately in many cases destructive/deadly wildfires in multiple Northern Hemisphere regions spanning a wide range of climates & ecologies, but they all share one key commonality. [Thread]

The extraordinary wildfire outbreak across Oregon, eastern ...

2026-07-26T03:17:37Z

The extraordinary wildfire outbreak across Oregon, eastern Washington, and southern British Columbia has become even more alarming amid critical fire weather conditions. Over 500,000 acres have already burned in OR & WA alone, and that number could be >1 million acres by Mon.

Growing signs of prolonged & potentially intense heatwave ...

2026-07-25T00:34:22Z

Growing signs of prolonged & potentially intense heatwave across SW by early Aug. A broad Four Corners ridge will strengthen far beyond usual levels on its western flank, possibly due in part to indirect effects from a yet-to-develop East Pacific hurricane. Details TBD. #CAwx

Unfortunately, and as anticipated, yesterday's widespread ...

2026-07-25T00:19:31Z

Unfortunately, and as anticipated, yesterday's widespread lightning-following-heat event amid severe drought has sparked a large number of additional wildfires, expanding existing outbreak across OR, WA, & BC. Numerous heat signatures & large smoke plumes are evident. #ORwx #WAwx

A major new wildfire outbreak is now underway across interior ...

2026-07-17T00:04:29Z

A major new wildfire outbreak is now underway across interior Pacific Northwest, with dozens (or more) new wildfires already popping up in eastern Oregon & Washington following tens of thousands of lightning strikes in region experiencing moderate to extreme drought. #ORwx #WAwx

Well, the extreme heatwave across the Northern Rockies/Northern ...

2026-07-12T20:39:18Z

Well, the extreme heatwave across the Northern Rockies/Northern Plains/Upper Midwest is living up to expectations with some locations (as of only 2pm local time) reaching or breaking all-time (any month) temperature records today in Wyoming and eastern Montana. #MTwx #WYwx

New Weather West post is now out: Exceptionally broad and ...

2026-07-10T21:52:29Z

New Weather West post is now out: Exceptionally broad and persistent west-central U.S. ridging to bring periods of elevated heat and monsoon moisture to CA and the SW, with record heat across Intermountain West. Plus: dry lightning risk in California?
https://weatherwest.com/archives/43915

On Thu, Jul 9 at 11am PT, I'll have a livestream to discuss ...

2026-07-09T02:22:35Z

On Thu, Jul 9 at 11am PT, I'll have a livestream to discuss building "heat dome" that will eventually expand to encompass most of western & central US by mid Jul. I'll discuss impacts, including record heat, wildfire risk, & monsoon moisture/thunderstorms. https://youtube.com/live/Uys8re8I0BI?feature=share

Countless scientific and professional societies in the United ...

2026-07-08T02:18:04Z

In reply to nevent1q…8kdx
_________________________

Countless scientific and professional societies in the United States have already issued public statements of alarm, and many have submitted formal public comment to the federal government--as have thousands of individuals. You can, too, directly via: https://www.regulations.gov/commenton/OMB-2026-0034-0001

The American Physical Society has offered a nice overview of the ...

2026-07-08T02:17:59Z

In reply to nevent1q…qpsk
_________________________

The American Physical Society has offered a nice overview of the most science-relevant implications of these new proposed rules, as well as a tool to help craft your response:
https://www.aps.org/initiatives/advocate-amplify/policy/federal-grants-rule-change

You, too, can submit a comment in 6 days that remain before the ...

2026-07-08T02:17:53Z

In reply to nevent1q…49zk
_________________________

You, too, can submit a comment in 6 days that remain before the July 13 deadline. You certainly don't need to be a scientist, or work at a university, or for the federal government--all American taxpayers will be affected if this proposal is finalized. Some resources are below:

I just submitted my formal comment on the disastrous proposal to ...

2026-07-08T02:17:48Z

I just submitted my formal comment on the disastrous proposal to transform essentially all U.S. federal grantmaking--affecting every sector of American science, technology, education, & health--into an overtly partisan political process. Full text here: https://weatherwest.com/wp-content/uploads/2026/07/Daniel-Swain-comments-on-OMB-proposed-rule-changes-July-2026.pdf

There are growing indications that large, intense, & perhaps ...

