Tropical Weather Discussion
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000
AXNT20 KNHC 141202
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
702 AM EST Tue Nov 14 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 0600 UTC surface analysis and satellite imagery through
1115 UTC.

...SPECIAL FEATURES...
A 1008 mb low pressure center is near 34N31W, about 300 nm to the
SSW of the Azores. A surface trough extends from the low center
to 30N30W 27N33W 26N40W. Rainshowers are possible from 25N
northward between 28W and 40W. The low center is supported aloft
by a middle level to upper level cyclonic circulation center, that
is near 34N29W. Precipitation: widely scattered to scattered
moderate and isolated strong rainshowers from 30N to 37N between
25W and 30W. This low pressure center has a medium chance of
becoming a subtropical cyclone during the next couple of days as
it moves to the NE, before upper-level winds become unfavorable.
Expect near gale-force winds during the next day or two.

...ITCZ/MONSOON TROUGH...
The monsoon trough passes through coastal sections of Sierra Leone
near 08N13W to 08N17W. The ITCZ continues from 08N17W to 08N22W,
04N30W, 05N41W, and 03N46W. Precipitation: scattered strong from
03N to 05N between 10W and 13W. scattered moderate to isolated
strong from 04N to 09N between 14W and 20W. widely scattered
moderate to isolated strong from 03N to 08N between 17W and 25W.
isolated moderate to locally strong from 08N to 13N between 20W
and 53W. rainshowers are possible elsewhere from 15N southward
from 60W eastward. Upper level SW wind flow covers the Atlantic
Ocean to the S and SE of the line from 26N15W to 25N22W to 14N50W
to 08N52W. Broken to overcast multilayered clouds and possible
rainshowers are in this same area.

...DISCUSSION...

THE GULF OF MEXICO...
An upper level trough passes through coastal South Carolina, to
east-central Florida into the SE corner of the area. The trough
supports a cold front, that passes through 32N73W to the Florida
coast near 29N81W. A surface trough is from 120 nm to 180 nm to
the east of the cold front from 26N to 32N. Upper level NW wind
flow is moving across the entire Gulf of Mexico.

Upper level SW wind flow is moving from the NW corner of the
Caribbean Sea, across Cuba, and beyond the Bahamas. The upper
level SW wind flow is part of a larger-scale area of anticyclonic
wind flow that is extending from the Caribbean Sea, across the
Greater Antilles, into the Atlantic Ocean. Precipitation:
rainshowers are possible from 25N southward from 90W eastward.

Mist and fog are being reported from Alice Texas to interior
sections of the deep South of Texas.

A surface ridge passes through SW Louisiana, through the deep
south of Texas, to Mexico near 20N98W, into the Isthmus of
Tehuantepec of southern Mexico.

The current pressure gradient is expected to relax somewhat by
Wednesday. The wind speeds will be decreasing, into gentle-to-
moderate breezes, and gentle southerly return flow re-
establishing itself across the NW waters.

THE CARIBBEAN SEA...
Large-scale upper level anticyclonic wind flow spans the area.
A ridge extends from the SW corner of the area, beyond 30N65W in
the Atlantic Ocean.

A surface trough extends from a 1005 mb low pressure center that
is near 11N78W, to 15N81W. Precipitation: scattered strong from
the Colombia/Venezuela border near 09N73W to the Caribbean Sea
from 13N southward between 73W and 80W.

A second surface trough extends from 23N75W in the Atlantic Ocean,
across Cuba to 18N81W. Precipitation: widely scattered moderate
to isolated strong from 20N northward from 63W westward. Upper
level anticyclonic wind flow is moving on top of this area, with
the upper level ridge that runs from the SW corner of the
Caribbean Sea to 30N65W in the Atlantic Ocean.

A third surface trough is along 17N83W, into the Gulf of Honduras.
Widely scattered moderate to isolated strong from 14N northward
from 73W westward, in the NW corner of the Caribbean Sea.

Moderate to fresh tradewinds prevail, and they are expected to
persist through Tuesday. Global models indicate a broad and
stretched out area of surface low pressure developing from the
waters NE of Cuba to Jamaica and into the SW Caribbean Tuesday
night into Wednesday quickly moving E-NE and merging with a
frontal boundary in the SW North Atlc Wednesday night into
Thursday.

...HISPANIOLA...
Widely scattered moderate to isolated strong rainshowers are in
the Windward Passage. Some showers are reaching parts of SW Haiti.
Surface observations are not reporting rainshowers. Cumulonimbus
clouds are being reported in Santo Domingo in the Dominican
Republic. Upper-level W-to-NW wind flow is moving across the
area. Low-level moisture convergence continues to be maximized
across the region within E-SE tradewinds. This overall pattern
will persist through Thursday with precipitation expected to
increase during the next 24 to 48 hours.

THE ATLANTIC OCEAN...
A surface trough is along 24N27W 21N28W 17N29W. Upper level
SW wind flow covers the Atlantic Ocean to the S and SE of the
line from 26N15W to 25N22W to 14N50W to 08N52W. Broken to overcast
multilayered clouds and possible rainshowers are in this same
area.

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

$$
MT



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