Severe Storm Outlook Narrative (AC)
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ACUS11 KWNS 091949
SWOMCD
SPC MCD 091948
MTZ000-WYZ000-IDZ000-092115-
Mesoscale Discussion 1618
NWS Storm Prediction Center Norman OK
0248 PM CDT Wed Jul 09 2025
Areas affected...portions of eastern Idaho into southern Montana
Concerning...Severe potential...Watch possible
Valid 091948Z - 092115Z
Probability of Watch Issuance...60 percent
SUMMARY...Severe gusts will become an increasing concern as at least
scattered thunderstorms develop and mature through the afternoon. A
Severe Thunderstorm Watch issuance may be needed.
DISCUSSION...Deepening CU over eastern ID/southern MT are indicating
attempts at thunderstorm initiation atop a destabilizing boundary
layer with eroding convective inhibition. 19Z mesoanalysis shows
boundary-layer lapse rates already reaching 9 C/km in some spots,
with 500+ J/kg MLCAPE. RAP forecast soundings indicate a dry
boundary layer extending to 500 mb, which is being overspread by
stronger mid-upper level flow and 30 kts of effective bulk shear
(i.e. straight hodographs indicating speed shear). Organized,
high-based multicells should traverse portions of the the northern
Rockies, accompanied by mainly a severe gust threat. If confidence
increases in greater coverage of severe gusts, a Severe Thunderstorm
Watch may be needed.
..Squitieri/Mosier.. 07/09/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BYZ...GGW...RIW...TFX...PIH...MSO...BOI...
LAT...LON 45111508 46501254 47021071 47090875 46540812 45790811
45150871 44900926 44541039 44241175 44011271 43841336
43811402 43871457 45111508
MOST PROBABLE PEAK WIND GUST...65-80 MPH