Meteorological noise

From Glossary of Meteorology

meteorological noise

Originally, the small-scale, high-frequency solutions to the fundamental equations of hydrodynamics, which may obscure the solution required for numerical forecasting.

However, the meaning must be extended to include unwanted frequencies in general, and the term "noise" may be applied legitimately by the investigator of atmospheric tides to the moving cyclonic-scale weather patterns.
See noise filtering, Kalman–Bucy filter.