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SPC MD 606

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Mesoscale Discussion 0606
NWS Storm Prediction Center Norman OK
0448 PM CDT Thu May 13 2021

Areas affected...southwest NE...far northwest KS

Concerning...Severe potential...Watch unlikely 

Valid 132148Z - 132345Z

Probability of Watch Issuance...20 percent

SUMMARY...An isolated risk for large hail and localized severe gusts
may accompany the stronger storms that manage to develop late this
afternoon into the evening.  Storm coverage and severe-producing
storms will likely remain too isolated to warrant a severe
thunderstorm watch issuance.

DISCUSSION...Visible satellite imagery late this afternoon shows a
cluster of strong to severe storms over the western part of the NE
Sandhills and another discrete storm near the NE/CO/KS border. 
Ample heating has occurred downstream/southeast of the ongoing
activity (as of 2140 UTC) with mid 70s deg F temperatures.  Forecast
soundings show rather cool mid-level temperatures (-17 deg C at 500
mb), which is resulting in 500-750 J/kg MLCAPE despite relatively
marginal boundary layer moisture (mid-upper 40s deg F dewpoints). 
As a mid-level shortwave trough over the northern High Plains/Black
Hills vicinity continues to approach the region this evening,
support for additional storms developing or maintaining their vigor
into the early evening hours seems plausible.  The strong veering
flow with height increasing to 80 kt at 250 mb will aid in storm
venting and possibly hail production considering the long, straight
hodographs and cool mid-level temperatures.  Given the current
forecast expectation for limited storm development south of the NE
Sandhills thunderstorm cluster, a severe thunderstorm watch will
likely not be needed farther south over northwest KS and adjacent
parts of NE this evening.

..Smith/Grams.. 05/13/2021

...Please see for graphic product...


LAT...LON   40330216 40610135 40499997 39509995 39350084 39600189

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