Storm Prediction Center Mesoscale Discussion 380

   Mesoscale Discussion 0380
   NWS Storm Prediction Center Norman OK
   0205 PM CDT Sun Apr 07 2024

   Areas affected...Portions of far southeastern SD into IA...
   northwestern IL...and extreme northeastern MO

   Concerning...Severe potential...Watch unlikely 

   Valid 071905Z - 072130Z

   Probability of Watch Issuance...5 percent

   SUMMARY...An isolated threat for strong/gusty winds and perhaps a
   brief tornado may exist with any low-topped thunderstorms that can
   develop. Watch issuance is not expected.

   DISCUSSION...Recent visible satellite imagery shows a cu field
   gradually deepening across IA and vicinity along an occluded front
   extending eastward from a deep surface low in northeastern NE.
   Low-topped convection has recently developed in far southeastern SD,
   in close proximity to the surface low. Boundary-layer moisture
   remains modest across this region, with surface dewpoints generally
   in the mid 40s to around 50. Still, filtered diurnal heating of this
   airmass is contributing to around 75-125 J/kg of 0-3 km MLCAPE in a
   narrow zone focused along the front per latest mesoanalysis
   estimates. Near-surface vorticity is also likely maximized along
   this boundary, with modest low-level shear present based on recent
   VWPs from KDMX/KDVN.

   Even with the moisture/instability limitations, there should be some
   chance for ongoing low-topped thunderstorms to gradually increase in
   coverage and intensity over the next few hours this afternoon into
   IA and perhaps northwestern IL. Given steepened lapse rates through
   the cloud-bearing layer, isolated strong/gusty winds appear possible
   with the more robust cores. A brief tornado/landspout or two may
   also occur, mainly focused along the occluded front where
   near-surface vorticity overlaps with maximized 0-3 km CAPE and steep
   boundary-layer lapse rates. However, the overall severe threat this
   afternoon is expected to remain too isolated/marginal to justify
   watch issuance.

   ..Gleason/Goss.. 04/07/2024

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

   ATTN...WFO...DVN...DMX...FSD...

   LAT...LON   41259366 41669477 42599600 43429738 43439631 42619311
               42269227 41289055 40359085 40309160 40899231 41259366