It's north versus south. Simple as that.

If you want to know what's happening on the racecourse mid Atlantic, don't look at the Race 13: Oban Atlantic Homecoming leaderboard.

A cluster of seven southerly positioned boats currently top the leaderboard, including our three teams scrapping for overall victory in the race around the world, Ha Long Bay, Viet Nam, Perseverance and Zhuhai.

While to the north more than 130 miles adrift we find Our Isles and Oceans and Dare To Lead, with PSP Logistics and Bekezela 200 miles behind.

Image: Race Viewer at 1200 UTC on 10 July

This is ocean racing, so anything could still happen, but right now the boats 300 miles further north might just be sitting pretty. The reason is a tricky ridge of light air separating a high pressure behind the fleet and a counter rotating low pressure ahead of the fleet. And stuck in the middle, our group of seven being stalked by the ridge of light air which is threatening to shadow them all the way to the British Isles. While on the northern battlefield the wind is forecast to fill in soon from the perfect angle just aft of their starboard beam, which could serve up some fast reaching conditions for the next day or so. If this plays out, could we see a home victory for Our Isles and Oceans?

Currently the light air ridge, like a very, very steep hill between the fleet and Scotland, looks set to disfigure and may also extend across the path of the northern four, but by then there's a chance this group may have closed the gap considerably, or even taken the lead.

As Simon Rowell said in his morning weather update to the boats “For all of you it’s now a case of either staying ahead of, or sneaking round the top of the high – the next 2-3 days will be fascinating for us onshore, and the cause of much caffeine consumption for you out there."

So what could this mean for the overall race? This is where we need to summon the spirit of Sir Isaac Newton to run the numbers, but essentially were our top three teams to finish further down the leaderboard, the effect of the Jokers in play from Perseverance and Zhuhai would be hugely diminished.

Warm up the cerebellum, let's see if we can pull this off for you.

Note. The following paper napkin calculation is without the foresight of the Ocean Sprint bonus points race currently unfolding.

Ha Long Bay, Viet Nam is leading the race on 119 points - add 3 points for first at this race's Scoring Gate = 122.
Perseverance has 105 - add 1 point for third at the Scoring Gate = 106.
Zhuhai has 104.

Perseverance and Zhuhai are set to double any finishing points having both played their Joker in this race. (Ha Long Bay, Viet Nam spent its Joker earlier in this edition of the race).

If as an example Ha Long Bay, Viet Nam won this race and took the maximum eleven points, the team would move up to 133 points.

If Perseverance finished second, it would get ten points, the Joker doubling this to 20 and shoot up to 126 points.

Effectively it would close the gap by nine points in this scenario and instead of being 16 points behind, it would be only seven points back with a real shot at the overall win with one race to go. If you're a Zhuhai fan the same theory applies, give or take a few points.

However, and this is why the weather and positions on the field of play are so important right now. If the three leading boats overall were to finish together further down the leaderboard, things would look very different.

If we imagine Ha Long Bay, Viet Nam finishing eighth and getting four points and Perseverance finishing ninth taking three points, Joker doubles this to six, the gain on the leader is reduced from nine points to just two, despite still only finishing one place apart. Ouch, right?

In that scenario Ha Long Bay, Viet Nam would be on 126 and Perseverance 112. That's more points than available for the win on the final race from Oban to its point of origin Portsmouth and therefore, game over!

Of course there are many other scenarios that could still unfold, especially if Perseverance and Zhuhai can finish ahead of Ha Long Bay, Viet Nam, but right now the position of the boats in relation to this weather ahead is without doubt the most critical moment of this edition of the Clipper Round the World Race.

You’re not going to want to miss this. Race Viewer action updated hourly here.

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