The threat for heavy thunderstorms with flooding potential exists over the long holiday weekend for Ia. According to the European model, light showers are forecast for extreme northern Ia, southern Mn and Wi by early tomorrow AM where drier weather is needed to allow planting progress. The American models are not as wet, but bring moderate rainfall to southern Mn corn belt areas by late tonight and early tomorrow developing southeastward and increasing in strength into northeastern Ia during the day tomorrow. This wet weather would delay field working progress over the weekend. According to the wetter model, western and southern Ia could possibly receive 2" to 4" rains over the weekend into next week. The best potential for thunderstorms will be during the nighttime and early morning hours each day, the potential for widespread heavy rainfall does exist. This may lead to river flooding and possibly flash flooding in some areas. Additional rains are forecast early to mid next week over the northwestern corn belt including northern Ia, southern Mn and Dakotas and eventually including southern Wi as well. Further east over central Il, In and into Oh, scattered thunderstorms will occur throughout the Memorial Day holiday weekend, although there will be several dry periods as well. The best rain chances appear to be Saturday night and Sunday. Temperatures will slowly warm through the weekend, with highs in the mid 70s prevailing by Memorial Day. Warmer temperatures are forecast for the 6-10 day period with scattered thunderstorms. The warm trend should continue in the 11-15 day period as well.