Daniel Swain

EXCEPTIONAL HEATWAVE BREWING FOR NEXT WEEK IN COLORADO

A powerful ridge is about to park itself over the West next week -- stronger and closer to Colorado than anything we’ve seen in a long time.

#COWX #Colorado #Snowpack #Heatwave #COsnow

Early signs of historic March heatwave for the Southwestern U.S.? (Not what we need...) - YouTube The latest in a recurring series of live, virtual, & interactive #weather and #climate-focused "office hours" hosted by Dr. Daniel Swain. 3/9/2026 topic: I'l...

I'll have a livestream to discuss early indications on Tuesday (Mar 10 at 3pm PT) and then likely also a new Weather West post later this week. Stay tuned...

Map snapshot depicting the predicted relative anomalousness of 500mb GPH from the ECMWF ensemble over the Western U.S. in about a week from now. A large anomalous ridge, featuring a huge region of bright orange and red colors (depicting extremely high positive GPH anomalies) is centered right in the middle of the map.

Current indications are that late spring or even mid-summer-like (in some places) heat will arrive and persist for a fairly extended duration across a wide swath of the American West, centered on the Four Corners to Southern CA region. This will induce rapid melt of remaining snowpack.

Map snapshot depicting the predicted relative anomalousness of surface temperatures from the ECMWF ensemble over the Western U.S. in about a week from now. A a huge region of bright orange and red colors (depicting extremely high warm temperature anomalies) is centered right in the middle of the map, and covers essentially the entire region.

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.

Early signs of historic March heatwave for the Southwestern U.S.? (Not what we need...) - YouTube The latest in a recurring series of live, virtual, & interactive #weather and #climate-focused "office hours" hosted by Dr. Daniel Swain. 3/9/2026 topic: I'l...

Join me for a live virtual office hour on Tue Mar 10 at 3pm PT to discuss potential for a genuinely extreme, and potentially even historic, March heatwave in American Southwest (including CA) later this month. I'll talk dynamics, impacts & implications.

I'll have more to say about this by Tuesday, but...yeah. No Miracle March in the cards for Western snowpack this year--quite the opposite, in fact. I'll take a closer look and have a livestream and blog post soon to discuss.

This is definitely the kind of thing where "low-ish likehood this century" is not particularly reassuring, to be very clear.

A large-scale collapse of the AMOC remain a "low-ish likehood (this century, at least) but very high consequence" scenario--and is associated with wide/deep scientific uncertainty. Also, even a lesser "slowdown" (vs collapse) would have big consequences and that is considerably likelier.

As you say: We shall see! But I do think am an unusually inclined to speculate from "wrong side" of Spring Predictability Barrier than usual in this specific, "bullish" case for a significant EN in 2026. There is just too much warm water volume and too good of atm/ocn coupling thus far to ignore...

...Combined with other differences in large scale SST, that increases my a priori expectation that models are on to something this time around (i.e., positive feedbacks likelier to materialize). Also--that means global teleconnections have better chance of being "classic" (vs other recent events).

The other thing I'm looking at is indeed the current, projected, and plausible atmospheric coupling. The *extratropical* northeastern Pacific is wildly warmer than in any recent EN event...

No kidding! It will be an important test of predictive systems but...preconditions right now currently look most like 97-98 but with 25 years of climate warming so I'm not surprised models are going wild right now.

There is of course still real uncertainty involved. But if I could bet on it, I'd be comfortable investing a fair bit in "moderate or stronger EN by late summer" given the observational and predictive evidence (and also their trend over time).

Here, I'm not just basing this off of I've single model or even broader ensemble. There oceanic & atmospheric conditions in place right now that strongly suggest this kind of evolution is likely. More so than 2023 or 2015. The SPB is somewhat conditional, and this is type of yr it might be weaker.

Yeah.

Time series plot depicting predicted Nino 3.4 region ocean temperature anomalies from the latest (Mar 2026) ECMWF ensemble. It depicts an extremely rapid rise in such temperatures, from modest negative anomalies to strong positive anomalies, by mid-summer 2026--indicative of a transition from weak-moderate La Nina conditions to moderate-strong El Nino conditions over just a few months.

Whew.

All signs are increasingly pointing to a significant, if not strong to very strong, El Niño event. I'll have more to say in coming weeks & months, but for now I'll just say that this is increasingly likely to become a major regional-to-global climate driver in 2026-2027.

If you want to read the full version of the letter I submitted to NSF regarding NCAR, you can download a copy directly from Weather West (link below). [4/4] weatherwest.com/wp-c...

Thank you to the dozens (or more!) colleagues, collaborators, & members of general public who have already submitted their feedback in support of NSF. I have heard from everyone from climate modelers to physicians to fire chiefs to farmers--truly a remarkable outpouring. [3/4]

NCAR Information and Support The AMS is a global community committed to advancing weather, water, and climate science and service.

