Swells From Tropical Storm Paulette To Affect Leewards

Tropical Storm Paulette is being affected by strong wind shear currently in the Central Atlantic. However, conditions are forecast to become favorable later this weekend for strengthening, and this system is now forecast to near Bermuda at or near hurricane strength.

This is the seventeenth tropical cyclone of the 2020 Atlantic Hurricane Season and the earliest 16th named storm in Atlantic history. The previous record was Philippe, which formed on September 17th, 2005.

This tropical cyclone is not forecast to directly impact Trinidad, Tobago, or the Lesser Antilles. However, Paulette has produced long-period swells that are propagating to the region, with adverse impacts possible across the Leewards tonight through tomorrow.

List of names for the 2020 Atlantic Hurricane Season. The next named tropical cyclone will be called Sally.

A trough extending southward from its large circulation has degraded the weak pressure gradient across T&T and the Lesser Antilles. This means very hot conditions are forecast on Friday, with light to no winds. This also will allow for late morning afternoon showers and thunderstorms to develop, across the Western half of Trinidad.

In addition, as this system moves to the north and northeast of the Lesser Antilles, our usual east-to-west predominant wind regime will transition to a south to north, and then southwest to westerly winds. This change in wind direction will result in showers and possibly severe thunderstorms favoring the Northern and Eastern halves of Trinidad on Friday afternoon due to sea breeze convergence.

Friday night into Saturday, strong thunderstorms off the Northern Coast of Venezuela will move offshore toward Trinidad, bringing hazardous seas in the Gulf of Paria and adverse weather across Trinidad on Saturday due to southerly winds.

At 5:00 PM AST, the center of Tropical Storm Paulette was located near latitude 22.1 North, longitude 50.1 West. Paulette is moving toward the west-northwest near 9 mph (15 km/h). A west-northwestward or northwestward motion with some increase in forward speed is expected through the weekend.

Maximum sustained winds are near 50 mph (85 km/h) with higher gusts. Some slight weakening is expected during the next day or so, but Paulette is then forecast to restrengthen by Saturday. Paulette is expected to become a hurricane by Sunday. Tropical-storm-force winds extend outward up to 205 miles (335 km) from the center. The estimated minimum central pressure is 997 millibars.

Tropical Storm Paulette Forecast Track as of 5:00 PM AST Thursday 10th September 2020. (National Hurricane Center)
Tropical Storm Paulette Forecast Track as of 5:00 PM AST Thursday 10th September 2020. (National Hurricane Center)

Watches & Warnings

Tropical Storm Paulette Watches and Warnings as of 5:00 PM AST Thursday 10th September 2020. (National Hurricane Center)
Tropical Storm Paulette Watches and Warnings as of 5:00 PM AST Thursday 10th September 2020. (National Hurricane Center)

There are no coastal watches or warnings in effect.

Hazards Affecting Land

Tropical Storm Paulette probabilities for tropical-storm-force winds as of 5:00 PM AST Thursday 10th September 2020, as well as the most likely time of arrival of tropical-storm-force winds. (National Hurricane Center)
Tropical Storm Paulette probabilities for tropical-storm-force winds as of 5:00 PM AST Thursday 10th September 2020, as well as the most likely time of arrival of tropical-storm-force winds. (National Hurricane Center)

SURF: Swells generated by Paulette are expected to reach portions of the Leeward Islands tonight and Friday and will continue to spread westward to portions of the Greater Antilles, Bahamas, Bermuda, and the southeastern United States into the weekend. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office.

A high surf advisory goes into effect Thursday night for Antigua, Barbuda, Montserrat, St Kitts, Nevis, Anguilla, and the British Virgin Islands. A High Surf Warning Goes Into effect Friday for Antigua, Barbuda, Anguilla, and the British Virgin Islands. For T&T, while long-period swells are forecast Friday into Saturday, mainly affecting Northern and Eastern Coasts, adverse impacts are not anticipated at this time.

This system is of no direct threat to the Windward Islands, including Trinidad and Tobago.

Tropical Storm Paulette Forecast Discussion

Tropical Storm Paulette in the Central Atlantic Ocean (Weathernerds)

Continuous bursts of deep convection have been ongoing to the north and northeast of Paulette’s center of circulation, with the cyclone being affected by nearly 40 kt of deep-layer southwesterly shear. The highest intensity estimates are Dvorak classifications of T3.0/45 kt from TAFB and SAB, and that value remains the initial intensity. The shear should reach its peak magnitude this evening, which is likely to cause Paulette to weaken slightly during the next 24 hours. However, gradual re-strengthening is forecast to begin in about 36 hours, and the rate of intensification is expected to increase in 2 to 3 days when the shear could fall to 10 kt or less, along with a more unstable atmosphere and warmer sea surface temperatures. Paulette is now forecast to become a hurricane by day 3 and continue to intensify through the end of the forecast period. As was advertised in the previous forecast package, the new NHC forecast intensities have been bumped up on days 3 through 5 and now lie near or just below the IVCN intensity consensus and the HCCA corrected consensus aid.

Paulette’s heading over the past 6-12 hours has been toward the west-northwest or 300/8 kt. The cyclone’s trajectory is expected to oscillate between northwest and west-northwest for the next 4 days, being dictated by the strength of the subtropical ridge to the north and the depth of the steering flow depending on Paulette’s intensity. The updated NHC track forecast during this period has been nudged a bit to the north, mostly to account for an adjustment of the initial position. The model guidance all agree that Paulette should turn northward around the western side of a central Atlantic high-pressure area by day 5, with the expected hurricane likely to make a tight recurvature near Bermuda. There remains some uncertainty on exactly where that turn will occur, but for now the NHC forecast lies between the tighter-turning ECMWF and HCCA models and the more gradually-turning GFS and HWRF models.

Key messages for Tropical Storm Paulette (National Hurricane Center)
Key messages for Tropical Storm Paulette (National Hurricane Center)

Key Messages:

  1. Paulette is expected to approach Bermuda as a hurricane this weekend and make its closest approach to the island on Monday and Tuesday. While the exact details of Paulette’s track and intensity near the island are not yet known, the risk of strong winds, storm surge, and heavy rainfall on Bermuda continues to increase.
  2. Swells produced by Paulette are expected to affect portions of the Leeward Islands, the Greater Antilles, the Bahamas, Bermuda, and the southeastern United States into the weekend. These swells could cause life-threatening surf and rip current conditions.

Forecast Discussion by Forecaster Berg from the NHC.

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