Extreme Winds and Seas to Usher in the New Year

28 12 2020

Dale C. S. Destin |

Extreme wind and marine events are forecast for this week across the northeast Caribbean, including Antigua and Barbuda. The howling wind event will take place Thursday – NEW YEAR’S EVE, through Saturday – January 2, whereas the life-threatening marine event will take place New Year’s Eve night through Sunday – January 3. Warnings and advisories for strong winds, rough seas and high surfs will be required for most islands.

Northeast Caribbean: Estimated max 3-second gusts; max sustained 10-minute winds; average of the top 10% of significant wave heights and average of top 10% of swells

The angry winds and seas could cause notable socio-economic impacts to the islands. Similar actions by nature, earlier this year, caused ships to turn away from Antigua and Barbuda and cancelled ferry services. There were also reports of LIAT aborting landings in some islands; banana trees being downed in some countries and power outage in some areas.

The kick-off of these unwelcome but not unusual events is expected on Thursday. The pressure gradient will rapidly and significantly steepen, which will become evident by the closeness of the isobars – lines of equal pressure, on our weather maps. The closer the isobars, the steeper the pressure gradient, the stronger the winds and vice versa.

Gale-force gusts, the equivalent to tropical storm-force gusts, are likely – gusts exceeding 78 km/h (over 48 mph). Otherwise, the winds will frequently be above 40 km/h (over 25 mph). The maximum sustained 10-minute wind speeds will likely reach around 50 km/h (31 mph), whereas the maximum sustained 1-minute winds will reach around 56 km/h (35 mph). The strongest winds are forecast for New Year’s Day, especially across open waters, windward coastal areas and elevated places. The prevailing wind direction will be northeast.

Visualization of wind gusts (shaded) wind direction (short solid lines) and isobars (long solid lines with numbers – pressure in millibars) – December 31 2020 to January 4 2021

As the winds go, so go the seas. The tumultuous winds will cause the seas to rise and become extremely threatening – very rough in open waters on Thursday through Sunday. Significant wave heights could peak at or above 4 metres (over 13 feet), locally exceeding 5 metres (near 17 feet). The highest seas are also expected on New Year’s Day. These seas will be non-navigational for small craft and even some non-small-craft operators.

Significant wave heights according to the ECMWF WAM Model – December 31 2020 to January 5 2021

High swells and surfs (breaking waves) are also forecast for Sunday. Swells in excess of 2.5 metres (over 8 feet) and surfs in excess of 3 metres (over 10 feet) are likely. These breaking waves will make for very dangerous conditions for beachgoers and others using the coastlines.

The events will make for a high threat to the life and livelihood and property and infrastructure of mariners and users of the nearshore areas. There is also the potential for extensive impacts including the following:

  • Loss of life
  • Injuries
  • Damage or loss of boats and fishing equipment
  • Saltwater intrusion and disruptions to potable water from desalination
  • Coastal flooding from sea water splashing onto low lying coastal roads
  • Sea search and rescue disruptions
  • Cancellations to transportation (especially by sea)
  • Scarcity of sea food
  • Disruption or cancellation to sporting and recreation events (especially marine activities)
  • Businesses and economic losses

To be safe, mariners should stay in or near port and beachgoers should stay out of the waters for affected coastlines. Also, residents should secure light and loose objects, which can be blown away, and caution should be taken when driving. The anticipated blustery winds could make some outdoor activities uncomfortable, if not outright dangerous. These winds can also create dangerous fallen or blowing objects.

The turbulent winds will unsettle the atmosphere, resulting in brief heavy showers. However, rainfall accumulations will only be of minimal concern, at most.

These events will affect virtually the entire Caribbean Basin, at different times. They will start across the Bahamas and the Western Caribbean on Tuesday and reach the northeast Caribbean on Thursday. Then, they will spread across the southern Caribbean by Friday – New Year’s Day. The extreme events will come to an end by Sunday, January 3, 2021, although seas will likely still be hazardous for some areas, beyond Sunday.

At times, it may feel like there is a tropical storm in the area, but I can ashore you that there is none. The hurricane season remains over.

Check and monitor your local forecasts, from your national weather service, for details specific to your location. This is a relatively broad scale view; hence, the numbers WILL change either way.

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Bomb Cyclone to Push Damaging Swells Across the Caribbean

16 01 2020

Dale C.S Destin|

The Caribbean Basin is about to see another round of large and damaging swells reaching its shorelines starting Saturday, from a bomb cyclone. Swells are forecast to exceed 3.5 metres (12 feet) and break at higher heights, as surfs, on coastlines. This is likely to be the biggest swell event since Swellmageddon of March 2018.

