Mesoscale Discussion 0257
   NWS Storm Prediction Center Norman OK
   0642 PM CDT Sat Mar 28 2020

   Areas affected...Northeast IA...Southwest WI...Northwest IL

   Concerning...Tornado Watch 69...

   Valid 282342Z - 290115Z

   The severe weather threat for Tornado Watch 69 continues.

   SUMMARY...Tornado threat has spread just north of tornado watch #69;
   however, areal extent north of watch may be too limited to issue a
   new ww.

   DISCUSSION...Narrow wedge of moist/unstable warm sector is advancing
   north ahead of the surface low across eastern IA toward southwestern
   WI. Northern-most supercell of significance (Fayette County) appears
   rooted in the boundary layer where near 60F surface dew points
   reflect the true warm sector. This storm should continue its
   northeast movement toward Clayton County, then perhaps into Grant
   County WI where it may struggle to remain surface based if dew
   points do not increase across this region. Unless it becomes more
   clear that the warm sector will advance appreciable north of watch
   #69, areal extent of tornado threat north of the watch appears too
   small to issue another watch. Will continue to monitor.

   ..Darrow.. 03/28/2020

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

   ATTN...WFO...LOT...MKX...DVN...ARX...DMX...

   LAT...LON   42709213 43209123 43078977 42398928 41918994 42089179
               42709213