Note : If he mentions heavy rain, that refers to Kyogre. You can either catch Kyogre first or wait for the weather to reset.
: Fly to the mentioned route immediately. You will notice the screen glowing with intense sunlight . Look for a new cave entrance (a hole in a wall) that wasn't there before. Find Groudon Pokemon Emerald
: The scientist will report unusual weather patterns. You are looking for him to mention a drought or "extreme sunlight" on a specific route. Note : If he mentions heavy rain, that refers to Kyogre