Definition
An unscheduled planning forecast issued by an Air Route Traffic Control Center (ARTCC) weather coordinator describing conditions expected to begin within four to twelve hours that may affect the flow of air traffic in a specific center's area.
Plain English
A short-notice weather heads-up written for air traffic controllers that warns of weather likely to disrupt traffic flow in a particular region within the next 4 to 12 hours.
Context Anchor
Pilots may encounter this term in weather and air traffic flow planning, especially when widespread weather could affect routes, delays, or traffic volume in a large region.
Derivation
"Meteorological" comes from the Greek meteoron, meaning something high in the sky, and is the root of meteorology, the study of weather. "Impact Statement" is borrowed from planning language meaning a written assessment of how something will affect operations. Together: a written assessment of how weather will affect ATC operations.
Why Pilots Care
Allows pilots to anticipate weather that may cause delays, reroutes, or cancellations and to adjust flight planning accordingly.
Intuition Check
Do not read this as a report that weather has already caused a problem. In FAA use, it is a planning forecast about expected weather and its likely effect on air traffic flow.
Example Sentence 1
The Center weather coordinator issued a Meteorological Impact Statement warning of a line of thunderstorms expected to cross the western arrival corridor within six hours.
Example Sentence 2
According to the Meteorological Impact Statement, strong winds and turbulence were forecast over the mountains after 1400 local time.