[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 282357
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
657 PM EST Thu Dec 28 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 1800 UTC surface analysis and satellite imagery through
2315 UTC.

...ITCZ/MONSOON TROUGH...

The monsoon trough passes through the coastal areas of Liberia
near 05N09W to 03N17W. The ITCZ continues from 03N17W to 04N27W
03N35W 04N41W and 02N52W in NE Brazil. Precipitation: scattered
moderate to strong from 02N to 05N between 31W and 35W. widely
scattered moderate to isolated strong from 03N to 07N between 36W
and 46W, and from 10N southward between 52W and 60W.

...DISCUSSION...

...THE GULF OF MEXICO...

Upper level SW wind flow covers the NW two-thirds of the Gulf of
Mexico. Middle level-to-upper level cyclonic wind flow is in the
SW corner of the area.

A stationary front passes through 28N82W inland in Florida, to
27N90W in the central Gulf of Mexico, to 26N95W 20N96W, curving NW
into Mexico, to the Texas Big Bend. A surface trough, also, is
along 27N87W 25N89W 22N90W. Broken to overcast low level clouds
and possible rainshowers are to the north of the stationary front,
and from the northern coast of the Yucatan Peninsula to 26N
between 85W and 93W.

...THE CARIBBEAN SEA...

An upper level ridge extends from the area of Colombia/Panama
toward the area of the Yucatan Peninsula/Yucatan Channel. A middle
level trough is under the upper level ridge in the same area.

Broken low level clouds and isolated moderate rainshowers are to
the west of the line 21N83W 16N77W 11N75W, in the westernmost part
of the Caribbean Sea, and reaching the coastal plains and inland
areas from Panama to Honduras to the SE part of the Yucatan
Peninsula. Other similar clouds and possible rainshowers are from
17N southward from 80W eastward. Broken low level clouds and
possible rainshowers are in the Caribbean Sea and in the Atlantic
Ocean from 17N to 22N between 60W and 72W. The clouds and possible
rain are affecting Puerto Rico and Hispaniola, and the other
islands of the NE Caribbean Sea.

24-hour rainfall totals in inches, for the period that ended at
28/1200 UTC, according to the PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...are: 0.59 in
Trinidad, 0.28 in St. Thomas in the Virgin Islands, 0.20 in
Curacao, 0.19 in Nassau in the Bahamas, 0.10 in San Juan in
Puerto Rico, 0.02 in Guadeloupe.

...HISPANIOLA...

Upper level NE wind flow, and comparatively drier air in
subsidence in water vapor imagery, cover Hispaniola.

SURFACE OBSERVATIONS...rainshowers are being reported in Santo
Domingo in the Dominican Republic. Mostly cloudy skies are in
Santiago and Puerto Plata. earlier rainshowers were reported in
Puerto Plata. fair skies are being observed to the east of Santo
Domingo, and from Port-au-Prince in Haiti to Barahona in the
Dominican Republic.

The GFS MODEL forecast for 250 mb shows that W-to-NW wind flow
will move across the island during the next 2 days. A ridge will
extend from Colombia into the NW corner of the Caribbean Sea. The
GFS MODEL forecast for 500 mb shows that E-to-SE wind flow will
move across the area during most of day one of the 48-hour
forecast period. Hispaniola will be to the south of an east-to-
west oriented Atlantic Ocean ridge. The wind direction will be
variable at the end of day one. SW wind flow will move across the
area during day two, still with the same ridge from day one. The
GFS MODEL forecast for 700 mb shows that day one will consist of E
-to-SE wind flow, with Hispaniola being in the middle of an
anticyclonic circulation just to the north of it, and an inverted
trough immediately to the west of it. The anticyclonic circulation
center is forecast to move eastward. Anticyclonic wind flow will
move across the area during the next 2 days. It appears that an
inverted trough may be reaching the eastern half of Hispaniola at
the end of day two.

...THE ATLANTIC OCEAN...

Upper level SW wind flow is moving across the area of a cold
front, that passes through Bermuda, to 30N73W and 29N76W. A
stationary front continues from 29N76W, to inland Florida near
28N82W, to 27N90W in the central Gulf of Mexico. A surface trough
is within 270 nm to the SE of the frontal boundary, between 63W
and Andros Island in the Bahamas. Precipitation: isolated moderate
rainshowers within 30 nm on either side of the line that passes
through 32N56W to 30N60W. Rainshowers are possible elsewhere to
the NW of the line that passes through 32N55W 27N64W 22N77W.

An upper level trough extends from a 24N39W cyclonic circulation
center, to 17N48W, 17N59W, to 16N65W in the eastern Caribbean
Sea. widely scattered moderate to isolated strong rainshowers are
from 20N to 27N between 33W and 42W. High level clouds are to the
south of 27N16W 24N30W 17N40W 15N50W 13N63W, moving northeastward
with the upper level SW wind flow.

A surface ridge extends from a 1029 mb high pressure center that
is near 34N25W, through 32N37W, to 26N63W. Surface anticyclonic
wind flow covers the Atlantic Ocean from 15N northward between
Africa and 60W, and from 20N northward from 63W eastward.

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

$$
MT
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