Animation of bomb cyclone, east of Canada, with pressure pattern, wind speeds and directions, as forecast by the Global Forecasting System (GFS) Model. Time in UTC

The event will be kicked off by a relatively inconspicuous low-pressure system (LPS), currently over the northeast United States. The LPS will go through explosive development (bombogenesis) over the next 24 hours and become a ginormous and powerful bomb cyclone (extratropical cyclone) over the northwest North Atlantic, with hurricane-force winds.

Although this system will form over 3220 km (2000 miles) away, it will have a significant impact on the region, through its strong winds pushing unusually high waves to our shores. The first set of these swells will reach the Bahamas on Saturday; the northeast Caribbean, including Antigua and Barbuda, on Sunday and the Guianas on Monday. The event will likely last three days from its start time. So, for the northeast Caribbean, its Sunday through Tuesday.

Animation of swells forecast to move across the region from the bomb cyclone, as predicted by the European Centre for Medium-Range Weather Forecasts (ECMWF) wave model (WAM). Time in UTC.

Swells will rise to to in excess of 3.5 metres across most of the Atlantic waters of the islands. There swells will produce even higher surfs or breaking waves. These surfs could be as much as twice the height of the incoming swells, depending on the bathymetry/topography of the near shore seafloor. This is expected to cause beach closures, as swimming conditions will become quite hazardous. Other impacts include:

  • major beach erosion;
  • flooding of some low-lying coastal roads;
  • disruptions to marine recreation and businesses;
  • disruptions to potable water from desalination;
  • damage to coral reefs and
  • Financial losses.

Advisories and warnings will be required for the weekend and or the first half of next week. The event will also be felt along the East Coast of the United States, Canada, Greenland, Iceland, the United Kingdom and Norway. Rowers of the Talisker Whisky Atlantic Challenge will also be negatively impacted, exponentially increasing the challenge of an already very challenging race.

High surf warnings or advisories will be required for coastal areas for much of the Caribbean this weekend and into the middle of next week

The impact on shorelines will not be the same everywhere. Depending on the depth and the natural shelter of the coastal waters, the impact will be different. Moderately sloping, shallow, north and or north-facing shorelines are expected to see the highest swells and surfs.

The bomb cyclone will go from a central pressure of 1004 hectopascals (hpa) (which is the same in millibars) to around 968 hpa in 24 hours and to a minimum of 955 hpa in 48 hours, just east of Newfoundland and Labrador, Canada. This represents an explosive drop of 59 hpa – more than one hpa per hour; thus, meeting the definition of a bomb cyclone – a drop in pressure of an extratropical cyclone of at least 24 hpa in 24 hours or less.

By Saturday, this weather bomb will be packing Category 1, hurricane force winds – 119 to 153 km/h (74 to 95 mph). These are the winds that will, in turn, generate large waves that will traverse the Atlantic and pound the shorelines of the Caribbean, inundating some low-lying coastal areas.

Of course, the hurricane force winds do not even have the remotest of chance of reaching the Islands; however, some of the wind energy, transferred into the seas will reach us in the form of ocean waves – ground swells. As you may know, waves do not transport water; they transport energy, which can de destructive when they break on shorelines.

Animation of wind directions and speeds forecast to impact the region, as predicted by the ECMWF Integrated Forecasting System (IFS) Model. Time in UTC.

Talking about winds, they are expected to surge – getting to the general range of 25 to 45 (16 to 28 mph), across the region again late Saturday and likely continue into Monday. Storm-force gusts to near 65 km/h (40 mph) are expected, especially in showers. Thus, both high wind advisories and small craft warnings are highly possible late Saturday through Monday morning.

Our (Caribbean) weather will also become wet again over the weekend and into midweek. There is a very high chance of occasional brief showers, as the high winds will destabilise the atmosphere via mixing and low-level convergence.

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Another Windy, Rough and Wet Week Ahead

16 12 2019

Dale C. S. Destin|

Rough Seas – Photo by Getty Images

This is a new week, but similar weather is expected to last week’s – windy and wet with rough seas. Winds are expected to surge over the next 24 hours, resulting in the winds becoming fresh to strong by Monday night. This will in turn cause hazardous seas and wet weather across much of the Caribbean Basin, including Antigua and Barbuda.

The winds and seas will be a threat to the life and property of mainly mariners. Some outdoor activities, on land, could also become dangerous.

By late Monday, the winds will rise to the range of 26 to 42 km/h (16 to 26 mph) with stronger gusts . It is expected that the winds will gusts to near storm-force/gale-force – 63 km/h (39 mph), mainly over open waters, exposed coastal areas and elevated terrains.

Given the expected winds, a high wind advisory may be required, particularly for the areas listed above. If a high wind advisory is issued, residents should secure loose and light outdoor items, which can be blown away, and caution should be taken when driving.

