Tropical Weather Discussion
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AXNT20 KNHC 132339

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
705 PM EST Fri Jan 13 2017

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2315 UTC.


A strong pressure gradient between lower pressure across South
America and a ridge anchored across the SW North Atlantic is
generating gale force winds in the SW Caribbean Sea from 9.5N-
12.5N between 74W-79W with NE winds 30-35 kt and seas 11-13 ft.
This gale will last 24 hours. See latest NWS High Seas Forecast
under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details.


The monsoon trough extends from the African coast near 07N13W to
03N22W. The intertropical convergence zone axis extends from
03N22W to 01N30W to 01N40W to the coast of South America near
01S45W. Scattered moderate to strong convection is from 01N-06N
between 12W-20W. Isolated moderate convection is from 01S-04N
between 38W-44W.



10-20 kt E to SE surface return flow is over the Gulf of Mexico
maintaining warm temperatures. The Gulf has patches of scattered
showers moving W to NW. Showers are over central Florida, over
the SE Gulf, over N Yucatan Peninsula, NW of the Yucatan
Peninsula, and along the coast of SE Louisiana. An upper level
ridge is over the Gulf with axis along 95W. Very strong
subsidence covers the entire Gulf. This overall synoptic pattern
is expected to persist through the remainder of the weekend. The
next front is not expected until Tuesday evening along the coast
of Texas.


Gale conditions are along the coast of N Colombia. See above. A
shear line extends from Trinidad near 11N60W to N Colombia near
11N74W. Scattered showers are within 60 nm of the shear line,
especially along the coast of Venezuela. Elsewhere, radar
imagery shows scattered showers over Puerto Rico advecting in
from the Atlantic. Hispaniola and E Cuba has similar conditions
especially over the upper elevations. More scattered showers are
over the Gulf of Honduras and along the coast of Costa Rica. In
the upper levels, a broad upper level ridge is over the
Caribbean Sea with axis along 60W. Strong subsidence covers the
entire Caribbean. Expect showers along the shear line to become
diffuse over the next 24 hours, however, a new line of showers
will advect to the coast of Venezuela with the NE surface flow.


Fresh to strong NE winds prevail across the island and adjacent
coastal waters. This wind field is due to a relatively strong
pressure gradient between the NW Caribbean and the Atlantic low
near 21N53W. Scattered showers are over the northern portions of
the island especially over higher elevations. Expect showers to
continue as the NE flow persists through the remainder of the


A 1031 mb high is centered over the W Atlantic near 33N72W. A
ridge axis extends WSW to N Florida. A 1011 mb low is centered E
of the Lesser Antilles near 21N53W. A surface trough extends SW
from the low to 16N57W. Scattered showers are within 60 nm of
the low and trough. An upper level low is centered near 25N47W.
Upper level diffluence E of this center is producing isolated
moderate convection from 21N-28N between 33W-48W. Expect in 24
hours for the surface low to drift to 19N52W with a trough
remaining to the SW. Also expect another surface trough to be
over the central Atlantic from 31N38W to 24N41W with showers.

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