Nostr notes by Daniel Swain

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

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!

I apologize to all the journal editors whose requests to review ...

2025-11-12T03:38:06Z

I apologize to all the journal editors whose requests to review papers I have declined recently--I know it's getting hard to find qualified & willing peer reviewers. But recent volume has been extraordinary: multiple requests daily, including 4 *from same journal* in <48hrs! 👀

With an active weather pattern (wet, but also warm) setting up ...

2025-11-11T21:27:20Z

With an active weather pattern (wet, but also warm) setting up across California in the coming days, I'll have a live YouTube virtual office hour on Wed, Nov 12 @ 10am PT to discuss. Also during this hour: "ask me anything" re: the Bill Gates climate memo. https://www.youtube.com/live/4i3IzkVKxis

High latitude blocking, and especially when located near or over ...

2025-11-08T23:21:59Z

In reply to nevent1q…vxve
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High latitude blocking, and especially when located near or over Greenland, tends to severely disrupt mid-latitude weather patterns for weeks at a time--resulting in unusually persistent troughs/ridges and associated warm/cold air outbreaks that can defy seasonal predictions.

The persistent Greenland block will be associated with a striking ...

2025-11-08T23:21:53Z

In reply to nevent1q…yqjy
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The persistent Greenland block will be associated with a striking region of well above average temperatures in the Arctic and possibly also much of the U.S. (except for the West Coast--where more persistent troughing and rain will keep things relatively cooler).

Interestingly, one of the causes of this high-amplitude/wavy jet ...

2025-11-08T23:21:46Z

In reply to nevent1q…w0sj
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Interestingly, one of the causes of this high-amplitude/wavy jet stream pattern is a rather extreme upstream "block"--a persistent and highly anomalous high pressure system over Greenland. This is actually expected to persist, even as CONUS ridge/trough pattern breaks down...

Widespread rainfall, likely on order of at least a couple of ...

2025-11-08T23:21:40Z

In reply to nevent1q…wuyj
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Widespread rainfall, likely on order of at least a couple of inches, is likely later next week in Norcal; in SoCal, rain of some magnitude appears increasingly likely but there is wider plausible range (from light-moderate to rather heavy). But confidence is high in *some* rain.

Then, by late week, pronounced ridge-trough pattern over ...

2025-11-08T23:21:34Z

In reply to nevent1q…v7ju
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Then, by late week, pronounced ridge-trough pattern over continental U.S. will shift eastward & partially break down--likely opening the "storm door" along the West coast. A pretty wet period is likely thereafter, with moderate to even heavy rain extending all the way into SoCal.

As the ridge-trough sequence reached maximum amplitude on Tue, ...

2025-11-08T23:21:27Z

In reply to nevent1q…9lkv
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As the ridge-trough sequence reached maximum amplitude on Tue, very warm temperatures will continue in the West but anomalously cold temperatures will develop in the East. In fact, there may even be a day or two of record cold temps in parts of the Southeast.

Over the next few days, balmily warm temperatures will occur ...

2025-11-08T23:21:20Z

In reply to nevent1q…dsmg
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Over the next few days, balmily warm temperatures will occur across western North America, including California (where temperatures into the 90s are likely in SoCal). Some record warm daytime temperatures are possible, & notably warm overnight temperatures will continue as well.

A high-amplitude flow pattern, characterized by near-record ...

2025-11-08T23:21:14Z

A high-amplitude flow pattern, characterized by near-record strength ridging and troughing (respectively) over the western and eastern U.S. and a very wavy jet stream, will bring a progression of notable weather to North America in the coming days.

Quick Weather West update today for sake of discussing fairly ...

2025-11-03T23:58:33Z

Quick Weather West update today for sake of discussing fairly strong atmospheric river that will arrive in NorCal Tue-Wed, bringing widespread rain, gusty winds, and maybe isolated t-storms. Warm still, though, so Sierra rain vs snow, & dry in SoCal. #CAwx https://weatherwest.com/archives/43576

I just recorded a short video--essentially an updated version of ...

2025-11-03T21:18:09Z

I just recorded a short video--essentially an updated version of my social media threads--on the Bill Gates climate memo. Despite agreeing with some points therein, I still think its framing is fundamentally flawed and thus also its key conclusions. https://www.youtube.com/watch?v=Nd_iYnzEmYQ

So...strength and persistence of ridging over NorCal appears less ...

2025-11-01T12:55:51Z

In reply to nevent1q…smx7
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So...strength and persistence of ridging over NorCal appears less than originally indicated, but it'll likely hold strong over SoCal. Warmer than avg temps will mostly continue, due to strong warm advection, which translates to mild & damp in Norcal and dry/warm in SoCal. [3/3]

The wet PacNW/dry SoCal precipitation "dipole" I ...

2025-11-01T12:55:44Z

In reply to nevent1q…gz98
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The wet PacNW/dry SoCal precipitation "dipole" I mentioned last week will still be in effect, but its axis will be somewhat farther south. This means the SF and maybe even Monterey Bay areas could see some decent rain, with heavier stuff falling along North Coast/northern mtns. #CAwx [2/3]

Quite warm and dry weather will continue across CA this weekend, ...

2025-11-01T12:55:36Z

Quite warm and dry weather will continue across CA this weekend, but next week is looking a bit different than originally predicted. Subtropical ridging will indeed persist, keeping SoCal mostly or completely dry for foreseeable future--but NorCal looks notably wetter. [1/3] #CAwx

I wanted to offer some thoughts on the Gates climate memo that ...

