[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041733
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1233 PM EST WED JAN 4 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
1715 UTC.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends across Africa reaching the Atlantic
waters near 05N08W to 02.5N17W. The ITCZ begins from that point
to 03N27W to 00N50W. Isolated showers and thunderstorms are
observed on either side of these boundaries from the Equator to
05N between 10W-30W.

...DISCUSSION...

GULF OF MEXICO...

At 1200 UTC, a cold front is analyzed across the Gulf of Mexico
based on visible satellite pictures, Theta-E values and surface
observations. At this time, the front extends from near Tampa Bay
to the central Gulf at 24N90W to the central Bay of Campeche.
Mosaic Doppler Radar from the SE U.S. shows bands of showers
across central and south Florida ahead of the front, which is
forecast to move through south Florida tonight, causing a wind
shift to the northwest. These winds will bring a cooler and drier
airmass. A second cold front stretches from the western Florida
Panhandle to near Brownsville, Texas. These fronts will merge
later today with the merging front reaching the SE Gulf and the
Yucatan Peninsula this evening. Then, the front is forecast to
stall across the Straits of Florida later tonight into Thursday
and gradually dissipate. A stronger cold front will enter the NW
Gulf Thursday evening, reaching from the Florida Panhandle to
26N94W to near Tampico Mexico by Friday evening. Fresh to strong
northerly winds and building seas will follow this front, with the
potential of gale force winds across the western Gulf on Saturday.
Aloft, broad mid-to upper level ridge characterized by NW flow
dominated the entire Gulf of Mexico.

CARIBBEAN SEA...

The most recent scatterometer data provided observations of fresh
to strong trade winds across the south-central Caribbean. Gentle
to moderate winds are noted across the remainder of the east and
central Caribbean with light to gentle winds across the NW part
of the basin. Little change in the overall pattern is expected
over the next 24-48 hours. The aerial extent and strength of the
trades will increase by Friday night as the Atlantic high
pressure intensifies and extends a ridge toward the NE Caribbean.
Shallow moisture embedded in the trade wind flow will move across
the region producing isolated to scattered passing showers. In
the upper-levels a trough extends from Hispaniola to the SW
Caribbean. Water vapor imagery shows strong subsidence in mostly
moderate to strong west to northwesterly flow over the entire
Caribbean basin. This flow is being induced by the trough.

HISPANIOLA...

Water vapor imagery depicts a shortwave trough extending across
the eastern portion of Dominican Republic. Cloudiness and isolated
showers are observed over this area and adjacent coastal waters...
including the Mona Passage. The trough is expected to move east
away from the island during the next 24 hours. A drying trend will
prevail after that.

ATLANTIC OCEAN...

A cold front extends from 30N76W to central Florida. Fresh to
strong southerly winds are ahead of the front, particularly N of
28N. Scattered showers and thunderstorms are also ahead of the
front. This system will extend from Bermuda across the central
Bahamas to the Straits of Florida late tonight, then stall and
weaken Thursday. A dissipating cold front enters the forecast
region near 31N29W and continues along 27N40W to 27N54W. This
front is associated to a very complex low pressure system across
the NE Atlantic. Isolated showers and thunderstorms are near the
frontal boundary. A ridge dominates the remainder of the
discussion area. A strong upper level jet originates near 10N60W
and extends through 14N50W to 22N30W to 25N20W to the African
coast at 26N with satellite derived winds indicating speeds of 100
to 120 KT. Expect fresh to locally strong trade winds and building
seas across the Atlantic waters E of the Lesser Antilles Friday
and Saturday as the Atlantic high pressure intensifies.

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

$$
GR
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