SPC MD 1482
[html]MD 1482 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF SOUTHWESTERN INTO SOUTH CENTRAL MONTANA AND ADJACENT PORTIONS OF IDAHO AND WYOMING
Mesoscale Discussion 1482
NWS Storm Prediction Center Norman OK
0202 PM CDT Thu Jul 14 2022
Areas affected...Parts of southwestern into south central Montana
and adjacent portions of Idaho and Wyoming
Concerning...Severe potential...Watch unlikely
Valid 141902Z - 142200Z
Probability of Watch Issuance...20 percent
SUMMARY...Scattered thunderstorms are likely to initiate during the
next few hours, with isolated supercells posing some risk for severe
hail, and at least a bit more substantive risk for severe wind
gusts, by 3-5 PM MDT. It is not clear that at severe weather watch
will be needed, but trends will continue to be monitored.
DISCUSSION...Downstream of a notable short wave perturbation
approaching the northern California/southwestern Oregon coast, a
weak lower/mid tropospheric warm advection regime is overspreading
portions of the northern Rockies. Associated forcing for ascent
during the next few hours may augment orographically forced lift,
which is already contributing to initial attempts at deep convective
development across the higher terrain.
With continuing insolation, models suggest that moisture is
sufficient to contribute to CAPE on the order of 1000-1500 J/kg for
an increasingly deeply mixed boundary layer, which may beco*e
characterized by 40-45+ degree F surface temperature/dew point
spreads by late afternoon. Beneath a belt of 30-60 kt
west-southwesterly flow in the 500-300 mb layer, it appears that
strong deep-layer shear may beco*e conducive to the evolution of
organizing convection, at least initially including a couple of
supercell structures. Some of these may beco*e capable of producing
severe hail, before precipitation loading and sub-cloud cooling
driven by melting and evaporation, increasingly contribute to the
risk for a few severe surface gusts, aided by the downward mixing of
the higher momentum from aloft.
..Kerr/Thompson.. 07/14/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BYZ...RIW...TFX...PIH...MSO...
LAT...LON 46291107 46150871 45720725 44740721 44880922 44551079
44831260 45601306 46291107
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Source: SPC MD 1482 (http://ht**://www.spc.noaa.gov/products/md/md1482.html)