[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011003
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Thu Oct 1 2020

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
0900 UTC.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 33W, from 15N southward,
moving west at 10 to 15 knots. Scattered moderate convection is
observed west of the wave axis along the ITCZ from 07N to 09N
between 34W and 36W.

An Atlantic Ocean tropical wave is along 57W/58W, from 17N southward,
moving west at 10 to 15 knots. Scattered moderate to isolated
strong convection is evident near the tropical wave from 10N to
13N between 52W and 57W.

A Caribbean Sea tropical wave is along 81W/82W, from 20N
southward through western Panama and into the eastern Pacific,
moving west 10 to 15 knots. Scattered moderate to isolated strong
convection is observed from 12N to 17N between 80W and 83W. A broad area of low
pressure is expected to form in a day or so over the northwest
Caribbean Sea or the extreme southern Gulf of Mexico in the vicinity
of the wave as it moves slowly west-northwestward. There is a
high chance a tropical depression will form over the next five
days. Interests in Belize, the Yucatan Peninsula, and western Cuba
should monitor the progress of this disturbance.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of
Gambia near 13N17W to 09N20W. The ITCZ continues from 09N20W to
10N30W, to 10N29W, and from 07N35W to 09N55W. Scattered moderate
convection is observed from 06N to 12N between 16W and 21W. Other
areas of convection are described above in the Tropical Waves
section.

GULF OF MEXICO...

A stationary front extends from southwest Florida to the northwest
part of the Yucatan peninsula near Merida, then farther to the
southwest over the extreme eastern Bay of Campeche to Ciudad del
Carmen. Clusters of moderate to strong thunderstorms are active
along the front to the north of the Yucatan peninsula. Recent
scatterometer passes indicated northerly winds are 20 to 25 kt
over the southern Bay of Campeche and in some areas within 120 nm
north of the front. Seas are estimated to be 5 to 8 ft over the
southwest Gulf. Farther north, 1020 mb high pressure is centered
south of Lake Charles Louisiana. Gentle to moderate NE winds are
noted across much of the northern and western sections of the
Gulf, with 2 to 4 ft seas. No other shower or thunderstorm
activity is observed.

For the forecast, the stationary front will slowly dissipate
tonight and early Fri. A reinforcing cold front will move through
the northeast Gulf Fri, eventually stalling across South Florida
and the southeast Gulf through late Sat. Meanwhile, developing low
pressure over the northwest Caribbean and Yucatan peninsula will
support strong to near gale force winds and building seas over the
mainly the south central Gulf from late Fri to early next week.

CARIBBEAN SEA...

Moderate to fresh trade winds and 5 to 7 ft seas are evident over
much of the eastern and central Caribbean this morning between
high pressure over the Atlantic and lower pressure related to the
tropical wave in the western Caribbean described in the section
above. A few clusters of showers and thunderstorms are also noted
across the central Caribbean, where the E trade winds converge
with SE winds closer to the axis of the tropical wave.
Observations from Leeward Islands show brief episodes of fresh to
strong winds in fast-moving rain squalls.

Showers and thunderstorms may increase over the Windward Islands
and adjacent Caribbean waters later today as the tropical wave
near 57W moves into the area accompanied by scattered to numerous
showers and a few thunderstorms. Winds and seas may increase over
the northwest Caribbean through Sat depending on the development
and track of the low pressure in that area. This may tighten the
pressure gradient enough to support fresh to strong trade winds
south of Hispaniola by late Fri. Otherwise, little change is
expected through early next week.

ATLANTIC OCEAN...

A few areas of thunderstorms are active along a stationary front
reaching from 32N73W to near Settlement Point, Grand Bahama, then
continues across South Florida. Deep layer moisture remains
fairly high east of the frontal boundary, and converging SE flow
is supporting other areas of thunderstorms mainly north of 27N
east of the front to 65W. An upper trough is supporting a cluster
of thunderstorms farther east near 29N60W. The main synoptic
feature over the Atlantic is a 1034 mb high pressure area centered
well to the north near 41N40W. A recent scatterometer pass
indicated a surface trough embedded in the ridge just to the south
of the high pressure. This is supporting an area of fresh to
strong winds and 8 ft seas from 30N to 32N between 35W and 40W.
Another area of fresh to locally strong trade winds and 8 to 9 ft
is just east of the Leeward and Windward Islands associated with
the tropical wave in that area. Elsewhere, moderate to
occasionally fresh trade winds and 5 to 7 ft seas characterize
the tropical and subtropical North Atlantic.

For the forecast west of 65W, the stationary front will gradually
dissipate through Fri. A reinforcing cold front will move into
the waters off northeast Florida late Fri and early Sat, before
also stalling from near 31N75W to South Florida by late Sat and
dissipating through Sun. Meanwhile the high pressure over the
central Atlantic and the lower pressure in the northwest
Caribbean will support moderate to fresh trades winds south of
20N, occasionally pulsing to strong winds north of Hispaniola
during the overnight hours. Looking ahead, a third weak front will
move south and stall from 31N72W to Central Florida by Mon night.

$$
Christensen
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