The National Weather Service in San Juan, Puerto Rico, is warning that waves to 10 feet are forecast along the northern coast of St. Thomas starting Thanksgiving Day, with a high risk of dangerous rip currents.
“A long-period northerly swell is expected to cause hazardous marine and coastal conditions across the Atlantic waters and passages, and along the northern exposed beaches of the islands from Thanksgiving Day through the weekend,” according to a news release the Weather Service issued on Monday.
Seas are forecast to build to around 8 feet or higher for the Atlantic waters, and the long-period swell is expected to cause rough surf conditions and life-threatening rip currents from the northwest to east coast of Puerto Rico, including Culebra and some beaches of northern Vieques, the release stated.
Across the USVI, the main threat is expected along the west to the northern coast of St. Thomas, but the threat of strong rip currents could spread and increase across the rest of the islands during the weekend, the National Weather Service stated.
According to the release, potential hazards and impacts include:
- Marine: Seas are forecast to build quickly to between 6 and 8 feet, and occasionally up to 10 feet by Thursday afternoon across the offshore Atlantic waters, and between 5 and 7 feet or higher across the Atlantic coastal waters, including the local passages. Small Craft Advisory conditions are expected to continue during the weekend as the swell slowly subsides across the offshore Atlantic waters.
- Coastal areas: The swell is likely to cause large breaking waves between 8 and 12 feet, and occasionally higher at times, along the outer reefs and unprotected, north-exposed beaches of Puerto Rico, and between 6 and 10 feet, and occasionally higher, in similar areas of Culebra and along the northwestern coast of St. Thomas. Breaking waves of these heights are associated with life-threatening rip currents and high surf conditions.
- Timing: The swell is forecast to peak Thursday evening into Friday morning, and then slowly subside through Sunday.