Météo du 15 janvier

Les alizés d’est, sud-est sont relativement bien établis le long des côtes brésiliennes jusqu’aux 20° de latitude sud. La route pour  gagner au sud et mettre le cap à l’ouest dans l’Atlantique Sud est donc relativement claire pour la tête de flotte.  Pour autant, aujourd’hui, mais surtout demain, les vents molliront un peu avec le risque de quelques ruptures du flux dans les nuages et sous les averses.

Meteo JANV. 15, 2015 07:05

*** SYNOPSIS ***
00Z THURSDAY (15-JAN-2015):
1)    Northern doldrums boundary is near 3N. Doldrums will be wider with
lighter and more variable winds east of 27W. West of 27W, light ENE/E
increasing to light-moderate at 30W.
2)    The southern doldrums boundary lies between the equator and 1N.
3)    South of the Equator, SE trade winds are found down to 3S, building
backing to ESE south of 3S.
4)    South of 5S, steady ESE trades, mainly moderate in strength. Some
patches of randomly spaced lighter and stronger breeze, likely
associated with areas of more enhanced trade wind cumulus.
5)    The moderate ESE trades extend to 20S, but some easing is likely
during the day west of 35W to the Mainland coast.
6)    The South Atlantic high (1021mb) is near 28S/30W, shifting east to 24W
with time but with a ridge extending west-northwest to 18S/39W. This
ridge axis will mark the boundary where E’ly winds to the north shift
NE/N to the south.
7)    A deep low (991mb) is near 38S/40W, with a cold front northwest to
south of Florianopolis. A broad zone of fresh to strong N’ly off Cabo
Frio and extending south/southeast, ahead of the cold front and around
the southwestern quadrant of the South Atlantic high.
8)    This low will be moving quickly east-southeast, and the front
northeast. However, the front will stall near or south of 30S for the
most part. There will be a band of stronger N/NE winds from off Vila
Velha extending south toward the front.
00Z FRIDAY (16-JAN-2015):
1)    The doldrums will be expanding and shifting south. Very light winds
are expected to develop between 2N and 1S, along with more widespread
showers and thunderstorms possible.
2)    South of 2S, winds generally ESE all the way south to 22S. Winds will
back more ENE/NE west 35W and south of 15S. A general backing trend
will be noted with distance south.
3)    High pressure (1022mb) will be near 27S/24W, elongating west to east
between 25S/34W and 28S/9W. West of the high pressure, winds back NE
to N to set up pre-frontal gradient ahead of a cold front.
4)    Deep low pressure (965mb) near 46S/20W. An associated cold front will
extend north of the low to 38S, then west-northwest to 32S/33W before
becoming stationary and extending to the coast near Florianopolis.
5)    Winds between the front and southern side of the high pressure will be
mainly moderate NW between 26S and 31S.
6)    The front will be stationary or shifting south with time.
7)    A second high (1020mb) near 38S/47W. This high will be shifting
quickly east.
00Z SATURDAY (17-JAN-2015):
1)    Little change in the SE/ESE trade winds from the Doldrums, south.
There will be lighter E’ly winds now over the waters south of the
doldrums to about 5S. The ESE/SE trades will be well established south
of 5S to 20S. The wind field will be a little unstable, with embedded
showers..
2)    A persistent are of stronger, more consistent wind will be in a zone
around 12S/30W.
3)    South of 18S, winds will be backing NE/NNE between 30W and the
Brazilian coast.
4)    High pressure (1021mb) will be centered near 28S/26W. A ridge will
extend west of the high to near 25S/33W. This ridge axis marks the
shift from E/NE trades to the north, to N/NW pre-frontal winds to the
south around the southwest quadrant of high pressure.
5)    A zone of accelerated NE flow is expected to persist south and east of
Cabo Frio.
6)    A stationary front will lie west to east along 31S. A second high
(1022mb) moves to 35S/20W.
7)    The true westerlies will be found south of the second high, moving
north with time.
00Z SUNDAY (18-JAN-2015):
1)    Steady, moderate E/ESE winds north of 15S.
2)    Lighter winds south of 15S and east of 35W where the South Atlantic
high becomes a ridge extending from 23S/32W to 30S/18W then to 37S/2W.
3)    A cold front will north of 35N at 30W. Strong N winds off Cabo Frio
back to strong NW’lies ahead of the front and south of the high
pressure ridge.
4)    Low pressure will be developing off the southern Brazilian coast and
at the western end of the cold front.
**************************************
General Forecast along race route
*** THURSDAY (15-JAN-2015) ***
* 05N to 05S *
WIND: North of 3N, NE 10-15. Between 3N and the Equator, E 5-10 except much
lighter and more variable east of 27W. From the Equator south to 5S, SE
tending ESE 8-13, stronger near 5S.
SEAS: 1m or less.
WEATHER: Frequent showers in the doldrums. Clearing south of the Equator.
* 05S to 22S *
WIND: SE 10-15 south of 05S to 10S, Increasing ESE 13-18 south of 10S.
Generally tending ESE/E with distance south. Easing under 10 west of 35W.
SEAS: 1-2m.
WEATHER: A mix of clouds and sun. Some showers, especially close to coast
and between 07S and 15S.
* 22S to 30S and west of 30W*
WIND: becoming NE/N 10-15 near 30W increasing to 15-20 west of 36W.
SEAS: 1m at 30W increasing to 2m off Brazilian coast.
WEATHER: Mix of clouds and sun.
*** FRIDAY (16-JAN-2015) ***
* Equator to 10S *
WIND: Light north of 1S. SE/ESE 10-15.
SEAS: 1-2m
WEATHER: Partly cloudy.
* 10S to 24S *
WIND: ESE/E at 10S backing E/NE 24S. Generally 12-16.
SEAS: 1-2m
WEATHER: A mix of clouds and sun. Some showers, especially close to coast
and between 07S and 15S.
* 24S to 30S and 30W to 40W *
WIND: NE/N 10-15 near 30W increasing to 15-20 west of 36W.
SEAS: 1m at 30W increasing to 2m off Brazilian coast.
WEATHER: Mix of clouds and sun. Showers and squalls near 30S.
*** SATURDAY (17-JAN-2015) ***
* 05S to 10S *
WIND: SE/ESE 10-15, increasing 14-18 near 10S.
SEAS: 1-2m
WEATHER: Partly cloudy. Showers possible toward 10S.
* 10S to 24S *
WIND: ESE/E 12-16 at 10S backing E/NE 10-15 at 24S.
SEAS: 1-2m
WEATHER: A mix of clouds and sun. Some showers, especially close to coast
and between 10S and 15S.
* 24S to 30S and 30W to 40W *
WIND: NE/N 10-15 near 30W increasing to 15-19 west of 36W.
SEAS: 1m at 30W increasing to 1-2m off Brazilian coast.
WEATHER: Mix of clouds and sun.