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Mesoscale Discussion 703
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   Mesoscale Discussion 0703
   NWS Storm Prediction Center Norman OK
   0632 PM CDT Mon May 09 2022

   Areas affected...portions of central and eastern Iowa into far
   southwest Wisconsin

   Concerning...Severe potential...Watch possible 

   Valid 092332Z - 100100Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Thunderstorm development and coverage may increase over
   the next few hours. A few severe thunderstorms may develop,
   supporting a large hail risk in addition to a few damaging gusts. A
   tornado also cannot be ruled out. Conditions are being monitored for
   the need of a WW issuance.

   DISCUSSION...A towering cumulus field along and immediately ahead of
   a dryline continues to build across central/north-central IA, where
   signs of convective initiation attempts have become evident in the
   Boone County, IA vicinity. A 990 mb surface low and accompanying
   mid-level impulse continues to track northward while crossing the
   U.S. border into Manitoba. As such, upper support is lacking across
   IA, with low-level dryline convergence and late afternoon
   boundary-layer mixing serving as the primary factors for convective
   initiation. Upper 60s F surface dewpoints overspread by a well-mixed
   boundary layer (8 C/km 0-3km lapse rates) are contributing 3000 J/kg
   MLCAPE. Modest veering in the lowest 3 km supports modestly curved
   hodographs (evident via RAP forecast soundings and some of the
   latest KDMX/KDVN VAD profiler data. Any storms that can develop,
   mature and sustain themselves will likely become supercells. Given
   surface temperatures exceeding 90F though, supercell structures are
   expected to be relatively high-based, with large hail and damaging
   gusts the main threats (given 8 C/km mid-level lapse rates and a
   well-mixed boundary layer extending past 850 mb in depth). Given the
   magnitude of buoyancy and modest low-level veering of the vertical
   wind profile, a tornado cannot be ruled out.

   Confidence in storm development is not overly high given the overall
   lack of deep-layer ascent. Still, conditions are being closely
   monitored for a WW issuance given the presence of the aforementioned
   favorable thermodynamic/kinematic environment.

   ..Squitieri/Thompson.. 05/09/2022

   ...Please see for graphic product...


   LAT...LON   41359384 41779391 42529358 43099324 43319290 43449179
               43419081 43169045 42699036 42039092 41569162 41409249
               41339337 41359384 

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