El Nino Watch
Lines on the map for tropical cyclones: past track and forecast positions from JMA and JTWC.
Hazards
For JMA and JTWC storms the map item has a line (GeoJSON LineString, [lon, lat]) joining the past track and the forecast positions, and a point at the current position. The payload lists each forecast point with time, winds and distance to Samui.
Limits. Forecast points beyond 72 h are uncertain by several hundred km.
Colour = severity by distance: red within 300 km of Samui, orange within 800 km, green further away. The same storm can appear twice (JMA and JTWC) with slightly different positions and winds.
A storm's closest forecast approach is what decides whether the sea around Samui will close; watch storms whose line points toward the Gulf of Thailand.