Constellations
Orbital elements are fetched once and propagated in your browser, so nothing streams while you watch.
Vehicle type
Everything is drawn; switch one off to take it off the map.
Ship type
Everything is drawn; switch one off to take it off the map. A ship's type arrives with its static report, every six minutes, so freshly seen ships start as "not reported".
Minimum face height
Minimum quality
Water temperature
Defaults: 3 ft faces and Fair or better, which is what most people would paddle out for. Quality is a call from swell exposure, peak period and wind against each break's facing; nothing selected under water temperature means every band is shown.
Weather layers
Storms are tropical cyclones with an advisory in force (NHC, JTWC). Rain and snow are every 0.25° cell where the GFS weather model says it is falling this hour. Sunshine is assumed everywhere else.
Rain intensity
Bands are rainfall rate (WMO): light under 2.5 mm/h (0.1 in/h), moderate to 7.6 mm/h (0.3 in/h), heavy to 50 mm/h (2 in/h), violent above. Cells under 0.2 mm/h — a trace — are left out.
Snow intensity
Bands are snowfall rate: flurries under 0.1 in/h (0.25 cm/h), light to 0.5 in/h, moderate to 1 in/h, heavy above that. The rate is the model's liquid precipitation times a snow-to-liquid ratio that follows temperature (10:1 near freezing, more in colder air).
Clouds
Total cloud cover from the same GFS hour, to the nearest 5 %, drawn under the rain and snow wherever at least 30 % of the sky is covered. The three chips beside Clouds switch the types: partly cloudy to 60 %, mostly cloudy to 85 %, overcast from 90 % — switch Overcast off to lift the solid deck and keep the thin cloud. Land only hides clouds over the sea too.
Floods
Flooding in force: every flash flood, river flood, coastal flood and storm surge alert the US National Weather Service has out, the river gauges standing at or above their action stage, and the flood events GDACS is tracking worldwide. Areas are the alert's own outline where it has one, otherwise the zones it names. On by default.
Wind
The sustained wind at ten metres from the same GFS hour — the wind that keeps blowing, not gusts, which run higher and are not drawn. Over land and sea alike, nothing in the sky. Off by default, and drawn from 20 mph up unless you raise the floor. Arrows point the way the wind blows and are coloured by Beaufort band.
Rain over the tropical oceans and snow over polar sea ice are most of the area. The Stats lists follow these filters.
Aircraft colour
Category
Everything is drawn; switch one off to take it off the map.