Severe Storm Outlook Narrative (AC)
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ACUS11 KWNS 152248
SPC MCD 152248

Mesoscale Discussion 1647
NWS Storm Prediction Center Norman OK
0548 PM CDT Fri Sep 15 2017

Areas affected...Parts of eastern Nebraska...southeast South Dakota
and northwest Iowa

Concerning...Severe potential...Watch unlikely

Valid 152248Z - 160115Z

Probability of Watch Issuance...20 percent

SUMMARY...Scattered storms are likely to increase across
east-central Nebraska into far southeast South Dakota and perhaps
northwestern Iowa by late evening. Marginal hail and wind are

DISCUSSION...Isolated thunderstorms have formed over south central
NE just ahead of a cold front and along a surface trough where
temperatures have warmed into the 90s. Modest boundary layer
moisture exists ahead of the front, with mid 50s to lower 60s
dewpoints along with gusty south winds.

Southwesterly winds aloft are not particularly strong, but
sufficient to get storms moving in a northeastward direction. Model
consensus is for storms to continue to increase through evening near
the cold front, where moderate levels of MUCAPE should support
periodically strong updrafts. Lift and storm inflow will further be
aided by a southerly low-level jet of 35-45 kt, supporting a
marginal hail or wind threat. Storms are expected to remain
multicellular and rather disorganized, and as such a watch is not

..Jewell/Thompson.. 09/15/2017

...Please see for graphic product...


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