Time, dates and the time slider
If a layer shows yesterday, that is the data's own date. The forecast run you see started between one and four days ago, so on the time slider today sits a few stops right of the anchor.
More detail
Reading the clock. Once-a-day layers show a date instead of a clock time.
Why the slider does not start on today. Day zero on the slider is the day the forecast was run. HYCOM (U.S. Navy model) makes one new run a day.
How old a satellite layer is. Each observed layer shows its own age in the layer list.
Stops on the slider. The HYCOM (U.S. Navy model) forecast and the species maps have eight stops a day, three hours apart. Most GOES-19 layers have one an hour. The two live sea-temperature layers over the Gulf of America, the East Coast and Baja have one every five minutes. The once-a-day layers have one. A dimmed stop on the website, or a hollow dot on the iPhone app, means that layer has no data for that moment.
While the map stays open. A new satellite picture appears by itself as a new stop at the end of the slider. It appears within a few minutes for the two live sea-temperature layers and within about an hour for the other satellite layers, or sooner while an hourly GOES-19 layer is on the map. If you are sitting on the newest stop of a live or hourly layer, the map moves on to the new picture; on any other stop it stays where you put it. The iPhone app picks up a new forecast run when you come back to the app after some time away or open it again, and the website when you reload the page. If the iPhone app shows "Data may be outdated", it is drawing what it saved last time and has not finished fetching the newest data.
When two layers disagree. Two temperature layers on the same stop can show different moments: they come from different sources on different schedules.
The numbers
| How old a layer is | Every observed layer shows its own age in the layer list |
| The five-minute sea-temperature frame | Refreshes every five minutes over the Gulf of America, the East Coast and Baja |
| Which day the anchor is | The forecast's own run day, started between one and four days ago |
| When a new forecast arrives | Once a day |
| Stops per day, ocean forecast and species maps | Eight, three hours apart |
| Stops per day, GOES-19 satellite layers | One an hour |
| Stops per day, the once-a-day layers | One, shown as a date rather than a clock time |
| A stop the layer has no data for | Dimmed on the website, a hollow dot on the iPhone app |