Meteorologists say the remnants of Tropical Storm Isaac could bring welcome rain to some states in the Midwest this week, although it is unlikely to break the drought that gripped the region. States in the Mississippi River valley are the most likely to benefit from the storm. Some areas are more than a foot of rain short this year. The National Weather Service predicts 2 to 6 inches of rain later this week. Heavy showers could also aid traffic on the Mississippi River, which has seen temporary closures due to low water conditions.