SPC MD 1205

MD 1205 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF THE WESTERN DAKOTAS INTO EASTERN MONTANA

Mesoscale Discussion 1205
NWS Storm Prediction Center Norman OK
0706 PM CDT Sun Jul 12 2020

Areas affected...Portions of the western Dakotas into eastern
Montana

Concerning...Severe potential...Watch unlikely 

Valid 130006Z - 130200Z

Probability of Watch Issuance...20 percent

SUMMARY...A conditional risk for few storms capable of severe wind
and hail may develop this afternoon and evening across portions of
eastern Montana and the Dakotas. Storm development on the US side of
the international border is uncertain. A weather watch is unlikely
though trends will be monitored.

DISCUSSION...Visible satellite data showed a a developing cumulus
field underneath an overspreading band of high cirrus across eastern
Montana into southern Saskatchewan. The plume of higher cirrus marks
the effective edge of stronger forcing for ascent from an upstream
shortwave trough moving over the Pacific Northwest. Lift from the
approaching trough/jet max and continued boundary-layer warming will
work to destabilize the atmosphere through the next several hours.
SPC mesoanalysis indicates 1500-2500 J/kg of MLCAPE exists with
little remaining inhibition. Model guidance and satellite data
suggests that storms may develop along and just north of the
international border with little coverage farther south. Strong
vertical shear from the approaching jet max would favor supercells
with a damaging wind and hail threat. While a tornado cannot be
ruled out, low-level shear is not particularly strong. Convective
trends will be monitored, but current uncertainty suggests a watch
is unlikely.

..Lyons/Hart.. 07/13/2020

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

ATTN...WFO...ABR...BIS...UNR...BYZ...GGW...

LAT...LON   45720160 45120225 45010326 45300399 46080432 48350435
            48960423 48950228 46720157 45720160 

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from SPC Forecast Products http://www.spc.noaa.gov/products/md/md1205.html