Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0741 PM CDT Thu Sep 17 2026

Valid 180100Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL HIGH PLAINS AND INTERMOUNTAIN WEST...

...SUMMARY...
Thunderstorms with isolated severe wind gusts and hail will be
possible over parts of the Intermountain West early this evening. A
few strong to severe gusts may also occur across parts of the
central High Plains.

...Intermountain West...
An upper-level low is currently located over northern California,
evident on water vapor imagery. Mid-level flow is southwesterly over
much of the Intermountain West with a dry slot located from southern
Nevada northeastward into northern Utah and southeast Idaho.
Scattered thunderstorms have developed within the nose of the dry
slot from north-central Utah into eastern Idaho. Within this zone,
the RAP has a pocket of instability with MLCAPE in the 1000 to 1200
J/kg range. In addition, the WSR-88D VWP near Pocatello, Idaho has
0-6 km shear near 40 knots. RAP forecast soundings in the vicinity
have low to mid-level lapse rates around 8 C/km. This environment
should support a threat for hail and isolated severe gusts for a
couple more hours this evening.  

...Central High Plains...
On water vapor imagery, a mid-level shortwave trough is currently
located in the central Rockies. This feature will move into the
central High Plains this evening. At the surface, a warm front is
located from northern Kansas into southwest Nebraska. The front will
move northward into west-central Nebraska this evening. To the north
of the front, a moist axis is present with surface dewpoints from
the mid 60s to the lower 70s F. Near the moist axis, the RAP has
MLCAPE in the 1500 to 2000 J/kg range. In addition, the regional
WSR-88D VWP near North Platte has 0-6 km shear around 45 knots,
which will support an isolated wind-damage threat for a few more
hours this evening. Lapse rates are poor which will keep any severe
threat marginal.

..Broyles.. 09/18/2026