2026-07-05T20:53:11Z

There are growing indications that large, intense, & perhaps record-breaking mid-atmospheric high pressure system (aka a "heat dome") will develop somewhere between Rockies & Central Plains by mid-Jul. This could bring a widespread & severe heatwave across much of the U.S.

The #AspenAcresFire, still burning quite actively along southern ...

2026-07-03T19:46:59Z

The #AspenAcresFire, still burning quite actively along southern Colorado Front Range & having destroyed ~200 structures thus far, has become an exceptionally complex & challenging event from a firefighting perspective due to a confluence of climate, weather, & geography. [Thread]

Cooler-and-windier-than-average conditions will persist in the ...

2026-07-01T20:43:00Z

Cooler-and-windier-than-average conditions will persist in the Western U.S. for a few more days as persistent and unusual summer troughing continues. Meanwhile, in the Eastern U.S., a genuinely extreme, and possibly historic, heatwave will build under an intense ridge. [Thread]

A serious and still-escalating wildfire outbreak is now underway ...

2026-06-28T00:16:16Z

A serious and still-escalating wildfire outbreak is now underway across interior West, and has today expanded beyond NV & UT into western CO & AZ/NM. Extreme fire behavior and rapid spread is widespread; adverse conditions expected for 7+ days. #UTwx #COwx #AZwx #NMwx [Thread]

NOAA once again highlighting a rare, highest-end "extremely ...

2026-06-27T16:57:21Z

NOAA once again highlighting a rare, highest-end "extremely critical risk" region today around Four Corners/CO Western Slope for exceptionally adverse fire weather conditions amid severe drought. Numerous lightning holdovers are popping up during unusual summer wind event.

Well, not a great day for NOAA's new Wildfire Fire Data ...

2026-06-26T18:23:21Z

Well, not a great day for NOAA's new Wildfire Fire Data Portal to be non-functional given the historically high "extremely critical" risk across portions of the interior West! Hopefully this comes back online soon. https://fire.data.nesdis.noaa.gov/map/?l[c][0]=NGFS_GEC_SC&l[c][1]=NGFS_GEC_GC&d[dateTimeFormat]=UTC&d[startDate]=2026-06-26T18:11:17Z&d[endDate]=2026-06-26T18:16:17Z

NOAA is now highlighting a large region of "Extremely ...

2026-06-25T19:40:00Z

NOAA is now highlighting a large region of "Extremely Critical" fire weather conditions Fri near the heart of the severe-to-extreme drought region across interior West, w/expansion into Sat-Sun likely. While existing fires have quieted down today, that lull will be short-lived.

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

As earlier noted, a significant West Coast heatwave will build in ...

2026-06-10T16:58:03Z

As earlier noted, a significant West Coast heatwave will build in the coming days, persisting at least 7-10 days. A strong & at least somewhat persistent ridge will bring war-to-hot conditions West Coast wide. Heat will be most anomalous in PacNW, but will also be present in CA.

I know there's tremendous interest right now surrounding ...

2026-05-13T01:18:23Z

I know there's tremendous interest right now surrounding growing potential for a strong El Niño event, or even a so-called "super" El Niño. In this just-recorded live session, I break down the current forecast, its implications, and associated caveats. https://youtube.com/live/rZvJPlPDyME

Warm-to-hot spring temps, with both daytime and nighttime ...

2026-05-10T23:13:52Z

Warm-to-hot spring temps, with both daytime and nighttime conditions much warmer than mid-May averages, will redevelop over the next few days across most of the U.S. West under fairly strong ridging. This will be notable, though generally not record-breaking, early season heat.

A period of warmer weather will return the rest of this week ...

2026-04-28T20:00:44Z

A period of warmer weather will return the rest of this week across most of California before yet another spring low pressure system brings unsettled conditions again this weekend. This will be a much more "typical" and lower-impact April showers scenario than recent storms.

Still expecting an usually strong cold frontal passage (by NorCal ...

2026-04-11T17:59:41Z

Still expecting an usually strong cold frontal passage (by NorCal April standards) later this PM. Expect a period of intense rainfall & embedded thunderstorms with gusty wind at lower elevs (locally severe near SF Bay), plus a burst of heavy & accumulating Sierra snowfall. #CAwx

I've have a short-notice pop-up livestream today at 2:30pm PT ...

