David Demko

@davedemko.com

Atmospheric scientist • Engineer • Chasing storms 1997- • KY built, CO/OK deployed • http://TwisterData.com • Filter noise, amplify signal 📍Nederland, CO 🔁 Norman, OK

Wicked VAD wind profile derived from TLX 88D velocity data of the rear inflow jet punching in behind last night’s Oklahoma derecho, which produced pockets of 100+ mph surface wind gusts. ~50 knots of sfc-1km bulk shear w/ 60-65 knot flow at 700m + a 15 knot surface wind.

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Current high resolution VAD hodograph from Evansville, IN (KVWX) WSR-88D with KEVV surface wind. Storms producing tornadoes in southern Illinois sure are working with some potent kinematics.

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Good 12” here in Ned. Still snowing. After Larimer County got bullseyed yesterday I thought the 1’+ totals may skip to the north of the southwest Boulder County mountains. But, steady snow overnight brought things up to par with expectations. Woohoo! #cowx

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NOAA GOES 18 weather satellite’s Geostationary Lightning Mapper (GLM) instrument detected the atmospheric re-entry of NASA’s Artemis II Orion capsule over the Pacific Ocean between Hawaii and southern California just before 23:56 GMT — too cool! #ArtemisII #NASA #NOAA

Raucous wind storm ongoing in the mountains of western Boulder County. Estimate gusts in the 80-90 mph range at my exposed location. I really won’t ever get used to the way west-facing walls bow in and out with stronger gusts. Pushing the mantle around enough to slosh a glass of water pretty good.

Cool to see — two commercial aircraft passing in close proximity to each other in northern Montana currently, with their air speeds showing the difference between either fighting or drafting a 130 knot WNW to ESE jet stream

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Message exchange about the ongoing absence of winter in the Front Range. “Barker” is Barker Meadow Reservoir at ~8300’ in the mountains west of Boulder. I my time living in Ned, I’ve never seen Barker this ice free on Mar 1…nor seen much precip fall in liquid form. Wild.

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I love views like this — looking southwest from 40,000 feet over Liberal, Kansas at the demarcation between bare ground and snow cover left in the wake of the recent storm system

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Winds have eased some here in western Boulder Co. after last night’s blitz — strongest in 7 years here. My low-height (~1 m AGL) cup anemometer peaked at 71.9 mph. I suspect a standard 10 m measurement would have been 100+ mph. House’s west wall bowed with the gusts. Short vid from 12:20 AM. #cowx

Wow winds really ramping up very rapidly in western BoCo (Nederland) at this time. Currently (~10:35 PM MT) I’m recording gusts approaching 70 mph on my cup anemometer, which is only 3 feet above ground…and the worst is yet to come. #cowx

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A low temperature of 46°F here at 8450 ft AMSL this morning. It’s often cooler than this in July. Also, I’m not digging these < 20% RHs.

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The “other Erin” — spooky that OTD in 2007, the arguably most fascinating weather event of my career unfolded: the overland reintensification of TS Erin in OK. I was fortunate to contribute (as the final co-author) to Arndt et al. (2009, BAMS) on this event while at Oklahoma Mesonet

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‪Fire now 100% contained and Boulder Canyon Rd has been reopened in both directions. Response was rapid and forceful. Thank you firefighters and first responders!‬

May 9, 2016 | Katie, Oklahoma Witnessing strong tornadoes with no shroud of obscuring precipitation around them feels like catching lightning in a bottle.

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This is an awful development. Unidata has done more for the advancement of the atmospheric sciences and broad technology/scientific collaboration through open data, open-source software, accessible training and educational initiatives — among other things — than I can count.

NSF Unidata@unidata.bsky.social · last yr.

Due to the current gap in funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program is pausing most operations effective 12 May 2025. Nearly all staff will be furloughed until funds from our existing NSF grant become available. For more information, see buff.ly/d2TC1Oy

One of many tornadoes produced by supercell “A” during the May 3, 1999 tornado outbreak. This is tornado A8 as I observed it approaching the municipal airport on the northwest side of Chickasha, Oklahoma. The next tornado in this supercell’s sequence was A9 — the Moore F5.

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After hitting 70°F on Saturday, winter is showing off again. Measured 5” new snow depth and 23°F as of 10:30 AM MT at 8460’ 1 mile ESE Nederland in western Boulder County. #cowx

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As mentioned by SPC 20Z Day 1 outlook update maintaining the High Risk — check out the dramatic effect deep-layer ascent has had lifting the capping inversion into veritable irrelevance across the Mid South as shown by WFO Little Rock soundings between 12Z to 18Z. Wowzers!

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Palmer Divide magic. I got a fantasic aerial view of the persistent remnant deep snowpack on the Palmer Divide while flying near Limon, Colorado this afternoon. Sharp cutoff line between snow and no snow visible too toward the horizon, looking northeast away from the PD. #cowx

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