ZCZC SPCSWOMCD ALL
ACUS11 KWNS 212209 
SPC MCD 212209 
WIZ000-IAZ000-212345-

Mesoscale Discussion 0879
NWS Storm Prediction Center Norman OK
0509 PM CDT Tue May 21 2024

Areas affected...Central Iowa into northeast Iowa and far southwest
Wisconsin.

Concerning...Tornado Watch 277...

Valid 212209Z - 212345Z

The severe weather threat for Tornado Watch 277 continues.

SUMMARY...Intense to potentially violent tornado threat across
northeast Iowa and into southwest Wisconsin over the next 2 hours

DISCUSSION...The supercell which formed the intense to potentially
violent tornado which impacted Greenfield and other portions of
southwest Iowa this afternoon has re-intensified after storm
mergers. This storm and another strong supercell to its south are
moving into an increasingly favorable tornadic environment with a
STP of 5 to 6 (per SPC mesoanalysis). The backed surface winds and
vorticity rich environment in the wake of the morning convection
will provide ample low-level vorticity for a sustained tornado
threat into the early evening. One or more long-track, potentially
violent tornadoes are possible in this corridor over the next 90 to
120 minutes.

..Bentley/Thompson.. 05/21/2024

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

ATTN...WFO...DVN...ARX...DMX...

LAT...LON   43319094 43149080 42899079 42509117 41569273 41459346
            42039360 42679316 43289233 43499174 43489133 43499120
            43319094 

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