As the winds go, so go the seas – as the winds go up, the seas will go up also and become hazardous. Seas (significant wave height – SWH) are forecast to rise to a range of 2 to 3 metres (7-10 feet) with the potential extreme (10% chance) of reaching over 3.5 metres or 12 feet. Notwithstanding, the potential extreme SWH, seas are expected to occasionally reach near 4 metres (13 feet).  

Recall that seas are given as SWH, which is the average height of the highest 1/3 of the waves. Individual waves may be twice the SWH.

Given the expected height of the seas, particularly wind waves, a small craft warning is expected to go into effect for much of the waters of the Eastern Caribbean Monday night through Thursday morning. An advisory is in effect and one will be in effect after the warning.

Recall that a small craft warning generally means that wind speeds of 38 to 61 km/h (24 to 38 mph) and or seas of 9 feet or greater are expected to produce hazardous wave conditions to small crafts. If or when a warning is issued, small craft operators should stay in or near port and safeguard their vessels.

Impacts possible/likely/expected from hazardous seas include the following:

  • Loss of life;
  • injuries;
  • sea search and rescue disruptions;
  • disruptions to sea transportation;
  • scarcity of sea food;
  • damage or loss of boats and fishing equipment;
  • disruptions to marine recreation and businesses
  • and economic losses. 

Other impacts from the high winds, apart from hazardous seas, include:

  • injuries;
  • soil erosion;
  • localized disruptions of businesses;
  • disruption to outdoor and sporting activities;
  • disruption of transportation (air and especially sea) and
  • vehicular accidents and financial losses.

Wind of this strength could make some outdoor activities uncomfortable, if not outright dangerous. High winds can create dangerous fallen or blowing objects.

The strongest winds and the highest and most dangerous seas will take place on Tuesday. The highest seas will take place in the Atlantic waters of the islands.

The strong winds will be due to a very steep pressure gradient. Think of the pressure gradient like a hill and the wind as a car. The steeper the hill the faster the car will roll down the hill and vice versa. On a weather map, the steepest gradient and strongest winds are where the lines of equal pressure (isobars) are closest.

The higher than usual winds will destabilize the atmosphere, resulting in brief passing showers from time to time. Possible rainfall total for the week across the Eastern Caribbean is 25 to 150 mm (1-6 inches). The highest totals are likely across the southern Caribbean.

Last week, similar type weather took place. The area had fresh to strong winds with gusts in excess of 48 km/h (30 mph). The whole of the Eastern Caribbean had wet weather with some areas experiencing rainfall in excess of 150 mm (6 inches).

Seas will subside from warning to advisory levels by Thusday; however, it is unclear as to when seas will return to safe levels – when no warning, advisory or caution is required.

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Strong Winds and Hazardous Seas to Impact Parts of the Caribbean

22 01 2019

As the winds go, so go the seas. As the winds go up the seas will go up and become hazardous across the Bahamas, Cuba and Jamaica, in the western Caribbean, to around Anguilla in the northern Leeward Islands.

Hazardous Seas – Credit UCAR

The winds and wind waves have already started to pick up across the islands mentioned above, particularly the western Caribbean. The winds will eventually get to the range of 34 to 53 kmh (21 to 33 mph) through Thursday. Consequently, seas will become hazardous with wind waves of 2.5 to 3.5 metres (8 to 12 ft), occasionally reaching 4.5 metres (15 ft).

The highest and most dangerous waves will take place across the waters of the western Caribbean, where the winds will be the strongest. Outside of the islands listed above, including Antigua and Barbuda, the wind waves will unlikely reach 2.5 metres (8 ft), as the winds are not expected to get sufficiently high.

Advisories and or warnings to mariners, particularly small craft operators, will be required and already Puerto Rico and the Cayman Islands have issued such.

As a small craft operator, if an advisory is issued – inexperienced mariners, especially those operating smaller vessels should avoid navigating in these conditions. If a small craft warning is issued – you should stay in or very near port.

Potential impacts from this hazardous sea event include injuries or loss of life, damage or loss of boats and fishing equipment and disruption to sea transportation. Other possible impacts comprise of:

  • disruptions to sea search and rescue;
  • scarcity of seafood;
  • disruptions to off shore marine recreation and businesses;
  • business and economic losses.

On the other hand, the strong winds could result in disruptions to air transportation and outdoor sporting activities, soil erosion, vehicular accidents and financial losses.

As the winds go, so goes the seas; however, as the pressure gradient goes so go the winds. The winds will become strong because the pressure gradient will become quite tight across the northern islands. Think of pressure gradient like a hill and the wind as a car. The steeper the hill the faster the car will roll down the hill and vice versa.


Surface Chart for 2 pm (18 UTC) Today. Note the Seven Relatively Close Isobars (Black Lines) on the Left (Western Caribbean) Compared with the Four Widely Spaced one on the Right (Eastern Caribbean). The Pressure Gradient and Winds are Much Higher across the West than the East.

