ACUS11 KWNS 060045
SWOMCD
SPC MCD 060044
NEZ000-COZ000-060245-

Mesoscale Discussion 2247
NWS Storm Prediction Center Norman OK
0744 PM CDT Sat Sep 05 2026

Areas affected...parts of western Nebraska into northeastern
Colorado

Concerning...Severe Thunderstorm Watch 659...

Valid 060044Z - 060245Z

The severe weather threat for Severe Thunderstorm Watch 659
continues.

SUMMARY...The risk for large hail may wane over the next couple of
hours, but storms may persist and evolve into a southeastward moving
cluster with potential to produce strong to severe wind gusts while
approaching the North Platte vicinity through 8-10 PM MDT.

DISCUSSION...Strongest convective development remains focused
near/north of the Cheyenne Ridge vicinity of the Nebraska Panhandle.
This is occurring beneath a focused difluent mid/upper flow regime,
downstream of large-scale troughing centered near the Pacific coast,
and just to the west of the amplified Great Plains ridging.
Southeasterly low-level flow into this region has been enhancing
shear (due to pronounced veering with height) enough to support a
few evolving supercell structures over the past several hours.
However, southwesterly ambient deep-layer mean flow is quite weak,
with slow storm motions and little movement to the general area of
convective development.

Surface outflow has begun to consolidate into a strengthening
surface cold pool, with 2-4+ mb 2-hourly surface pressure rises
sampled in 00Z surface observations across the Scottsbluff, Alliance
and Sidney NE vicinity. As this advances southeastward/southward,
coincident with modest strengthening of a southerly low-level jet
across the high plains, it is possible that lift along/above the
outflow may support an upscale growing cluster of storms through
02-04Z. Stronger convective development seems more likely to
propagate southeastward toward the North Platte vicinity, than areas
to the south, aided by inflow of more moist, potentially unstable
air.

..Kerr.. 09/06/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!5cf6Rzc8TcgxLxLtBsR28BF92IyyGNUJsslWF1P3XDnhqvWEFq6SlS7pRUmWiH_0OiHQ634xa2CN-70elRwI-YrouPc$ for graphic product...

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

LAT...LON 42120270 41950179 41440085 40690213 40740327 41390359
41490350 42120270

MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


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