[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 181002
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
602 AM EDT TUE OCT 18 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 0600 UTC surface analysis and satellite imagery through
1000 UTC.

...SPECIAL FEATURES...

A middle to upper level trough is noted on water vapor imagery
over the W Atlc, with a broad base reaching the southern Bahamas.
The troughing aloft is supporting a 1005 mb low near 22N70W and a
large area of scattered heavy showers and isolated tstms from 17N
to 27N between 60W and 70W. The low is expected to slowly
intensify as upper-level winds become more conducive, and a
subtropical or tropical cyclone could form during the next day or
two as the low moves northward or north-northwestward. There is a
medium chance on this disturbance becoming a tropical cyclone
during the next two days.

...TROPICAL WAVES...

Tropical wave is in the eastern Atlantic extending from 07N to 15N
with axis near 28W, expected to move W at 5-10 kt over the next
24 hours. The wave is in a region of unfavorable deep layer wind
shear and CIRA LPW imagery from surface to 850 mb show pockets of
dry air in the wave environment. Shallow moisture and divergent
wind flow aloft support scattered showers from 08N to 13N between
25W and 29W.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends from the African coast near 12N16W to
06N22W to 04N41W. Aside from the convection associated with the
tropical wave, widely scattered moderate convection is from 0N to
06N between 15W and 44W.

...DISCUSSION...

GULF OF MEXICO...

A broad surface ridge anchored by a 1018 mb high over Atlantic
waters near 35N68W extends SW across the SE CONUS and into the
Gulf where it provides gentle to moderate E to SE flow, except
over the E Bay of Campeche where winds are from the NE. A surface
trough extends from 27N89W to N of the Yucatan Peninsula near
22N89W with possible isolated showers within 60 nm either side of
its axis. Middle to upper level ridging and strong dry air
subsidence support stable and fair weather conditions. Gentle to
moderate anticyclonic winds are expected to persist today,
increasing slightly tonight into Wednesday. The next cold front is
expected to emerge off the Texas and Louisiana coasts by Thursday
night into early Friday.

CARIBBEAN SEA...

A broad and elongated middle level trough extends across the W
Atlantic W of 60W and into the W Caribbean to a base over Panama
coastal waters. This middle level feature along with abundant
moisture in the region and favorable deep layer wind shear support
scattered showers within 90 nm of the Central America coast as
well as S of 18N between 68W and 82W. The extension of this
trough to the upper levels with a base across the southern Bahamas
and upper ridging across the E Caribbean generate diffluent flow
just N of Hispaniola and Puerto Rico, thus supporting scattered to
isolated showers in both islands and adjacent waters. Generally
low pressure is across the basin at the surface with gentle to
moderate S to SE winds in the E half of the Caribbean and light NE
flow elsewhere W of 80W. Global models are suggesting cyclogenesis
to occur N of Hispaniola and Puerto Rico today, which is already
resulting in a disruption of the usual trade wind flow across the
eastern Caribbean. As a low center organizes today through
Wednesday and lifts generally northward, lingering weak surface
troughing will extend across the Greater Antilles into the SW
Caribbean through Saturday.

...HISPANIOLA...

An upper trough over the W Atlantic waters with a base reaching
the southern Bahamas and an upper ridge between 50W and 65W
generate diffluent flow to the NNE of Hispaniola, thus supporting
isolated showers in the across the island. The island is expected
to remain within an area of weak surface troughing through
Wednesday as cyclogenesis occurs across the SW North Atlc waters
overnight through Wednesday. Showers are expected to increase
tonight and continue through the middle of the week.

ATLANTIC OCEAN...

A middle to upper level trough is noted on water vapor imagery
over the W Atlc, with a relatively broad base reaching the
southern Bahamas. The troughing aloft is supporting a 1005 mb low
near 22N70W and a large area of scattered heavy showers and
isolated tstms from 17N to 27N between 60W and 70W. The low
pressure is forecast to shift ENE this morning, then attempt to
become better organized later today as it begins to lift
northward. Strong easterly winds are expected to occur within 240
nm across northern portions of this low and a shearline that
extends from 20N52W to 22N63W to the low center. See special
features for further details. Farther east, the central Atlc is
under the influence of a stationary front extending from the
circulation associated with Tropical Storm Nicole well to the N of
the discussion area. The front extends from 30N38W SW to 23N44W to
20N53W. Surface ridging is elsewhere in the eastern Atlantic.

For additional information please visit
http://www.hurricanes.gov/marine

$$
RAMOS
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