Tropical Update: Cristobal Nears Landfall, Two Tropical Waves To Move Across T&T This Week

Tropical Update Overview:
Tropical Storm Cristobal – This tropical cyclone is nearing landfall near the southeastern coast of Louisiana, already bringing locally heavy rainfall, life-threatening storm surge to the Northern U.S. Gulf Coast.
Area of Interest – The National Hurricane Center is monitoring an area east to northeast of Bermuda for the development of a non-tropical low-pressure system, which could acquire subtropical characteristics later this week.
Tropical Wave 06 – This weak tropical wave is located 550 KM east of Trinidad and Tobago, forecast to bring unsettled weather to T&T late Monday into Tuesday, with locally heavy rainfall possible on Tuesday. See below for details.
Tropical Wave 07 – This weak tropical wave is forecast to move across the region sometime Thursday into Friday. However, there continues to be disagreements between models on both timing and impacts, with the best chances for rainfall occurring late Thursday through the first half of Friday.
Tropical Wave 08 – This tropical wave recently emerged off the African Coast and is forecast to traverse the Lesser Antilles this upcoming weekend. However, it is too soon to tell any definitive impacts this wave may bring, particularly as a significant surge of Saharan Dust is also north of the wave axis.

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, as well as Tropical Storm Cristobal.
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, as well as Tropical Storm Cristobal, as of 3:00 PM

Impacts to T&TNo direct tropical threats to Trinidad and Tobago are forecast over the next week but locally heavy rainfall is possible on Tuesday due to Tropical Wave 05. Throughout the week, a typical Wet Season pattern is in place, with isolated showers and thunderstorms possible, favoring Western and hilly areas during the late morning through the afternoon. Street flooding, gusty winds generally between 25-45 KM/H, occasionally in excess of 55 KM/H, and frequent lightning are possible. Flash flooding and landslides are less likely but possible.

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 Storm Cristobal

Tropical Storm Cristobal affecting the Northern U.S. Gulf Coasts. bringing gusty winds, locally heavy rainfall, and storm surge to the region.
Tropical Storm Cristobal affecting the Northern U.S. Gulf Coasts. bringing gusty winds, locally heavy rainfall, and storm surge to the region.

The National Hurricane Center (NHC) continues to monitor Tropical Storm Cristobal, which is nearing landfall across Southeastern Louisiana.

At 2:00 PM AST (1800 UTC), the center of Tropical Storm Cristobal was located near latitude 28.8 North, longitude 89.9 West. Cristobal is moving toward the north near 5 MPH (8 KM/H), and this general motion is expected to continue today, followed by a gradual turn toward the north-northwest late today or tonight. On the forecast track, the center of Cristobal will approach the northern Gulf of Mexico coast this afternoon, then move inland across Louisiana late today through Monday morning, and northward across Arkansas and Missouri Monday afternoon into Tuesday.

Data from NOAA Doppler weather radars and offshore oil platforms indicate that maximum sustained winds remain near 50 MPH (85 KM/H)
with higher gusts. Little change in strength is forecast before landfall. Gradual weakening will begin once Cristobal moves inland.

Tropical-storm-force winds extend outward up to 205 miles (335 KM), mainly to the east of the center.

During the past few hours, an oil rig located about 80 miles south of Mobile, Alabama, measured a sustained wind of 58 MPH (93 KM/H) and a gust to 64 MPH (103 KM/H) an elevation of 53 ft. A Weatherflow site at Ship Island, Mississippi, recently reported a sustained wind of 45 MPH (72 KM/H) and a gust to 59 MPH (95 KM/H).

The estimated minimum central pressure is 994 millibars.

Tropical Storm Cristobal in the Northern Gulf of Mexico (Weathernerds)
Tropical Storm Cristobal in the Northern Gulf of Mexico (Weathernerds)

This system is of no threat to the Lesser Antilles, including T&T.

Area of Interest

The National Hurricane Center is montioring an area east to northeast of Bermuda for subtropical development later this week as of the 2:00 PM Tropical Weather Outlook.
The National Hurricane Center is montioring an area east to northeast of Bermuda for subtropical development later this week as of the 2:00 PM Tropical Weather Outlook.

The NHC is also keeping an eye on an area east to northeast of Bermuda for the formation of a non-tropical low-pressure system, which may acquire subtropical characteristics later this week.

According to the NHC’s 2 PM Tropical Weather Outlook, “A non-tropical area of low pressure is expected to form a few hundred miles east or northeast of Bermuda within a couple of days. This system could then acquire some subtropical characteristics by mid-to-late week while the low meanders over the western Atlantic.”

The NHC is giving this system a low chance of development over the next 48 hours, near 0% and 20% over the next 5 days.

This system, regardless of formation, will be of no threat to Trinidad, Tobago, and the remainder of the Lesser Antilles.

