[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 112323
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
623 PM EST FRI NOV 11 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.

...SPECIAL FEATURES...

Gulf of Mexico Gale Warning: A reinforcing cold front is forecast
to sink south across the Gulf Saturday night and Sunday, while high
pressure ridging will surge southward across eastern Mexico. Northerly
winds will increase back to minimal gale force starting Saturday
evening, then will diminish below gale force shortly after sunrise
Sunday. Seas will build locally to 12 ft during the strongest
winds.

...ITCZ/MONSOON TROUGH...

The monsoon trough axis extends across Africa into the east
Tropical Atlantic near 12N16W to 07N22W. The intertropical
convergence zone axis extends from 07N22W to 05N40W to 10N60W.
Scattered moderate and isolated strong convection is within 180 nm
northeast of the axis between 40W and 50W. Scattered moderate
convection is within 180 nm north of the axis west of 55W.

...DISCUSSION...

...GULF OF MEXICO...

West-southwesterly flow aloft prevails over the Gulf early this
evening between upper level ridging extending from the southeast
Gulf to the southwest Gulf, and a broad middle to upper level low
approaching the Texas panhandle from the west-northwest. Moisture
and cloudiness continues to stream northeastward across northeast
and central Mexico, then across the Gulf northwest of the upper
ridging. Scattered to numerous showers and isolated thunderstorms
are likely across the same area of the upper level moisture, with
mainly dry conditions southeast of the upper ridging. A stationary
front extends from the central Gulf near 25N90W to 24.5N94W to
1016 mb low pressure near 22N96W to the coast of southeast Mexico
near 18N94W. Fresh to near gale force winds are reported within
150 nm north and northwest of the stationary front, while mainly
gentle to moderate easterly flow is found elsewhere across the
basin. The front will linger through Saturday, eventually merging
with a new front which is described in the special features
section above.

CARIBBEAN SEA...
Southerly upper level flow continues across much of the Caribbean
basin early this evening, except westerly over the waters north of
15N, around an upper level anticyclone over northern South
America. This flow is advecting middle to upper level moisture
from the deep tropics to the north. Very heavy rainfall is likely
occurring from western Colombia to across Costa Rica and Panama,
as well as portions of Nicaragua. Water vapor satellite imagery
indicates relatively dry air aloft north of 15N as a middle to
upper level trough extends into the northwest Caribbean from
22N80W to the Gulf of Honduras. At the surface, a trough, which
has the characteristics of a tropical wave, extends from the
southern coast of the Dominican Republic to 1011 mb low pressure
near 15N72W to 13N73W. Mainly moderate trades are observed across
the basin, except locally fresh across the approach to the
Windward Passage. The trough and low are forecast to dissipate
through Saturday as they drift westward. Winds will increase
locally to strong across the approach to the Windward Passage by
late Saturday night, with little change otherwise.

...HISPANIOLA...
A few isolated showers and thunderstorms developed over the Island
during the afternoon hours as a middle to upper level trough nears
the area from the west-northwest, supporting a surface trough
which extends toward the north coast of the island from the
northeast. Convection will likely diminish through the evening
with the loss of daytime heating, with isolated activity likely to
develop again on Saturday with a similar weather pattern in place.

ATLANTIC OCEAN...
A middle to upper level trough extends across the southwest north
Atlantic, extending from a vigorous upper level low centered well
north of the discussion area near 39N57W, southward through
25N60W, then southwest toward eastern Cuba. Very dry and stable
air continues to fill in behind this upper feature, which is
supporting a surface cold front extending from 32N54W to the
southeast Bahamas. Numerous showers and scattered thunderstorms
are occurring within 210 nm north of 24N ahead of the front.
Surface high pressure is building in behind the front with a west
to east ridge axis oscillating between 25N and 27N. The eastern
portion of the trough will continue to progress eastward, while
the western portion dissipates through early Saturday. A new cold
front will move into the northwest waters off of the southeast
U.S. coast Saturday night, stalling along 30N or 31N into Sunday
as high pressure ridging blocks further progress of the front. The
remainder of the basin is under the influence of a surface ridge,
anchored by a nearly stationary 1030 mb high centered southeast of
the Azores near 36N23W.

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

$$
LEWITSKY
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