SPC MD 431

SPC MD 431

MD 0431 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR IDAHO INTO FAR SOUTHWEST MONTANA

Mesoscale Discussion 0431
NWS Storm Prediction Center Norman OK
0442 PM CDT Fri Apr 12 2024

Areas affected…Idaho into far southwest Montana

Concerning…Severe potential…Watch unlikely

Valid 122142Z – 122345Z

Probability of Watch Issuance…5 percent

SUMMARY…Developing thunderstorms across southern Idaho are
expected to pose a severe wind and hail risk through the late
afternoon hours as they spread northeast into central Idaho and far
southwest Montana. Watch issuance is unlikely given the localized
nature of the threat and somewhat marginal environment.

DISCUSSION…Latest GOES visible and IR imagery show a cluster of
steadily deepening cumulus across south-central ID. This is likely
in response to a combination of quickly eroding MLCIN and increasing
ascent ahead of a mid-level wave approaching from the
south/southwest. Deep boundary-layer mixing is limiting buoyancy
with MLCAPE values generally between 250-500 J/kg; however, this has
resulted in 0-3 km lapse rates between 8-9 C/km, which will support
the potential for strong to severe downburst winds with deeper
convective cells. This potential will likely be maximized across
areas where temperatures have warmed into the mid/upper 70s. 30-40
knot mid-level winds are elongating mid-level hodographs enough to
support effective bulk shear values around 30-35 knots. This
kinematic environment, combined with steep mid-level lapse rates,
may allow for a supercell or two that will pose a severe hail risk
(though this scenario is less certain given the modest buoyancy).
The marginal nature of the buoyancy field and weak/nebulous forcing
for ascent should limit the overall extent of the severe threat as
storms spread north/northeast.

..Moore/Thompson.. 04/12/2024

…Please see www.spc.noaa.gov for graphic product…

ATTN…WFO…TFX…PIH…MSO…BOI…

LAT…LON 42091474 42131568 42301679 42471699 42911693 45631503
45711423 45631372 45271304 44931268 44571244 44261232
43851245 42141432 42091474

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