MD 1375 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR SOUTHWEST AND SOUTH-CENTRAL MT
Mesoscale Discussion 1375
NWS Storm Prediction Center Norman OK
0217 PM CDT Sat Jul 01 2023
Areas affected...southwest and south-central MT
Concerning...Severe potential...Watch unlikely
Valid 011917Z - 012145Z
Probability of Watch Issuance...20 percent
SUMMARY...Isolated severe gusts (60-70 mph) are possible this
afternoon as storms move east near I-90.
DISCUSSION...Water-vapor imagery shows a mid-level shortwave trough
moving east-northeast across Alberta and the northern Rockies early
this afternoon. Visible satellite/radar composite imagery shows a
cluster of intensifying strong to locally severe thunderstorms
extending from northeast ID northeastward to immediately east of
Helena. This activity will likely continue to develop and move east
during the afternoon as additional heating occurs downstream of the
storms over south-central MT. Early afternoon surface conditions
show temperatures warming through the 80s with dewpoints in the
lower to mid 50s. Forecast soundings show steep 0-3 km lapse rates
(9+ deg C/km) and MLCAPE approaching 1000 J/kg. The main limiting
factor for a more robust severe risk is the modest unidirectional
westerly flow (at or below 30 kt from 300 mb to the surface).
Nonetheless, the steep-lapse-rate environment and forcing for ascent
will likely lead to at least an isolated risk for severe gusts
accompanying stronger multicells on the leading edge of a cold pool
as it moves east across south-central MT this afternoon.
..Smith/Grams.. 07/01/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BYZ...GGW...RIW...TFX...MSO...
LAT...LON 46701090 46950802 46910795 46260738 45830748 45370811
45121034 44771148 44701288 45091308 45411284 46251166
46701090
