Upolu Point tidal current predictions

Now

Ebb 1.4 ktToward NNE (30°)

Next slack

Sat 2:17 AMHST

Next max flood

0.4 ktSat 3:49 AM

Next max ebb

1.6 kt9:59 PM

Knots along the channel: above the line the flood, running in toward WSW (241°); below it the ebb, running out toward NNE (30°). Times are Hawaii-Aleutian Standard Time. Today: slack 1:53 AM, flood 0.3 kt 3:23 AM, slack 5:06 AM, ebb 1.6 kt 9:35 AM, slack 1:57 PM, flood 0.4 kt 3:32 PM, slack 5:23 PM, ebb 1.6 kt 9:59 PM.

• Hurricane Watch Hurricane Watch issued September 25 at 2:17PM HST by NWS Honolulu HIUntil Sat 3:30 AM
  Full text

  * WHAT...East winds 35 to 45 knots. Seas 15 to 20 feet. * WHERE...Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters and Big Island Southeast Waters. * WHEN...Through Saturday afternoon. * IMPACTS...Extremely strong winds will cause hazardous seas which will likely capsize or damage vessels and severely reduce visibility.

  Mariners should remain in port, alter course, and/or secure the vessel for extreme conditions before conditions deteriorate further.

• Tropical Storm Warning Tropical Storm Warning issued September 25 at 2:17PM HST by NWS Honolulu HIUntil Sat 3:30 AM
  Full text

  * WHAT...East winds 35 to 45 knots. Seas 15 to 20 feet. * WHERE...Alenuihaha Channel, Big Island Windward Waters, Big Island Leeward Waters and Big Island Southeast Waters. * WHEN...Through Saturday afternoon. * IMPACTS...Extremely strong winds will cause hazardous seas which will likely capsize or damage vessels and severely reduce visibility.

  Mariners should remain in port, alter course, and/or secure the vessel for extreme conditions before conditions deteriorate further.

The flood is the tidal current running in from the sea, the ebb the current running back out. Slack water is the short turn between them, when the current is weakest: the time to cross a strong channel, anchor, or dive. Slack in a channel is not the time of high or low tide; it can come hours after.

Speeds are knots along the channel's main axis, and directions are degrees true toward which the water flows, as NOAA prints its tables. A current against the wind stands the waves up steep and close together.

Predictions are astronomical: the moon and the sun, not the weather. Strong wind, river flow after heavy rain and storm surge all change the real current.

• Tide times at Mahukona 5.4 mi
• Tide times at Kawaihae 16 mi
• Forecast for Hāwī, HI
• Open the live map with tidal currents
• All tidal current stations in Hawaii

Tidal current predictions from NOAA’s Center for Operational Oceanographic Products and Services (CO-OPS), station HAI1127, bin 27: original at NOAA. Marine alerts from the National Weather Service.