SPC MD 1479

MD 1479 CONCERNING SEVERE THUNDERSTORM WATCH 433... FOR NORTHWEST MINNESOTA AND FAR SOUTHEAST NORTH DAKOTA.

Mesoscale Discussion 1479
NWS Storm Prediction Center Norman OK
0826 PM CDT Thu Aug 13 2020

Areas affected...Northwest Minnesota and far southeast North Dakota.

Concerning...Severe Thunderstorm Watch 433...

Valid 140126Z - 140300Z

The severe weather threat for Severe Thunderstorm Watch 433
continues.

SUMMARY...Current storm activity and additional development is
expected to continue after sunset in watch 433.

DISCUSSION...Numerous storms have developed across northwest
Minnesota this evening with only transient organization. However, a
very unstable airmass and very steep mid-level lapse rates have been
sufficient to support a few reports of large hail. The ABR 00Z RAOB
was a decent proximity for the airmass near these storms with 4500
J/kg MLCAPE, -9 J/kg MLCIN, and a mid level lapse rate of 9 C/km.
This RAOB also showed the lack of flow which is limiting storm
organization with effective shear of only 22 kts, however, effective
shear is likely greater farther north near the warm front. Storms
are expected to continue to grow upscale over the next few hours and
some damaging wind is possible as a cold pool develops and
strengthens. Some increasing low-level flow may also help to support
some wind damage threat as 925mb flow increases to 35-40 kts.

..Bentley.. 08/14/2020

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

ATTN...WFO...DLH...FGF...ABR...BIS...

LAT...LON   46039827 46709785 47689710 48269671 48709616 48929540
            48999498 48969414 48809363 48519324 47929341 46859444
            46249541 45959634 45949680 45979741 46009816 46039827 

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