Tropical Update: Monitoring 4 Tropical Waves East of T&T

Tropical Update Overview:
Tropical Wave 41 – An active tropical wave is a few hundred kilometers east of the Lesser Antilles has low chances of development over the next 48 hours and five days, respectively. Based on present model guidance, much of the active weather associated with this system will move north of T&T on overnight tonight through Monday, with showers and isolated thunderstorms possible by Sunday afternoon.
Tropical Wave 42 – This tropical wave in the Central Atlantic is forecast to move across the region early to mid-week. Present model guidance shows an increase in showers and thunderstorms possible.
Tropical Wave 43 – A tropical wave located over the Eastern Atlantic is being monitored for development as it moves slowly west to west-northwest. This system is not forecast to threaten our area at this time.
Tropical Wave 44 – A new tropical wave has emerged off the Western African Coast, moving very slowly west. Though it is not tagged for development at this time, it certainly is worth monitoring as we head into the peak hurricane season.
U.S. Mid-Atlantic Area of Interest – As the remnants of Hurricane Laura emerge off the U.S. Mid-Atlantic Coasts, models are hinting at an area of low-pressure developing. Presently, this area has low chances of development.

Total Precipitable Water Imagery showing the Tropical Waves (analyzed by the National Hurricane Center, Weather Prediction Center, and TTWC) that exist east of Trinidad and Tobago.
Total Precipitable Water Imagery showing the Tropical Waves (analyzed by the National Hurricane Center, Weather Prediction Center, and TTWC) that exist east of Trinidad and Tobago.

Impacts to T&T – Through early Sunday, a dry mid- and upper-level atmosphere will limit deep convective activity. However, following the passage of Tropical Wave 41, a southerly flow may bring moisture and instability across T&T and the Windwards. This may fuel isolated areas of heavy rainfall late Sunday through Wednesday as Tropical Wave 42 moves through, bringing additional moisture to the region. Showers and thunderstorms may reduce visibility and produce gusty winds up to and in excess of 55 KM/H. Street or flash flooding will be possible in slow-moving showers and thunderstorms. In thunderstorm activity, frequent lightning is also possible. Gusty winds may cause power dips/outages, downed trees, and localized wind damage.

Before we dive into the Tropical Update, a few notes:

  • Tropical waves are a normal part of the rainy season.
  • Not every tropical wave will form into a tropical cyclone.
  • Weaker tropical waves produce 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 41

Tropical Wave 41 is analyzed from 18N, along 58W. Most of the convective activity is associated with the northern wave axis, north of Trinidad and Tobago. (Weathernerds)
Tropical Wave 41 is analyzed from 18N, along 58W. Most of the convective activity is associated with the northern wave axis, north of Trinidad and Tobago. (Weathernerds)

As of the 8:00 PM Tropical Update, the 41st tropical wave for the 2020 Atlantic Hurricane Season is located from 18N, along 58W based on our analysis. The wave axis is moving westward around 10-15 knots (18-27 KM/H) with scattered moderate to strong convection mainly along the northern portion of the wave axis, north of Trinidad and Tobago.

The axis of this tropical wave is forecast to move across the Lesser Antilles on Sunday, with much of the active weather remaining north of T&T until after midday Sunday through Monday. This active weather will be due to a southerly wind flow following the passage of the tropical wave, bringing moisture and instability across T&T, with localized climatic effects enhancing activity.

Tropical Weather Outlook from the National Hurricane Center, giving Tropical Wave 41 low chances of tropical cyclone formation over the next 5 days as it moves across the Central Atlantic.)
Tropical Weather Outlook from the National Hurricane Center, giving Tropical Wave 41 low chances of tropical cyclone formation over the next 5 days as it moves across the Central Atlantic.)

As of the 12Z and 18Z runs of the top-performing models for tropical development, none of the operational models bring this system as a tropical storm until it reaches the Western Caribbean. The EMCWF (EPS) Ensemble models show less than 50% of the members bringing winds of tropical depression (25 knots) strength and less than 5% showing tropical-storm strength.

Regardless of formation, the strongest winds and heaviest rainfall is forecast to remain well north of Trinidad and Tobago on Sunday through Monday. The system is forecast to bring southerly winds to move across T&T late Sunday through Tuesday, advecting moisture and instability across the islands. This may fuel isolated showers and thunderstorms, as the surface to mid-level conditions are favorable through early Monday, but surface convergence appears to be unfavorable Monday through Tuesday. Hot mornings may allow for heat-driven convection.

According to the National Hurricane Center’s tropical weather outlook at 8:00 PM, “ A tropical wave located a few hundred miles east of the Windward Islands is producing disorganized showers and thunderstorms. Some gradual development of this system is possible during the next several days while it moves westward at 15 to 20 mph through the Lesser Antilles and the eastern and central Caribbean Sea. Regardless of development, this system will likely produce gusty winds and locally heavy rainfall across portions of the Windward and Leeward Islands on Sunday.

Chances of tropical cyclone development remain low over the next 48 hours and 5 days at 20% and 30% respectively, as this system moves across the region.

