SPC MD 1337

MD 1337 CONCERNING SEVERE THUNDERSTORM WATCH 388... FOR NORTHEAST SOUTH DAKOTA...SOUTHEAST NORTH DAKOTA...WEST-CENTRAL MINNESOTA
MD 1337 Image


Mesoscale Discussion 1337
NWS Storm Prediction Center Norman OK
1033 PM CDT Fri Jul 23 2021

Areas affected...northeast South Dakota...southeast North
Dakota...west-central Minnesota

Concerning...Severe Thunderstorm Watch 388...

Valid 240333Z - 240530Z

The severe weather threat for Severe Thunderstorm Watch 388
continues.

SUMMARY...Severe gusts or marginally severe hail remains possible
with a cluster of cells moving the North/South Dakota border.

DISCUSSION...A primary cluster of storms continues east/southeast
near the ND/SD border, with new development on the southwest flank.
A 75 mph gust was recently measured in McPherson County SD. VWPs
across ND show increased northwest winds just above the surface,
indicating the deeper cold advection. This is aiding additional
storms on the northwest side of the primary cluster.

Temperatures aloft remain cool due east of the advancing convection,
and the boundary layer remains very moist and unstable. Height falls
with the upper trough will continue, favoring at least a continued
threat across the remainder of WW 388 and perhaps to the east. Parts
of west-central MN may need a watch should the storms continue to
produce severe gusts.

..Jewell.. 07/24/2021

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

ATTN...WFO...MPX...FGF...ABR...BIS...

LAT...LON   46239998 46659987 46819947 47059658 46689565 45749551
            45329597 45209676 45189913 45250017 45400041 46239998 

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SPC MD 1336

MD 1336 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR EASTERN SOUTH DAKOTA INTO SOUTHWEST MINNESOTA
MD 1336 Image


Mesoscale Discussion 1336
NWS Storm Prediction Center Norman OK
0907 PM CDT Fri Jul 23 2021

Areas affected...eastern South Dakota into southwest Minnesota

Concerning...Severe potential...Watch unlikely 

Valid 240207Z - 240430Z

Probability of Watch Issuance...20 percent

SUMMARY...Clusters of storms will move from South Dakota into
Minnesota, possibly with strong gust potential.

DISCUSSION...Sporadic storms have developed within a broad band of
precipitation extending from north-central NE into eastern SD.
Despite cooler boundary-layer temperatures, robust moisture is in
place with PWAT over 2.00" measured on GPS sensors near FSD.

Warmer midlevel temperatures exist in this region compared to
farther north, which is hampering hail potential. In addition,
deep-layer shear is less with only 25-30 kt winds at 500 mb. Despite
this, a growing cluster of storms may be able to produce strong,
water-loaded downdrafts, as instability remains favorable downstream
into MN. Convective trends will continue to be monitored for upscale
growth that may necessitate watch consideration.

..Jewell/Edwards.. 07/24/2021

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

ATTN...WFO...MPX...FSD...ABR...

LAT...LON   43379743 43259832 43439886 43829913 44209909 44579855
            44819762 45079593 44859553 44449524 43999528 43689585
            43569655 43379743 

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