314
ACUS11 KWNS 161937
SWOMCD
SPC MCD 161936
COZ000-NEZ000-WYZ000-162100-

Mesoscale Discussion 1689
NWS Storm Prediction Center Norman OK
0236 PM CDT Wed Jul 16 2025

Areas affected...portions of southeastern Wyoming...eastern Colorado
and far western Nebraska

Concerning...Severe potential...Watch likely

Valid 161936Z - 162100Z

Probability of Watch Issuance...80 percent

SUMMARY...Initial thunderstorms moving off the higher terrain in
northern CO and southern WY should gradually organize into a mix of
supercells and clusters this afternoon. Hail, severe wind gusts and
a tornado or two are possible.

DISCUSSION...Initial convective development across WY and CO has
shown a steady increase in vertical development/lightning over the
last hour. These initial storms should continue to intensify early
this afternoon within a broad, but weak upslope flow regime. A
stalled front along the I-25 corridor will likely serve as a focus
for more robust thunderstorms over the next couple of hours as the
environment continues to destabilize.

As the initial convection matures, 40-50 kt of deep-layer flow will
favor storm organization into supercells or clusters. Steep
mid-level lapse rates (>8 C/km) and the potential for supercells
suggest hail is likely with the stronger storms. A few hailstones
may approach 2 inches in diameter. A few damaging gusts are also
possible. While low-level shear is not overly strong, enhanced
low-level vertical vorticity from terrain effects and near the
stalled front could support a brief tornado.

Severe potential is expected to steadily increase this afternoon and
into this evening hours. With time, storms should begin to grow
upscale with a greater risk for severe winds toward the eastern
Plains. However, lingering inhibition and cooler temperatures to the
east of the stalled front may hamper the severe threat to some
degree. Regardless, a WW is likely needed along the Front Range and
into parts of WY and far western NE in the coming hours.

..Lyons/Smith.. 07/16/2025

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

ATTN...WFO...GLD...PUB...BOU...CYS...

LAT...LON   40360318 39480300 38810295 37880271 37280204 37050216
            37030343 37260483 38630554 39260576 40760637 41930631
            42560543 42350405 41500343 40360318

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN