Denis Webser,

by Denis Webster, Tiger Lily II

Denis Webster is a meteorologist who just completed his 20th season cruising the Caribbean aboard his Hylas 47, Tiger Lily II

Factoring weather into route planning

World Cruising Routes

Atlantic Crossing Guide

Passage planning invariably involved weather at some point. This section is not designed to provide detailed weather information on wind speeds or direction or wave data, but rather an overview of what should be expected along the route. There is an abundance of passage planning and pilot charts, which will require more detailed study on a month to month basis before the final decisions are made. Rather, what follows is a compilation of weather conditions that might be expected on routes in the seasons given.

Only well traveled routes in the South Atlantic and Caribbean are covered. For simplicity, routes have been divided as follows:

1. East to west Atlantic crossings
2. Eastern Caribbean Island chain
   • Northbound
   • Southbound
3. Moving west in the Caribbean
   • North route
   • South route
4. Moving north and south in the Western Caribbean
5. Moving to and from the US East Coast

Each of these sections will contain a ‘Best time’ to make these passages and a brief description of the type of weather to be expected.

Many crews will, of course, have time constraints and weather will not be a top priority. Prevailing conditions of less favorable timeframes will be covered under the heading ‘Other times’, along with strategies to use in planning to travel during those times.

East to west Atlantic crossings

Best Time: Mid to late November until the end of December. In the past, boats were accustomed to leaving the Coast of Africa in October. However, over the past several years, hurricanes or tropical storms have occurred with disturbing frequency in November and even in early December. This has occurred so frequently that NOAA has extended the official hurricane season to November 30. Winds at the end of the hurricane season at the end of November are generally in 15 – 20 kts and mostly easterly. Seas are generally 1 to 1.5 metres. By leaving in mid November there is a risk of encountering a tropical wave or depression. In December, winds slowly increase in speed and by the end of December are normally 20 knots. Wind directions will vary from NE to E. Troughs, rain, and thunderstorms often occur along this route in November.

Other Times: January to March: Wind direction is predominantly NE in the 20 – 25 knot range during this time period with corresponding 2 – 3 metre seas. There may be periods of lighter winds, particularly between high-pressure cells moving to the north. Conditions are generally drier with only passing showers.

April – June: Winds will be back to the 15 – 20 knot range by this time. However, troughs, both at the surface or aloft, often produce squalls and rainshowers. Wind directions may vary considerably, but predominantly from east.

June 1 – Mid November Attempting this passage in hurricane season is risky and likely to have light winds and rainy, squally weather from tropical waves, depressions and hurricanes.

Eastern Caribbean Islands Chain

Northbound

Best time: Mid November until the end of December and April to June

Winds are generally southeast or easterly at 15 – 20 knots and seas 1 – 1.5 metres at this time. Lingering weak tropical waves in November or ‘between season’ troughs (see description Southbound below) occasionally persist but are of short duration. If moving from the south (Trinidad) to the Virgin Islands or St Martin, this is the time to move.

From April to June, winds once again become easterly to south easterly at 15 – 20 kts. Precipitation increases slowly during this period and troughs with associated showers and squalls become more frequent.

Others times: January to March

Winds abruptly change to NE 20 and sometimes 25 with seas of 2 – 3 metres near the end of December. This cycle of strong winds is often referred to as “Christmas” winds. The acceleration zones between islands often result in 3 metre waves and winds into the mid 30 knot range. Breaks in this cycle of strong winds occur, but only for a day or two, to allow boats to move north more comfortably. These breaks become longer by March and will often last several days.

Others times: June to mid November

June is often a windy month with easterly winds near 20 kts. Tropical waves often begin and gradually gain in intensity and occasionally developing into depressions and hurricanes. Winds become light in July through October and generally southeast. Rain and thunderstorms are frequent.

Southbound

Best Time: March to May Winds become more easterly and speeds are generally in the 15 – 20 knot range. Although not a beam or broad reach on some of the northern chain courses, the speeds make for good sailing. Generally this time of year is free of precipitation except for troughs which form and linger over areas without moving for several days.

A close 2nd best time: from mid December to March. Travelling south from the Virgin Islands or St. Martin during this period can be anywhere from exhilarating to delightful broad reaching. Winds generally will be northeasterly 20 and sometimes 25 kts with periodic lulls as High Pressure cells move east.

Other times: June – July, or October to mid December. Winds during this timeframe are often from the SE, so in order to avoid sailing hard on the wind, it is best to wait for winds to swing east. Wind speeds (except for June, which tends to be windy), will be 15 kts or less. Precipitation will be more frequent with tropical waves and troughs passing through the area.

