MESOSCALE DISCUSSION 0370
   NWS STORM PREDICTION CENTER NORMAN OK
   0333 PM CDT SUN APR 18 2004
   
   AREAS AFFECTED...CNTRL MN
   
   CONCERNING...TORNADO WATCH 83...
   
   VALID 182033Z - 182230Z
   
   ...ENVIRONMENT IS FAVORABLE FOR SEVERE TSTMS NEXT FEW HOURS ACROSS
   CNTRL MN...
   
   LATEST RADAR FROM MINNEAPOLIS SHOWS STORMS RAPIDLY DEVELOPING ALONG
   AND NORTH OF WARM FRONT WHICH EXTENDS FROM BBB/STC/RZN. VERY STRONG
   TEMPERATURE GRADIENT NOTED...WITH UPPER 80S/90S ACROSS SWRN MN AND
   UPPER 30S/LOWER 40S NORTH. COVERAGE IS EXPECTED TO INCREASE VERY
   QUICKLY IN ATMOSPHERE CHARACTERIZED BY SBCAPE VALUES NEAR 2000 J/KG.
   
   
   SUPERCELLS ARE LIKELY...GIVEN DEEP LAYER SHEAR VALUES AOA 50 KT.
   TORNADOES WILL BE POSSIBLE WITH ANY SURFACE BASED STORM THAT HAS
   MAXIMIZED SHEAR ALONG THE BOUNDARY. RECENT 0-1KM SRH HELICITY VALUES
   ARE NEAR 150 M2/S2 AND ARE CONSIDERABLY LARGER FARTHER EAST. THREAT
   INITIALLY MAY BE FROM LARGE HAIL AS STORMS STRUGGLE TO OVERCOME THE
   TREMENDOUS SHEAR. HOWEVER...TORNADO THREAT WILL INCREASE AS SFC LOW
   APPROACHES.
   
   IN ADDITION TO THE THREAT OF TORNADOES...VERY LARGE HAIL IS LIKELY
   WITH STORMS...ESPECIALLY IN ORGANIZED SUPERCELLS. LOCALLY RUN HAIL
   MODEL SUGGESTS HAIL GREATER THAN 2" IS POSSIBLE.
   
   ..TAYLOR.. 04/18/2004
   
   
   ATTN...WFO...DLH...MPX...FGF...
   
   44869508 45769577 46829334 46629237 46069248 45429274
   45189342 45009403