Note, unlike the blog from yesterday that spoke about swell waves, this blog is focusing on wind waves. What is the difference? Swells are waves generated by distant winds and are of danger primarily to users of the near shore, beaches and coastlines. On the other hand, wind waves are locally generated and are mainly of danger to mariners using off shore waters.

The strong winds and hazardous seas will subside to relatively safe levels by late Friday. Keep following my blog and other media – TwitterFacebook and Instagram for more on this event and all things weather and climate.





Steep Pressure Gradient to Cause Hazardous Conditions Across the Region

27 12 2018

Dale C. S. Destin|

Strong and gusty winds are forecast to move across most of the Caribbean this weekend – Friday through Sunday. These winds will make for hazardous conditions onshore and especially offshore. Some activities on land will become dangerous and marine conditions will be very hazardous for small craft operators.

The high winds and seas may be reminiscent of the passage of a weak tropical storm, but they won’t be due to any such system. The elevated winds will be the result of a very steep pressure gradient, due to the strength and location of the centre of a high-pressure system. The pressure gradient – the horizontal change of pressure, will be around 25% higher than normal.

Very hazardous seas in excess of 2.5 metres and rising to 3.5 metres (9 to 12 feet) will take place Friday through Sunday across the northeast Caribbean. Winds and seas will start building on Thursday – peaking on Saturday. Seas will occasionally reach 4.5 metres (15 feet).

These hazardous conditions will peak about a day earlier across the western Caribbean (including the Bahamas) and a day later across the southern Caribbean.

The winds will range between 34 and 45 km/h (21 and 32 mph) across the northeast Caribbean Friday through Sunday. Gusts to gale-force i.e. 64 km/h (40 mph) are expected. These kinds of winds very unusual for the region outside of being associated with a tropical cyclone (hurricane, tropical storm or tropical depression). The wind will generally blow from the east.

Possible impacts of the strong winds and hazardous seas include:

  • injuries or loss of life;
  • damage or loss of boats and fishing equipment;
  • disruptions to marine recreation and businesses;
  • disruptions to air and especially sea transportation;
  • disruptions to outdoor sporting activities;
  • disruptions of sea search and rescue;
  • scarcity of sea food;
  • vehicular accidents and
  • economic losses.

The worst affected area is likely to be the northern Caribbean – including the Leeward Islands and areas further west. Marine warnings are expected to be issued by most islands. Winds will be strongest over open waters, elevated terrains and windward coastal areas – eastern coastal areas.

Small craft operators and even some not so small crafts operators should stay in or very near port this weekend. Work at high and exposed evaluations should be avoided. Some outdoor activities may need to be postponed or adjusted for the conditions. Secure or take indoors light and loose objects – patio furniture, trash can etc..

Be very caution if you need to drive a high-profile vehicle, as strong winds could make for difficult, if not dangerous, driving of such automobile.

This event is not related to a tropical cyclone; nonetheless, some measures need to be put in place to mitigate the potential impacts – especially those related to the marine environment.

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Windy Weather to Cause More Hazardous Seas and Economic Losses

8 01 2018

Dale C. S. Destin |

Hazardous seas being caused by frequently strong winds – gusting to near gale force at times, will continue to keep most mariners in or near port over the upcoming week – causing further significant economic losses for many.

Seas around Antigua and Barbuda have been rough for most of the year, so far, and are set to remain that way or even worsen over the next seven days, at least. As usual, this type of weather is very disruptive to marine activities and have a negative economic impact, particularly on fisherfolk, those alone the fisheries value-chain and those involve in offshore pleasure cruises and adventures.

Small craft warning remains in effect for hazardous seas around Antigua and Barbuda and will likely remain in place for the rest of the week. Hence, small craft operators, especially inexperienced ones, should avoid navigating in these conditions.

Warnings are also in effect for beach-goers as high surfs are affecting beaches, producing beach erosion and dangerous swimming conditions. Beach-goers should avoid the waters, especially those on the northern and eastern side of the islands. These high surfs are likely to subside to more manageable levels by Tuesday.

High surfs can also cause strong rip currents, which can carry even the strongest swimmers out to sea, and seawater splashing onto low-lying coastal roads, causing damage. Further, high surfs can also knock spectators off exposed rocks and jetties. Breaking waves may also occasionally impact harbours making navigating the harbour channel dangerous.

The wind speed will range between 14 and 22 knots (16 to 25 mph) and at times gusting to near 30 knots (35 mph). The winds will be strongest on Tuesday and Friday and will blow from near east for most of the week.

Wind speed – valid at 6 am, Tue, Jan 9, 2018

Seas will remain hazardous with steep waves ranging between 2 and 3 metres (7 and 10 ft), occasionally reaching near 4 metres (13 ft), mainly in open waters on the eastern or windward side of the islands.