Moving west in the Caribbean

Many sailors with limited time schedules arrive in the Caribbean with plans to travel directly to Panama leaving limited time to spend in the island chain. Others plan on one or several season in the islands before moving west. There are two popular routes to Panama from Caribbean chain, one from the north part of the chain and the other from the south. Of course, sailing direct is also an option.

North Route

The north route runs from the Virgin Islands along the south coasts of Puerto Rico, the Dominican Republic and Haiti to Jamaica. One can then sail directly to Panama or stop at Providencia or San Andres – two offshore Colombian islands. With more time Cuba, Mexico, Belize and Honduras could be visited.

Best times: The north route can be traveled most easily in November and early December or from March to May. Winds during these periods are lighter and the seas flatter. Occasional cold fronts or dissipating weather systems sometimes bring rain or squalls, particularly along the coastal regions of the large islands. Winds are generally in the 15 to 20 knot range and blow generally from the easterly quadrant.

Other times: From mid December until March, the dry season cycle frequently produces 20 – 25 knot winds with short period, steep seas which make sailing more challenging. Wind direction tends to be from NE.

Winds from June to October tend to be lighter than 20 knots and frequently from the southeast quadrant. During this period, tropical waves depressions and hurricanes make moving about on this route risky. The western portion of this route is subject to early season tropical system development from mid May until the end of June. Rain, thunderstorms, and depressions make this period risky.

Note: Traveling to the south of large islands will result in winds being somewhat unpredictable. Acceleration zones such as the Windward and Mona Passage are well documented. Strong winds and high seas often result.

South Route

This route runs from the southern part of the island chain along the outer islands of Venezuela, the ABC Islands and the Colombian coast.

Best times: This route is best traveled in late October, November or the first part of December. April and May are also good months.

Weather conditions are similar to those for the north route, although slightly stronger winds and higher seas might be expected around the ABC Islands and the Colombian coast. June is also possible but it tends to be a windy month with more frequent rainsqualls and thunderstorms. Typical winds are easterly 15 – 20 knot range with seas of 1 – 2 metres.

Other times: The period from December to March is more challenging. The pressure gradient is enhanced by the combination of a semi permanent ‘thermal low’ over Colombia and strong high pressure moving south and east from North America. Gale force winds are not uncommon, along with steep seas, which exceed 6 metres. Colombian ports are often closed to yachts departing during this period. It is sometimes possible to move between cycles if the lower winds persist for long enough. A good strategy is to enjoy the ABC Islands and the Venezuelan offshore islands and make the trip to the western Caribbean later in the spring.

It is also possible to make this trip during the hurricane season – June to the end of November – but one must contend with tropical waves and depressions which produce squalls and thunderstorms. Hurricanes generally move north of this route, but they may generate large swells. Winds during the hurricane season tend to be light (15 knots or less) from the southeast quadrant.

Moving North and South in the Western Caribbean

The western Caribbean is a very diverse cruising area. Routes generally run parallel to the coastline of Nicaragua and Honduras through the offshore banks to Jamaica or west to the Bay Islands of Honduras and up the Guatemalan coast to Belize and Mexico. Weather conditions in this part of the Caribbean tend to be more challenging and timing plays a more important role in making passages.

North from Panama

Many vessels having arrived in Panama from Venezuela and Colombia spend time in the San Blas Islands of Panama, and rather than transiting the Panama Canal to the Pacific, they decide to move north instead.

Best time: April to mid May. Moving north at this time of year generally involves waiting for the wind to back into the east or better yet, south of east. Cold fronts become less frequent in early April and finally become absent from the Caribbean, stalling over the Gulf of Mexico. Winds slowly become easterly by early May, permitting a northerly course to be laid to the offshore islands of San Andres or Providencia or directly to Jamaica. From Providencia or San Andres, it is usually a good sail either behind the offshore reef system or between off-lying banks to the Bay Islands of Honduras or the Rio Dulce in Guatemala. This is also a favorable time for leaving from the Rio Dulce, Honduras, Belize, or Mexico to travel to Cuba or the United States.

Other times: Moving during the hurricane season is, at best, risky. In past years, early season depressions, broad troughs and even tropical storms have made a habit of forming in late May and June. In addition, during the period from June to November, heavy rains, thunderstorms and lightning are frequent throughout the coastline all the way to southern Mexico. October and November are also months for late season hurricanes in the Western Caribbean.

From December to March, winds are generally NE with typical speeds of 20 –25 kts. which make easting very difficult.

Moving South in the Western Caribbean

Best times: From Belize and the Rio Dulce This passage is best made from early April to late May. There is considerable easting to be made from Belize and Guatemala before rounding Cabo Gracios a Dios, the Cape at the eastern end of Honduras, and beginning the trip southward. Winds at this time of year tend to be lighter, although there will be occasional showers and thunderstorms. Once round the eastern corner, one can sail behind the Honduran barrier reefs or if winds are favourable, continue east offshore and then turn south between the banks. Winds can be stronger close to the northern coast of Honduras as this is an acceleration zone for east and northeast winds.

