A G3 solar-storm headline is only part of the space-weather picture

Three letters for three disturbances

Space-weather headlines can sound as though every disturbance from the Sun is the same event. NOAA’s Space Weather Prediction Center separates the effects into three scales: G for geomagnetic storms, S for solar radiation storms and R for radio blackouts.

Each scale runs from 1, described as minor, to 5, described as extreme. The letter identifies the type of disturbance; the number indicates severity within that type.

A G3 designation is a strong geomagnetic storm, not a universal rating for every solar effect.

Possible effects need context

NOAA’s geomagnetic scale lists potential effects on electrical systems, satellites, radio communication and satellite navigation. It also gives examples of how far south auroras have been seen at different levels.

These are descriptions of possible effects, not a promise that a particular community will lose electricity or see northern lights.

For someone in Gretna considering a night outside, a storm rating is therefore only a starting point. It does not establish viewing conditions at a particular address or time.

The center publishes alerts, watches and warnings separately from the explanatory scales. Check the bulletin’s event type, issue time and applicable period before sharing it.

A screenshot of an old warning can look urgent long after its time window has passed.

This is a guide to the terminology, not a report that a particular solar storm is affecting Virginia today.