|Mesoscale Discussion 718|
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Mesoscale Discussion 0718
NWS Storm Prediction Center Norman OK
0348 PM CDT Mon May 15 2017
Areas affected...northern ia
Concerning...Severe potential...Watch possible
Valid 152048Z - 152215Z
Probability of Watch Issuance...60 percent
SUMMARY...Isolated strong thunderstorms may develop across northern
Iowa late this afternoon into the evening hours. Large hail and
damaging winds are the primary threats. WW may be required by 23z.
DISCUSSION...Early-day MCS that moved across SD has progressed into
WI aided in part by weak low-level warm advection. Short-range
model guidance has struggled with this activity, likely due to weak
forcing, with multiple disjointed surface boundaries possibly being
influential later this evening for renewed development.
Latest satellite imagery suggests a mid-level vort max may be
approaching the Missouri River northwest of OMA. Ahead of this
feature, mid-level convection is gradually thickening and isolated
elevated thunderstorms are now evident ahead of the vort stretching
into northern IA. While boundary-layer cu is focused along the
southern-most outflow across central IA, there appears to be
sufficient CINH across this region such that deep convection may
struggle. Current thinking is deep convection will focus north of
the southern-most outflow with a gradual upward trend possible into
the evening hours. Hail and wind are the primary threats with this
slowly evolving activity.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 42319595 43429405 43569240 43059198 42619300 41749537
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