Grains are called to open higher in response to the stressful weather shift. The Monday afternoon Crop Progress report will help set the tone early in the week before focus turns to results from the Pro Farmer crop tour. In the Headlines Many areas are now under excessive heat warnings that started today and will remain open until Thursday. Almost one quarter of the population of the contiguous United States will be threatened with dangerous heat index levels that are expected to register up to 115 degrees. The latest weather model runs removed chances for moisture late next week to leave open a dry stretch of at least 10 days. The annual conference of economists and bankers at Jackson Hole, Wyoming will be held this week and will feature a speech by Federal Reserve Chair Jerome Powell. Traders will look for any clues about monetary policy going forward, but it will still be until September 20th before the next meeting for setting interest rates. Futures-implied odds currently price a probability of 89 percent that the fed funds rate does not change next month from the current level of 5.5 percent. Treasury yields have still been inching higher as market participants…