Chelsea River, below bascule bridge tidal current predictions

Now

SlackTurning

Next slack

Mon 12:47 AMEDT

Next max flood

0.3 kt8:49 PM

Next max ebb

0.3 ktMon 3:44 AM

Knots along the channel: above the line the flood, running in toward E (88°); below it the ebb, running out toward W (272°). Times are Eastern Daylight Time. Today: slack 12:07 AM, ebb 0.3 kt 2:59 AM, slack 6:32 AM, flood 0.3 kt 8:25 AM, slack 12:34 PM, ebb 0.3 kt 3:37 PM, slack 6:59 PM, flood 0.3 kt 8:49 PM.

• Coastal Flood Advisory Coastal Flood Advisory issued September 27 at 2:27PM EDT until September 29 at 12:00AM EDT by NWS Boston/Norton MAUntil Tue 12:00 AM
  Full text

  * WHAT...For the Coastal Flood Advisory, up to one half foot of inundation above ground level in low-lying areas near shorelines and tidal waterways (3.3 to 12.5 feet Mean Lower Low Water). For the High Surf Advisory, large breaking waves of 6 to 10 feet in the surf zone. * WHERE...Eastern Essex MA, Suffolk MA, Eastern Norfolk MA, Eastern Plymouth MA, Barnstable MA, Dukes MA and Nantucket MA Counties. * WHEN...For the Coastal Flood Advisory, until midnight EDT Monday night. For the High Surf Advisory, until 8 PM EDT this evening. * IMPACTS...Roads remain passable. Low lying areas and roads near Nantucket Harbor, including Easy Street, may experience pockets of shallow flooding less than one foot deep. Dangerous swimming and surfing conditions and localized beach erosion.

  If travel is required, allow extra time as some roads may be closed. Do not drive around barricades or through water of unknown depth. Take the necessary actions to protect flood-prone property. Inexperienced swimmers should remain out of the water due to dangerous surf conditions.

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. This is a subordinate station: NOAA predicts it from a nearby harmonic station by fixed corrections to the times and speeds of its slack waters and maxima, so the curve between them is less exact.

• Chelsea River, west of bascule bridgeSubordinate current station0.7 mi
• Charlestown Pier 1Harmonic current station0.9 mi
• Mystic River Bridge, northwest ofSubordinate current station1.1 mi
• East Boston, Pier 10, southeast ofSubordinate current station1.1 mi
• Mystic River Bridge, 0.1 nmi west ofSubordinate current station1.1 mi
• South Boston, Pier 4, 0.2 nmi NNE ofSubordinate current station2.2 mi
• Ted William TunnelHarmonic current station2.2 mi
• Snake Island, southwest ofSubordinate current station2.6 mi

• Tide times at Chelsea St. Bridge, Chelsea River 0.3 mi
• Tide times at Charlestown, Charles River entrance 1.6 mi
• Tide times at Boston 2.4 mi
• Forecast for Chelsea, MA
• Open the live map with tidal currents
• All tidal current stations in Massachusetts

Tidal current predictions from NOAA’s Center for Operational Oceanographic Products and Services (CO-OPS), station ACT1231, bin 1: original at NOAA. Marine alerts from the National Weather Service.