Significant wave height (ft) – valid at 6 am, Tue, Jan 9, 2018

These strong winds not only cause hazardous seas but also cause certain onshore activities to be uncomfortable, if not dangerous. Hence, certain outdoor work will be hampered, if not halted, at times; thus, reducing productivity in other sectors.

The windy conditions and hazardous seas will also be experienced by all the islands of the Eastern Caribbean along with Hispaniola and the Bahamas, particularly the Atlantic coastal waters or the eastern and northern coastal waters.

The strong winds are not due to any storm system but rather because of steep pressure gradients across the area. Recall that winds blow due to pressure differences or pressure gradients, and the greater the gradients the stronger the winds and vice versa.

Also, the strength and position of the ever-present subtropical/Atlantic high-pressure system modulate the steepness of the pressure gradient. The closer and or stronger the subtropical high, the steeper the gradient, the stronger the winds and vice versa.

The subtropical high-pressure system will be stronger than normal for much of the next week; hence, the forecast continuation of strong winds, hazardous seas, disrupted marine activities and economic losses.

Although windy, the weather will be mostly dry with only occasional brief showers likely.

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Storm-Force Wind Gusts and Hazardous Seas Are Returning to the Area

7 03 2017

Storm-force wind gusts and hazardous seas are returning to the area. The weather will be generally good but the increased winds will cause the lower atmosphere to become somewhat unsettled, giving rise to occasional showers.

The Met Office has already issued a small craft warning and this is expected to continue in place through, at least, Friday. Given the expected conditions, small craft operators should not venture far from port, especially on the windward side of the islands. Beachgoers should avoid the waters of the north and east facing beaches.

The expected strong gusts will also make some outdoor activities very uncomfortable if not dangerous. At least, light objects should be secured, as minimal storm conditions are possible. Please be guided accordingly.

The wind speed will steadily rise to 28 to 44 km/h (17 to 28 mph) by late Tuesday and continue in that range until Thursday; thereafter, subsiding. Wind gusts as high as 67 km/h (41 mph) are possible in showers. The prevailing winds will be east-northeast.

The major concern about the winds is the impact on the seas. They will cause the seas to become very hazardous, with heights reaching 4 metres (13 ft), occasionally reaching 5 metres (17 ft) late Tuesday and staying at those heights until Friday, when they will start to subside.

These conditions, especially the seas, will not be dissimilar to what would obtain during the passage of a tropical storm through the area. However, no such system will be around.

The brunt of this windy weather will be felt mainly over open waters on the windward side of the islands, windward coastlines and elevated places.

The gale-force or storm-force wind gusts and associated strong winds will be as a result of a very steep pressure gradient across the area. Recall that winds blow due to pressure differences or pressure gradients, and the greater the gradients the stronger the winds and vice versa.

The last episode of similarly strong winds and rough seas was a recent as last week.

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Very Hazardous Marine Conditions for Antigua and Barbuda

14 01 2017

Dale C. S. Destin |

 

High Surf

High Surf

The shoreline Antigua and Barbuda and the rest of the northeast Caribbean are getting hammered by high surfs. Additionally, starting today, seas in open waters will become very unfriendly to small craft operators. As a result, the weather authority in Antigua and Barbuda has issued special marine statements on the high surfs and rough seas.

Surfs are building – they are expected to range 8-12 feet (2.4-3.6 m) between today and Monday, affecting mainly northern and eastern coastlines. These high surfs are being generated by a low pressure system located just northeast of the area, which is pushing very large swells to our shores.

There is a high risk of rip currents, especially over the next 24 hours when the surfs are expected to peak. Rip currents are powerful channels of water flowing quickly away from shore, which occur most often at low spots or breaks in the sandbar and in the vicinity of structures such as groins such as jetties and piers.

The winds will become fresh to strongthey will frequently be in excess of 18 mph (16 knots) from today to Wednesday. The winds will peak at around 30 mph (22 knots) with occasional gale-force gusts to the around 39 mph (34 knots) today and Sunday likely.  These winds will primarily take place over open waters, coastal areas on the northern and eastern side of the islands and elevated areas.

windjan142017

windgustsjan142017

The seas will respond to the winds – they will become very rough, rising to as high as 3.6 metres (12 feet) on Saturday night Sunday. Waves will decrease to less than 2.0 metres (6 feet) by Wednesday.

seasjan142017

The cause of the strong winds – this is due to a significantly tight of the pressure gradient (horizontal differential of pressure) across, which will tighten a bit more over the next 24 hours. The relatively tight pressure gradient is in response to a strong high pressure system moving from west to east across the Atlantic from the United States. There are NO tropical cyclone (tropical depression, tropical storm or hurricane) in the area.

