Tropical Update: Quiet In the Atlantic Basin, Tropical Wave 24 To Move Across T&T Beginning of Upcoming Week

Tropical Weather Update:
Tropical Wave 23: This tropical wave moved across Trinidad and Tobago over the last 24 hours, bringing no significant change to the hot temperatures and settled weather across the islands.
Tropical Wave 24 & Tropical Wave 25: Tropical Wave 25 (further east) is being absorbed by Tropical Wave 24 (further west). These tropical waves are located in the Central/Eastern Atlantic, forecast to merge over the next 24 hours and move across Trinidad, Tobago and the remainder of the Southern Windwards on Monday into Tuesday, with severe weather possible, particularly on Monday. Models have backed off significant rainfall at this time, but locally heavy showers and thunderstorms are still possible.
Tropical Wave 26: A tropical wave has just moved off the West African Coast, forecast to move across T&T next Thursday into Friday. No significant rainfall is forecast from this wave, but with all tropical waves, an increase in showers, some may become heavy or develop into a thunderstorm, is possible.
No Tropical Cyclone Formation Forecast over the next 5 days across the North Atlantic.

Before we dive into the Tropical Updates on the tropical waves, a few notes:

  • Tropical waves are a normal part of the rainy season.
  • Not every tropical wave will form into a tropical cyclone.
  • Tropical waves at the beginning of the Hurricane Season are typically weak, producing more rainfall across Eastern parts of the islands with mostly cloudy conditions and a few showers across western parts of the islands.
  • Rainfall will be more isolated and intermittent with weaker tropical waves that do not have ITCZ or upper-level support.
  • Saharan Dust may weaken tropical waves.

You can read more about the weather associated with Tropical Waves, as well as what to expect as these waves move through the region below.

Tropical Wave 23

This tropical wave moved across the Lesser Antilles without much activity, though some showers were produced across the Northern Windwards and Leewards.

The axis of this wave extends its axis along 65W, between 20N and 5N, moving west at 15 knots. No impacts forecast for the Lesser Antilles, however, it has been producing some showers across Puerto Rico.

Tropical Wave 24 & 25

 Tropical Wave 24 and 25, in the Central/Eastern Atlantic, between 47W and 40W. These waves are forecast to merge and move across the Lesser Antilles on Monday into Tuesday, bringing isolated to scattered showers and thunderstorms. Favorable atmospheric conditions are forecast to support thunderstorms and enhanced showers. Street/flash flooding possible. Credit: Weathernerds.org
Tropical Wave 24 and 25, in the Central/Eastern Atlantic, between 47W and 40W. These waves are forecast to merge and move across the Lesser Antilles on Monday into Tuesday, bringing isolated to scattered showers and thunderstorms. Favorable atmospheric conditions are forecast to support thunderstorms and enhanced showers. Street/flash flooding possible. Credit: Weathernerds.org

Tropical Wave 24 is not the traditional African Easterly Wave. It formed from a mid-level trough, off the northwestern coast of Africa. The axis of Tropical Wave 23 wave extends along 46-47W, from 25N to 5N, moving at 15 knots westward. No significant deep convection is noted near the axis of this wave.

Further east, along 40W between 18N and 5N, Tropical Wave 25 is being absorbed by Tropical Wave 24. This wave has a surge of tropical moisture associated with its axis, as well as it is pulling the ITCZ further north.

Tropical Wave 24 is forecast to absorb Tropical Wave 25 over the next 24 hours, and the merged wave will move across the Lesser Antilles, including Trinidad and Tobago on Monday into Tuesday.

Favorable upper-level conditions on the western side of an upper-level anti-cyclone (upper level low) centered just east of Tobago, may provide the platform for thunderstorm development.

Models have backed off the severe rainfall accumulations given trends over the last 24 hours, but locally heavy rainfall and isolated thunderstorms are still possible, particularly on Monday. See below for specific details.

