Tracking Invest 95L: Development Chances Low, Gusty Winds Likely For Parts Of Windwards

Tropical Wave 14/Invest 95L Key Messages:
– Tropical Wave 14/Invest 95L has low chances of development over the next 48 hours and 5 days respectively as it nears the Lesser Antilles.
– Track: All major models and top-performing hurricane models take the core of this system between the north of Barbados and south of Dominica in the next 24 hours.
– Intensity: No models bring this system to tropical-storm-strength in the next 36 hours as it moves across the Lesser Antilles. However, regardless of development, sustained winds up to 50 KM/H and gusts to 75 KM/H possible, mainly northward of Barbados towards the Leeward Islands.
– Impacts (Rainfall): Generally one to three inches (25 mm to 75 mm) from Trinidad and Tobago to Guadeloupe, with isolated totals exceeding 75 mm along windward-facing slopes from St. Vincent through Guadeloupe.
– Impacts to T&T: Increased rainfall, cloudiness from Tuesday night through Thursday with scattered showers and isolated thunderstorms. Light winds from the south on Wednesday into Thursday may allow for heavier thunderstorms and showers along western and northern Trinidad, as well as Tobago.

Tropical Wave 14: Low Chances for Tropical Cyclone Formation

Tropical Weather Outlook as of 8:00 PM Tuesday 29th June 2021
Tropical Weather Outlook as of 8:00 PM Tuesday 29th June 2021

We’ve been monitoring a strong tropical wave in the Atlantic for five days or so, continuing to produce scattered showers, isolated thunderstorms, and strong winds around an area of low pressure.

The National Hurricane Center, in their 8 PM AST Tropical Weather Outlook, continues to tag Tropical Wave 14 as Invest 95L for tropical cyclone development. Model support for the development of this system is low.

From the National Hurricane Center’s Tropical Weather Outlook, as of 8:00 PM EST, Disorganized showers and thunderstorms continue in association with a tropical wave located a few hundred miles east of the Lesser Antilles. Development, if any, of this system should be slow to occur as the tropical wave moves quickly westward to west-northwestward at 20 to 25 MPH, passing through the Lesser Antilles on Wednesday and then across the eastern and central Caribbean Sea later this week. Regardless of development, this system could bring locally heavy rainfall to portions of the Lesser Antilles during the next couple of days.

As of the 8:00 PM EST Tropical Weather Outlook, this system has a low chance, 10%, of tropical cyclone formation over the next 48 hours and a low chance, 20%, of tropical cyclone formation over the next 5 days.

What We Know

Tropical Wave 14/Invest 95L approaching the Lesser Antilles, producing an area of scattered showers and thunderstorms. (Weathernerds)
Tropical Wave 14 approaching the Lesser Antilles, producing an area of scattered showers and thunderstorms. (Weathernerds)

After producing an impressive amount of thunderstorms and convection earlier on Tuesday, dry air has infiltrated Invest 95L, limiting convective activity on Tuesday night. Widely scattered showers and thunderstorms are ongoing associated with the plume of moisture ahead of the wave, near the area of broad circulation, and following the wave axis. Notably, a strong area of convection has developed just over the center of the low-pressure circulation, but it remains to be seen whether it will persist.

Tropical Wave 14 has been analyzed along 51W/52W from 17N southward, moving westward at 15 knots (28 KM/H). Invest 95L, a 1009 millibar surface low, is centered at 12N, 52W along the tropical wave. This places Invest 95L approximately 675 kilometers east of Barbados and 850 kilometers northeast of Trinidad and Tobago.

Invest 95L has encountered some dry air, though the moisture envelope remains quite large. It is located in an area with low wind shear and favorable upper-level conditions. However, even with warm sea surface temperatures and a marginally favorable atmosphere, development is forecast to be slow due to its fast movement to the west-northwest.

What We Forecast

Tropical Wave 14: Track

All major models and top-performing hurricane models take the core of this system between north of Barbados and south of Dominica on Wednesday afternoon into the night.

Forecast tracks from the top performing hurricane models for Tropical Wave 14/Invest 95L as of 00Z Wednesday 30th June 2021 (NCAR)
Forecast tracks from the top performing hurricane models for Tropical Wave 14 as of 00Z Wednesday 30th June 2021 (NCAR)

This tropical wave is mostly directed by a deep-layered high-pressure system anchored over the subtropics, slightly further south than its climatological position. This high-pressure system is forecast to dominate the Atlantic through the weekend, steering the subsequent disturbance towards the Lesser Antilles.

The strongest winds and heaviest showers are forecast to remain north of the center of circulation, keeping much of the adverse weather north of Barbados. Islands north of St Vincent and the Grenadines should remain alert for gusty winds accompanying heavy showers and thunderstorms.

Tropical Wave 14: Intensity

Although this tropical disturbance is producing strong winds already, no models develop this tropical wave into a tropical depression nor tropical storm before moving across the Lesser Antilles. Heavy rainfall and gusty winds are still possible.