Surface Chart

Surface Chart for Saturday 8 am, Showing a Tight Pressure a Tight Gradient as Evident by the Closeness of the Isobar (Pressure Lines)

Precautions – Sea-bathers should avoid the waters, mainly on the northern and eastern sides of the islands until Tuesday. Small craft operators should not venture far from port through Monday.

A high surf warning means that high surf will affect beaches in the advisory area, producing beach erosion and dangerous swimming conditions.

A small craft advisory means that wind speeds of 24-38 mph (21 to 33 kt) and or seas of 7 feet (2.1 m) or greater are expected to produce hazardous wave conditions to small craft. Inexperienced mariners, especially those operating smaller vessels should avoid navigating in these conditions.

The strong winds, especially if frequently gusting to gale force, could also make some outdoor activities very uncomfortable if not hazardous, please be guided accordingly.

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Easter to See More Hazardous Marine Weather Across Most of the Caribbean

26 03 2016

Dale C. S. Destin |

Fresh to strong gusty winds are causing hazardous seas across most of the Caribbean. This is expected to continue beyond Easter Monday (March 28).

Credit UCAR

Hazardous seas; Credit UCAR

Based on observations from met. offices and weather buoys, the winds were in the range of 15 to 22 knots (17-25 mph) with gusts in excess of 32 knots (37 mph).

In some areas, the winds were much stronger. At the Norman Manley International Airport, Jamaica, peak sustained winds of 26 knots (30 mph) were measured. No doubt parts of that island had gusts in excess of 34 knots (39 mph) – the equivalent to gale force or tropical storm force winds.

Weather report

Weather report from Norman Manley Int’l Airport – Mar 25, 2016, 2 pm local time

Winds were strongest across the Caribbean Sea, south of Jamaica. Today, Buoy 42058 measured winds in the range of 21 to 25 knots (24-29 mph) with gusts reaching 32 knots (37 mph).

Buoy data show the Caribbean Sea, especially south of Jamaica, is basically impassable by boat due to tremendously hazardous seas reaching as high as 4 metres (13 feet). Across the waters Eastern Caribbean, seas are near 2.5 metres (8 feet) and building.

Buoy data for March 25, 2016

Buoy data, seas for Mar 22-26, 2016 GMT/UTC

Buoy Data

Buoy data, wind speed Mar 22-26, 2016 GMT/UTC

The strong winds are in response to the high pressure gradient across the region. Winds blow as a result of differential pressure. The greater this differential is i.e. higher the pressure gradient, the stronger the winds and vice versa.

Surface chart depicting high pressure gradient evident by the closeness of the isobars (black lines)

Surface chart depicting high pressure gradient evident by the closeness and high quantity of the isobars (black lines)

As the winds increase, the friction on the underlying sea surface results in building seas or wind-driven waves. The stronger the winds, the higher the wind-driven waves and vice versa.

A further increase in the pressure gradient is forecast over the next 24 hours. Hence, winds and seas are expected to get higher. Thus, marine conditions are expected to become even more treacherous tomorrow.

Seas could exceed 4.5 metres (15 feet) across the waters between Jamaica and Panama. Meanwhile seas and could exceed 2.7 metres (9 feet) mainly on the Atlantic (east) side of Barbuda, Antigua, Guadeloupe, Dominica and Martinique.

Forecast Seas

Forecast Seas (feet), valid 2 pm (1800 UTC), Sat, March 26, 2016

The winds could increase by another 2 to 5 knots (2-6 mph) with gusts in the upper 20s to lower 40s knots ( upper 20s to upper 40s mph).

Forecast Winds

Forecast Winds (knots), valid around 11 am (1500 UTC) Sat, Mar 26, 2016

Forecast Gusts

Forecast Gusts (knots), valid around 11 am Sat, Mar 26, 2016

Clearly, it goes without saying that mariners should not venture far from port and sea-bathers should be extremely careful. As a matter of fact, sea-bathers should avoid the beaches on the northern and eastern sides of the islands. For Hispaniola and Jamaica, beach-goers should also avoid the waters on the southern side of those islands.

The strong winds could also make some outdoor activities very uncomfortable to perform, if not outright dangerous. This is especially true of work at elevations. Please be guided accordingly.

The winds will start to subside on Sunday. However, seas will not return to safe levels until around Wednesday.

Cuba is the only Island being spared by the strong winds and hazardous seas.

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Needed Showers but Unwelcome Hazardous Seas for Much of the Caribbean

7 03 2016

Dale C. S. Destin |

A cold front is sweeping the Caribbean, bringing much-needed showers but unwelcome strong winds and hazardous seas.

Rainfall

Already, more than an inch of rain has fallen in parts of Cuba and Hispaniola over the past 72 hours. Meanwhile, winds have reached near 20 knots (23 mph) with stronger gusts across Cuba. Seas are near 3 m (10 ft.) and rising, mainly across the northern waters of the Bahamas.

