Hazardous Seas Alert In Effect From Sunday through Tuesday. Dangerous, Long-Period Swells Expected.

The Hazardous Seas Alert

As we’ve mentioned throughout the week, a long-period swell event is forecast to affect Trinidad and Tobago beginning on Sunday through Wednesday.

The Trinidad and Tobago Meteorological Service has now issued another Hazardous Seas Alert (Yellow Level) for our coastal waters beginning at 8:00 PM Sunday 19th January through 3:00 PM Tuesday 21st January 2020. This comes on the heels of an 8-day rough seas event, attributed to strong, low-level winds.

Note that swells are slated to begin affecting our area shortly after midnight on Saturday into Sunday, well before the alert begins and continue into Wednesday, after the alert ends.

While waves may reach up to 3.5 meters (11.5 feet) in our coastal waters, further north in the Leewards, waves may reach up to 5 meters (16 feet). Hence, a number of islands, including Antigua & Barbuda, St. Vincent and the Grenadines, Barbados, Dominica and others, have high surf and small craft advisories, watches or warnings in effect for their respective areas.

Trinidad and Tobago is NOT under any tropical storm threat, watch or warning.

Based on the latest model guidance and analysis, swell periods may range from 11-16 seconds, capable of producing large, dangerous breaking waves in bays, beaches, and other nearshore areas. This means that wave heights in bays and beaches may reach up to 3 meters, depending on the bathymetry of the area.

Battering waves in nearshore areas are forecast between Sunday and Wednesday, particularly during high tide periods. Coastal flooding is also likely in low-lying coastal areas. Beach and coastal erosion are likely, particularly along Northern and eastern coastlines. Overall, there is a high risk of rip currents and large waves at beaches so disruptions to beachgoers and marine interests are expected.

Spring tides are also slated to begin on Wednesday, so we may see exacerbated effects on that day, during those high tide periods.

Information from the Trinidad and Tobago Meteorological Service concerning the Hazardous Seas Alert in effect from 8:00 PM Sunday through 3:00 PM Tuesday 21st January 2020.

“Strong low-level winds are expected to agitate sea conditions, mainly around Tobago and to the North and East of Trinidad. Waves are likely to reach heights between 2.5 m and 3.5 m in open waters. Long-period northerly swells are also forecast to affect nearshore activity around Tobago and Northern Trinidad.” according to the Trinidad and Tobago Meteorological Service. This “alert” status takes into account the possibility of the event occurring. This event is likely.

The color of the alert indicates the severity of the event and the probability of the event occurring. Currently, the alert level is at Yellow. This means that the hazard is likely and you need to be aware of the impacts of hazardous seas in your area. Moderate impacts are expected, so there is the chance of possible injuries and persons would need to take action to ensure safety. There may be minor damage to property.

Image Credit: Trinidad and Tobago Meteorological Service

7-Day Sea Forecast

Rough and hazardous seas will be attributed to two reasons. Firstly, strong low-level winds up to 55 KM/H sustained and 65 KM/H gusts will agitate coastal waters, predominantly eastern coastal areas of Trinidad and all coastal areas of Tobago.

Secondly, a long-period swell event with swell periods between 11-16 seconds will be affecting all our nearshore coastal areas, including areas not under the official alert. While swells in our northern and eastern areas may produce waves up to 3.0 meters in bays and beaches, battering waves are also possible in sheltered areas such as the Gulf of Paria.

Animation of swells forecast to move across the region from the bomb cyclone, as predicted by the European Centre for Medium-Range Weather Forecasts (ECMWF) wave model (WAM). Time in UTC.

These long-period swells (with 11-16 second periods) are forecast to begin affecting T&T’s coastal waters, originating from the North and Northeast. These swells will mainly affect Northern, Eastern, and Western coastal waters of both islands between Sunday 19th January and Wednesday 22nd January.

Seas Forecast

Sea state forecast through the next 7 days, as rough seas (waves in excess of 2.5 meters) are forecast across Trinidad and Tobago beginning on Sunday through Wednesday. A Hazardous Seas Alert will be in effect from Sunday through Tuesday.
Sea state forecast through the next 7 days, as rough seas (waves in excess of 2.5 meters) are forecast across Trinidad and Tobago beginning on Sunday through Wednesday. A Hazardous Seas Alert will be in effect from Sunday through Tuesday.

The general sea state through the next 7 days is as follows:

Saturday 19th January 2020: Moderate, with waves up to 2.0 meters throughout the period. Winds will be between 10-15 knots from the east to northeast. In sheltered areas, waves are forecast to be near or below 1.0 meters.

