Notes on reading the weather

How the models work, what they disagree about, and how to read them without a meteorology degree.

• The Météo-France models, what they do well and what they do not

  AROME sees the storm over your parish but stops at two days. ARPEGE reaches four days but averages your valley away. What each one is good at, where it goes wrong, and which to read for the question you actually have.

• Why your forecast should be twenty-one forecasts

  An ensemble forecast does not give you a number, it gives you a range — and the range is what tells you whether you can plan your week around it. How it works, and how to read one.