Mahaska County Emergency Management Updates for Possible Severe Weather April 10, 2011

Possible severe weather for April 10 2011

The forecast has generally remained the same since yesterday. The severe weather is expected to first impact the state this evening around 5:00 pm – 8:00 pm, followed by a second round of storms late Sunday afternoon and evening. The primary threat for storms tonight is in northern Iowa, with large hail and isolated tornadoes expected during the evening and overnight hours. Updated information indicates that the storms are likely to initially formulate near western Iowa, possibly as far south as the Omaha area, resulting in a higher potential for tornadoes to impact areas of central and western Iowa as well. The storms tonight are expected to develop quickly into isolated super cells, which are likely to produce large hail and tornadoes. Isolated tornadoes are most likely to form along the frontal boundary this evening, expected to settle along Highway 20 in northern Iowa.

The second round of severe weather expected to impact the state on Sunday has a greater potential for high-end, long-track tornadoes, large hail, and damaging winds in the eastern and NE part of the state. Some uncertainty still exists to exactly where the severe weather will initialize on Sunday, however there is high confidence that a severe weather outbreak will occur in the Midwest. The storms are expected to begin in the 3:00 pm – 7:00 pm time frame, with the latest models indicating initial storm development more towards eastern Iowa, closer to the Mississippi River. The Sunday storms are expected to initially be fast moving (50-60 MPH) super-cell storms tracking NE across the state and capable of producing large hail (2” or greater), EF2 – EF3 or stronger tornados, and damaging winds. The storms are expected to evolve into a squaw line later into the evening, with the main threat being damaging winds as it moves north and northeast.