The front is expected to reach Trinidad by around Thursday/Friday, which is very unusual for such a system to go so far south into the Caribbean.

As it moves across the region, showers will spread to the Virgin Islands today; the Leeward Islands late Tuesday/Wednesday; the Windward Islands and Barbados Wednesday/Thursday and Trinidad and Tobago Thursday/Friday.

Most of these islands will likely see rainfall totals in the range of 10-40 mm (0.40-1.60 in). At least minor inland flooding is possible across some islands.

FcastRain

Forecast 5-Day Rainfall Total for the Period March 7-11, 2016

Strong winds and rough seas will reach the various islands within 24 hours after the arrival of the front and continuing for up to 120 hours after the front passes. Thus, by Friday, most of the waters of the Caribbean will be having hazardous seas and will require the requisite warnings for mariners and sea bathers. Seas could peak near 3.5 m (12 ft.) across some areas.

Seas.png

Most areas will see sustained winds in excess of 20 knots (23 mph) with gusts across a few islands reaching gale force strength of near 40 knots (46 mph). Higher elevations can expect higher speeds.

WindGusts.png

With the combination of strong winds, sea swells and wind-driven waves, flooding of low-lying coastal areas due to large breaking waves is possible. Damage to coastlines can also be expected.

The strong winds could also render some routine outdoor activities uncomfortable if not hazardous.

We will continue to follow the progress of this system and keep you posted. Meanwhile, pay attentions forecast coming from your local meteorological office for information specific to you location.





Growing Concerns for the Atlantic Challenge Rowers

11 01 2016

Dale C. S. Destin |

Concerns are growing for Team Wadadli (or Team Antigua) and the rest of the rowers participating in the Talisker Whisky Atlantic Challenge. Marine conditions are expected to become extremely unfavourable, if not exceptionally dangerous for the seafarers.

Tweet of concern

Tweet of concern

By now, you may have heard of the very powerful extratropical low pressure system that could transition into the first tropical cyclone (generic term for tropical depressions, tropical storms and hurricanes) over the Atlantic in January since 1978.

Extratropical cyclone with centre marked by X, next to the red L. 0600 UTC, Jan 11, 2016 Surface Chart

Extratropical cyclone with centre marked by X, next to the red L. 0600 UTC, Jan 11, 2016 Surface Chart

Transition or not, the low/tropical cyclone is expected to generate across the paths of many of the rowers, ginormous seas, possibly reaching six metres (20 feet) and sustained storm force winds (greater than 34 knots/39 mph). Such severe marine conditions will easily cause boats to capsize and be injurious the occupants, if not worse.

Wave Height (ft), Valid Tue, Jan 11, 2016, Issued Jan 11 at 6 AM AST

Wave Height (ft), Valid Tue, Jan 11, 2016, Issued Jan 11 at 6 AM AST. The box at the top right indicates the seas Team Wadadli and many others could face tomorrow.

Wind Speed (kt), Valid Tue, Jan 11, 2016, Issued Jan 11 at 6 AM AST

Wind Speed (kt), Valid Tue, Jan 11, 2016, Issued Jan 11 at 6 AM AST. The box at the top right indicates the winds Team Wadadli and many other could face tomorrow.

Additionally, unfriendly winds and currents will stop, if not push rowers backwards, towards the starting point instead of the finish line – Antigua. Initially, the unfavourable winds will come from the south, then the west and then north over the next few days in the vicinity of the racers.

Last night, Team Wadadli was forced to “drop” its sea anchor as they were being push towards the bad weather by southerly winds. They also reported that the seas were building. It is not clear how long they will stay in “anchorage”. However, this strategy (of which there are very few) may not be the best for the situation.

tweet from team wadadli

Note that a sea-anchor also known as a drift anchor does not stop a boat from moving, it just slows and stabilizes it in heavy weather. The Race Tracker shows that Team Wadadli, as of 8 am this morning, was still moving towards the bad weather at 1.4 knots (1.6 mph), perhaps on a collision course with what could become Tropical Storm Alex, which is also moving towards them.

Tracker showing the locations and progress of the boats as of 8 am this morning

Tracker showing the locations and progress of the boats as of 8 am this morning

The Tracker also showed many, if not all of the boats were in a similar situation.

If Team Wadadli remains drift anchored, instead of finding away to get out of the southerly flow (drifting from south to north), they could find themselves in a lot of trouble along with many of their competitors.

By my projections, in the next 24 hours, Team Wadadli, could find itself well northeast of its current position, heading out over the North Atlantic, in seas over 4.5 metres (15 feet) and winds greater than 28 knots (32 mph). Of even greater concern is that they could get caught up in the southwesterly winds (winds blowing from the southwest) and move northeast with the bad weather for several days.