2025-10-30T17:05:45Z

I wanted to offer some thoughts on the Gates climate memo that has been circulating this week. While I can't directly speak for others, I can say that my own response is one of dismay & deep frustration (and that this view is shared by many climate/Earth scientists). [1/n]

Following today's light (to locally moderate) rainfall in ...

2025-10-25T21:57:24Z

Following today's light (to locally moderate) rainfall in northern California, a strong and persistent ridge appears likely to build across the American West and to linger for some time to come--bringing dry and much warmer than average conditions well into November. #CAwx #CAfire

Latest model projections regarding #Melissa are painting an ...

2025-10-23T18:30:39Z

Latest model projections regarding #Melissa are painting an increasingly dire scenario for Jamaica and possibly western Hispaniola (esp. Haiti) in terms of widespread risk of catastrophic flooding from exceptional rainfall amounts--possibly exceeding 3-4 feet (30-40+ inches).

But look at all that prescribed fire on the ground in NorCal at ...

2025-10-22T23:43:53Z

In reply to nevent1q…8tcg
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But look at all that prescribed fire on the ground in NorCal at the moment (thanks to this snapshot from the Watch Duty app!). Conditions where it's not raining are generally quite favorable for getting some "good fire" on the ground at the moment. #CAwx #CAfire

There was actually quite a bit of dry-ish lightning overnight. ...

2025-10-22T23:43:45Z

In reply to nevent1q…y7lr
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There was actually quite a bit of dry-ish lightning overnight. But fortunately, there are *no* new wildfires of significance despite a handful of igntions. Why? Well, fuel moisture matters! Recent rains greatly increased vegetation moisture, tamping down risk. #CAwx #CAfire

Well, it turns out that "sneaky" cut-off low I mentioned ...

2025-10-22T23:43:40Z

Well, it turns out that "sneaky" cut-off low I mentioned earlier this week ended up generating more extensive elevated convection last night into this AM, with a fair bit of lightning and even (isolated) reports of localized flooding from training showers! #CAwx #CAfire

I'll have a YouTube livestream later today (4pm PT) to ...

2025-10-13T19:17:59Z

In reply to nevent1q…67fr
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I'll have a YouTube livestream later today (4pm PT) to discuss in real-time, and might have another pop-up session tomorrow if conditions warrant. The most significant risk with this event will likely be flash flood/debris flow events near recent wildfire burn areas. #CAwx

This system will bring first travel-disruptive accumulating ...

2025-10-13T19:17:54Z

In reply to nevent1q…p3tn
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This system will bring first travel-disruptive accumulating Sierra snowfall of season, and may also generate significant/locally severe thunderstorm activity across SoCal. Thunderstorms could generate flash flooding, esp. near 2024-5 burn areas, & even a weak tornado or 2. #CAwx

An unusually cold and strong early season storm will affect most ...

2025-10-13T19:17:47Z

An unusually cold and strong early season storm will affect most of California over next 2 days. As rain sweeps southward, expect mountain snow, locally gusty winds, and a progressively higher chance of thunderstorms from north to south from SF Bay Area to LA region. #CAwx

I'll have a YouTube livestream at 5pm Pacific Time tomorrow ...

2025-09-23T02:03:27Z

In reply to nevent1q…nede
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I'll have a YouTube livestream at 5pm Pacific Time tomorrow (Tuesday, Sep 23) to discuss, and will likely include a radar and satellite tour as storms should be active by then. Will announce that separately in a few minutes once officially scheduled! #CAwx

An offshore low will combine with a copious tropical moisture in ...

2025-09-23T02:03:22Z

In reply to nevent1q…qqu2
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An offshore low will combine with a copious tropical moisture in presence of modest (but sufficient instability) some thunderstorms. These will initially be offshore, but will likely move inland along Central Coast (though are possible from LA to SF Bay Area and inland). #CAwx

Another round of very unusual September weather still on tap for ...

2025-09-23T02:03:14Z

Another round of very unusual September weather still on tap for much of CA this week. Another burst of (increasingly humid) heat peaks tomorrow before afternoon/evening clouds increase and a possibly widespread Central Coast thunderstorm outbreak develops late PM into Wed! #CAwx

The risk of new wildfires with this event will be low, due to ...

2025-09-20T16:26:45Z

In reply to nevent1q…xujg
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The risk of new wildfires with this event will be low, due to combo of recent scattered rains & continued high humidity plus wet character of storms. This could be a great cloud and & storm watching day, BTW, with a clearly defined arc of t-storms (but beware lightning!). #CAwx

The net result will likely be a widespread thunderstorm outbreak ...

2025-09-20T16:26:39Z

In reply to nevent1q…73l7
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The net result will likely be a widespread thunderstorm outbreak from around LA County northward to near Monterey Bay Area & eastward into San Joaquin Valley late Tue PM into early Wed. These could be pretty impressive storms, with torrential downpours & frequent lightning. #CAwx

On Tue, a slow-moving low will drift toward Central Coast. By ...

2025-09-20T16:26:31Z

In reply to nevent1q…tkr7
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On Tue, a slow-moving low will drift toward Central Coast. By this point, it will have entrained copious tropical moisture on its eastern flank. The airmass will be convectively quite unstable by CA standards, & mid-level ascent will provide trigger for t-storm development. #CAwx

A very unusual stretch of September weather will continue across ...

2025-09-20T16:26:25Z

A very unusual stretch of September weather will continue across California into next week. On Sunday, a weak stream of tropical moisture may drop some showers in far SoCal (near San Diego). But a more impressive/widespread thunderstorm outbreak will be possible Tuesday... #CAwx