Tropical Weather Discussion
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AXNT20 KNHC 130453

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1152 PM EST Fri Jan 12 2018

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 0000 UTC surface analysis and satellite imagery through
0430 UTC.


The monsoon trough passes through the coastal areas of Sierra
Leone near 07N12W, to 04N24W. The ITCZ continues from 04N24W to
01N32W, and 01N40W. Precipitation: isolated moderate to locally
strong rainshowers from 08N southward from 53W eastward.



An upper level trough is that digging through Alabama, the SE
U.S.A., and the eastern sections of the Gulf of Mexico, is
supporting a current cold front that is passing through: the
Florida Panhandle, into the S central Gulf of Mexico, to the
Isthmus of Tehuantepec of southern Mexico. A surface trough is
about 120 nm to the east of the cold front, from the Yucatan
Peninsula northward, beyond the Florida Big Bend. Comparatively
drier air in subsidence is apparent in water vapor imagery across
the entire Gulf of Mexico. Rainshowers are possible, in broken
low level clouds that cover the area from 94W eastward, including
across Florida. Isolated moderate rainshowers are in the Atlantic
Ocean from 20N northward from 68W westward.

A strong cold front extending from the Florida Big Bend to the
Yucatan Channel will exit the Gulf this evening. Reinforcing cold
air will move through the eastern Gulf on Saturday. High pressure
will build behind the front late this weekend. Another cold front
will cross the Gulf beginning on Tuesday night.


A surface trough is along 80W/81W from 10N to 16N, in the SW
part of the area. Rainshowers are possible from 17N southward
between 80W and 84W, mostly from 12N southward between 81W and

The southern part of a surface trough cuts across NW Cuba, into
the Gulf of Honduras. Isolated moderate rainshowers are in the NW
part of the Caribbean Sea, from 15N northward from 80W westward,
and from Jamaica to SE Cuba.

A second surface trough is near the SW corner of the area, along
09N75W from N Colombia beyond 08N81W in Panama. Isolated moderate
to locally strong rainshowers are in Colombia and Venezuela, from
06N to 11N between 72W in Lake Maracaibo of NW Venezuela and 78W
in eastern Panama.

Isolated moderate rainshowers are elsewhere, from 80W eastward,
in areas of broken low level clouds. Many of these areas of clouds
are moving toward the W and NW.

24-hour rainfall totals that are listed for the period that ended
at 13/0000 UTC...according to the PAN AMERICAN TEMPERATURE AND

A cold front, that is moving through the eastern sections of the
Gulf of Mexico, will extend from central Cuba to the Gulf of
Honduras on Saturday morning, and then it will stall from E Cuba
to Costa Rica on Saturday night. Fresh to locally strong N winds
are expected behind the front on Saturday, increasing to 20-30
knots on Sunday. The winds will be strong to near gale force along
the coast of Nicaragua on Sunday. Strong winds will pulse near
the NW Colombia coast each night. A large swell will affect the
tropical Atlantic Ocean waters through Tuesday.


Isolated moderate rainshowers are in the coastal waters of
Hispaniola, from 17N to 21N between the Mona Passage and the
Windward Passage. Rain has been reported at some locations across
Hispaniola during the last few hours, including in Port-au-Prince
in Haiti, and in Punta Cana in the Dominican Republic.

The GFS MODEL forecast for 250 mb shows that anticyclonic flow,
with a N-to-S oriented ridge across the area, will span the area during
the next 2 days. The GFS MODEL forecast for 500 mb shows that
anticyclonic wind flow will cover the area for most of the first
part of day one, from an Atlantic Ocean-to-Hispaniola ridge. N
wind flow will continue from the second half of day one and during
all of day two. An anticyclonic circulation center will develop
to the south of Jamaica from the first of half of day one through
day two. The GFS MODEL forecast for 700 mb shows that an inverted
trough will move from east-to-west across Hispaniola during the
first half of day one. Anticyclonic wind flow, with an Atlantic
Ocean-to-Hispaniola ridge, will continue from the second half of
day one until the middle of day two. NE wind flow will cover
Hispaniola for the second half of day two, as part of an inverted
trough that will be moving across Puerto Rico during that same
time period.


An upper level trough/shear axis passes through 32N39W to an
upper level cyclonic circulation center, that is near 24N57W.
A cold front passes through the Madeira Archipelago, to 29N24W and
28N34W. A dissipating stationary front continues from 28N34W to
25N45W and 24N57W. Precipitation: widely scattered moderate to
isolated strong rainshowers are from 19N to 27N between 44W and
58W. Other rainshowers are possible from 25N to 30N between 25W
and 44W.

An upper level cyclonic circulation center is near 17N41W. Broken
to overcast multilayered clouds cover the Atlantic Ocean from 10N
to 25N between 24W and 43W.

A strong high pressure center that is in the central Atlantic
Ocean will shift eastward. A cold front will move E from Florida
this evening, and extend from 31N72W to E Cuba on Sunday.
Reinforcing cold air will help push the front SE, in order to
extend from 31N65W to the Windward Passage by Monday evening.

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