Other teams, especially those that are east of longitude 35 degrees west, could suffer a similar fate.

I don’t know what’s the organizer’s criteria for the race to be suspended or cancelled but conditions must be getting pretty close to meeting them.

The low/tropical cyclone will severely affect this year’s edition of the Talisker Whisky Atlantic Challenge. If the rowers were up for a challenge, the upcoming days will fulfil their desire. Let’s hope they come out of it in flying colours with a heck of a story to tell.

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Cheerful Seas Ahead for Atlantic Challenger

4 01 2016

Dale C. S. Destin |

Good news for rowers taking part in the Talisker Whisky Atlantic Challenge, racing to Antigua and Barbuda.  After angry seas for most of the last 15 days, since the challenge started, cheerful marine conditions are expected to greet the challengers after midweek.

The daredevil rowers, including Team Wadadli (Antigua) are currently experiencing fresh to strong winds of 17 to 23 knots (20-26 mph) with wind gusts as high as 30 knots (35 mph). Seas are very rough with heights of 2.4 to 3 metres (8 to 10 feet).

Wave Height (m), Valid Mon, Jan 4, 2016, Issued Jan 4 at 6 AM AST

Wave Height (m), Valid Mon, Jan 4, 2016, Issued Jan 4 at 6 AM AST

The current marine conditions are extremely dangerous. For such conditions in coastal waters, warnings would be in effect and small craft operators, such as these rowers, would be told not to venture far from port. However, I guess, therein lies part of the challenge.

The race was set to start on December 16 but was delayed by hazardous marine conditions to December 20.

Although not very reliable beyond a week, wind wave models are forecasting relatively comfortable sea conditions from around January 7 to January 19. After the middle of this week, the winds will generally stay under 16 knots (18 mph) and seas less than 1.8 metres (6 feet). Until then, the racers will continue to be battered by angry waves.

Wave Height (m), Valid Thu, Jan 7, 2016, Issued Jan 4 at 7 AM AST

Wave Height (m), Valid Thu, Jan 7, 2016, Issued Jan 4 at 7 AM AST

The Talisker Whisky Atlantic Challenge dates back to 1997. Initially, it was a bi-annual event but it‘s set to become annual confrontation of the Atlantic. It rows-off from the Canary Islands and ends, as of 2005, at the Historic Nelson’s Dockyard, English Harbour, Antigua and Barbuda. It covers a journey of around 4.7 million metres (2930 statute miles).

The Progress of the Rowers as of 8 am AST. Team Wadadli's Position is Marked in Plum with a bold White Outline

The Progress of the Rowers as of 8 am AST. Team Wadadli’s Position is Marked in Plum with a bold White Outline

For the first time a team from Antigua and Barbuda is taking part in the race. The team can be followed here on facebook. They are currently in 11th place; however, the focus for them is on the challenge of completing such a race.

Boats should start to arrive in Antigua at in the next 17 days, or so, to hundreds of welcoming Antiguans along with the seafarers families and friends.

Let’s hope the weather after Wednesday give them much cheers until they reach our shores.





A Tropical Wave to Shower the Leeward Islands

21 06 2015

Dale C. S. Destin |tropwaveJun21

A tropical wave is expected to raise our rainfall total over the next 24 hour. It will likely shower the island with 5 to 10 mm (0.20 to 0.40 in) of rain as it traverses the region. It’s possible that rainfall total could reach as high as 25 mm in some places.

forecast_June22

Already, the system has dumped over 25 mm of rain on parts Barbados with more rain in the forecast. The Windward Islands and the rest of the Leeward Islands are also in for some much needed showers, from the tropical wave.

Many of the islands are in the midst of droughts and are thirsty for rainfall. For example: as of the end of May, Antigua only had two more months of surface water remaining, according to Ian Lewis, Water Production Manager of the water authority. Meanwhile, the Government of St. Lucia has declared a “water emergency”.

The wave will also cause a surge in the winds and seas across the Eastern Caribbean. Winds are expected to rise to near 20 knots, mainly over open water and elevated places. Wind gusts to near 28 knots will also take place.

Seas_June 21

In response to the strong winds, the seas will become hazardous with heights reaching 2.4 m (8 ft), especially on the eastern side of the islands.

The winds alone will make some outdoor activities, such as working at heights, uncomfortable if not dangerous.

While the rain is expected to subside by the end of tomorrow (Monday), strong winds and rough seas will continue until Wednesday. Given the situation, mariners should really stay near shore until winds and seas subside to safe levels.

Given the rainfall deficits across much of the region, the possible rainfall totals from the tropical wave are only “drops in the bucket”. However, we are in a very desperate position; hence, we will cheer for every and any shower.








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