Tropical Weather Discussion
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AXNT20 KNHC 122252

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
551 PM EST Tue Dec 12 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.


The monsoon trough enters the Atlantic Ocean through Liberia and
continues to near 06N13W. The Intertropical Convergence Zone
extends from near 06N13W to 07N20W to 04N35W to the coast of NE
Brazil near 02N51W. Scattered moderate isolated strong convection
is within about 180 nm north of ITCZ axis W of 30W.


A reinforcing and dry cold front extends from northern Florida
across the northern Gulf waters to south Texas. The front will
move across the southeast Gulf by early Wed morning followed by
moderate to fresh NW winds over the eastern Gulf, and gentle
moderate northerly winds elsewhere. A 1033 mb high pressure
located over Texas extends a ridge the remainder of the Gulf
region. Cold air stratocumulus clouds are noted ahead of the
front. Patches of low level clouds with embedded light showers
are over the Bay of Campeche where a surface trough is analyzed
on the 1800 UTC surface map. The next cold front will enter the
northern Gulf Thu, and reach from the Florida Big Bend area in the
NE Gulf to near Tampico Mexico by early Fri.

A quasistationary frontal boundary persists across the basin and
extends from eastern Cuba to the SW Caribbean near 10N82W. The
most recent scatterometer pass showed fresh to strong northerly
winds within about 240 nm to the W of the front and mainly south
of 20N. A band of broken to overcast multi-layered clouds prevails
to the W of the front affecting from eastern Cuba to western
Panama and Costa Rica. Some convective activity is also noted
along the frontal boundary just south of Jamaica. A swirl of low
clouds is seen on visible satellite imagery near 15N71W related to
a weak easterly perturbation. Light to gentle winds dominate the
eastern Caribbean with seas generally below 5 ft based on
altimeter data and buoy observations. The front is forecast to
meander across the central Caribbean and gradually weaken through

Moisture is forecast to increase across the island on Wed as the
frontal boundary currently located over eastern Cuba drifts eastward
across the Windward Passage into Hispaniola. This will increase
the likelihood of showers Wed and possibly Thu.

A quasistationary frontal boundary enters the forecastv area near
31N59W, then continues SW to the SE Bahamas and eastern Cuba into
the Caribbean Sea. A band of multi-layered clouds with embedded
showers is associated with the front. A reinforcing cold front is
just moving off NE Florida and it is forecast to reach from near
Bermuda to NW Cuba early on Wed. A weak and narrow surface
ridge extends from the Gulf of Mexico NE across S Florida to near
Bermuda ahead of this reinforcing front. A third cold front enters
the Atlantic Ocean through Mauritania, west Africa and continues W
then NW to near 23N34W. The remainder of the Atlantic Ocean is
under the influence of a 1033 mb high pressure located just south
of the Azores. Fresh to locally strong anticylonic flow is seen S
and SW of the ridge, and generally E of 53W, where a surface trough
is found drifting W.

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