Tropical Wave 06

Tropical Wave 06 is analyzed along 56W, producing cloudiness and isolated to scattered showers east of Trinidad and Tobago. (Weathernerds)
Tropical Wave 06 is analyzed along 56W, producing cloudiness and isolated to scattered showers east of Trinidad and Tobago. (Weathernerds)

As of the 3:00 PM Tropical Update, the sixth tropical wave for the 2020 Atlantic Hurricane Season is located along 55/56W, from 13N southward based on our analysis based on total precipitable imagery and satellite imagery.

Based on our analysis, the axis of the wave is approximately just under 550 kilometers east of Trinidad and Tobago, but much of the active weather follows the wave axis.

Scattered showers and moderate convection are ongoing on both sides of the wave axis, with stronger convection following the wave axis. The wave is moving west at 10 to 15 knots (18.5-28 KM/H) and is forecast to traverse the Lesser Antilles late Monday into Tuesday.

Presently, favorable low-level convergence and upper-level divergence are coinciding with the wave axis, as well as abundant total precipitable moisture, moving associated with the wave. Wind shear (from the southwest) remains strong, preventing persisting showers and thunderstorms from moving westward.

Through Tuesday, wind shear is forecast to relax slightly, between favorable to neutral levels, which may allow for a favorable environment for isolated heavy to violent showers and thunderstorms to develop.

Guidance from the top global models is in agreement with periods of showers and isolated thunderstorms beginning overnight Monday through Tuesday, with locally heavy rainfall possible on Tuesday.

See below for details.

Tropical Wave 07

Activity associated with Tropical Wave 06 along 55/56W and Tropical Wave 07 between 43-41W in the East Atlantic Note that Saharan Dust concentrations are high near TW07. (Weathernerds)
Activity associated with Tropical Wave 06 along 55/56W and Tropical Wave 07 between 43-41W in the East Atlantic Note that Saharan Dust concentrations are high near TW07. (Weathernerds)

As of the 3:00 PM Tropical Update, the axis of Tropical Wave 07 is approximately along is along 43W to 40W, from 11N southward, moving westward 10-15 knots (18.5-28 KM/H).

Convection is limited near the wave axis due to dense Saharan Dust near the northern area of the wave axis, but abundant moisture is present ahead of and behind the wave.

This weak wave is forecast to traverse the region sometime late Thursday into Friday, but there is still great uncertainty in the exact timing of the movement of the wave axis over T&T, as well as the associated impacts.

Models have trended (over the last 24 hours or 4 model cycles) towards a drier passage of this wave, with heavier precipitation remaining offshore, to our south and east of Trinidad. This wave remains 4-5 days away, so by mid-week, we’ll have significantly better clarity on what Tropical Wave 07 may bring.

As of right now, dense Saharan Dust remains its main impediment for shower and thunderstorm development as wind shear is favorable to moderate, forecast to remain at those levels through the week as the wave progresses westward.

Tropical Wave 08

The axis of Tropical Wave is along 19W/20W with a significant surge of Saharan dust to the north and west of the wave axis. (Weathernerds)
The axis of Tropical Wave is along 19W/20W with a significant surge of Saharan dust to the north and west of the wave axis. (Weathernerds)

As of the 3:00 PM Tropical Update, the axis of Tropical Wave 08 is approximately along is along 19/20W, from 10N southward, moving westward 10-15 knots (18.5-28 KM/H).

Scattered moderate convection is located within 180 nautical miles of the wave axis, mainly behind the wave. It is too soon to tell what weather this wave may bring, as it is now forecast to traverse our area next Sunday into Monday.

What does all of this mean for Trinidad and Tobago?

5-Day Weather Forecast For T&T
5-Day Weather Forecast For T&T

The remainder of Sunday: Isolated showers are possible through the afternoon favoring Western Trinidad, with thunderstorm activity remaining mostly in the Gulf of Paria. A mostly settled late afternoon into the night is forecast.


Monday: Barring the odd isolated early to mid-morning showers across both islands, a mostly sunny start to Monday is forecast. Moisture ahead of Tropical Wave 06 is forecast to begin moving across Trinidad and Tobago after midday, fueling afternoon isolated showers and isolated thunderstorms, favoring the Western half of Trinidad and hilly areas, interrupting partly to mostly cloudy skies. Thunderstorm chances remain low to medium. Activity is forecast to settle by the evening, with cloudiness increasing. Isolated showers are forecast to develop after nightfall, with isolated thunderstorms possible after midnight. No significant rainfall is expected at this time.

Gusty winds, up to 55 KM/H, and street flooding are possible in heavy to violent showers and isolated thunderstorms. Seas to remain slight to moderate, with waves up to 1.5 meters in open waters and near calm in sheltered areas but may become choppy during heavy showers and thunderstorms.


Tuesday: The axis of Tropical Wave 06 is forecast to move across T&T during Tuesday. As with most tropical waves, the active weather usually follows the wave axis. Periods of showers, light to moderate rain and isolated thunderstorms are possible after midnight, throughout the day, gradually settling by the evening. Thunderstorm chances remain medium throughout the day, favoring the early morning period, as well as the late morning through the afternoon. These conditions are forecast to interrupt variably cloudy skies, with heavier rainfall favoring Trinidad.

