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Clark Evans

@clarkevanswx.github.io
2.1K followers 530 following 897 posts

I study high-impact weather, help develop high-resolution models to improve weather forecasts, and mentor scientists. Constantly striving to help those around me flourish. My views expressed here are mine alone.

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Clark Evans @clarkevanswx.github.io · 29/09/2026
Looking at the 0.5”/50th% cluster analyses from @gingerwx.bsky.social from the 28/1200 UTC model cycle, it seems to be an ECMWF (wetter) vs. GFS/GGEM (drier) battle. Subtle changes will have an outsized influence on the final outcome.
Rainfall cluster analyses, showing three cluster-mean forecasts and the full ensemble mean rainfall forecast. Covers data 1-2 (through Thursday morning).
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Clark Evans @clarkevanswx.github.io · 26/09/2026
Just noticed that this week’s Drought Monitor moved portions of the northern Denver metro area into the D4 Exceptional Drought category. It’s exactly where I would’ve expected it - and I’m smack dab in its center. Sigh.
Drought Monitor for 9/24/26, showing D4 exceptional drought in the northern Denver metro area.
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Clark Evans @clarkevanswx.github.io · 19/09/2026
Narrator: the very light rain in the general area at the end dissipated in place.
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Clark Evans @clarkevanswx.github.io · 05/09/2026
Sam’s post prompted me to look up the track verification stats for Lowell - and sheesh, Google DeepMind (GDMI)…
Left: track forecast errors for Hurricane Lowell, right: track forecast improvement vs. a no-skill baseline for Hurricane Lowell. Both tell the same story: Google DeepMind’s forecast has been vastly superior to those of NOAA’s operational models and the NHC official forecast.
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Clark Evans @clarkevanswx.github.io · 28/08/2026
70°F and clear with light winds for a ~95% lunar eclipse >>> -1°F and clear with moderate winds for a total lunar eclipse
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Clark Evans @clarkevanswx.github.io · 24/08/2026
Yes, those are hailstones falling on the riders around :45 - the second time I’ve seen a grand-tour stage annulled by hail (the other being in the 2019 Tour de France)!
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Clark Evans @clarkevanswx.github.io · 20/08/2026
Today at work: a live demo of an immersive visualization of a global storm-scale MPAS forecast I generated earlier this summer. Behind the headset: none other than the NOAA OAR Director. It was fun to play a small part in this really cool demonstration! (And then try it out on my headset at home!)
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Clark Evans @clarkevanswx.github.io · 15/08/2026
This song *really* confused me when it started, sounding like “You Get What You Give,” followed by the New Radicals’ lead singer with the lead vocals. But it works!
Lyrics of “The Game of Love,” sung by Michelle Branch and the New Radicals
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Clark Evans @clarkevanswx.github.io · 12/08/2026
A public library that lets you check out Kestrels? Sign me up! For this and many other things here (boulder climbing, outdoor play areas, books, and more), great idea, Thornton!
Four Kestrel weather metersAnythink Nature Library, Thornton, CO
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Clark Evans @clarkevanswx.github.io · 11/08/2026
IYKYK, right @danshafer.bsky.social?
MKE post-security - the recombobulation area!
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Clark Evans @clarkevanswx.github.io · 09/08/2026
Same vibe:
City of Boulder staff image, 2010: “This photo illustration shows what city planners believe the Flatirons could look like today if the city had not enacted land-use policies such as the Blue Line, which restricted city water service over a certain elevation. The illustration is part of a set of photos created by city planners to show what the city has received in return for its land-use and development policies over time.”

https://www.dailycamera.com/2010/11/27/boulder-planners-show-off-benefits-pitfalls-of-land-policies/#
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Clark Evans @clarkevanswx.github.io · 06/08/2026
The 2006 ASP Colloquium on The Challenge of Convective Forecasting: then and (a subset of) now!
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Clark Evans @clarkevanswx.github.io · 05/08/2026
Come for the demonstration of MPAS’s utility toward future NOAA operational modeling systems, stay for the 👀🍫 of a five-day radar loop from a global storm-scale MPAS forecast with HRRR/RRFS physics! I’m kicking off Wednesday’s talks at the #AMSMadisonSummit - hope to see you in the morning!
