(Undated)- Gas prices in Minnesota are expected to start dropping soon after an unexpected spike over the last week. Experts say unexpected refinery shutdowns led to a jump of 30 to 40 cents per gallon around the state. Regulations that allow the sale of winter-blend gasoline will go into effect this weekend. Analysts say that will help push gas prices lower, as petroleum companies already have winter-blend gasoline in stock and ready to deliver.