Sunday 20th January 2020: Moderate to Rough, with waves generally up to 3.0 meters in open waters. However, after midnight Saturday into Sunday, long period swells are forecast to begin affecting our Northern and Eastern coasts. This is forecast to cause large breaking waves in our nearshore areas. In addition, winds are forecast to increase up to 25 knots, agitating seas in our open waters.

Monday 20th January 2020: Rough, with waves generally between up to 3.0 meters in open waters, occasionally up to 3.5 meters. In sheltered areas, near 1.0 meters, occasionally up to 1.5 and choppy. Long Period Swells to affect the region yet again. This the peak of this brief rough seas event.

Tuesday 21st January 2020: Rough, with waves generally up to 3.0 meters in open waters, occasionally up to 3.5 meters. Both winds and swells are forecast to be on the decline but long-period swells continue to affect our coastal waters.

Wednesday 22nd January 2020: Moderate, with waves up to 2.5 meters throughout the day, gradually subsiding to 2.0 meters by the end of the day Long period swells will also subside by the late afternoon. Seas to return to slight to moderate conditions on Thursday, with waves between 1.5 meters to 2.0 meters in open waters.

Thursday 23rd January to Friday 24th January 2020: Slight to Moderate, with waves between 1.0 to 2.0 meters throughout the days. Long period swells are forecast to have subsided.

Approximate high tides for Port of Spain, Trinidad, and Scarborough, Tobago are seen below. Low-lying coastal areas may experience coastal flooding, particularly 30 minutes prior and 30 minutes after when peak high tides occur.

High Tide Forecast for Trinidad over the next 7 days. A Hazardous Seas Alert will be in effect from Sunday through Tuesday.
High Tide Forecast for Trinidad over the next 7 days. A Hazardous Seas Alert will be in effect from Sunday through Tuesday.
High Tide Forecast for Tobago over the next 7 days. A Hazardous Seas Alert will be in effect from Sunday through Tuesday.
High Tide Forecast for Tobago over the next 7 days. A Hazardous Seas Alert will be in effect from Sunday through Tuesday.

Marine interests are advised to prepare for adverse sea conditions and beachgoers are advised to refrain from heading to bays and beaches beginning Sunday through Wednesday.

Impacts on T&T’s Shorelines (Sunday through Wednesday)

Impacts possible from rough seas include the following:

  • Loss of life;
  • Injuries;
  • Sea search and rescue disruptions;
  • Disruptions to sea transportation;
  • Scarcity of seafood;
  • Damage or loss of boats and fishing equipment;
  • Disruptions to marine recreation and businesses
  • Economic losses.

Other impacts from the high winds, apart from hazardous seas, include:

  • Injuries;
  • Coastal erosion;
  • Localized disruptions of businesses;
  • Disruption to outdoor and sporting activities;
  • Disruption of transportation (air and especially sea) and

Wind of this strength could make some outdoor activities uncomfortable, if not outright dangerous. High winds can create dangerous fallen or blowing objects.

The strongest winds and the highest and most dangerous seas will begin on Thursday. The highest seas will take place in the Atlantic waters of the islands.

There is also the potential for loss of life. There is a high risk of rip currents, strong currents that can carry even the strongest swimmers out to sea.

Rip currents are powerful channels of water flowing quickly away from the shore, which occur most often at low spots or breaks in the sandbar and near structures such as groins, jetties, and piers. If caught in a rip current, relax and float. Don’t swim against the current. If able, swim in a direction following the shoreline. If unable to escape, face the shore and call or wave for help.

There is also the potential for injuries to beachgoers; beach closures; localized disruptions to marine recreation and businesses and financial losses.

High tides combined with onshore wind and swell actions could result in localized coastal flooding and beach erosion.

High surfs can knock spectators off exposed rocks and jetties. Breaking waves may occasionally impact harbors making navigating the harbor channel dangerous.

Saltwater will likely splash onto low-lying coastal roads such as the South Trunk Road at Mosquito Creek, the Guayaguayare Mayaro Road at the Guayaguayare Sea Wall, and the Manzanilla-Mayaro Road. Bays and beaches may become inundated.

Coral reefs may experience increased stress and damages, in addition to localized beach erosion, particularly in areas where battering waves focus.

Note that for those still heading to the beaches, particularly along Eastern coastlines, a significant amount of seafoam may be whipped up due to strong winds.

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