Forecast Discussion

Forecast valid from 17/08/2018 to 18/08/2018

Departamento Meteorologico Aruba


The center of Tropical Storm Ernesto at 17/0900 UTC is near 45.6N
36.4W or 620 nmi to the NW of the Azores. Ernesto is moving NE at
22 knots. The maximum sustained wind speeds are 40 knots with
gusts to 50 knots.


A tropical wave is in the E Atlc with axis extending from 05N-17N
along 29W, moving W at 10-15 kt. The wave is in a moderate deep
layer wind shear environment, and both CIRA LPW and GOES-16 water
vapor imagery at the lower levels show dry air affecting the
wave. These two factors are contributing to the lack of
convection at this time.

A tropical wave is in the central Atlc with axis extending from
06N-20N along 54W, moving W at 15-20 kt. The wave is in a low
deep layer wind shear environment, and CIRA LPW imagery shows
abundant low level moisture associated with it. However, some dry
air intrusion is noted in the NW wave environment shown both in
CIRA LPW and water vapor imagery at the lower levels. This dry
air has acted to reduced the convection to scattered moderate
isolated strong from 10N-15N between 50W-60W.


Isolated moderate to locally strong rainshowers cover the
NW corner of the Caribbean Sea, from 14N northward from 79W
westward. Upper level anticyclonic wind flow covers the
Caribbean Sea from the Windward Passage westward.

Nocturnal near gale force easterly trade winds are expected
along the northwest coast of Colombia overnight, and then
again tonight. A tropical wave along 68W will continue
westward across the central Caribbean tonight, and pass
through the western Caribbean waters during the upcoming
weekend. A second tropical wave will reach along 55W on
today, and pass through the eastern Caribbean Sea on
Saturday and Sunday. The tropical wave will be accompanied
by locally strong rainshowers through early Saturday.

Next update will be issued 18/08/2018 16:00UTC