Particularly during heavy to violent showers and thunderstorms, gusty winds in excess of 55 KM/H are possible. Seas to remain slight, with waves up to 1.5 meters in open waters and near calm in sheltered areas but may become choppy during heavy showers and thunderstorms. Street flooding and frequent lightning are likely in heavy downpours and thunderstorms respectively. Flash flooding and landslides are less likely, but also possible.


Wednesday: During the first half of Wednesday, lingering moisture from Tropical Wave 06 is forecast to fuel isolated showers, a medium chance of thunderstorms across Trinidad, but favoring offshore areas. Mostly cloudy skies are forecast through the afternoon.

As abundant low-level moisture is forecast to continue moving across Trinidad and Tobago, with southeasterly winds, sea-breeze convergence, daytime heating, and orographic effects are forecast to trigger showers and isolated thunderstorms during the late morning through the afternoon.

However, by the late afternoon, a ridge of high pressure is forecast to briefly dominate conditions decreasing low-level moisture through the remainder of Wednesday, allowing for a mostly settled evening into the night. No significant rainfall is expected at this time.

Gusty winds, up to 55 KM/H, and street flooding are possible in heavy to violent showers and isolated thunderstorms. Seas to remain slight to moderate, with waves up to 1.5 meters in open waters and near calm in sheltered areas but may become choppy during heavy showers and thunderstorms.


Thursday: The forecast confidence in Thursday’s forecast remains low, due to disagreements amongst models on the timing and intensity of Tropical Wave 07. A mostly settled Thursday is forecast with a few isolated showers during the early morning before sunrise and then again during the late morning through the afternoon. There is a low chance of thunderstorms throughout the day. Moisture ahead of Tropical Wave 07 is generally forecast to begin moving across the Windwards by late Thursday into Friday. Isolated heavier showers and thunderstorms are possible overnight. No significant rainfall is expected at this time with heavier rainfall remaining to our south and east.

Particularly during heavy to violent showers and thunderstorms, gusty winds in excess of 55 KM/H are possible. Seas to remain slight, with waves up to 1.5 meters in open waters and near calm in sheltered areas but may become choppy during heavy showers and thunderstorms. Street flooding and frequent lightning are likely in heavy downpours and thunderstorms respectively.


Friday: Based on the latest model guidance, the axis of Tropical Wave 07 is forecast to move across T&T sometime between late Thursday and Friday, though there is still disagreement on timing and intensity. During the first half of Friday, isolated to scattered showers and isolated thunderstorms are possible across both islands. A high-pressure system will regain dominance by the late morning through the afternoon, with a surge of Saharan Dust following, leading to a mostly settled but hazy second half of the day. Similar to Thursday, forecast confidence for Friday also remains low. No significant rainfall is expected at this time with heavier rainfall remaining to our south and east.

Particularly during heavy to violent showers and thunderstorms, gusty winds in excess of 55 KM/H are possible. Seas to remain slight, with waves up to 1.5 meters in open waters and near calm in sheltered areas but may become choppy during heavy showers and thunderstorms. Street flooding and frequent lightning are likely in heavy downpours and thunderstorms respectively.

Possible Impacts This Week

Winds: Sustained surface winds between 25 KM/H and 45 KM/H with gusts up to and in excess of 55 KM/H possible in heavy showers or thunderstorms across Trinidad and Tobago.

With wind gusts in excess of 55 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.

High Wind Event Precautions
High Wind Event Precautions

Rainfall: Daily rainfall accumulations are forecast to be less than 5-10 millimeters, with areas that experience isolated downpours or thunderstorms, isolated totals up to 25 millimeters are possible.

Specifically on Tuesday, 24 hour accumulations are forecast to be less than 25 millimeters across both islands, with isolated totals up to 45 millimeters.

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.

Frequent Lightning: In addition, with forecast thunderstorms, frequent lightning is likely. Lightning can cause power outages, voltage dips, damage to life and property, particularly during cloud-to-ground lightning strikes. Thunderstorms are forecast to generally remain offshore, more so in the Gulf of Paria.

Why I May Not/Will Not See Constant Rainfall?

A frequent complaint is the forecast is wrong because I didn’t experience any rainfall. Scattered showers mean that you, individually, may experience some showers intermittently throughout the day and there is a higher chance for this activity than isolated activity. Widespread showers mean that nearly all persons and areas may experience rainfall.

This week, isolated to scattered activity is forecast.

Forecast - Isolated, Scattered, Widespread - What do they mean?

Tropical Cyclone Climatology

Tropical Cyclone Points of Origin during the month of June. Though much of the points of origin are west or north of T&T as we move through the first month of the Hurricane Season, we still need to pay attention to some of these waves and the ITCZ, which have historically brought major flooding events to T&T, hence all low-pressure systems in the Atlantic should be closely monitored, as we do in the Tropical Update.

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