Storm Prediction Center Mesoscale Discussion 1979

   Mesoscale Discussion 1979
   NWS Storm Prediction Center Norman OK
   0244 PM CST Fri Dec 10 2021

   Areas affected...Parts of west central through northeastern Missouri
   and adjacent portions of southeastern Iowa and west central Illinois

   Concerning...Severe potential...Watch possible 

   Valid 102044Z - 102245Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Isolated supercell development potentially becoming
   capable of producing tornadoes appears possible across parts of
   north central Missouri prior to 6 PM CST.  While it is not certain
   that a watch will be needed, trends are being monitored for this
   possibility.

   DISCUSSION...The center of a deepening surface cyclone is now north
   of Topeka, with a corridor of 3-5 mb 2-hourly surface pressure falls
   along a developing warm frontal zone to its east shifting
   east-northeastward across northern Missouri.  This is occurring in
   advance of consolidating, larger-scale mid-level troughing forecast
   to progress east of the the Colorado Rockies into the central Great
   Plains by 11/00Z.  This is preceded by a short wave perturbation of
   subtropical eastern Pacific origin, which appears to still include
   one prominent mid-level cyclonic vorticity center approaching the
   Kansas City area.

   It appears that the stronger forcing for ascent associated with the
   cyclonic vorticity center will progress east-northeast of the Kansas
   City area, before substantive boundary-layer destabilization can
   take place.  However, models suggest that a narrow corridor of at
   least modest, but deepening, boundary layer moisture is possible
   along a 50-60+ kt southwesterly pre-frontal 850 mb jet axis across
   western through northern Missouri.  As the surface warm frontal zone
   continues to advance north of the Missouri River/Interstate 70
   corridor, the environment along it might become conducive to
   isolated strong to severe storm development prior to 11/00Z,
   particularly south of Chillicothe into areas southeast of
   Kirksville.

   Even with some moistening, relatively warm mid-level temperatures
   may tend to minimize mixed-layer CAPE, but beneath 90-100 kt
   southwesterly 500 mb flow, hodographs are forecast to become
   favorable for supercells potentially accompanied by a risk for
   producing tornadoes.

   ..Kerr/Thompson.. 12/10/2021

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

   ATTN...WFO...LSX...DVN...SGF...EAX...

   LAT...LON   39889333 40579133 39709124 39329135 38859228 38509349
               39009388 39889333