What We Forecast For Tropical Wave 24 (Merged With 25)

The Takeaway: Beginning after midday on Sunday, an increase in cloudiness is forecast, with a few isolated showers and even an isolated thunderstorm, favoring coastal Western Trinidad into the Gulf of Paria. After midnight Sunday into Monday, isolated showers and a few, highly localized thunderstorms are forecast to begin.

Peak thunderstorm activity is likely during the late morning through the afternoon, with isolated heavy showers and thunderstorms forecast, mainly across Trinidad.

Conditions are forecast to become more settled by the late evening on Monday, with an additional round of showers and isolated thunderstorms on Tuesday as the hind leg of this wave affects T&T. By late Tuesday, conditions are forecast to become more settled.

Locally Heavy Rainfall & Flooding: Based on the latest model runs on Friday evening, from Sunday afternoon (2:00 PM) through Tuesday afternoon (2:00 PM), models are in agreement of locally heavy rainfall, mainly across Eastern Trinidad. Based on our analysis, generally of fewer than 20 millimeters across most areas on both islands. Rainfall totals of up to 50 millimeters are possible eastern halves of both islands Trinidad and Tobago.

Regardless, a heavy rainfall event is forecast. Generally, with heavy showers and thunderstorm activity, street flooding, particularly in flood-prone areas or areas with poor drainage, is possible as well as flash flooding in areas where more prolonged heavy rainfall may occur, based on the above-mentioned forecast rainfall totals.

Frequent Lightning: In addition, with thunderstorms, frequent lightning is likely. The highest chance for thunderstorm activity is forecast for Monday.

Gusty Winds: Gusty winds, generally up to 50 KM/H are possible Gusty winds are most likely prior to, in the vicinity of, or occur during heavy showers or thunderstorms. With wind gusts up to 50 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.

High Wind Event Precautions
High Wind Event Precautions

Landslides: Particularly in areas that receive heavy rainfall, landslides and/or mudflows may occur across both islands. These landslides, in addition to gusty winds, may down trees, utility poles and impede traffic on roadways. As significant rainfall accumulation and gusty winds have decreased, so too has the threat of landslides. However, areas along the North Coast are particularly unstable due to the geology of the region. Hence, it does not require a significant amount of rain to trigger a landslide.

Tropical Wave 26

Tropical Wave 26, in the Far Eastern Atlantic. This wave is forecast to move across the Lesser Antilles next Thursday into Friday, bringing isolated to scattered showers and thunderstorms. Street/flash flooding possible. Credit: Weathernerds.org
Tropical Wave 26, in the Far Eastern Atlantic. This wave is forecast to move across the Lesser Antilles next Thursday into Friday, bringing isolated to scattered showers and thunderstorms. Street/flash flooding possible. Credit: Weathernerds.org

Tropical Wave 26 has just moved off the West Coast of Africa, along 18-19W, between 20N and 5N, moving west at approximately 15-20 knots. This wave is still more than 5 days away but latest model guidance weakens this wave notably as it moves across the Lesser Antilles late next week.

As with most tropical waves, a surge in moisture is forecast to support an increase in cloudiness, showers and isolated thunderstorms, particularly between Thursday and Friday of next week.

Additional updates on specific impacts will be posted within the daily tropical update. As of present, no significant rainfall is forecast.

Tropical Cyclone Climatology

Tropical Cyclone Points of Origin during the month of July. This month, the attention goes to tropical waves moving across the Atlantic, particularly as they near the Lesser Antilles, as well as low-pressure systems in the Gulf of Mexico and troughs Southeast of the United States.

In July, we turn our eyes to East of the Lesser Antilles, the Southeastern areas of the United States and the Gulf of Mexico for the formation of tropical cyclones in the Atlantic Basin, historically. However, tropical cyclones can form in the Atlantic Basin, without regard for the location once conditions support development. Stay updated with the latest tropical update!

There are NO tropical cyclone threats to the Eastern Caribbean, including Trinidad and Tobago at this time in the latest Tropical Update.

2019 Atlantic Hurricane Season Names
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