[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 082319
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
619 PM EST TUE NOV 8 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
2100 UTC.

...ITCZ/MONSOON TROUGH...

The monsoon trough axis extends from the African coast near 10N14W
to 09N18W. The intertropical convergence zone axis extends from
09N18W to 06N26W to 08N31W, then resumes from 07N38W to 08N55W.
Scattered moderate convection is within 420 nm northeast of a line
from 04N24W to 11N32W.

...DISCUSSION...

GULF OF MEXICO...

A broad upper-level ridge prevails over much of the basin. A mid-
level shortwave trough is noted on water vapor satellite imagery
along 91W-93W, supporting a 1015 mb surface low centered near
27N91W, with a surface trough that extends from 30N92W to the low,
then southward to near 20N93W. Scattered showers and isolated
thunderstorms are occurring mainly along and northwest of these
surface features. Elsewhere, a surface ridge extends from a 1025
mb high centered over upstate South Carolina near 34N83W. Earlier
scatterometer data depicted light to gentle easterly winds across
the western Gulf west of 90W, while moderate to fresh easterlies
prevail east of 90W. The low and trough are forecast to drift
eastward through Wednesday. A cold front is expected to move
across the northern Gulf waters on Wednesday and provide fresh to
strong northeast winds north of the front, and fresh to strong
north-northwest winds west of the boundary across the offshore
waters of eastern Mexico. The front is forecast to gradually
become stationary from near Fort Myers, Florida to the west-
central Gulf near 24N95W, to the southwest Gulf near 18N95W by
Thursday afternoon.

CARIBBEAN SEA...

An upper-level trough extends from the north-central Caribbean
near the north coast of Haiti, south-southwest through 15N78W to
near the border of Nicaragua and Honduras. Water vapor satellite
imagery indicates very dry air aloft west of this upper-level
trough. Ahead of the upper-level trough, moist southwest flow is
present. A surface trough is located across Puerto Rico, with a
second surface trough over the western Caribbean just offshore of
eastern Honduras and Nicaragua, extending to the southeast towards
the northwest coast of Colombia. Isolated showers and thunderstorms
are noted from the northeast Caribbean islands including across
Puerto Rico to the Mona Passage, and also just to the east of the
surface trough over the western Caribbean. Earlier scatterometer
data depicted fresh to strong northeast flow from the Windward
Passage southwest to near the eastern tip of Jamaica, as well as
in the lee of Cuba. Otherwise, mainly moderate trades prevail,
except light to gentle northwest winds to the west of the western
Caribbean surface trough. The fresh to strong northeast flow is
expected to diminish in the next 24 to 48 hours, while winds
offshore of the coast of Colombia increase to fresh levels as the
local pressure gradient tightens.

...HISPANIOLA...

A surface trough extends from northeast to southwest across the
island, helping to support scattered showers and isolated
thunderstorms. The trough is expected to remain nearly stationary
and linger across the region through the next 24 to 48 hours, with
similar convection expected. The greatest coverage will likely be
during the afternoon hours with peak daytime heating.

ATLANTIC OCEAN...

A deep layered low pressure system is near 36N61W with a surface
pressure of 998 mb, and gale force winds on the western side
north of 32N. Multiple cold fronts and troughs rotate outward from
the parent low to across our basin, mainly north of 19N between
50W and 70W. Scattered showers and isolated thunderstorms prevail
within 360-420 nm east of a line from 32N55W to 25N63W to 22N73W.
Earlier scatterometer data indicated moderate to fresh winds north
of 29N between 60W and 70W, fresh to strong northeast flow south of
22N west of 65W as well as through the Straits of Florida, with
moderate north to northeast flow elsewhere west of 65W. Surface
high pressure over upstate South Carolina will slide to the
southeast reaching to near 27N73W by Wednesday afternoon, and then
dissipating by Thursday afternoon. This will occur as a cold front
moves off the southeast U.S. coast, reaching from 32N78W to
northern Florida by Wednesday afternoon, and then quickly racing
eastward and reaching from 32N67W to the northern Bahamas by
Thursday afternoon. Fresh to near gale force winds are forecast
north of 27N on either side of the front.

Elsewhere, a middle to upper-level low is centered near 23N30W
with a north to south trough extending from the low. Upper level
ridging is building in across the area west of the trough. An
active surface trough is located in the tropical north Atlantic
south of 17N along 60W, with scattered showers and thunderstorms
mainly from 09N to 18N west of 53W. Another surface trough is
embedded in the ITCZ, extending from 11N33W to 05N34W. Associated
convection is described in the ITCZ section above and is all
sheared off well to the northeast ahead of the middle to upper-
level trough. A ridge axis extends across the waters between both
troughs, from near 32N35W to 20N56W.

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

$$
LEWITSKY
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