||A cold front moved southeast across the Dakotas into northwest Iowa during the late afternoon and evening hours. The airmass became quite unstable ahead of the cold front with high temperatures reaching near 90 F. and dew points around 70. CAPE values were around 4000 J/kg by the late afternoon as lifted indices fell to around -9. There was a decent amount of CAPE available in the -10 to -30 C. layer of the atmosphere. I spite of this, very little hail was realized with the freezing level around 16,000 ft. Shear was fairly weak during the day and increased to around 30 kts during the evening hours. A narrow line of thunderstorms developed in northwest Iowa during the early evening hours, then drifted south-southeast into west central and central Iowa during the night. One of the storms produced a brief spin-up tornado in Calhoun County west of Jolley. The LCL level was relatively high in the area, at around 1500 meters. That may have limited the lift of the tornado. It touched down in a field and caused little damage. Many of the storms produced gusty winds and for a brief period of time the line produced severe winds as they moved into an area of higher DCAPE air with values in the 800 to 1000 J/kg range. There were scattered reports of crop damage and downed trees as the storms passed. During the late evening, an area of severe thunderstorms to the northeast of the DMX CWA back developed into northeast Iowa. One of the storms produced Nickel size hail southeast of Waterloo.