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Clark Evans @clarkevanswx.github.io · 02/08/2026
🫡
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Clark Evans @clarkevanswx.github.io · 02/08/2026
Hello again to a great city on a Great Lake. A couple of years away just reinforces that Milwaukee’s parks rock hard and every city would do well to emulate them.
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Clark Evans @clarkevanswx.github.io · 23/06/2026
He brought joy to Milwaukee and the entire state of Wisconsin for over a decade. We got to watch him grow up, as a player and as a person - son, father, and husband. He was Milwaukee epitomized. Thank you, Giannis, for everything.
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Clark Evans @clarkevanswx.github.io · 22/06/2026
The sun set behind Twin Sisters in Rocky Mountain National Park this summer solstice along the Front Range.
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Clark Evans @clarkevanswx.github.io · 17/06/2026
Black-crowned night heron along Coal Creek in Lafayette, CO over the weekend. A beautiful bird in person and one of a few 9-point birds in Wingspan!
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Clark Evans @clarkevanswx.github.io · 07/06/2026
Here’s what it looked like toward the sun at the time of the first photo. If you squint, you can see crepuscular rays in most directions.
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Clark Evans @clarkevanswx.github.io · 07/06/2026
The Front Range, in two photos: 1) Friday, near sunset, with clouds splitting the sun’s rays in a spectacularly evident way. 2) Saturday, a political advertisement for a CU Regent candidate. Not a QR code to his website, but a QR code to his Strava. 🤷‍♂️
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Clark Evans @clarkevanswx.github.io · 17/05/2026
I did not have “tornado warning near Meeker, CO” on my bingo card for today…
Radar image showing a tornado-warned thunderstorm near Meeker, CO
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Clark Evans @clarkevanswx.github.io · 25/04/2026
$1 for each precious minute of a 4-hour meeting two years ago in which my former faculty colleagues and I did right by our students when university administration would not. Thank y’all, @edsbs.bsky.social @hollyanderson.bsky.social @newap-georgia.bsky.social et al. for fighting for what is right.
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Clark Evans @clarkevanswx.github.io · 18/04/2026
I also got the blessing of meeting the 14-month old daughter of two of my former advisees on the way out of town to Indianapolis airport. As an added bonus, their county is the 1,000th in the US that I’ve visited…because like many other meteorologists, it’s fun to track them!
Clark’s counties visited map, tracking all US counties in which I’ve visited in blue, lived in green, and run a race in red.
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Clark Evans @clarkevanswx.github.io · 18/04/2026
I enjoyed visiting Purdue this week, during which I gave a seminar on the great modeling work at GSL and had great discussions with students, postdocs, and faculty. Thanks to @meteodan.bsky.social for inviting me, to @tornatrix.bsky.social for the picture, and to everyone for their hospitality!
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Clark Evans @clarkevanswx.github.io · 14/04/2026
Snow atop the Flatirons, Green Mountain, and the west ridge for the first time in a * long* time. #cowx
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Clark Evans @clarkevanswx.github.io · 10/04/2026
A quick trip to the mothership. Hi, friends!
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Clark Evans @clarkevanswx.github.io · 29/03/2026
Denver Botanic Gardens, March 28 - Lilacs approaching full bloom. Beautiful, but still way too early.
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Clark Evans @clarkevanswx.github.io · 22/03/2026
I appreciated this quote from former Wisconsin Governor Gaylord Nelson in the spring edition of the Wisconsin Natural Resources magazine: “The ultimate test of man’s conscience may be his willingness to sacrifice something today for future generations whose works of thanks will not be heard.” (1/3)
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Clark Evans @clarkevanswx.github.io · 21/03/2026
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Clark Evans @clarkevanswx.github.io · 14/03/2026
Magnolias at the same park, also way too early. (But if they don’t get scorched by cold tonight, they’ll probably be in full bloom next weekend.)
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Clark Evans @clarkevanswx.github.io · 14/03/2026
Same spot, one week later. Hello, tulip! Hello, daffodil! (Way too early…)
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Clark Evans @clarkevanswx.github.io · 11/03/2026
Here's an example from the 0100 UTC 11 March NBM for Erie, CO, looking at high/low temperatures for next Wednesday to Saturday. The whiskers are the 10-90th percentile. The 50th percentile highs are 89-93°F, but the means are in the low-mid 80s because of a very few extreme outliers. #COwx
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Clark Evans @clarkevanswx.github.io · 09/03/2026
Enjoy this photo of a bald eagle high above me earlier this afternoon!
