break in the weather; weather turning bad
Refers to a change for the worse in weather conditions, often used in forecasts or when describing a sudden deterioration.
A break in the weather is expected tomorrow.
There is a risk of the weather turning bad from the afternoon.
Compound of 天気 (weather) + の (possessive particle) + 崩れ (noun form of 崩れる, 'to collapse, break down'). Literally 'collapse of the weather'.