Mesoscale Discussion 1055
   NWS Storm Prediction Center Norman OK
   
   Areas affected...Northern Missouri...southeast Iowa...and northwest
   Illinois

   Concerning...Severe potential...Watch unlikely 

   Valid 3:45PM CDT - 5:45PM CDT

   Probability of Watch Issuance...20 percent

   SUMMARY...An ongoing squall line and developing T-storms along a
   cold front will continue to pose an isolated hail/wind risk through
   the early evening hours. This threat will remain limited given the
   marginal kinematic environment.

   DISCUSSION...A loosely organized squall line continues to move from
   southern IA into northern MO. While this line has struggled to
   intensify substantially (likely due to meager 20-30 knot effective
   bulk shear values and a weak line-normal shear component), the
   increase in MLCAPE through the afternoon has allowed this line to
   persist with occasional intense updrafts (noted in GOES IR imagery
   and upticks in vertically integrated ice). Some outflow
   consolidation is noted in regional velocity data, suggesting that
   damaging, to perhaps severe, winds remain possible in addition to
   isolated large hail.

   To the east, cells are developing along a diffuse cold frontal zone
   across eastern IA into northwest IL. Although this region has warmed
   sufficiently for MLCAPE values to increase to near 1000 J/kg,
   upper-level flow diminishes with eastward extent, resulting in a
   modest kinematic environment. Additionally, storm motions along the
   boundary may favor a tendency for destructive storm interactions
   with time that will modulate a more substantial severe threat.
   Nonetheless, cold temperatures aloft and minimal inhibition will
   support periodic intense updrafts that may be capable of large hail
   and sporadic strong winds. This activity will likely persist into
   the early evening, but given the limited nature of the kinematic
   environment a watch is not anticipated.