Tropical Storm Karen Key Messages:
– Tropical Storm Karen is forecast to produce locally heavy
rainfall and gusty winds are likely across Trinidad, Tobago,
Barbados and the remainder of the Windwards between Sunday and Monday. Tropical Storm Warning in Effect for T&T, Grenada and its dependencies. Adverse Weather Alert (Orange Level) In Effect.
– Between 2 to 6 inches (50 to 150 mm) with isolated totals up to 8 inches (200 mm) are possible across the Southern Windwards. There is an elevated threat of street flooding, flash flooding and riverine flooding Sunday into Monday.
– Rough seas with waves between 2.5 meters and 4.0 meters are possible in open waters east of T&T on Sunday into Monday, with battering swells along the Atlantic Coasts.
— Winds up to 65 KM/H expected with gusts to 85 KM/H possible. Winds of this strength will produce wind damage including downed trees, utility poles and roof damage. Localized power outages possible.
— As repeatedly mentioned previously, short-notice tropical storm warnings were a possiblility. This should not take away from the main threat of this system – heavy rainfall.
Alerts, Watches & Warnings
The government of Trinidad and Tobago has issued a Tropical Storm Warning for Trinidad and Tobago. The Trinidad and Tobago Meteorological Service has issued a Tropical Storm Warning for Grenada and its dependencies.
The government of Barbados has issued a Tropical Storm Watch for St. Vincent and the Grenadines.
A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within the
next 12 hours.
Tropical Storm Warnings may be issued later today for other portions of the Windward Islands. A Tropical Storm Watch will likely be issued later today for Puerto Rico and the Virgin Islands. Elsewhere, interests in the Leeward Islands should monitor the progress of Karen.
For storm information specific to your area, please monitor products issued by your national meteorological service.
Tropical Storm Karen
Since 2:00 AM Wednesday, the National Hurricane Center has been monitoring a Tropical Wave, now designated Invest 99L, for tropical cyclone development. At 5:00 AM Sunday, it was upgraded to a Tropical Storm, named Karen.
At 5:00 AM, the center of newly formed Tropical Storm Karen was located near latitude 11.9 North, longitude 60.2 West. Karen is moving toward the west-northwest near 15 KM/H and this general motion is expected to continue today. A turn toward the northwest is forecast to occur on Monday, followed by a turn toward the north on Tuesday. On the forecast track, Karen will move across the Windward Islands this afternoon and tonight, and emerge over the southeastern Caribbean Sea Monday morning. On Tuesday, Karen is expected to approach Puerto Rico and the Virgin Islands.
Maximum sustained winds are near 65 KM/H with higher gusts to 85 KM/H. Little change in strength is forecast during the next 48 hours.
Tropical-storm-force winds extend outward up to 205 kilometers from the center. Barbados recently reported a sustained wind of 59 KM/H and a gust to 72 KM/H. The estimated minimum central pressure is 1005 millibars.
What We Know & Forecast
Scatterometer surface wind data and observations from the Windward Islands indicate that the low-pressure system just east of Tobago has become better defined. Infrared and microwave satellite imagery also show that deep convection has increased and has become better organized around the center. Barbados recently reported a 10-minute wind of 32 kt gusting to 39 kt and the earlier scatterometer data showed a large field of 30-32 kt winds in the eastern semicircle. Based on these data, the low has been upgraded to Tropical Storm Karen. Tropical Storm Warnings have been issued for the southern Windward Islands as a result.
The initial motion estimate is an uncertain 285/10 kt. The latest NHC model guidance is in very good agreement on Karen moving northwestward around the southwestern periphery of a deep-layer ridge for the next 24-36 hours, followed by a turn toward the north into a break in the ridge currently located over the northern Leeward Islands and Puerto Rico. In the 72-96 hour period, Karen is forecast to slow down and possibly even stall and turn westward on day 5 as another large ridge moves eastward across the southeastern United States and builds to the north of the cyclone. The official track forecast lies close to the tightly-packed consensus track models TVCN, NOAA-HCCA, and TVCX.
Little, if any, change in intensity is expected for the next 48 hours due to strong northeasterly vertical wind shear. However, the upper-level flow is expected to be difluent, which should help Karen maintain its current intensity despite the otherwise unfavorable shear conditions. By 72 hours and beyond, Karen is forecast to move underneath an upper-level anticyclone, which should result in a significant decrease in the shear and also enhance the upper-level outflow, allowing for some strengthening to occur. The NHC intensity forecast closely follows a blend of the intensity consensus models IVCN and HCCA, and the Decay-SHIPS model.
A Tropical Storm Watch will likely be required for Puerto Rico and the Virgin Islands later today, and Tropical Storm Warnings may be issued for other areas in the Windward Islands later this morning.
Hazards Affecting Land
The primary threat from this system will be heavy rainfall between Sunday and Monday across T&T.
The Southern and Central Windwards are forecast to be affected by this Tropical Storm, with most impacts across the Southern and Central Windwards.
As repeatedly mentioned, this system will be a heavy rain threat above all else.
Peak sustained surface winds of 65 KM/H with gusts in excess of 85 KM/H are possible in heavy showers or thunderstorms across the entirety of the Southern and Central Windwards, including Trinidad and Tobago. These peak sustained winds are forecast to occur Sunday into Monday, particularly Sunday night.
With wind gusts in excess of 65 KM/H, whole trees are expected to be in motion and there may be some inconvenience when walking against the wind gusts. 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. Older/weaker trees may fall, bringing down utility poles and lines. Power outages expected.
The rainfall forecast has remained mostly the same. Across much of the Southern Windwards, including Trinidad and Tobago, we expect rainfall totals between 2 to 6 inches (50 to 150 millimeters) with isolated totals up to 8 inches (200 millimeters). Across Trinidad and Tobago, the heaviest rainfall is forecast between Sunday and Monday. This is near one month’s worth of the average rainfall for the month of September inside 48 hours.
Thunderstorms and Lightning
With thunderstorms, locally severe wind (up to 85 KM/H), violent rainfall rates (in excess of 50 millimeters per hour) and lightning are all possible.
Gusty winds and lightning pose a threat to our power grid, causing localized power outages. Lightning may also strike trees, homes or utility poles causing damage to property. Lightning can also be deadly to persons outside during a thunderstorm.
Seas and Surf
On Sunday, seas are forecast to be rough in open waters with long-period swells between 2.5 and 4.0 meters in open waters, continuing to batter the Altlantic Coasts of the Southern Windwards.
On Monday, seas are forecast to be moderate to rough with long-period swells between 2.0 to 3.0 meters in open waters, with the third day of battering the Atlantic Coasts of the Southern Windwards.
Seas will return to a moderate state by Tuesday as Tropical Storm Karen moves into the Caribbean Sea. However, between late Saturday and early Tuesday, large waves and dangerous near-shore conditions will make marine conditions unsafe for mariners and sea bathers. Large, battering waves may pose a threat to life and property within the surf zone.
What should I do?
Firstly, don’t panic. However, as repeatedly mentioned, the main threat is flooding. Adequate preparations should be made to safeguard life and property. Create a safety plan in case of emergency as an Adverse Weather Alert Orange Level is in effect. A tropical storm warning is also in effect for T&T
Practice common sense safety and remain indoors during inclement weather.
The Office of Disaster Preparedness and Management has put together a comprehensive guide for preparing for the 2019 Wet and Hurricane Season.