Tropical Weather Discussion
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AXNT20 KNHC 111726

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1226 PM EST Wed Jan 11 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
1700 UTC.

A 1009 mb low is centered 29N55W that is supported aloft by a
vigorous middle to upper level low nearly collocated with the
surface feature near 29N56W. The associated cold front extends
from the low S-SW to 20N60W into the NE Caribbean Sea. Near gale
to gale force N-NE winds are occurring within close proximity to
the low center within the NW quadrant. See latest NWS High Seas
Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more

The Monsoon Trough extends from the African coast near 06N11W to
05N16W to 02N21W. The Intertropical Convergence Zone axis extends
from 02N21W to the Equator near 23W. Isolated moderate convection
is from 02N-06N between 06W-17W...and S of 04N between 43W-52W.


Mid-level ridging and dry air aloft noted on water vapor imagery
is supportive of surface ridging that extends from across NE
Florida southwestward to southern Mexico near 21N97W. Moderate to
fresh anticyclonic 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 remainder of the week and into the weekend. The next
front is not expected until Tuesday night.

West-southwesterly flow aloft prevails over the basin between an
upper level trough over southern Mexico and the east Pacific
region and an upper level ridge anchored over South America.
Another middle to upper level low is also noted on water vapor
imagery centered over the SW North Atlc near 29N56W supporting a
cold front analyzed from 20N60W SW across the NE Caribbean to
17N65W becoming a shear line to 14N75W to the coast of Costa Rica
near 10N83W. Scattered showers and isolated tstms are occurring
within 120 nm N of the shear line between 78W-84W...with isolated
showers elsewhere within 90 nm either side of the shear line. In
addition...strong to near gale force NE winds are occurring in the
Windward and Mona passage regions...including downwind areas to
the south of Hispaniola and to the E and SE of Jamaica.
Otherwise...fresh to strong NE to E winds are expected to persist
through Saturday as high pressure remains anchored to the N across
the SW North Atlc. The front and shear line boundary is expected
to remain nearly stationary or drift slightly eastward through
Thursday as it becomes diffuse by Thursday night into Friday.

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 remainder of the week into the weekend.

A middle to upper level low is centered near 29N56W that supports
a nearly collocated 1009 mb surface mentioned in the
Special Features section above. The associated cold front extends
from the low S-SW to 20N60W into the NE Caribbean Sea. Scattered
showers and isolated tstms are occurring from 23N-34N between
50W-58W. The remainder of the SW North Atlc is under the influence
of a surface ridge anchored by a 1035 mb high centered off the
coast of the Carolinas near 36N69W. Mostly fresh to occasional
strong 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 the
remainder of the week and weaken well E of the Lesser Antilles by
next weekend. Farther east...a weakening 1016 mb low is centered
near 25N42W with a surface trough extending N-NW to beyond
32N45W. In addition...another surface trough is analyzed from
26N30W to 32N38W providing focus for scattered showers and
isolated tstms from 23N-32N between 18W-32W...and from 32N-37N
between 26W-38W. This area of convection continues to be enhanced
by an upper level trough axis extending from 33N37W to a base near

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