There is still time for you, too, to submit your feedback to the January "Dear Colleague Letter" (see link below for context and instructions). The deadline for email submissions (directly to NSF_NCAR@nsf.gov) is March 13 (next week!). [2/4]

Page 2 of letter by Daniel Swain. It begins: constructive suggestions regarding how the already remarkable institutional efficiency and societal impact of NCAR could be further enhanced through increased (not decreased) federal support in the years to come. Please note: To ensure the highest level of technical rigor, this response focuses exclusively on the core atmospheric and natural hazard science topics within the author’s primary domain of expertise; for this reason, I have omitted a response to Topic 4 (Space Weather)." NCAR weather modeling and atmospheric observing capabilities a) Management and operations of weather-related observational platforms, modeling and science as a stand-alone activity. The proposed management of weather-related research as a stand-alone activity is a scientifically regressive path that ignores the fundamental physical reality of the Earth system. Modern atmospheric science has demonstrated (largely, it is worth noting, due to groundbreaking researc

Page 3 of letter by Daniel Swain. It begins: b) Management and operations of weather-related observational platforms, modeling and science as combined with other NSF investments/facilities. The highly specialized nature of the NCAR-Wyoming Supercomputing Center (NWSC) infrastructure represents an extraordinary value proposition that cannot be replicated by combining it with more generalized NSF programs. The NWSC is not a generic high-performance computing (HPC) facility; it is a laboratory uniquely optimized for atmospheric science workflows, with a hardware and storage architecture specifically designed to handle the massive, high-bandwidth data demands of Earth system modeling. Furthermore, its model of providing an excellent, free-at-point-of-use technical support team ensures that the focus remains on the science rather than the overhead of systems administration. This centralized expertise allows individual researchers, smaller labs, and even entire universities—who would otherwi

Page 4 of letter by Daniel Swain. It begins: NCAR Mesa Lab (located in Boulder, Colorado) a/b) Ownership of the NSF NCAR Mesa Lab building for public and private use. Far more than just an office building, NSF NCAR Mesa Lab is an iconic and purpose-built facility designed specifically for the study of atmospheric science. Its position at the physical interface of the Rocky Mountain foothills and the Great Plains is a deliberate reflection of its mission, serving as a visible symbol—in an iconically American setting—of the federal government's enduring commitment to science in service of society. For many in the field, including myself, the Mesa Lab holds singular importance as a focal gathering point for the global atmospheric science community. My own early career exposure to weather and Earth system modeling, in fact, occurred within these walls, and I have long felt that the facility’s architecture and location inspire a necessary sense of awe regarding the atmosphere’s complexity a

Page 1 of letter by Daniel Swain. It begins: Dear Acting Director Stone and the NSF NCAR restructuring team: I am writing to provide a formal response to the Request for Information (RFI) regarding the proposed restructuring of the NSF National Center for Atmospheric Research (NCAR) and its critical weather science infrastructure contained within the January 23, 2026 Dear Colleague Letter (DCL) entitled “NSF Intent to Restructure Critical Weather Infrastructure.” I submit these comments in my professional capacity as an atmospheric research scientist within the University of California, where my research focuses on the physics and dynamics of atmospheric processes related to extreme weather events and their role in shifting natural hazard and disaster risk. My perspective is informed by a public-sector career dedicated to bridging the gap between fundamental atmospheric research and real-world application in an academic context, with a particular focus on understanding and mitigating

I just submitted my letter to NSF responding to its proposal to dismantle the National Center for Atmospheric Research (NCAR). I argue that doing so would be an astonishing and avoidable misstep, and that federal support for the institution should in fact be *increased.* [1/4]

After unfortunately very much experience with this, it's possible they will still need to eventually see Dr. Yao at Stony Brook in NY or Dr. Davis at Mayo Clinic in Rochester to get the NOD2 contribution properly assessed. It's why I now have to go to NY several times per year! Good luck...

I have no illusions regarding underlying motives that run much deeper than what's stated directly. But writing this is far from the only action I've personally taken; not everything is publicly visible. NCAR actually has a lot of support; signaling & coordinating that support is indeed valuable.

If you want to read the full version of the letter I submitted to NSF regarding NCAR, you can download a copy directly from Weather West (link below). [4/4] weatherwest.com/wp-c...

Thank you to the dozens (or more!) colleagues, collaborators, & members of general public who have already submitted their feedback in support of NSF. I have heard from everyone from climate modelers to physicians to fire chiefs to farmers--truly a remarkable outpouring. [3/4]

NCAR Information and Support The AMS is a global community committed to advancing weather, water, and climate science and service.