From Jamaica or Cuba: Moving south from the northern islands can be done from early December until late May. Winds will be typically 20 kts and more northeasterly from December until April and cold fronts will penetrate well into the Caribbean basin until late April. After that time easterly winds of 15 to 20 kts could be expected. Seas will gradually abate from 2 – 3 metres to 1 – 1.5 metres by May.

Other times: This area is best avoided from early June until mid July because early season depressions often form in this region. During hurricane season, thunderstorms are a regular occurrence in coastal areas. Short passages between tropical waves are possible. Longer voyages are best left for more favourable months. Winds tend to be lighter than 20 kts.

Moving between the US East Coast and the Caribbean

From Florida to the Western Caribbean

Best times: The routes from Mexico, Belize and western Cuba all involve gaining easting. The best months for this trip are late April to mid May. By late April, cold fronts have weakened in strength in the Gulf of Mexico or have begun to stall in the northern part. Ahead of the fronts, winds tend to be easterly or southeasterly, with speeds averaging 10 to 15 kts. The location and strength of the Gulf Stream current is a major factor in these trips. Care should be taken to avoid strong winds blowing counter to the Gulf Stream current, as rough seas are the result.

Other times: From December until early April, frequent cold fronts penetrate well into the Caribbean. Winds ahead of these fronts tend to be easterly at 15 – 20 kts. Behind these cold fronts, winds are mostly NE 20 and sometimes stronger, with 2 – 3 metre seas. The winds behind the fronts sometimes blow for several days until the next cold front approaches. It is possible to make a passage between fronts, but the position and features of the Gulf Stream current should be monitored to ensure a smooth passage. Wind against current will produce large steep seas. Rain, gusty winds, and occasional thunderstorms are often associated with cold fronts.

From the Eastern Caribbean to the US East Coast

Best time: Mid April to mid May The northern route, via Bermuda, and directly to the eastern US seaboard, usually involves waiting for favourable winds. Leaving the eastern Caribbean for Bermuda will require some easting. Winds will gradually shift from NE 20 kts. to east at 15 – 20 kts during this period, allowing for some easting. Attention should be paid to the position of the Azores’ high, as some motoring may be required if the ridge extends east across your route.

Before departure, monitor the Atlantic storm tracks as low pressure areas exit the US coast. If sailing directly to the US, ensure that they are exiting to the north of your planned route. Atlantic storms migrate north as the season progresses. After mid May, vessels run the risk of encountering early season depressions and rapid development of extra tropical cyclones along the East Coast of the US. These have become more frequent in recent years.

The southern route, via the Bahamas, can be transited by using intermediate stops in the Dominican Republic, Turks and Caicos, and the Bahama Islands, or by sailing direct to Florida. Departures can be planned as soon as windspeeds fall to acceptable limits. Winds in early April begin to diminish in strength, typically becoming more easterly and with speeds of 15 – 20 kts. Showers and thunderstorms will become more frequent on both routes in the latter part of this timeframe, as troughs form between the dry and rainy season. By mid May, developing weather systems in the Gulf of Mexico and western Caribbean should be closely monitored for rapid development and movement north.

From the US East Coast to the Eastern Caribbean

Best time: Early April to mid May, depending upon the departure point from the East Coast. Storm tracks have begun to move north by late March. There will be periods when the Azores/Bermuda High will establish its presence as far east as the coast bringing easterly or southeasterly winds of 15 knots.

A timed departure can be made with these winds from Chesapeake Bay and southward, either to Bermuda or direct to the Eastern Caribbean.

Departures from Florida can either take a route to Bermuda or east through the Bahamas. In early April, winds will tend to be NE 15 – 20 kts with seas of 1 – 1.5 metres and will gradually subside and become easterly to southeasterly 15 knots and seas of 1 metre by mid May.

The high pressure ridge at this time of year may be interrupted periodically by troughs or weak cold fronts permitting periods of sailing even along the ridge line.

Other times: Mid November to mid December. The traditional snowbird routes from the East Coast and the Bahamas to the east Caribbean almost always involves waiting for weather. Winds and seas tend to be romping up at this time of year. Cold fronts are becoming stronger and the gale tracks moving further south. Crossing the Gulf Stream is necessary from any point of departure and monitoring the location of the stream, eddies and forecast winds are essential.

Strategies involve picking favourable conditions for crossing the Gulf Stream and a forecast for reasonably benign conditions to allow the vessel to get south of the North Atlantic gale track.

Departures are risky at this time of year because of late season hurricanes, tropical depressions, and developing Atlantic storms are frequent features.