Meeting the Meltemi

The greatest hazard for Olympic sailors will be the Athens winds says GBR meteorologist Fiona Campbell

Over the last four years Olympic sailors have been relentlessly training, competing in events, struggling to qualify, struggling to find money to fund their campaigns and while honing themselves and their gear (where allowed) to the utmost degree. Come start of racing at the Athens Olympics they and their race boats will be about as finely tuned as is possible, yet the one ingredient that could turn the form book on its head are the meteorological conditions to be found in the sailing area off Gylfada.

"It is definitely a nightmare for the sailors," confirms Fiona Campbell, who as team GBR's meteorologist has been studying the Athens weather intensively.

Athens itself lies in a valley surrounded by mountains and the Olympic sailing area is located some 25km south of the city centre off the fashionable holiday area of Gylfada. Here there are a number of large buildings along the shore and Mount Imittos due east that can affect the breeze locally.



The Gylfada coast is oriented northwest-southeast with the Olympic fleets divided into four race zones as illustrated above, the Europes and Lasers on the most southerly, the Finns, Ynglings and Stars on the most northerly.

The most likely breeze the sailors will experience in Athens is also the most unpredictable. By virtue of the fact that it both funnels down the valley and across the mountains before hitting the race area, the offshore Meltemi has the ability to cause chaos on the race course.

"The Meltemi is offshore, very strong and occasionally very gusty," says Campbell of this north to northeasterly wind. "It’s extremes: there are huge lulls and huge gusts more often than not one directly after the other. The extremes of the day might be 8-28 knots. In other Mediterranean places you go, there’s a sea breeze where you can pick the pattern, you can pick the shifts, you can time the shifts - the Meltemi is not one of those breezes."

Over the course of the day it gets increasingly gusty as the heat increases and unfortunately this reaches its maximum at around 1pm and onwards, exactly the time racing is scheduled during the Olympics.

The Meltemi was blowing for when we were out on the race area week before last and there were distinct patches where the wind was gusting to more than 20 knots and others where there were five knots or almost no wind at all. Blowing across Athens the wind is very dry and comes complete with all the dust and dirt from the city.

On a bigger scale, the Meltemi is driven by a heat low over Turkey similar to the low that can form over Spain in the summer, also driven by the heating. For Athens to feel the effects of the Meltemi it is necessary for this low to squeeze against an area of high pressure to the NNE of Greece.

"In August you would expect it 50-70% of the time, maybe more," says Campbell. "It can last from two to ten days but normally you are looking at three to five days. So for those racing for the whole 14 days you could get half and half. Someone who is racing for 14 days would be really unlucky to have the Meltemi or the sea breeze all the time. Those sailing for six days could easily have six days of sea breeze or six days of Meltemi."

If the Meltemi is blowing it is the dominant wind in the area, otherwise there is usually a conventional sea breeze. This is southerly and usually around 5-10 knots, 12 knots at the maximum.

"In August you can spend the day in 5-7 knots and not much more," says Campbell. "When it gets really hot, it becomes really stable so it almost goes the opposite. At home we’d be looking for the temperature difference to drive the sea breeze. Here you are pretty much always going to get that because the sea surface temperature is around 25degC and you’d be lucky if the minimum temperature at night dips much below 25degC, so you are always going to get the temperature difference, but what you don’t want is for it to be too big. If you have got that you generally have high pressure and that is pushing down on top of the sea breeze, which is why it is lighter."

The different prevailing conditions also affect the visibility. When the Meltemi blows the sky is cloudless and the visibility good. In the moist sea breeze clouds and a layer of haze builds up. "You often can’t see the Acropolis on the sea breeze," says Campbell.

In sea breeze conditions thunderstorms can also develop. These tends to stay inland but if they do reach the sea they can reap carnage. "Two years ago at the pre-Olympics, there were Tornados and 49ers catapulting back into the Olympic marina..." she remembers.

The problem for Campbell and the sailors comes on the crossover days when the wind either stalls completely or it is possible course D to the north would still be feeling the effects of the Meltemi while boats on course A might be seeing a sea breeze, although Campbell believes it is probable racing won't take place on these days.

The final extreme, which Campbell says they have yet to experience, is when Athens falls under a large area of high pressure. "In the Meltemi the temperature is up to 30-34degC. The sea breeze is around the same - up to 36-37deg. But if you get the stable high pressure it can go up to 40deg when there will basically be no wind. That is when everyone stays indoors and that is when you get the massive power cuts because everyone turns aircon on at the same time!"

Westerlies and easterlies have been experienced but are unlikely in August, she says, as is the gradient southerly breeze that Finn sailors experienced during their World Championship.

For the sailors the Meltemi will make sailing at the Olympics something of a lottery. "When there is a sea breeze it is down to boat speed, whereas in the Meltemi there is a lot of looking and probably a lot more luck," says Campbell. "The Meltemi is more patchy. Sea breeze is patchy, but it is a slightly more understandable and predictable breeze both for me and the sailors."

Because of this we can expect to see the Olympics being a highly scoring regatta. Iain Percy sums up: "It is going to be down to keeping your head and putting in the results. It will be a high scoring series given the number of boats. The last warm-up regatta we did which was the epitomy of this place when the winner won with an average of sixth place in 12 boats. And then the guy who came eighth had an average of 6.5."

Despite the conditions, the law of averages is expected to prevail and as ever the cream will rise to the top as the regatta progresses, even if it is in a less dramatic manner.