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.

Stay updated on the situation by following us via our social media platform:  twitter,  facebook,  instagramtumblrflickrgoogle+, and youtube.

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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.

We will keep you updated via our social media platform, which includes twitter, facebook, wordpress, instagram, tumblr, and google+. You are invited to follow for all things weather and climate.





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.





Hold on to Your Hats and Skirts!

31 12 2014

Dale C. S. Destin |

Forecast Wind Speeds - Sun Jan 4, 2015

Forecast Wind Speed – Sun Jan 4, 2015

Hold on to your hats and skirts and batten down the hatches. Strong winds and very rough seas to kick off the new year across Antigua and much of the Caribbean.

The winds will become stronger with peak sustained speed near 25 mph (22 knots) over the weekend across Antigua and Barbuda. The winds will also be very gusty with gusts as high as 37 mph (32 knots) possible, just 2 mph short of storm force.

Forecast Wind Gust - Sun Jan 4, 2015

Forecast Wind Gust – Sun Jan 4, 2015

The strong winds will stirrup very rough seas in our area. Seas could peak as high as 3.6 metres (12 ft) Sunday and continue above 2.4 metres (8 ft) until, at least, the middle of next week. By next Thursday there could be a transition from wind waves to swell waves from a frontal low pressure system.

Forecast Wave Height - Sun Jan 4, 2015

Forecast Wave Height – Sun Jan 4, 2015

The strong winds are in response to the steepening of the pressure gradient across the area. You may recall that winds are the horizontal movement of air. They only occur due to the spatial deferential in atmospheric pressure. The change in pressure across a particular area is called the pressure gradient. The steeper the gradient or greater the pressure difference between two points, the stronger the winds and vice versa.

Warnings are already in effect for hazardous seas that are bound to get much worse. Mariners should consider staying near shore until winds and seas subside, perhaps late next week.

The strong winds could make certain activities uncomfortable, if not dangerous. For example, working at elevation could be dangerous and should be curtailed until the winds return to normal speeds.

The worst conditions will be seen in the western Caribbean Seas, juts north of Columbia. The winds are expected to peak near 44 mph (38 knots) with gusts near 54 mph (47 knots); this is tropical storm strength and under tropical cyclone criteria would require a tropical storm warning. Wave heights will approach 6 metres (20 ft).

This area of storm force winds is pushing large waves outward which will cause most of the Caribbean Sea to be rough for the next several days. Mariners should avoid travelling not only the Atlantic waters of the Caribbean but also the Caribbean Sea, especially the western Caribbean Sea south of Jamaica.

Feel free to share with us your experiences of this strong wind and very rough seas event and follow us on wordpress: anumetservice.wordpress.com twitter: @anumetservice facebook: /anumetservice tumblr: anumetservice.tumblr.com to keep current with weather and climate info.

Happy New Year!








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