Onshore Current Advection
ProWhether the forecast current is pushing water up the slope toward shallower ground (red) or pulling it offshore (blue). Switched off over flat bottom, so a blank deep basin is normal.
Updates daily; forecast in 3-hour steps
More detail
What you see. White is current running along the depth contours. Blank is flat bottom, or the strip along the beach. It is roughly the speed of that push. The color scale runs to about 0.8 knots either way. On the website the crosshair readout gives the speed in knots when your distance unit is nautical miles. A moderate value can be a fast current on a gentle rise or a slow one on a steep wall.
How to use it. Use it along the shelf edge, canyon walls and banks, the places where the bottom really slopes. Trust a direction that holds across several frames. A turn of the tide can flip red to blue. In Layer Settings you can change the Colormap, the Range and the Opacity.
How it relates to the other current layers. Currents shows how fast the same forecast current runs, and the Currents button shows which way. This layer picks out only the part of that current that crosses the slope. Surface Convergence shows where the flow squeezes together.
Who makes it. RipIQ makes this layer itself from the forecast surface current of HYCOM (U.S. Navy model) and the charted bottom depth (GEBCO, with NOAA's finer charts along the U.S. coast). The layer covers the Gulf of America, the East Coast and Baja.
Its limits. It does not include the push of wind and waves on the boat, so it will not match your drift. It uses the surface current only. It is blank within about 1.25 nautical miles of the beach. There are eight frames a day, three hours apart. The newest frame is from a run started between one and four days ago, and the time slider reaches up to 7 days ahead as a forecast.
The numbers
| How often it updates | 8 frames a day, three hours apart |
| How fresh it usually is | The newest frame is from a run started between one and four days ago |
| How detailed it is | About 5 nautical miles of real detail in the current |
| Where it covers | Gulf of America, East Coast and Baja, and only where the bottom really slopes. Flat basin is blank |
| How far back you can look | 8 days back |
| How far forward you can look | Up to 7 days ahead, as a forecast |
| Observed or modeled | Calculated by RipIQ, from the current of HYCOM (U.S. Navy model) and a fixed bottom chart |
| What you see on screen | Red is onshore, blue is offshore, white is along the contours. On the website the readout is in knots when your distance unit is nautical miles. The color scale runs to about 0.8 knots either way |
Source: computed by RipIQ from HYCOM model surface currents and GEBCO seafloor depth.