This winter storm looks to be the worst of the season for parts of Iowa. The Gulf of Mexico is going to open up sending moisture streaming northward. There will be a nose of warm air in the mid-levels of the atmosphere, creating the scenario for a potentially significant freezing rain event over central/southern Iowa. The key to ice accumulations with this storm seems to be the placement of the sub-freezing surface temperatures. Surface temperatures may actually rise above freezing in the far south, where precipitation may turn into plain old rain. However, where surface temperatures remain at or below freezing, the ice accumulations could reach 0.5"+. North of the line, ice accumulations may be from 0.25-0.5" or more as well. Farther north into central/northern Iowa, precip should be more snow, with heavy accumulations possible... 6-10". Ames/Des Moines seems to be located in the area that will see potentially significant icing, followed by a few inches of snow.
My way-to-early prediction for Ames/Des Moines is 0.3" of ice accumulations followed by 5" of snow.
My way-to-early prediction for Ames/Des Moines is 0.3" of ice accumulations followed by 5" of snow.