Tropical Wave 42

Tropical Wave 42 is analyzed further east from 20N southward and elongated along 44W. (Weathernerds)
Tropical Wave 42 is analyzed further east from 20N southward and elongated along 44W. (Weathernerds)

As of the 8:00 PM Tropical Update, the 42nd tropical wave for the 2020 Atlantic Hurricane Season is located from 20N southward and elongated along 44W, based on our analysis. It is moving west at 10-15 knots (18-27 knots). Scattered moderate convection and isolated thunderstorms are from 07N to 13N between 41W and 51W.

Models show moisture associated with this wave moving across the region mid-week next week, with any active weather remaining north of T&T and the Windward Islands. As of the 12Z and 18Z runs of the top-performing models for tropical development, none of the operational models bring an organized tropical system across the Eastern Caribbean. The EMCWF (EPS) Ensemble models show less than 20% of the members producing winds of tropical depression (25 knots) strength and none showing tropical-storm strength.

Tropical Wave 43 & Tropical Wave 44

Tropical Wave 43 is analyzed from 15N southward, at 28W. We're monitoring this tropical wave for tropical development by late next week. Tropical Wave 44 is analyzed from 15N southwards, at 18W. (Weathernerds)
Tropical Wave 43 is analyzed from 15N southward, at 28W. We’re monitoring this tropical wave for tropical development by late next week. Tropical Wave 44 is analyzed from 15N southwards, at 18W. (Weathernerds)

As of the 8:00 PM Tropical Update, the 43rd tropical wave for the 2020 Atlantic Hurricane Season analyzed from 15N southward, along 28W. The wave axis is moving westward around 5 knots (9 KM/H). This tropical wave is being monitored for tropical cyclone development from the National Hurricane Center.

As of the 12Z and 18Z runs of the top-performing models for tropical development, both the GFS and EMCWF show support for development, remaining north of the Lesser Antilles. The EMCWF (EPS) Ensemble models show up to 60 % of the members bringing winds of tropical depression (25 knots) strength and less and less than 10% showing tropical-storm strength. Only 39% of members show an organized low-pressure center in the Central Atlantic. It is too soon to tell where this system may eventually track, though models are hinting at a strengthening high-pressure system that could push this system closer to the Leewards later next week into the weekend.

This tropical wave will near the region late next week, but much of the active weather will remain north of T&T.

Tropical Weather Outlook from the National Hurricane Center, giving Tropical Wave 43 medium chances of tropical cyclone formation over the next 5 days as it moves across the Central Atlantic.)
Tropical Weather Outlook from the National Hurricane Center, giving Tropical Wave 43 medium chances of tropical cyclone formation over the next 5 days as it moves across the Central Atlantic.)

According to the National Hurricane Center’s tropical weather outlook at 8:00 PM, “Another tropical wave is located over the eastern Atlantic Ocean just southwest of the Cabo Verde Islands. This system is expected to move very slowly for the next several days, and some development is possible early next week over the eastern or central tropical Atlantic.”

Chances of tropical cyclone development remain low over the next 48 hours and medium at 5 days at near 0% and 40% respectively.

As of the 8:00 PM Tropical Update, the 44th tropical wave for the 2020 Atlantic Hurricane Season analyzed from 15N southward, along 18W. The wave axis is moving westward around 5 knots (9 KM/H).

As of the 12Z and 18Z runs of the top-performing models for tropical development, both the GFS and EMCWF show support for development, remaining north of the Lesser Antilles. The EMCWF (EPS) Ensemble models show up to 80 % of the members bringing winds of tropical depression (25 knots) strength and less and less than 25% showing tropical-storm strength. Only 27% of members show an organized low-pressure center in the Central Atlantic. It is too soon to tell where this system may eventually track, though models are hinting it remaining out at sea.

Mid-Atlantic Area of Interest

A low pressure area is expected to form off of the southeastern coast of the United States by early next week. (Weathernerds)
A low pressure area is expected to form off of the southeastern coast of the United States by early next week. (Weathernerds)

As of the 8:00 PM Tropical Update, we’re monitoring an area off the U.S. Mid-Atantic for the formation of a low-pressure system which could form into a tropical cyclone.

Tropical Weather Outlook from the National Hurricane Center, giving this area low chances of tropical cyclone formation over the next 5 days as it moves across the far Western Atlantic.)
Tropical Weather Outlook from the National Hurricane Center, giving this area low chances of tropical cyclone formation over the next 5 days as it moves across the far Western Atlantic.)

As of the 12Z and 18Z runs of the top-performing models for tropical development, the GFS and the EMCWF, the top operational models bring this system into a strong low-pressure system off the Eastern Americas. The EMCWF (EPS) Ensemble models show 85% of the members bringing winds of tropical depression (25 knots) strength and less than 15% showing tropical-storm strength.

According to the National Hurricane Center’s tropical weather outlook at 8:00 PM, “ A low pressure area is expected to form off of the southeastern coast of the United States by early next week. Additional subsequent development is possible as the system moves east-northeastward across the northwestern Atlantic Ocean.

Chances of tropical cyclone development remain low over the next 48 hours and 5 days at near 0% and 30% respectively, as this system moves across the area.

Tropical Cyclone Climatology

Tropical Cyclone Points of Origin during the last week of August into the first week of September.

List of names for the 2020 Atlantic Hurricane Season, which will be updated each tropical update as new systems develop.
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