High behind a front, e.g

• Body behind the front
• Cold front, e.g
• Weather phenomenon, or this puzzle's theme
• Weather-forecaster's concern
• Warm front cause
• Polar or tropical weather phenomenon
• Cold front cause
• Meteorologist's concern

Wiktionary Word definitions in Wiktionary
n. (context physics meteorology English) a widespread body of air, the properties of which can be identified as: having been established while that air was situated over a particular region of the earth's surface (airmass source region) and undergoing specific ...