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Clark Evans @clarkevanswx.github.io · 07/03/2026
March 7, Erie. Winter’s done - spring’s here.
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Clark Evans @clarkevanswx.github.io · 05/03/2026
March 5, Boulder. Drop 0.25-0.5” of liquid into the ground tomorrow and follow it up with the predicted warm up and it’s going to get green in a hurry around here.
Green leaves on trees outside of the Boulder NOAA facility
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Clark Evans @clarkevanswx.github.io · 28/02/2026
Lenticulars over the Sangre de Cristos. No, there’s not really snow below 9-10k ft. #COwx
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Clark Evans @clarkevanswx.github.io · 25/02/2026
Faintly from the DOC campus. It was better from the east coming into town on Valmont.
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Clark Evans @clarkevanswx.github.io · 20/02/2026
Almost six weeks ahead of schedule for the annual wildlife closure at Lagerman Reservoir outside of Longmont because it’s been so warm that the waterfowl are already setting to nesting.
TRAIL CLOSURE:
02/19/2026 10:44 AM MST
The western end of Lagerman Reservoir is closed for nesting birds until Aug. 31. The seasonal wildlife closure normally begins April 1, but it is closed early this year because birds are already nesting due to warm weather.
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Clark Evans @clarkevanswx.github.io · 28/01/2026
Kudos to Kade for their fantastic presentation!
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Clark Evans @clarkevanswx.github.io · 26/01/2026
@nws.noaa.gov Director Ken Graham presented on NOAA’s modeling grand challenge at #AMS2026 this morning. He announced that the NWS is moving to MPAS as its modeling dynamical core, with his #1 moonshot goal being a global, fully coupled 3-km Earth prediction system using MPAS.
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Clark Evans @clarkevanswx.github.io · 25/01/2026
If weather had a personality, I suspect “33 and Rain” would be going around Houston today saying, “well, well, well - look who isn’t so bad after all!” With rain ending, it looks like the city might be mostly spared. Image is the overnight obs from KIAH.
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Clark Evans @clarkevanswx.github.io · 24/01/2026
I think the closest would be to manually add the shaded field a second time as a contoured field. Here’s an example of 500 hPa height both shaded and contoured. Toggle the + option above the fields on mobile (or control-click on a new field on computer) to add fields beyond the predefined options.
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Clark Evans @clarkevanswx.github.io · 23/01/2026
It’s not quite crème de la crème cold air, as Lance Bosart might say — it takes -40°C at 850 hPa — but INL at -37°C last night is pretty impressive nonetheless. There is an ample supply of low-level cold air pushing south to facilitate the impending winter storm.
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Clark Evans @clarkevanswx.github.io · 17/01/2026
Nature is healing, eh @cyclogenesis.bsky.social?
Live stream of stage 1 of the Women’s Tour Down Under cycling stage race in Australia, kicking off the 2026 cycling season
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Clark Evans @clarkevanswx.github.io · 03/01/2026
Timeline cleanse: lenticulars over Lyons. Photo looking north from Lagerman Resevoir in Longmont. #COwx
Lenticular clouds over the Front Range of Colorado.
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Clark Evans @clarkevanswx.github.io · 31/12/2025
The local home improvement store speaks my language. Psst: sunset is already ten minutes later than its earliest time.
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Clark Evans @clarkevanswx.github.io · 27/12/2025
Here’s Friday’s 0600 UTC GSL MPAS forecast valid at 0100 UTC Saturday to match the time of your image. Looks reasonably good?
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Clark Evans @clarkevanswx.github.io · 11/12/2025
Wavy over the Flatirons and along the Front Range.
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Clark Evans @clarkevanswx.github.io · 10/12/2025
August 12, 2019. Exact same spot.
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Clark Evans @clarkevanswx.github.io · 10/12/2025
Here are some of the ways that even a small donation has a tangible impact in Weld County and adjacent communities! The Memory Care lots are a really neat idea that will roll out early in 2026, and the Summer Reading program and YES!fest are long-running successes.
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