059
ACUS11 KWNS 212240
SWOMCD
SPC MCD 212240
NEZ000-COZ000-WYZ000-220015-

Mesoscale Discussion 1366
NWS Storm Prediction Center Norman OK
0540 PM CDT Fri Jun 21 2024

Areas affected...Parts of far eastern WY...northeast CO...and the NE
Panhandle

Concerning...Severe Thunderstorm Watch 443...

Valid 212240Z - 220015Z

The severe weather threat for Severe Thunderstorm Watch 443
continues.

SUMMARY...The greatest threat for large hail, severe/damaging winds,
and perhaps a tornado should spread eastward this evening over the
Nebraska Panhandle and northeast Colorado.

DISCUSSION...Weak low-level upslope flow is aiding widely spaced
supercells across far eastern WY into northeast CO and the western
NE Panhandle early this evening. Surface dewpoints and low-level
moisture increase with eastward extent across these areas based on
latest observations, with greater instability also being estimated
by recent mesoanalysis. Strong deep-layer shear should continue to
support a supercell mode in the short term, with large to isolated
very large hail around 1.5-2.5 inches in diameter possible.
Severe/damaging downdraft winds around 60-70 mph may also occur,
especially where low-level lapse rates have become steepened with
daytime heating. The southern supercell in northeast CO is the
strongest storm across this region at the moment. It should have
access to an unimpeded low-level moisture feed, and will likely
maintain its intensity in the short term. A brief tornado may also
occur this evening, particularly if supercells can be maintained
farther east into the NE Panhandle where greater low-level
moisture/lower LCLs are present. Based on latest observational
trends, Severe Thunderstorm Watch 443 has been locally extended in
area to include more of the western NE Panhandle and northeast CO.

..Gleason.. 06/21/2024

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LBF...BOU...CYS...

LAT...LON   40760432 41790439 42560416 42930351 42900230 41720146
            40770131 40430165 40460339 40760432