Tropical Weather Discussion
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AXNT20 KNHC 131652

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1151 AM 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 1200 UTC surface analysis and satellite imagery through
1615 UTC.

A strong pressure gradient between lower pressure across South
America and a ridge anchored across the SW North Atlc and Florida
peninsula is generating near gale to gale force winds in the SW
Caribbean Sea. These conditions are expected to pulse during the
late night and early morning hours through Sunday. 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 05N10W to
05N15W to 03N21W. The Intertropical Convergence Zone axis extends
from 03N21W to the Equator near 41W. Scattered moderate
convection is S of 09N between 09W-17W. Isolated moderate
convection is from 02N-06N between 37W-52W.


Middle level ridging remains anchored across the eastern Gulf
waters and portions of the SW North Atlc that supports surface
ridging with axis extending from central Georgia SW to southern
Mexico near 21N98W. Moderate to occasional fresh E-SE winds are
occurring across the basin this afternoon with mostly fair skies
noted on visible satellite imagery. This overall synoptic pattern
is expected to persist through the weekend. The next front is not
expected to emerge off the Texas and Louisiana coasts and into the
NW Gulf until Tuesday night into Wednesday.

West-southwesterly flow aloft prevails over the basin between
broad upper level troughing over southern Mexico and Central
America...including a portion of the adjacent east Pacific waters
and an upper level ridge anchored over the northeastern South
American continent. Another middle to upper level low is also
noted on water vapor imagery centered over the central Atlc near
23N52W supporting a shear line analyzed from 12N60W W across
Tobago to NW Venezuela near 11N69W to northern Colombia near
12N73W. Scattered to occasional numerous showers are occurring
within 90 nm either side of the shear line boundary. In
addition...strong to near gale force NE winds are occurring in
close proximity to the coast of Colombia due to a strengthened
pressure gradient across the region. Otherwise...fresh to strong
trades persist elsewhere. The shear line boundary is expected to
remain nearly stationary and gradually become diffuse through

Fresh to strong NE winds prevail across the island and adjacent
coastal waters this afternoon. This wind field is due to a
relatively strong pressure gradient across the region and SW North
Atlc waters. Isolated showers are expected to continue as the NE
flow persists through the weekend.

A middle to upper level low is centered near 23N52W that supports
a nearly collocated 1013 mb surface low centered near 21N53W. The
associated cold front extends from a triple point near 23N50W S-SW
to 15N54W and becomes a shear line into the far SE Caribbean Sea
near Tobago. A partial occlusion extends from NW of low to the
triple point with the warm front analyzed from 23N50W to 23N44W.
Widely scattered showers and isolated tstms are occurring from
21N-28N between 43W-55W. The remainder of the SW North Atlc is
under the influence of a surface ridge anchored by a 1032 mb high
centered near 33N70W and a 1031 mb high centered near 35N61W.
Mostly moderate to fresh NE to E winds prevail on the southern
periphery of the ridge which are forecast through Sunday. The low
pressure area along the front is expected to drift southward
through Saturday and weaken well E of the Lesser Antilles by
Saturday night into Sunday. Farther east...a surface trough
extends from 21N42W to 26N38W providing focus for scattered
showers and isolated tstms from 19N-31N between 32W-42W. This
area of activity continues to be enhanced by marginal middle to
upper level diffluence to the east of the upper level low.

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