[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111023
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
523 AM EST Sun Nov 11 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 0600 UTC surface analysis and satellite imagery through
1030 UTC.

...SPECIAL FEATURES...

...Gulf of Mexico Gale...

A strong cold front is expected to move into the northwest Gulf
of Mexico by Monday afternoon. Winds up to gale force will follow
this stronger front over the western Gulf as it reaches from near
Pensacola, Florida to Tampico, Mexico by late Monday. This feature
will likely bring strong gales over the southwest Gulf Tue, possibly
reaching storm force off Veracruz, as the front reaches from near
Tampa, Florida to Coatzacoalcos, Mexico. Winds and seas will
diminish Wed as the front sweeps southeast of the region. Refer to
the High Seas Forecast product under AWIPS/WMO headers
HSFAT2/FZNT02 KNHC for more details.

...TROPICAL WAVES...

An Atlantic tropical wave is along 27W south of 09N. Scattered
moderate to isolated strong convection is noted 90 nm on either
side of the wave axis with scattered disorganized convection N and
S of the ITCZ near the wave.

An Atlantic tropical wave is along 39W/40W south of 10N.
Scattered moderate convection is present 120 nm on either side of
the wave axis. Scattered moderate isolated strong convection is
related to the proximity of the ITCZ nearby.

An Atlantic tropical wave is along 52W south of 16N. Scattered
moderate convection is noted from 13N to 15N between 45W and 50W.

A Caribbean tropical wave is in the Gulf of Honduras south of 19N along
85W/86W from 20N southward. No convection is observed with this
wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Sierra Leone near
08N13W to 07N17W. A segment of the ITCZ continues from 07N17W to
west to 05N25W. Other segments of the ITCZ reach from 06N28W to
05N37W, and from 05N41W to 05N50W. Convergent trade wind flow
south of strong high pressure over the central Atlantic is
supporting numerous moderate to strong convection within 150 nm
north and 90 nm south of the ITCZ.

GULF OF MEXICO...

A stationary front extends from Naples Florida to 24N96W to
18N94W. Strong easterly winds are noted in scatterometer and
buoy data north of the front and north of 24N. Earlier altimeter
data showed seas to 13 ft off the Mexican coast from Tampico to
Veracruz, although seas are subsiding.

The front will lift north and weaken as it lifts northward today
ahead of a stronger cold front moving off the Texas coast by late
Mon. Strong winds and building seas will follow the front,
reaching gale force over the NW Gulf by late Mon. Strong gales
will follow the front over the western Gulf as it reaches from
Panama City Florida to Coatzacoalcos Mexico early Tue, with brief
storm conditions possible off Veracruz. Winds and seas will
gradually diminish Wed into Thu as the front sweeps southeast of
the region.

CARIBBEAN SEA...

A recent scatterometer pass indicated fresh to strong NE winds
pulsing through the Windward Passage. This is indicative of a
relatively tighter pressure gradient between building high
pressure off the U.S. east coast and troughing over the eastern
Caribbean related to a sharp upper trough reaching from the
central Atlantic to Puerto Rico. This pattern will persist
through tonight, with areas of fresh strong winds also pulsing
off the central coast of Colombia, near Cabo Beata on the
southern coast of Hispaniola, and through the Gulf of Guacanayabo
in southeast Cuba.

Meanwhile thunderstorms and strong winds are noted on the
northern portion of a tropical wave analyzed well east of the area
in the tropical north Atlantic along 52W, and this is expected
reach the waters northeast of the Leeward Islands by tonight. The
tropical wave will drift through the eastern Caribbean by mid
week. Fresh to strong trade winds and 8 to 10 ft seas with
easterly swell will follow over the tropical north Atlantic
region. As the tropical wave shifts east, a cold front will move
into the southwest north Atlantic area to the north, temporarily
weakening the subtropical ridge and allowing winds across the
basin to diminish through mid week across the eastern and central
Caribbean. The strong cold front will also be moving across the
Gulf of Mexico, and bring fresh to strong N winds and seas to 12
ft into the Yucatan Channel and the NW Caribbean Wed through Thu.

ATLANTIC OCEAN...

Moderate to fresh northerly winds are observed north of a cold
front extending from 31N71W to West Palm Beach Florida. Seas to 8
ft in northerly swell are also apparent, at least over waters
north of 30N. Subsidence associated with a sharp upper trough is
maintaining generally fair weather from Bermuda to the Turks and
Caicos, but upper divergence on the eastern side of the upper
trough is supporting a few showers and thunderstorms across the
waters northeast of the Leeward Islands. Buoy and altimeter
satellite data show generally 4 to 6 ft seas over open waters.

The front will stall and weaken over the northern Bahamas
through today. The front will lift north and becoming diffuse Mon
ahead of a stronger front moving off the northeast Florida coast
late Tue. The second front will reach from 31N73W to western
Cuba Wed when a reinforcing push of cold air will bring strong
northerly winds and building seas to the waters north of 27N by
late Wed. As this happens, troughing on the northern end of a
tropical wave will move into the waters northeast of the Leeward
Islands Mon and Tue, coming into phase with favorable conditions aloft
on the southeast side of the upper trough, thus enhancing
convection, lowering surface pressure and allowing surface winds
to increase. The resultant developing low pressure will move
N-NW, reaching north of Puerto Rico Wed, before interacting with
the stalling front Thu well to the northeast of the southern
Bahamas. Strong to near- gale force winds are possible with this
low, and it currently has a medium chance of tropical cyclone
development by mid week before interacting with the stalling
front to its northwest.

Farther east, 1027 mb high pressure is centered near 33N43W,
supporting mostly fresh trade winds over the deep tropics. Various
recent altimeter passes indicate 8 to 11 ft swell across most of
region.

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

$$
Christensen
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