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Mesoscale Discussion 465
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   Mesoscale Discussion 0465
   NWS Storm Prediction Center Norman OK
   0447 PM CDT Tue Apr 16 2024

   Areas affected...portions of eastern/southeastern Iowa into
   northwestern Illinois

   Concerning...Tornado Watch 117...

   Valid 162147Z - 162315Z

   The severe weather threat for Tornado Watch 117 continues.

   SUMMARY...The ongoing convective line has evolved into semi-discrete
   supercells which will allow for an increase in the risk for all
   hazards over the next couple of hours. A favorable
   shear/thermodynamic environment may also support a strong (EF-2+)

   DISCUSSION...As of 2140 UTC, regional radar and satellite data
   showed the ongoing convective line in southeastern IA has trended
   towards more semi-discrete elements, especially with southward
   extent, over the last hour. The broader environment remains
   favorable for severe storms with moderate buoyancy and strong
   deep-layer shear established. Low-level shear has also increased
   ahead of the storms with backed surface flow supporting 300-400
   m2/s2 of effective SRH observed from area VADs and SPC mesoanalysis.
   With a more supercellular mode emerging, the potential for stronger
   mesocyclones within a strong low-level shear environment suggests an
   increasing potential for tornadoes, in addition to the continued
   risk for damaging winds and hail. STP values of 2-3 along with 0-3km
   CAPE of 50-100 J/kg favor strong low-level stretching of vertical
   vorticity. Large low-level hodogaphs may also support the risk for a
   strong (EF-2+) tornado with the longer lived supercells. This
   increasing risk may extended near the Quad Cities and farther east
   into parts of northwestern IL over the next couple of hours.

   ..Lyons.. 04/16/2024

   ...Please see for graphic product...


   LAT...LON   40139192 40529199 41239180 41809172 42069158 42239133
               42469092 42449068 42489007 42298974 41508988 40649056
               40219150 40139192 

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