There is still time for you, too, to submit your feedback to the January "Dear Colleague Letter" (see link below for context and instructions). The deadline for email submissions (directly to NSF_NCAR@nsf.gov) is March 13 (next week!). [2/4]

Page 2 of letter by Daniel Swain. It begins: constructive suggestions regarding how the already remarkable institutional efficiency and societal impact of NCAR could be further enhanced through increased (not decreased) federal support in the years to come. Please note: To ensure the highest level of technical rigor, this response focuses exclusively on the core atmospheric and natural hazard science topics within the author’s primary domain of expertise; for this reason, I have omitted a response to Topic 4 (Space Weather)." NCAR weather modeling and atmospheric observing capabilities a) Management and operations of weather-related observational platforms, modeling and science as a stand-alone activity. The proposed management of weather-related research as a stand-alone activity is a scientifically regressive path that ignores the fundamental physical reality of the Earth system. Modern atmospheric science has demonstrated (largely, it is worth noting, due to groundbreaking researc

Page 3 of letter by Daniel Swain. It begins: b) Management and operations of weather-related observational platforms, modeling and science as combined with other NSF investments/facilities. The highly specialized nature of the NCAR-Wyoming Supercomputing Center (NWSC) infrastructure represents an extraordinary value proposition that cannot be replicated by combining it with more generalized NSF programs. The NWSC is not a generic high-performance computing (HPC) facility; it is a laboratory uniquely optimized for atmospheric science workflows, with a hardware and storage architecture specifically designed to handle the massive, high-bandwidth data demands of Earth system modeling. Furthermore, its model of providing an excellent, free-at-point-of-use technical support team ensures that the focus remains on the science rather than the overhead of systems administration. This centralized expertise allows individual researchers, smaller labs, and even entire universities—who would otherwi

Page 4 of letter by Daniel Swain. It begins: NCAR Mesa Lab (located in Boulder, Colorado) a/b) Ownership of the NSF NCAR Mesa Lab building for public and private use. Far more than just an office building, NSF NCAR Mesa Lab is an iconic and purpose-built facility designed specifically for the study of atmospheric science. Its position at the physical interface of the Rocky Mountain foothills and the Great Plains is a deliberate reflection of its mission, serving as a visible symbol—in an iconically American setting—of the federal government's enduring commitment to science in service of society. For many in the field, including myself, the Mesa Lab holds singular importance as a focal gathering point for the global atmospheric science community. My own early career exposure to weather and Earth system modeling, in fact, occurred within these walls, and I have long felt that the facility’s architecture and location inspire a necessary sense of awe regarding the atmosphere’s complexity a

Page 1 of letter by Daniel Swain. It begins: Dear Acting Director Stone and the NSF NCAR restructuring team: I am writing to provide a formal response to the Request for Information (RFI) regarding the proposed restructuring of the NSF National Center for Atmospheric Research (NCAR) and its critical weather science infrastructure contained within the January 23, 2026 Dear Colleague Letter (DCL) entitled “NSF Intent to Restructure Critical Weather Infrastructure.” I submit these comments in my professional capacity as an atmospheric research scientist within the University of California, where my research focuses on the physics and dynamics of atmospheric processes related to extreme weather events and their role in shifting natural hazard and disaster risk. My perspective is informed by a public-sector career dedicated to bridging the gap between fundamental atmospheric research and real-world application in an academic context, with a particular focus on understanding and mitigating

I just submitted my letter to NSF responding to its proposal to dismantle the National Center for Atmospheric Research (NCAR). I argue that doing so would be an astonishing and avoidable misstep, and that federal support for the institution should in fact be *increased.* [1/4]

Satellite photos show California's sudden snowpack meltdown: Now you see it, now you don't Satellite images show the Sierra Nevada before and after a major heat wave melted significant portions of California's snow.

Now you see it, now you don't. Near the end of this extremely warm winter, California's snow is rapidly melting. My colleague @castleman.bsky.social shares some striking satellite images. He spoke with @weatherwest.bsky.social about the remarkably rapid loss of snow: www.latimes.com/california/s...

Time series plot depicting predicted Nino 3.4 region ocean temperature anomalies from the latest (Mar 2026) ECMWF ensemble. It depicts an extremely rapid rise in such temperatures, from modest negative anomalies to strong positive anomalies, by mid-summer 2026--indicative of a transition from weak-moderate La Nina conditions to moderate-strong El Nino conditions over just a few months.

Whew.

All signs are increasingly pointing to a significant, if not strong to very strong, El Niño event. I'll have more to say in coming weeks & months, but for now I'll just say that this is increasingly likely to become a major regional-to-global climate driver in 2026-2027.

Should be back up now.

No, the site is down for unknown reasons (i.e., it's not just you). Working to fix it, but the timing is pretty terrible given other obligations! It has become increasingly difficult to operate a highly-trafficked website on a shoestring budget in 2026, that is for sure. 👀