From Mike Powell@618:250/1 to All on Thu Apr 4 08:36:00 2024
ACUS01 KWNS 041206
SWODY1
SPC AC 041205
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0705 AM CDT Thu Apr 04 2024
Valid 041300Z - 051200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR WESTERN AND
NORTHERN IDAHO AND INTO WESTERN MONTANA...
...SUMMARY...
A few locally severe thunderstorms are possible across parts of
western and northern Idaho into western Montana, mainly this
afternoon and evening. Isolated hail and gusty winds are the
expected hazards.
...Parts of ID into western MT...
Water-vapor imagery this morning shows a potent mid-level low and
associated trough along the West Coast. This mid- to upper-level
feature will move southeastward into northern CA later today.
Increasing large-scale ascent to the northeast of this low will
support scattered thunderstorm development from northern NV into
western ID, with more isolated storms possible near a surface front
extending eastward across west-central MT. Despite very modest
low-level moisture across the region, steep lapse rates owing
primarily to cold mid-level temperatures, will yield weak buoyancy
by mid afternoon (below 500 J/kg MLCAPE). Long hodographs in
combination with the weak instability may result in a couple of
transient supercell structures. A localized threat of marginally
severe hail (generally in the 0.75-1.25 inch range) and gusty winds
of 50-60 mph could accompany the stronger storms.
Elsewhere, a mid-level ridge building over the Great Plains and
large-scale mid-level trough/low over the East will influence
conditions in those regions.