Mesoscale Discussion 0912
NWS Storm Prediction Center Norman OK
0619 PM CDT Sat Jun 13 2020
Areas affected...Portions of eastern Montana
Concerning...Severe potential...Watch unlikely
Valid 132319Z - 140115Z
Probability of Watch Issuance...20 percent
SUMMARY...A few isolated to widely scattered storms are possible
this evening in northeast Montana. Large temperature/dewpoint
spreads will favor strong to severe wind gusts. Isolated large hail
is also possible in the stronger storms. A WW is not currently
expected given uncertainty in overall storm coverage. Trends in
upscale growth will be monitored, however.
DISCUSSION...Clusters of high-based cumulus have continued to deepen
along a surface trough in eastern Montana. Thus far, updrafts have
intensified and subsequently dissipated, likely due to some
remaining MLCIN and dry air entrainment. Surface observations for
Jordan, MT suggest that capping may be eliminated soon when
modifying RAP forecast soundings. With modest mid-level height falls
this evening, there is potential for isolated to widely scattered
organized thunderstorms to impact portions of eastern Montana. The
very well-mixed boundary layer will favor strong to severe
convective gusts. Steep mid-level lapse rates and around 30-40 kts
of effective shear would suggest large hail may also occur, though
on a more isolated basis. Outflow interactions from nearby storms
may contribute to additional storm development as activity moves
northward. Storm coverage is enough in question that a WW is not
expected. Trends in convective upscale growth will be monitored,
however.
..Wendt/Grams.. 06/13/2020
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BYZ...GGW...
LAT...LON 46380688 46670714 47010743 47470766 48390811 48870800
49060685 48920569 47610483 46700495 46060547 45770576
45680615 45680635 45830659 46380688
Read morefrom SPC Forecast Products http://www.spc.noaa.gov/products/md/md0912.html
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