World ARC Weather - Leg 15

Prepared by: Bruce Buckley (Weather Australia)

Weather situation
A weak tropical low centred to the northwest of Cocos Island has a tropical convergence line extending from it towards the east southeast – from 9:00S 98:00E to 12:00S 110:00E. This low is likely to gradually develop over the next few days and should be the dominant weather feature for this leg of the World ARC. Thunderstorm activity is expected to continue to be quite active along this convergence line for the next 4 to 5 days. The convergence zone separates weaker and more erratic ESE trade winds to the north from fresher trade winds to the south. In general a route slightly south of the direct route to Cocos will provide winds typically 2 knots stronger than for the direct route once a day out of Bali.

Weather
The weather should be predominantly fine from Bali across to near 111E, although isolated showers are possible. Then isolated thunderstorm activity is expected to be encountered. The shower and thunderstorm activity is expected to increase markedly once the fleet gets south of 10S through to Cocos Islands.

Monday 13th
ESE to easterly winds 6/12 knots near Bali freshening to 10/15 knots during the late afternoon to evening. A few patches to 17 or 18 knots overnight for lead yachts, particularly if they are slightly south of the direct route to Cocos.

Tuesday 14th
Easterly to ESE winds 12/17 knots tending SE 10/15 knots through the middle of the day with a few softer patches below 10 knots appearing. Winds generally east to SE 8/13 knots by the evening.

Wednesday 15th
ESE winds 8/13 knots freshening to 10/15 knots as the day progresses. Some small patches to 17 knots around.

Thursday 16th
ESE winds 10/15 knots freshening to 13/18 knots during the afternoon and evening. Winds gradually tending more easterly for the lead yachts. Local squalls likely near thunderstorms.

Friday 17th
Easterly winds 13/18 knots tending ENE for the lead yachts. Some patches near 20 knots. Local squalls likely near thunderstorms.