Tropical Storm Peter Moving Northeast Of Leeward Islands

Key Messages:
– Tropical Storm Peter is not forecast to directly impact the Lesser Antilles.
– Rain bands from the periphery of Peter are forecast to affect the northern Leeward Islands, the Virgin Islands, and Puerto Rico through Tuesday.
– Swells from Peter are forecast to affect the Leewards through Monday with the Bahamas and the Greater Antilles thereafter.
Peter will cause a reduction of wind speeds across the region, allowing for very hot temperatures, light winds, and localized afternoon showers or thunderstorms favoring western areas of islands across the Lesser Antilles through Monday.

Tropical Storm Peter has continued to fight off strong wind shear as it moves safely northeast of the Lesser Antilles.

From the 47th tropical wave of the 2021 Atlantic Hurricane Season to move off the African Coast, Invest 95L strengthening into Tropical Depression Sixteen on Saturday and then Tropical Storm Peter early Sunday morning.

Peter is forecast to move into the North Atlantic Ocean without any direct threats to land at this time. Tropical Storm Peter, is not forecast to directly affect the Lesser Antilles, including Trinidad and Tobago. There are no alerts, watches, or warnings for T&T from the Trinidad and Tobago Meteorological Service at this time.

The Latest From The National Hurricane Center

Tropical Storm Peter's Forecast Track as of 5:00 PM Sunday 19th September 2021. (National Hurricane Center)
Tropical Storm Peter’s Forecast Track as of 5:00 PM Sunday 19th September 2021. (National Hurricane Center)

At 5:00 PM AST, the center of Tropical Storm Peter was located near latitude 18.4 North, longitude 57.8 West. Peter is moving toward the west-northwest near 28 KM/H, and this general motion along with a gradual decrease in forward speed is is expected through Tuesday. A turn to the northwest is expected to occur by Wednesday. On the forecast track, the center of Peter is expected to pass well north of the Leeward Islands on Monday and Tuesday.Maximum sustained winds are near 75 KM/H with higher gusts. Little change in strength is forecast tonight. Some slight weakening is expected on Monday.

Tropical-storm-force winds extend outward up to 205 kilometers primarily to the northeast of the center. The estimated minimum central pressure is 1007 millibars.

Tropical Storm Peter’s latest information as of 5:00 PM Sunday 19th September 2021. (National Hurricane Center)

Tropical Storm Peter’s Watches & Warnings

Tropical Storm Peter’s Tropical Storm Watches and Warnings as of 5:00 PM Sunday 19th September 2021. (National Hurricane Center)

There are no coastal watches or warnings in effect at this time.

Rainfall around the southern periphery of Tropical Storm Peter could produce rainfall totals of 1 to 3 inches, with locally higher amounts possible, across portions of the Northern Leeward Islands, including the Virgin Islands, as well as Puerto Rico through Tuesday. This rainfall may lead to areas of urban and small stream flooding. Heavy rainfall is already affecting parts of the Northern Leeward Islands.

Swells generated by Tropical Storm Peter are expected to reach the northern Leeward Islands tonight and Monday, and then the Bahamas by midweek. These swells could cause life-threatening surf and rip current conditions. Please consult products from your local weather office.

Tropical Storm Peter’s probabilities for tropical-storm-force winds as of 5:00 PM Sunday 19th September 2021. (National Hurricane Center)

This system is of no direct threat to Trinidad and Tobago.

Tropical Storm Peter’s Forecast Discussion

Tropical Storm Peter (

Over the last several hours, after having a relatively cloud-free center of circulation, deep convection has developed with cold cloud tops. Based on data from an Air Force Reserve Hurricane Hunter aircraft investigating the system earlier and satellite estimates, Peter has sustained winds of 40 knots or 75 KM/H.

The outlook for Peter is not favorable, as the vertical wind shear that stripped Peter of its deep convection earlier today is forecast to increase further through tonight and persist for at least a few days. Global model simulated satellite imagery suggests this latest burst of convection will also become removed from the center within several hours, with the cyclone struggling to maintain persistent deep convection throughout much of
the 5-day forecast period.

Therefore, despite being over very warm waters, Peter is forecast to slowly weaken over the next several days. There
are some indications, particularly by the GFS, that Peter could open back into a wave within a few days which adds some additional uncertainty to the intensity forecast.

The storm is forecast to continue to move in this west-northwestward direction for the next couple of days as it is steered to the south of a subtropical ridge. This ridge is expected to weaken in a few days which should cause the cyclone to slow its forward motion and turn northwestward. Late in the forecast period, a turn to the north and possibly northeast is expected to occur as Peter gets caught in the flow around a large trough to its north.

Based on the track, intensity, and wind radii forecast, no tropical storm watches or warnings are required for the northern Leeward Islands, Virgin Islands or Puerto Rico. However, interests there should monitor the progress of the system as locally heavy rain is possible on Monday and Tuesday when it is expected to pass to the north of the area.

But this model shows…

Individual model runs are just one possible outcome from a myriad of outcomes. Weather does not always follow what is modeled, and even what may be forecast. Beware of individual model runs being posted on social media.

Always check the National Hurricane Center for the latest information for tropical cyclones and your local meteorological offices for country-specific advisories.

What should I do?

This system is not forecast to affect the Southern Windward Islands, including Trinidad and Tobago. Don’t panic. There are no immediate or direct tropical storm threats heading to T&T, so feel free to ignore the “storm coming” chain messages that pass through WhatsApp every hurricane season.

If you are a risk-averse person, now is a good time to check your inclement weather, flood, or hurricane season plan, ensuring your preparedness supplies are not expired, stocked, and in a safe location.

The Office of Disaster Preparedness and Management has compiled a comprehensive guide for preparing for the Wet and Hurricane Season.

Tropical Cyclone Climatology

2021 has already produced 17 tropical cyclones in the Atlantic Basin, with the next system being named Sam for the 2021 Atlantic Hurricane Season. For this time of year, most systems form in the Caribbean, the Gulf of Mexico, and off of the Eastern United States.

As we head through the second half of September and into October, we’ll continue to monitor the entire Atlantic closely as tropical cyclones could form from tropical waves, non-tropical low-pressure systems in the North Atlantic, and from the Central America Gyre in the Western Caribbean Sea or the southwestern Gulf of Mexico.

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