2026-04-10T20:55:54Z

I've have a short-notice pop-up livestream today at 2:30pm PT to discuss the outbreak of unusually widespread thunderstorms across Northern California this PM, including the potential for a few supercells/severe storms containing hail & isolated tornado. https://www.youtube.com/live/IYuMLzu_6MI

I couldn't agree more with Kate that it's okay--even ...

2026-04-08T20:07:32Z

I couldn't agree more with Kate that it's okay--even necessary--to get mad, stay mad, and channel that anger along any number of constructive avenues in this disconcerting moment. https://grist.org/science/kate-marvel-nasa-departure-human-nature-book

Since there's, uh, absolutely nothing else going on in the ...

2026-04-08T04:24:18Z

Since there's, uh, absolutely nothing else going on in the world right now, you might consider reading this late evening blog update on a potential NorCal thunderstorm outbreak over the next few days and a chaotic Pacific-wide weather pattern this April.👀 https://weatherwest.com/archives/43818

Finally: This also applies to use of non-nuclear weapons against ...

2026-04-07T19:26:21Z

In reply to nevent1q…y3dh
_________________________

Finally: This also applies to use of non-nuclear weapons against nuclear & petrochemical facilities in densely populated regions. While consequences for global climate in such a scenario are lower, the risk of large scale radiological or other toxic contamination is very real.

There are innumerably many reasons why any exchange of nuclear ...

2026-04-07T19:26:16Z

In reply to nevent1q…40rh
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There are innumerably many reasons why any exchange of nuclear weapons is horrifying to contemplate. But I want to dispel rumors that newer science suggests that large-scale consequences would be much less severe than perceived during Cold War era. That simply isn't the case.

While it is true that there are genuine scientific uncertainties ...

2026-04-07T19:26:10Z

In reply to nevent1q…6w9d
_________________________

While it is true that there are genuine scientific uncertainties surrounding the details and dynamics re: how hypothetical nuclear exchanges of different size and location, and subsequent mass fire/firestorm events, would actually play out, *that is very much beside the point.*

Additionally, soot, smoke, and other particles generated by ...

2026-04-07T19:26:04Z

In reply to nevent1q…we3p
_________________________

Additionally, soot, smoke, and other particles generated by large-scale conflagrations in fuel-rich regions (which includes cities, ports, & large petrochemical facilities) can be lofted into stratosphere, where they can linger for months to years & disrupt global climate.

Essentially all locations on Earth are connected via atmospheric ...

2026-04-07T19:25:58Z

In reply to nevent1q…mx6n
_________________________

Essentially all locations on Earth are connected via atmospheric circulation (i.e., global wind patterns). Radiological or other contamination can spread far beyond its source region, especially if initially lofted to great heights by a large explosion or ensuing conflagration.

This isn't even a question of "nuclear winter" (a ...

2026-04-07T19:25:53Z

In reply to nevent1q…e7gr
_________________________

This isn't even a question of "nuclear winter" (a real, if still scientifically debated, hypothetical risk stemming from a much larger-scale exchange). Instead, it's a question of large-scale radiological and toxic contamination as well as disruption of global weather patterns.

I can't believe we have reached this point, but this bears ...

2026-04-07T19:25:47Z

I can't believe we have reached this point, but this bears crystal clear emphasis: Our global climate system ensures that even "limited" use of lower-yield "tactical" nuclear weapons against civilian or industrial targets would have major regional-to-global scale consequences.

A couple of notable early season wind-driven grass and brush ...

2026-04-03T21:00:20Z

A couple of notable early season wind-driven grass and brush fires in SoCal today, most notably the 1,500+ acre #SpringsFire just north of Lake Perris. Evacuation orders have been expanding and structures are immediately threatened; it's quite warm, dry and windy out there.

A second, colder wave of precipitation is likely later today, and ...

2026-04-01T18:25:37Z

In reply to nevent1q…f40s
_________________________

A second, colder wave of precipitation is likely later today, and a few more thunderstorms are possible at lower elevations (along with somewhat lower elevation snowfall in the mountains, maybe including a couple inches down to ~Lake Tahoe level).

Well, I do have some good news to report: yesterday's weather ...

