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Arthur Witt

@arthurwitt.bsky.social
354 followers 133 following 185 posts

Research Meteorologist at the National Severe Storms Laboratory (retired). Fan of Tangerine Dream (1975-1990), Stellardrone, Prog Rock, J-Law.

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Arthur Witt @arthurwitt.bsky.social · 13/10/2026
Although it may be convenient to use "diameter" here, given that the pictured hailstone has an aspect ratio of ~2, "maximum dimension" would be more accurate. www.ncei.noaa.gov/monitoring-c...
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Arthur Witt @arthurwitt.bsky.social · 06/10/2026
Thank you @wxjaime.bsky.social for your award-winning research helping to advance hail science.
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Arthur Witt @arthurwitt.bsky.social · 11/08/2026
Widespread radar velocities of 40-50 m/s on the lowest elevation scan.
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Arthur Witt @arthurwitt.bsky.social · 10/08/2026
For anyone interested in radar-based hail detection, and who did not attend the 32nd SLS conference last week, here is a copy of our poster. #32SLS #AMSMadisonSummit
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Arthur Witt @arthurwitt.bsky.social · 27/07/2026
Yikes! The tornado path went across the center of Appleton, WI.
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Arthur Witt @arthurwitt.bsky.social · 27/07/2026
Very distinct TDS in both ZDR and CC.
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Arthur Witt @arthurwitt.bsky.social · 27/07/2026
The 12Z GRB sounding aptly indicated the risk of very large hail (high CAPE and very elongated hodograph) with this morning's intense hailstorms across northern WI (multiple reports of hail up to 3 inches in diameter).
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Arthur Witt @arthurwitt.bsky.social · 01/07/2026
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Arthur Witt @arthurwitt.bsky.social · 01/07/2026
Well-defined BWER with this storm southwest of Ripon, WI.
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Arthur Witt @arthurwitt.bsky.social · 29/06/2026
Oops.
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Arthur Witt @arthurwitt.bsky.social · 29/06/2026
??? - Why no SVR warning on this storm?
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Arthur Witt @arthurwitt.bsky.social · 25/06/2026
Intense supercell with likely tornado south of Beaver, OK.
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Arthur Witt @arthurwitt.bsky.social · 24/06/2026
Tornado likely occurring with the supercell south of Fort Morgan.
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Arthur Witt @arthurwitt.bsky.social · 24/06/2026
Giant hail (4+ inches) likely with this intense supercell north of Fort Morgan, based on mid-level radar signatures: strong mesocyclone, ZDR < -1 dB and CC < 0.7
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Arthur Witt @arthurwitt.bsky.social · 23/06/2026
I didn't expect to see this today: three-body scatter spike (TBSS) from a hailstorm located south of Richmond, VA.
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Arthur Witt @arthurwitt.bsky.social · 23/06/2026
Giant hail signature with the supercell south of Sterling, CO. Max Z = 76 dBZ collocated with a CC of 0.6 on the 0.5 degree scan.
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Arthur Witt @arthurwitt.bsky.social · 23/06/2026
TVS from KCYS.
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Arthur Witt @arthurwitt.bsky.social · 23/06/2026
This is getting very serious - supercell currently over Sterling, CO.
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Arthur Witt @arthurwitt.bsky.social · 22/06/2026
MESH is likely way too low with its estimate of max expected hail size, given the intense, rotating updrafts in these two supercells.
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Arthur Witt @arthurwitt.bsky.social · 22/06/2026
Very intense updraft with the supercell NW of Sterling, CO. Storm-top divergence of around 100 m/s, as seen from the Denver WSR-88D.
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Arthur Witt @arthurwitt.bsky.social · 22/06/2026
Two prominent BWERs with the supercells near Kimball, NE, as seen from the Denver WSR-88D.
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Arthur Witt @arthurwitt.bsky.social · 22/06/2026
And the supercell NW of Kimball, NE also has a distinct BWER and strong mid-level mesocyclone.
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Arthur Witt @arthurwitt.bsky.social · 22/06/2026
Supercell over Kimball, NE has a distinct BWER and strong mid-level mesocyclone.
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Arthur Witt @arthurwitt.bsky.social · 20/06/2026
Very intense supercell hailstorm west of McCook, NE.
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Arthur Witt @arthurwitt.bsky.social · 18/06/2026
Getting pretty intense again NE of Enid, OK, with another supercell hailstorm having a strong mid-level mesocyclone.
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Arthur Witt @arthurwitt.bsky.social · 18/06/2026
Here's the MRMS graphic:
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Arthur Witt @arthurwitt.bsky.social · 18/06/2026
This supercell is located in a region of high 0-3 km Storm-Relative Helicity (SRH).
