Display this 'Weathering' explanation on your smart board/interactive whiteboard. Model how to write an explanation to your Upper Primary students using this colour-coded model. Discuss the purpose, structure and language features of explanations.
Follow this lesson with a Shared Writing lesson where you and the students co-write an explanation using the same colour-coded structure.
I have been using this colour-coding structure with Upper Primary students for years. The quality and amount of writing that struggling students can produce when they only need to focus on one colour at a time never ceases to amaze me.