What you need to know about the weather to cross the Atlantic eastward

Crossings across the Atlantic are usually spoken of as days of running westward before fair winds (although, as sailors, we are rarely content and crave spice to turn mortal danger into achievement!).

After leaving the Caribbean, we head north through the Equine Latitudes (30 ° N), where the Azores high ridges go towards Florida, and the wind becomes light and variable.

After passing through this ridge, we will be able to follow the route north of high pressure zones with predominantly westerly winds, but much further south to avoid storms from northbound low pressure zones.

It is impossible to pinpoint the exact latitude where we meet the westerly winds when they change.

The minima develop and move to the northeast, displacing the Azores elevations and allowing stronger winds to travel south.

This advance to the extreme south will produce a succession of depressions separated by higher pressure transition ridges, and then acceleration of the wind as the next depression passes.

The driving force for this is the current driving the lows, and it also depends on how firmly the Azores High is established.

If the current goes north then there will be a good passage, but if it sinks south the lows will more aggressively influence the route and stronger winds will blow.

This balance between low and high pressure depends on the season, as the current usually migrates north in the summer and south in the winter.

This is a continuation of the UK weather; as the summer progresses, we lose more aggressive lows, and the Azores high becomes more stable.

If that were the only factor, returning to Europe in the summer would be warmer and easier.

But - and this is a big but - hurricane season starts in early June, and while hurricane season can be returned (with good weather and a fast boat), most insurance companies will not cover the transition as the risk is very high.

Thus, the timing of the transition should only be selected by waiting for the worst winter storms to pass, but leaving the tropics before the hurricane season begins.

Hurricane trends

We are seeing some trends in the hurricane season, and over the past five years, hurricanes have occurred each year prior to the official start of the hurricane season.

These were tropical storms, and although they are relatively small compared to hurricanes, they still carry winds between 34 and 63 knots.

Typically, these early tropical storms develop east of the Bahamas and spread northward.

Since many yachts traditionally leave the Caribbean at the end of April, the increase in storms early in the season must be considered when sailing.

Whether it's Europe or the United States, leaving in May is common.

Because of the east trade wind, we are first pushed northward, and we sail on the starboard tack along a convenient route.

In some years this may continue until the westerly winds blow, but in other years yachts may be pushed almost to Bermuda before a more easterly course is taken.

This gives a mixed weather pattern with low pressure passing close to the north, but we must also watch for cold fronts leaving the US coast to the east and moving over our route.

It can be quite active in terms of weather, as warm humid air forced northward from the tropics collides with cooler, drier air from the northeast.

This creates an area of cyclogenesis where minima develop and deepen, and we often see them develop west of the route near Cape Hatteras.

After development, they move to the northeast, leaving us in a more variable wind south of the minimum.

Stop or not at the crossing of the Atlantic Ocean in an easterly direction?

This can provide several different swimming opportunities. Plus, it's even useful as one of the rewards along the route is places worth visiting.

Bermuda may be a playground for the rich, but it is also an interesting island with an interesting history; whether to go there or not depends on personal choice, as well as on how far north we will be carried.

I have crossed the Atlantic Ocean eastward to the north of the islands, but we usually have time to cut a corner and head east before approaching them, especially when it comes to time.

During normal times, the Azores is a must-see destination, and since all of the eastern Atlantic crossing routes pass close by, it would be a shame not to make a stop.

However, due to restrictions imposed by COVID, yachts may have to skip Bermuda and / or the Azores.

Some yachts bound for the UK or Northern Europe go nonstop anyway to close the distance.

The further north the trade winds carry us as we leave the Caribbean, the more we can shorten the distance on our way to the UK.

However, there is always a compromise, and in this case, these are the North Atlantic lows.

Since minima usually develop somewhere around Cape Hatteras, they will then move northeast, passing between Newfoundland and the Azores.

Therefore, the further we move north, staying west of the Azores, the closer we will be to the centers of the minimums.

During this time, usually in late May - early June, large and deep depressions can still pass near the route, so the further north (west of the Azores), the more likely there is a strong wind and storm.

Even if we cross the Atlantic from the US in an easterly direction, we usually head southeast first, and while you can use the tail of the Gulf Stream to accelerate, it is safer to go south of the Gulf Stream into warmer waters (less fog) and better head towards the Azores. staying on the south side of the lows rather than risk headwinds on the north side.

From the Azores to Europe

Once we get to the Azores, our route to Northern Europe will depend on how favorable the forecast is and how we can tether to the low pressure system in the northwest.

Typically, this will require a short delay in the north until the Azores highs clear before returning home quickly.

Traveling to the Mediterranean should be easier: light winds near the Azores become strong northerly as we get closer to Europe.

These are the Portuguese trade winds, occurring between the Azores High and the semi-permanent low pressure over Spain, which is typical of spring and summer.

Out-of-season transfers are possible, but they are associated with certain concerns.

If sailing early, there is a risk of storms near the Azores.

North of Bermuda and north of the Azores, storms in March are likely to be up to 15%, as shown on US pilot maps, declining in April and significantly decreasing in May.

The North Atlantic in winter is not the most suitable place for yachting, especially if it is a pleasure sailing.

06.06.2021