The Inter Tropical Convergence Zone (ITCZ) is currently
centred along the latitude band from the equator to 2S. It is relatively
subdued at the moment. However the thunderstorm activity is expected to
increase markedly on Saturday as trade wind surges from both hemispheres meet.
This means the region affected by heavy rain and thunderstorms is likely to
expand both northwards and southwards. The northern limit of the heavy rain and
thunderstorms looks likely to hover along around 2N from Saturday through Monday.
In the region south of Cape Sao Roque there should be passing squally shower
activity but there does not appear to be thunderstorms over the ocean until you
get to and north or the Cape. There are also very active thunderstorms over the
mainland area of Brazil and these should continue. For those sailing close to
the north coast of Brazil this is likely to be an issue but it should not be
for the remainder of the fleet.
Scattered squally showers are likely up to Cape Sao Roque.
After this scattered thunderstorms are likely with areas of heavy rain until 2N
is reached. Squally weather can also be expected with the thunderstorm
activity, primarily on the western side of the thunderstorm clusters. Then
passing trade wind showers are to be expected once north of 2N.
Winds (Initially for the region from Recife to Cape Sao
Roque but moving towards Grenada at a mean speed of around 150nm per day).
SE winds 8/13 knots shifting more ESE as you head northwards
towards Joao Pessoa. A gradual increase in the wind speeds is also likely into
the 10/15 knot range during the afternoon but the winds should drop back into
the 7/12 knot range during the evening.
Winds are likely to hold ESE but with more of a tendency to
turn to the east near Cape Sao Roque. Speeds generally in the 10/15 knot range
although patches of 15/18 knot winds can be expected near and north of the
Cape. Squalls in passing showers and thunderstorms to around 30 knots are
possible, primarily north of the Cape.
A significant increase in shower and thunderstorm activity
is expected with gusty winds. The direction should be mostly easterly although
there will most likely be periods of ESE as well. Winds are likely to be mostly
in the 13/18 knot range when not in the squalls. Lighter pockets of wind should
follow the passage of the squalls. Winds are likely to gradually increase to
16/20 knots during the afternoon and evening with more periods close to 20
knots in the evening.
Continuing quite showery with scattered squally
thunderstorms still moving through. Squalls to 35 knots or so are possible.
Winds should be mostly east to ESE although leading yachts could experience
periods of ENE winds. Speeds are likely to be mainly in the 13/18 knot range
although there are likely to be bands of lighter winds, in the order of 10
knots, on the northern side of the lines of thunderstorms.
Still showery, locally heavy, with scattered thunderstorms for
most yachts. Winds are likely to shift to a north easterly, particularly for
the front of the fleet. The rear of the fleet could hold more of an easterly to
ESE wind. Speeds should be mostly in the 15/20 knot range. Those in the pure NE
trade winds may see some pulses to 22 or 23 knots. Softer patches are likely
between the thunderstorm clusters for those further back in the fleet.
Longer range outlook
The NE trade winds are likely to become established at a
good 15/20 knots across the fleet with patches of 20/25 knot winds blowing
through. The ITCZ is likely to continue to be quite active for those at the
rear of the fleet.