2026-04-01T18:25:30Z

Well, I do have some good news to report: yesterday's weather system "overperformed" somewhat in NorCal! Convective activity and even some stronger thunderstorms developed in the unusually warm/moist/unstable airmass, bringing some more widespread downpours than expected.

A reminder that the long-awaited pattern change, featuring much ...

2026-03-30T23:19:05Z

A reminder that the long-awaited pattern change, featuring *much* cooler temperatures & some precipitation (mainly north & in higher mountains), will arrive by Tue. This won't meaningfully ameliorate the now-historic low snowpack conditions, but it sure will be nice for a change!

Although we are, finally, nearing the end of this bonkers March ...

2026-03-29T22:02:31Z

Although we are, finally, nearing the end of this bonkers March heatwave, it is *still* not over yet: temperatures have resurged once again across wide swath from CA's Pacific coast eastward to Central Plains, with widespread daily to monthly record highs occurring yet again. 🫠

New post on Weather West: As historic March heatwave finally ...

2026-03-28T23:47:03Z

New post on Weather West: As historic March heatwave finally fades, a brief cooler/wetter interlude will occur across the U.S. West in early April before warmth & dryness likely return. Also: a deeper dive into now record-low Western snowpack. https://weatherwest.com/archives/43769

The astonishing rate of March snowmelt in Colorado River Basin ...

2026-03-27T16:22:50Z

The astonishing rate of March snowmelt in Colorado River Basin continues, and is now well into record-low territory (even, it appears, relative to pre-SNOTEL era). And the extreme regional heatwave is only slowly fading, with unprecedented March melt continuing in meantime.

I can't believe we're doing this again, but...we're ...

2026-03-25T21:14:49Z

I can't believe we're doing this again, but...we're doing this again. Another day of record-shattering Match heat across interior West & Central U.S., w/countless March (& even some April) monthly records broken. Some locations are even breaking monthly records set...last week.

While there's still uncertainty in how much rain (& high ...

2026-03-25T12:38:11Z

In reply to nevent1q…vmvc
_________________________

While there's still uncertainty in how much rain (& high mtn snow) will actually fall, current likeliest outcome is some respectable April accumulations. I'd expect 0.5-1 inch between the 2 systems at lower elevations of NorCal, w/ 1-3 inches of liquid equiv in mtns. SoCal = TBD.

By Mar 31/Apr 1, the ridiculous ridge will finally move eastward, ...

2026-03-25T12:38:04Z

In reply to nevent1q…8muf
_________________________

By Mar 31/Apr 1, the ridiculous ridge will finally move eastward, opening door for a pair of decent April storm systems to affect most of the West (including CA). The first storm will be warm, with rain even in high mountains, but second will be colder w/accumulating mtn snow.

The extraordinary March 2026 heatwave continues across the ...

2026-03-25T12:37:58Z

The extraordinary March 2026 heatwave continues across the western and central U.S. Yet more daily to monthly record high temperatures will occur over the next few days, and snowpack will reach new March record lows. But some relief is on the horizon...

Given recent discussion regarding indirect role of anomalous ...

2026-03-24T23:14:47Z

Given recent discussion regarding indirect role of anomalous precip (& associated upstream diabatic heating) in amplifying record-breaking heatwaves, even thousands of miles away (inc. Mar 2026 event), I wanted to share this excellent paper from 2025: https://www.nature.com/articles/s41467-025-60811-4

Another day, another sequence of monthly record-breaking March ...

2026-03-24T23:00:10Z

Another day, another sequence of monthly record-breaking March heat across portions of 8 Western U.S. states. Note: some of these monthly "records" might not technically be such anymore following even more extreme record-shattering heat in the same locations...just last week. 🫠

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.

On Mon, Mar 23 at 2pm PT, I'll have another heatwave-focused ...

2026-03-22T21:10:57Z

On Mon, Mar 23 at 2pm PT, I'll have another heatwave-focused livestream. I'll discuss the astonishing March heatwave (which will resurge this week), plus prospects for more substantial but temporary relief in form of cooler (& wetter?) early Apr pattern. https://www.youtube.com/live/yNA52Sriz8s

Yet another day of record-shattering heat, and now it extends ...

2026-03-22T21:00:23Z

Yet another day of record-shattering heat, and now it extends clear across the continental U.S. All-time monthly record high temperatures are occurring from the Desert Southwest eastward to the Mid-Atlantic today, with at least daily records being set from Pacific to Atlantic.

