SPC MD 1229
MD 1229 CONCERNING SEVERE THUNDERSTORM WATCH 404... FOR EASTERN WYOMING INTO WESTERN SOUTH DAKOTA AND THE NEBRASKA PANHANDLE

Mesoscale Discussion 1229
NWS Storm Prediction Center Norman OK
0353 PM CDT Mon Jun 10 2024

Areas affected...Eastern Wyoming into western South Dakota and the
Nebraska Panhandle

Concerning...Severe Thunderstorm Watch 404...

Valid 102053Z - 102300Z

The severe weather threat for Severe Thunderstorm Watch 404
continues.

SUMMARY...The threat for severe wind/hail continues across the
northern High Plains with more focused corridors of greater
wind/hail potential noted based on recent observed trends across
northwest South Dakota and southeastern Wyoming into the Nebraska
Panhandle.

DISCUSSION...Over the past hour, an organized squall line has
emerged from a cluster of initially semi-discrete cells across
northwest SD. This line has a history of producing severe wind,
including a measured 66 mph gust. This line will continue to pose a
severe wind risk through the eastern edge of WW 404; however,
downstream into central SD, lower quality moisture/buoyancy should
result in a gradual weakening trend through the late afternoon/early
evening. Some indications of this weakening have already been noted
as portions of the line are slowly becoming outflow dominant.
Downstream watch issuance does not appear likely at this time, but
convective trends will continue to be monitored to ensure the line
weakens as expected as it exits WW 404. 

Further south, a cluster of semi-discrete cells continues to move
east along the front. MRMS hail estimates suggests the more intense
cells have been capable of large to very large hail (possibly up to
2 inches in diameter). The expectation over the next hour or so is
for these semi-discrete cells to continue to pose a large hail risk
as they migrate towards an axis of greater (2000-2500 J/kg) SBCAPE.
Continued thunderstorm development along the front should favor a
gradual transition to an organized line with an increasing wind
threat. When this transition occurs remains somewhat unclear, but
most indications suggest this may occur around or just after 22 UTC
across far southwest SD and the NE Panhandle.

..Moore.. 06/10/2024

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

ATTN...WFO...ABR...BIS...LBF...UNR...BOU...CYS...

LAT...LON   40760474 40920503 41240519 42380502 43210460 44120464
            44460436 45020372 45430340 45760320 45990299 46140255
            46150178 46050135 45870106 45550092 45140090 44190105
            43850114 42440150 41510236 41210283 41060330 40750437
            40760474 

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https://www.spc.noaa.gov/products/md/md1229.html