ZCZC SPCSWOMCD ALL
ACUS11 KWNS 242333 
SPC MCD 242333 
WIZ000-MNZ000-IAZ000-NEZ000-250130-

Mesoscale Discussion 2012
NWS Storm Prediction Center Norman OK
0633 PM CDT Tue Sep 24 2019

Areas affected...Eastern NE...IA...Southern MN...Western WI

Concerning...Tornado Watch 660...

Valid 242333Z - 250130Z

The severe weather threat for Tornado Watch 660 continues.

SUMMARY...Severe threat continues across ww660.

DISCUSSION...Diffluent high-level flow is spreading across the upper
MS Valley ahead of a pronounced short-wave trough. In response,
scattered strong/severe thunderstorms have developed ahead of the
front with several supercell structures now evident from western IA
into south-central MN. This activity is maturing quickly and
additional supercells should emerge over the next few hours as a
reservoir of moisture/instability currently extends ahead of these
storms into northern WI. Latest hail algorithm suggests most
supercells are producing hail in excess of 1" and long-lived
supercells appear possible given the large-scale support and
instability present. Tornado threat continues with these discrete
supercells.

..Darrow.. 09/24/2019

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

ATTN...WFO...ARX...MPX...DMX...FSD...OAX...

LAT...LON   40739703 45559447 45549118 40759397 40739703 

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