Forecast intensity from the top-performing hurricane models for Invest 95L as of 00Z Wednesday 30th June 2021. Note that this tropical disturbance moves across the Lesser Antilles in the next 24-36 hours, where most models have this system below tropical-storm-strength, (NCAR)
Forecast intensity from the top-performing hurricane models for Tropical Wave 14 as of 00Z Wednesday 30th June 2021. Note that this tropical disturbance moves across the Lesser Antilles in the next 24-36 hours, where most models have this system below tropical-storm-strength, (NCAR)

None of the operational models from top global models (EMCWF, GFS, UKMET) shows this system developing into an organized tropical storm over the next 36 hours, where it will be moving across the Lesser Antilles.

Further into the forecast period, few models attempt to bring the disturbance into a tropical storm but this remains unlikely due to increasing shear as the system moves into the Caribbean Sea.

Still, through the next 36 hours, sustained winds up to 50 KM/H and gusts up to and in excess of 75 KM/H are possible, mainly north of Barbados. This disturbance is forecast to produce between 25 millimeters to 75 millimeters of rainfall, with localized higher totals along windward-facing slopes of the Central Windward Islands and French Antilles.

Possible Impacts

Rainfall and flooding: With one to three inches (25 to 75 millimeters) of rainfall within 36 hours, localized street and flash flooding will be possible across all islands from Trinidad and Tobago to as north of the Leeward Islands.

Winds: With sustained winds, up to 50 KM/H and gusts up to and in excess of 75 KM/H, tree and roof damage are possible, particularly in areas with stronger gusts.

Generally, with wind gusts in excess of 75 KM/H, winds may damage trees, power lines, and small structures. Older/weaker trees may fall, bringing down utility poles and lines. Whole trees are expected to be in motion, and there may be some inconvenience when walking against the wind gusts. During heavy showers and thunderstorms, it is recommended to remain indoors. Light outdoor objects may topple or become airborne such as garbage cans, potted plants, loose galvanize or construction material, and other outdoor furniture. Tents may jump.

Landslides: Particularly for the Central Windward Islands north of St. Vincent and south of Guadeloupe, landslides are possible in elevated areas following and during heavy rainfall.

LightningLightning is possible in thunderstorm activity. Lightning can cause power outages, voltage dips, damage to life and property, particularly during cloud-to-ground lightning strikes.

For St. Vincent ONLY – Lahars: Heavy rainfall may remobilize La Soufriere’s ashfall across the Orange and Red Zones of St. Vincent, causing dangerous lahars to cascade through rivers and valleys.

Statements Issued For Several Islands

There are no tropical storm watches, warnings, or any other tropical cyclone-related warnings for the Lesser Antilles, as no tropical storms have formed nor are threatening the Lesser Antilles Tuesday night. However, several alerts and statements are in effect for a number of islands.

Trinidad and Tobago, Grenada and its dependencies.

There are no alerts, watches, or warnings in effect for Trinidad, Tobago, Grenada, and its dependencies. An information statement was issued Tuesday evening by the Trinidad and Tobago Meteorological Service stating that “current analyses suggest that on its projected track, the center of the system is forecast to reach the Leeward Islands by Wednesday night.” In addition, the TTMS notes that at this time, Invest 95L “poses no direct threat to Trinidad and Tobago or Grenada and its dependencies.”

St. Vincent and the Grenadines

There are no alerts in effect for St. Vincent and the Grenadines at this time. However, a Weather Information Statement has been issued for the country at 5:00 PM Tuesday, advising residents and motorists in areas prone to flooding and landslides, or near rivers and streams, should be alert.

Barbados

Alerts in effect from the Barbados Meteorological Service for Barbados as of Tuesday night.
Alerts in effect from the Barbados Meteorological Service for Barbados as of Tuesday night.

There are several yellow-level alerts in effect for Barbados over the next 72 hours, concerning excess rainfall, marine interests and wind.

A Weather Information Statement is also in effect as of Tuesday night concerning Invest 95L, “On its current forecast track, the relatively strong wind field is expected to pass north of Barbados on Wednesday afternoon, 30th June 2021. Total rainfall accumulations of 1 to 2 inches with isolated higher amounts are possible across Barbados during the next 36 hours.”

The Barbados Meteorological Service is urging the public to monitor both Invest 95L and 97L over the next few days.

Martinique, Guadeloupe and the French Antilles

Alerts in effect from Meteo France for the French Antilles (Meteo France) due to Invest 95L
Alerts in effect from Meteo France for the French Antilles (Meteo France)

For the French Antilles, including Martinique, Guadeloupe, St. Martin, and St. Barthelemy, yellow-level alerts are in effect for all countries concerning heavy showers and thunderstorms. For Martinique, there is also a yellow-level alert concerning strong winds from Meteo France.

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

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?

Don’t panic. If you are located in or north of Barbados, follow the advice of local officials. Based on current guidance, this system is likely to be a strong tropical wave traversing the region, which is normal during June through November.

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 put together a comprehensive guide for preparing for the Wet and Hurricane Season.

Tropical Cyclone Climatology

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

As we head through the first half of July, we’ll begin to monitor more closely tropical waves east of the Lesser Antilles.

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