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Atlantic Tropical Weather Discussion

AXNT20 KNHC 272319

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
719 PM EDT THU OCT 27 2016

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
2300 UTC.

Tropical wave extends from 09N43W to 14N42W moving W at 10-15 kt.
The wave remains low-amplitude and relatively difficult to track
as a result. Subtle 700 mb trough is noted in global model fields
between 41W-47W. Isolated moderate convection remains within close
proximity to the ITCZ axis from 07N-12N between 41W-45W.

Tropical wave extends from 11N69W to 22N67W moving W at 10-15 kt.
The wave coincides with 700 mb troughing between 67W-72W. The
northern portion of the wave is soon to merge with a stationary
frontal boundary to the north and west and a shear line analyzed
to the west. Widely scattered moderate convection is from 18N-25N
between 62W-68W...and from 14N-17N between 67W-70W.

The Monsoon Trough extends from near 15N27W to 11N36W to 09N42W.
The Intertropical Convergence Zone axis extends from 09N42W to
08N52W. Scattered moderate and isolated strong convection is from
10N-14N between 24W-29W...with scattered moderate convection
elsewhere from 08N-17N between 28W-40W...and from 07N-10N between


A middle to upper level trough is noted on water vapor imagery
with axis extending from over the lower Mississippi River valley
S-SW to a broad base over the SW Gulf and southern Mexico near
19N94W. This troughing aloft is inducing a weak surface trough
analyzed across the SW Gulf from 24N92W to 19N92W providing focus
for widely scattered showers and isolated tstms generally S of 25N
W of 90W. Elsewhere to the east of the upper level troughing...
southerly flow aloft prevails with plenty of moisture advection
and cloudiness covering much of the eastern Gulf waters...Florida
peninsula and Florida Straits. Scattered showers and isolated
tstms are occurring generally S of 27N E of 90W. Aside from
convection...a strengthened pressure gradient exists between
higher pressure across the SE CONUS and an area of developing
low pressure across the western Caribbean Sea. Fresh to strong
easterly winds are expected across eastern portions of the basin
through Thursday night into early Friday with slightly weaker
winds...moderate to fresh E-NE winds occurring across western
portions of the basin through Friday night.

Southerly flow aloft prevails between an upper level trough over
the western Gulf of Mexico and an upper level anticyclonic
circulation centered over the central Caribbean near 16N70W.
Tropical moisture continues to advect northward and interact with
a shear line analyzed from the Windward Passage near 20N73W to the
northern coast of Jamaica into a 1009 mb low centered near 17N84W.
A surface trough extends S-SE from the low to 15N83W to 10N81W.
Scattered showers and widely scattered tstms are occurring N of
16N W of 79W...with widely scattered showers and isolated tstms
occurring elsewhere N of 14N W of 75W and S of 14N W of 79W.
Convection ongoing across Costa Rica and Panama continues to be
enhanced due to the close proximity to the Monsoon Trough analyzed
along 09N. Farther east...beneath the diffluence generated by the
upper level ridging...a tropical wave along 69W continues to
provide focus for scattered showers and tstms occurring north of
Puerto Rico...but also across the central Caribbean from NW
Venezuela to across Hispaniola from 10N-23N between 70W-75W.
Energy associated with the tropical wave is expected to continue
moving westward however northern portions will continue to merge
with the previously mentioned shear line that lies across the
Windward Passage region.

Upper-level anticyclonic wind flow prevails across the island.
Scattered showers and isolated tstms are occurring across western
and central portions of the island this evening along with the
adjacent coastal waters. Little change in the synoptic pattern is
expected through the next 24-36 hours as energy from the tropical
wave along 69W merges with the shear line analyzed across the
Windward Passage region.

A surface ridge prevails across the SW North Atlc anchored by a
1027 mb high centered near 35N73W. With generally lower pressures
to the south across the Caribbean Sea due to a developing area of
low pressure across the NW Caribbean and a tropical wave along
69W...a strengthened pressure gradient persists generally W of
65W. Strong to near gale force E-NE winds persist with plenty of
cloudiness and precipitation W of a line from coastal South
Carolina SE to 20N68W. To the east...a stationary front extends
from 32N50W SW to 23N70W then becomes a shear line to the Windward
Passage. Isolated showers and possible tstms are occurring N of
27N within 90 nm either side of the stationary front. As mentioned
above with the tropical wave...front...and shear line all coming
together across an area N of Hispaniola and Puerto Rico...
scattered showers and tstms are occurring from 18N-25N between
62W-69W. A surface trough extends from 16N57W to 22N57W with
isolated showers and tstms occurring from 17N-21N between 54W-
57W. Finally across the NE Atlc discussion waters...a 1003 mb
surface low centered near 33N24W extends a surface trough from the
low to 31N23W to 26N29W. Isolated showers and tstms are from 29N-
35N between 19W-24W.

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