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

Fair to say that the Western U.S. heatwave has reached ...

2026-03-18T22:39:31Z

Fair to say that the Western U.S. heatwave has reached record-shattering status, with dozens of locations breaking all-time March monthly heat records & some now approaching *April* records. Swath of record heat extends clear from Pacific to Great plains, & from Canada to Mexico.

Lots of buzz online about an upcoming major March heatwave for ...

2026-03-09T16:09:31Z

Lots of buzz online about an upcoming major March heatwave for the American SW & California. And in this case, it does indeed appear increasingly likely than an extremely anomalous and even record-breaking heatwave may envelop much of the SW about a week from now.

I'll host a short-notice livestream later this afternoon ...

2026-03-02T19:08:02Z

I'll host a short-notice livestream later this afternoon (Mon, 3/2, at 2pm PT) to discuss recent news that winter 2025-2026 was the warmest on record--by far--across the Western United States. I'll discuss snowpack, water supply, and wildfire implications. https://www.youtube.com/live/KJrPxdzBNKY

Exceptionally warm-to-hot late winter conditions expected across ...

2026-02-27T19:26:47Z

Exceptionally warm-to-hot late winter conditions expected across the Southwest through the weekend, peaking Fri and Sat. Numerous daily record highs (and record warm overnight minimums) will be set, along with some Feb monthly records possible. [Thread] #CAwx #AZwx #NVwx

There has been an amazing outpouring of support for the National ...

2026-02-26T19:38:49Z

There has been an amazing outpouring of support for the National Center for Atmospheric Research (NCAR) amid its proposed dismantling from people, institutions, & companies all across the country. You, too, can help by sending feedback to NSF by Mar 13th: https://www.ametsoc.org/ams/advocacy-policy/ncar-information-and-support/

New on Weather West: If we're going to see an extremely moist ...

2026-02-22T23:22:36Z

New on Weather West: If we're going to see an extremely moist & warm #AtmosphericRiver this wk in NorCal that will bring rain atop recent heavy snow, why is major flooding *not* expected? It a story of (lacking) storm dynamics & snowpack resilience. #CAwx https://weatherwest.com/archives/43727

Following last week's heavy & disruptive Sierra Nevada ...

2026-02-22T04:42:21Z

Following last week's heavy & disruptive Sierra Nevada snowfall, an extremely warm atmospheric river will cause substantial rain to fall atop snowpack even at high elevations this week. *However,* widespread serious flooding is *not* expected...for now. Why? [Thread] #CAwx

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

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

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

In this short clip from yesterday's livestream, I discuss the ...

2026-01-30T18:37:27Z

In this short clip from yesterday's livestream, I discuss the causes of & broader context surrounding severe cold/Arctic outbreaks (like the one ongoing in eastern U.S.) & why they can be even more disruptive against a backdrop of strong long-term warming. https://www.youtube.com/watch?v=yvph-7VKTG8

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.

Another piece I wanted to share on this anniversary of the ...

2026-01-08T05:01:02Z

Another piece I wanted to share on this anniversary of the January 2025 fires is a more recent one by David Wallace-Wells, which incorporates a more up-to-date perspective on lessons learned (or...not) since the dual Los Angeles catastrophes.
https://www.nytimes.com/2026/01/05/opinion/los-angeles-fires-lessons.html

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

Yet another round of heavy showers and thunderstorms, some strong ...

2025-12-26T00:24:36Z

Yet another round of heavy showers and thunderstorms, some strong to even severe, immediately inbound into the SF Bay Area this evening. Yet more strong/damaging winds likely, plus torrential downpours & urban flooding in some areas. A brief tornado remains possible. #CAwx

Well, it has turned into a sleepless night for many in the SF Bay ...

2025-12-25T11:31:07Z

Well, it has turned into a sleepless night for many in the SF Bay Area due to severe weather. Squall lines containing severe thunderstorms have brought torrential rain (leading to flash flooding) and damaging wind gusts of 60-80 mph. Lots of NWS warnings out. Quite a storm! #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

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

Nostr notes by Daniel Swain

On Wed, Oct 21 at 3pm PT, I'll have a livestream to discuss ...

Just did some number crunching using latest (Oct 1) ECMWF ...