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Arthur Witt @arthurwitt.bsky.social · 18/06/2026
Impressive supercell hailstorm with a strong mid-level mesocyclone and marginal BWER, located NE of Enid, OK.
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Arthur Witt @arthurwitt.bsky.social · 17/06/2026
It's very fortunate that the worst part of this hailstorm occurred right between Springfeild and Decatur, IL.
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Arthur Witt @arthurwitt.bsky.social · 17/06/2026
Even more impressive on the next volume scan.
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Arthur Witt @arthurwitt.bsky.social · 17/06/2026
Major three-body scatter spike (TBSS) with the supercell just east of Springfield, IL.
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Arthur Witt @arthurwitt.bsky.social · 17/06/2026
Storms are starting to develop in northern Missouri, right in the center of the current Significant Tornado bullseye.
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Arthur Witt @arthurwitt.bsky.social · 12/06/2026
Watch out for vertical side-lobes!
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Arthur Witt @arthurwitt.bsky.social · 11/06/2026
KILX changed its PRT on the next volume scan and now the velocity data is much better.
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Arthur Witt @arthurwitt.bsky.social · 11/06/2026
KILX is having some major data-quality problems with the velocity data on its batch cuts. The velocity data from KDVN is much better.
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Arthur Witt @arthurwitt.bsky.social · 11/06/2026
The current main tornado threat area:
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Arthur Witt @arthurwitt.bsky.social · 11/06/2026
Although the T/Td profile is impacted by previous storm activity, that is one mighty impressive hodograph.
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Arthur Witt @arthurwitt.bsky.social · 11/06/2026
"May the odds be ever in your favor"
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Arthur Witt @arthurwitt.bsky.social · 03/06/2026
Great new malpais.app features: multi-panel and vertical cross-section (RHI) options
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Arthur Witt @arthurwitt.bsky.social · 29/05/2026
When I first started analyzing Doppler radar data at NSSL in the early 1980's, we did this via hand analysis on paper printouts in B-scan format. For those not familiar with B-scan format, here are examples from NSSL's WG display (left side of each image):
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Arthur Witt @arthurwitt.bsky.social · 27/05/2026
For users of Rob's great new radar viewer malpais.app, if you are not very familiar with all the WSR-88D 4-letter IDs and their locations, here's a useful way to quickly get this information. Go to mrms.nssl.noaa.gov/qvs/product_..., select Overlays (lower right) and then the box for WSR-88D
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Arthur Witt @arthurwitt.bsky.social · 14/05/2026
I like the new data readout, but will admit to not liking the colormaps. I prefer these colormaps that I used with NSSL's WDSS-II GUI (WG); they are higher resolution versions of those used by the real-time MRMS. I can try to get ahold of the WG colormap files (in XML) and provide copies if desired.
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Arthur Witt @arthurwitt.bsky.social · 09/05/2026
Lots of quarter to golf-ball size hail at my home 12 miles east of Noble, OK. Report submitted via mPING.
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Arthur Witt @arthurwitt.bsky.social · 08/05/2026
Alan mentioned in this episode the Tornado Debris Signature Detection Algorithm that NSSL developed several years ago. Jeff Snyder and I presented this poster on the algorithm at the 29th SLS conference in 2018 (Stowe, VT):
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Arthur Witt @arthurwitt.bsky.social · 29/04/2026
Another useful feature of the MRMS Hail Swath product is the way it allows one to get a quick feel for storm character/evolution in terms of right vs left moving storms and when/where storm splits may have occurred.
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Arthur Witt @arthurwitt.bsky.social · 28/04/2026
Nasty looking storm about to hit Sulphur, OK.
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Arthur Witt @arthurwitt.bsky.social · 28/04/2026
For the second day in a row, Springfield, MO is hit by a hailstorm, but this one is far more intense than yesterday's storm.
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Arthur Witt @arthurwitt.bsky.social · 27/04/2026
The value of mPING reports when a hailstorm moves over a large high-population-density area. Similar coverage, if not better, than what we were able to do during the SHAVE project.
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Arthur Witt @arthurwitt.bsky.social · 27/04/2026
Looking back at the storm that produced 4.5 inch hail at Alpine, AR (0228 UTC, 26 April), whereas MESH only indicated up to 2.5 inch hail, there's a very distinct giant hail signal in the CC data at -30 C (8 km) up to 20 min prior to the report (image shows Z,CC,MESH from 0210-0230 UTC, every 5 min)
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Arthur Witt @arthurwitt.bsky.social · 23/04/2026
Wow - so much useful information in one display!
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