MD 1675 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PORTIONS OF EASTERN MONTANA
Mesoscale Discussion 1675
NWS Storm Prediction Center Norman OK
0652 PM CDT Fri Aug 12 2022
Areas affected...portions of eastern Montana
Concerning...Severe potential...Watch unlikely
Valid 122352Z - 130115Z
Probability of Watch Issuance...20 percent
SUMMARY...An isolated severe wind/hail threat may persist across
eastern MT over the next few hours with thunderstorm clusters. A WW
issuance appears unlikely given the isolated nature of the more
intense storms.
DISCUSSION...A modest uptick in the severe threat has been noted
across eastern Montana over the past hour, both with a supercell
crossing the U.S. border from Saskatchewan, and with loosely
organized convection near Billings, MT. Despite the presence of a CU
field beneath the anvils of ongoing convection across eastern MT,
buoyancy is scant given the presence of a dry boundary layer
extending to nearly 500 mb (per latest RAP forecast soundings). More
appreciable flow is confined well above 500 mb, contributing to bulk
effective shear values at/below 30 kts. The overall mediocre
CAPE/shear parameter space suggests that storms should remain
isolated and loosely organized over the next couple of hours, with
an isolated severe gust or hailstone possible with the ongoing
storms given steep low and mid-level lapse rates. It is not entirely
out of the question for storms in western MT to grow upscale and
approach eastern MT with a severe gust threat, but the confidence in
this scenario is low. As such, the expected sparse nature of the
severe threat suggests that a WW issuance is not currently
warranted.
..Squitieri/Goss.. 08/12/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BYZ...GGW...TFX...
LAT...LON 48930973 49160938 49250811 49060742 48190579 46560453
45870432 45430470 45210579 45190692 45250782 45470874
45790954 46720981 47650979 48930973
