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SPC MD 736

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Mesoscale Discussion 0736
NWS Storm Prediction Center Norman OK
0353 PM CDT Tue May 26 2020

Areas affected...Central Iowa through southeastern Minnesota

Concerning...Tornado Watch 229...

Valid 262053Z - 262200Z

The severe weather threat for Tornado Watch 229 continues.

SUMMARY...Potential for additional tornadoes is becoming more
unclear, but what potential lingers appears maximized across the
Fort Dodge to Mason City vicinity of north central Iowa through 4-5
PM.  It is not certain that a new Tornado Watch will be needed north
of WW 229, but trends will continue to be monitored for this

DISCUSSION...The surface low center has migrated to the north of the
Kansas City metropolitan area, with latest Rapid Refresh suggesting
that strongest ambient low-level vertical vorticity remains focused
along a frontal zone to its northeast, roughly along the I-35
corridor, southwest through north of the Des Moines area.  Strongest
2-hourly surface pressure falls have shifted to the north-northeast
of Des Moines, with the progression of the sheared mid-level
perturbation, and the nose of a weakening (but still 30+ kt)
southerly 850 mb jet is approaching the eastern Iowa/Minnesota
border area.

In general, strongest low-level vertical shear appears to have
weakened somewhat, and may be more displaced from the stronger
ambient near surface vertical vorticity. Given current trends, the
risk for additional tornadoes remains more unclear, but what
potential lingers during the next hour or two seems maximized across
the Fort Dodge through Mason City vicinity.

..Kerr.. 05/26/2020

...Please see for graphic product...


LAT...LON   41879487 43009460 43799380 44499290 43869199 42409263
            41899283 41099309 41009438 41879487 

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