Another very hot October day, especially across coastal central ...

Global model ensembles are in strong agreement that a prolonged ...

New Weather West post out this evening! I discuss the hyperactive ...

In case you missed it live, this session was recorded and is now ...

On Thu, Sep 10, at 10am PT I'll offer another major update ...

The ECMWF seasonal ensemble has just updated for September, and ...

At last, a clearer forecast re: California and Marie! Marie is ...

Update: The tropical weather feature of great interest--Tropical ...

#PlaskettFire is burning intensely on all flanks this evening, ...

I'll host a short-notice, "pop-up" livestream TODAY, ...

This is a very 2026 map title. 👀 But it also illustrates ...

I've been talking a lot about the disastrous recent loss of ...

My commentary on Marshall et al 2026's climate change rapid ...

In case you missed it, my latest livestream update on the very ...

I'm seeing headlines, "citing" me, to effect of ...

The #GannFire, burning upslope in the Central Sierra foothills ...

A dangerous wind shift (visible on radar imagery) has just ...

In addition to the potential unfolding WUI wildfire disaster in ...

Remarkable amount of fire on the ground, and smoke in the air, ...

If the latest FIRIS perimeter for #WoodsideFire is accurate, this ...

New post out on Weather West on the upcoming intense, ...

An intense and long-duration heatwave now appears likely by late ...

In recent weeks, there has been a remarkable surge in large, ...

The extraordinary wildfire outbreak across Oregon, eastern ...

Growing signs of prolonged & potentially intense heatwave ...

Unfortunately, and as anticipated, yesterday's widespread ...

A major new wildfire outbreak is now underway across interior ...

Well, the extreme heatwave across the Northern Rockies/Northern ...

New Weather West post is now out: Exceptionally broad and ...

On Thu, Jul 9 at 11am PT, I'll have a livestream to discuss ...

Countless scientific and professional societies in the United ...

The American Physical Society has offered a nice overview of the ...

You, too, can submit a comment in 6 days that remain before the ...

I just submitted my formal comment on the disastrous proposal to ...

There are growing indications that large, intense, & perhaps ...

The #AspenAcresFire, still burning quite actively along southern ...

Cooler-and-windier-than-average conditions will persist in the ...

A serious and still-escalating wildfire outbreak is now underway ...

NOAA once again highlighting a rare, highest-end "extremely ...

Well, not a great day for NOAA's new Wildfire Fire Data ...

NOAA is now highlighting a large region of "Extremely ...

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

As earlier noted, a significant West Coast heatwave will build in ...

I know there's tremendous interest right now surrounding ...

Warm-to-hot spring temps, with both daytime and nighttime ...

A period of warmer weather will return the rest of this week ...

Still expecting an usually strong cold frontal passage (by NorCal ...

I've have a short-notice pop-up livestream today at 2:30pm PT ...

I couldn't agree more with Kate that it's okay--even ...

Since there's, uh, absolutely nothing else going on in the ...

Finally: This also applies to use of non-nuclear weapons against ...

There are innumerably many reasons why any exchange of nuclear ...

While it is true that there are genuine scientific uncertainties ...

Additionally, soot, smoke, and other particles generated by ...

Essentially all locations on Earth are connected via atmospheric ...

This isn't even a question of "nuclear winter" (a ...

I can't believe we have reached this point, but this bears ...

A couple of notable early season wind-driven grass and brush ...

A second, colder wave of precipitation is likely later today, and ...

Well, I do have some good news to report: yesterday's weather ...

A reminder that the long-awaited pattern change, featuring *much* ...

Although we are, finally, nearing the end of this bonkers March ...

New post on Weather West: As historic March heatwave finally ...

The astonishing rate of March snowmelt in Colorado River Basin ...

I can't believe we're doing this again, but...we're ...

While there's still uncertainty in how much rain (& high ...

By Mar 31/Apr 1, the ridiculous ridge will finally move eastward, ...

The extraordinary March 2026 heatwave continues across the ...

Given recent discussion regarding indirect role of anomalous ...

Another day, another sequence of monthly record-breaking March ...

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

On Mon, Mar 23 at 2pm PT, I'll have another heatwave-focused ...

Yet another day of record-shattering heat, and now it extends ...

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 ...

A reminder that the long-awaited pattern change, featuring much ...

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