Thunderstorm & lightning alert

A yellow lightning-bolt banner ⚡ appears on the METAR and on any TAF period containing thunderstorm or lightning activity.

• At the station — a thunderstorm group in the body, e.g. TSRA, +TSRA, TSSN, or bare TS.
• In the vicinity — VCTS (thunderstorm 5–10 nm out).
• Lightning in remarks — e.g. OCNL LTGICCG OHD, FRQ LTG VC; distant strikes show as LTG DSNT (10–30 nm) and are labeled distant.

The sensor-inoperative flag TSNO is deliberately ignored — it does not indicate activity.

Related model measure of instability: CAPE.