SPC MD 1328

MD 1328 CONCERNING SEVERE THUNDERSTORM WATCH 397... FOR FAR NORTHEASTERN MONTANA...WESTERN NORTH DAKOTA

Mesoscale Discussion 1328
NWS Storm Prediction Center Norman OK
0834 PM CDT Thu Jul 23 2020

Areas affected...Far Northeastern Montana...Western North Dakota

Concerning...Severe Thunderstorm Watch 397...

Valid 240134Z - 240330Z

The severe weather threat for Severe Thunderstorm Watch 397
continues.

SUMMARY...An isolated severe threat is expected to continue across
far northeast Montana and western North Dakota for another hour or
so. Isolated large hail and wind damage will be the primary threats.
Weather watch issuance will probably not be needed beyond the 03Z
expiration time of WW 397.

DISCUSSION...The radar imagery shows a cluster of strong
thunderstorms from far northeastern Montana extending
south-southeastward into far western North Dakota. The storms are
located along the western edge of a strongly unstable airmass with
the RAP estimating MLCAPE in the 2000 to 3500 J/kg range. The storms
are also located just ahead of a shortwave trough that is moving
northeastward through the northern High Plains. The instability and
large-scale ascent should be enough to keep thunderstorms going for
a few more hours. Moderate deep-layer shear, evident on regional
WSR-88D VWPs will be sufficient to maintain a severe threat for
another hour or two. But the threat should become more isolated with
time as instability begins to decrease across the northern Plains
this evening. For this reason, additional weather watch issuance is
not expected.

..Broyles.. 07/24/2020

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

ATTN...WFO...BIS...GGW...

LAT...LON   49050436 48800459 48090406 47890408 47220415 46900380
            47440260 49010322 49050436 

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