Definition
The direction and speed at which an individual thunderstorm cell is traveling across the ground, typically displayed on a Multi-Function Display (MFD) as a vector arrow extending from the cell, with the length or accompanying data indicating speed.
Plain English
Which way a thunderstorm is going, and how fast. On the cockpit display it usually shows up as an arrow sticking out of the storm.
Context Anchor
Seen on cockpit weather displays that show thunderstorm information, especially when reviewing weather on a multi-function display before or during a flight.
Derivation
“Storm” refers to disturbed weather, and “cell” is used in weather to mean one distinct, organized area of storm activity. “Movement” means its change in position over time. Together, the phrase points to the path a particular storm area is taking.
Why Pilots Care
Knowing storm cell movement lets pilots choose routes that keep distance from active thunderstorms.
Grounding Statement
If the storm symbol is moving toward your planned path, the safest choice may be to change course early and leave plenty of room.
Intuition Check
Do not read storm cell movement as a live guarantee of exactly where the storm is now or where it will be. It is a recent-data indication of the storm area’s general direction, and sometimes speed, so it must be used with caution and extra spacing.
Example Sentence 1
The MFD showed the storm cell movement as a short arrow pointing northeast at 25 knots, so the pilot decided a southerly deviation would clear the cell well before reaching it.
Example Sentence 2
Tracking storm cell movement over several minutes helped us decide the cells would pass south of our destination.