Tropical Weather Discussion
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AXNT20 KNHC 151746

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1245 PM EST Wed Nov 15 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.

A broad area of lower pressure is noted across the SW North Atlc
region anchored by a pair of 1008 mb lows analyzed along a
stationary front. The dominant 1008 mb low is centered near 28N63W
with the front extending NE to 32N58W...and SW to the other 1008
mb low near 25N69W. To the SW...a surface trough extends SW to
eastern Cuba near 20N76W and into low pressure across the western
Caribbean Sea. The area of low pressure is supported aloft by a
middle to upper level trough extending from 34N72W to a broad
base over the Florida Straits near 23N82W. Scattered showers and
tstms continue across a large area surrounding the stationary
front from 20N-32N between 52W-74W. As the northeastern most low
pressure area deepens during the next 12 to 24 hours...near gale
to gale force S to SW winds are forecast to increase by this
evening generally N of 28N E of the front to 52W. This wind field
is expected to persist through late Thursday night and decrease
into strong to near gale conditions by Friday morning. See the
latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/
FZNT02 KNHC for more details.

The monsoon trough extends from the African coast near 08N13W to
08N20W. The Intertropical Convergence Zone axis extends from
08N20W to 09N30W to 06N45W. Widely scattered moderate and isolated
strong convection is from 01N-06N between the Prime Meridian and
07W. Widely scattered moderate convection is from 03N-12N between
14W-38W. Scattered moderate convection is from 07N-11N between


NW flow aloft prevails over the Gulf basin this afternoon as an
upper level trough lies over the SW North Atlc and Florida
peninsula to a base over the Yucatan Channel region. Mostly stable
conditions are occurring at the surface as a ridge axis extends
from the Mid-Atlc coast across the SE CONUS to the SW Gulf and
east-central Mexico near 22N99W. Skies are mostly clear with the
exception of a few possible isolated showers within 120 nm N of a
surface trough analyzed from 19N92W to 24N97W. Otherwise...
gentle to moderate anticyclonic winds are forecast through Friday.
The next cold front is expected to emerge off the Texas and
Louisiana coasts by late Saturday into Saturday night.

A broad area of lower pressure across the basin continues to be
focused on a 1007 mb low centered S of Jamaica near 16N78W. A
surface trough extends S-SW from the low to near 10N81W and
supports scattered showers and strong tstms from 07N-16N between
73W-87W...including portions of southern Nicaragua...Costa
Rica...and Panama. Another area of similar convection is occurring
across the central Caribbean and Hispaniola near between 68W-74W.
Otherwise...gentle to moderate N-NE winds are noted across the NW
Caribbean waters to the NW of the low...while trade wind flow E of
the low will continue to be disrupted as outside of convection...
gentle to moderate southerly winds will prevail through the
upcoming weekend. The low is expected to slowly drift eastward and
then remain nearly stationary S-SW of Hispaniola early next week.

Scattered to numerous showers and scattered strong tstms are
expected to persist across the island the next few days as deep
moisture advects NE over the region due to an upper trough to the
NW over the SW North Atlc...Cuba...and NW Caribbean Sea. Convection
will likely be heaviest in the afternoon and evening hours during
maximum heating. Localized flooding and life-threatening mud
slides are also possible during this time.

Aside from the special features section above highlighting the
broad area of low pressure analyzed across much of the SW North
Atlc...northwestern portions are under the influence of a cold
front analyzed into the discussion area near 32N63W SW to 29N70W
becoming stationary to the NW Bahamas near 27N77W. Isolated
showers are within 75 nm either side of the front while the
stronger convection to the E remains associated with the Special
Feature. Farther east...the central Atlc is under the influence of
a surface ridge anchored by a 1021 mb high centered near 29N43W.
Finally...while mostly tranquil conditions are noted across the
eastern Atlc...weakening surface troughing extending from a 1006
mb low centered in the vicinity of the Azores near 39N26W is
supporting possible isolated showers N of 28N between 20W-32W.

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