[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 021048
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Fri Oct 2 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
1000 UTC.

...SPECIAL FEATURES...

Low pressure in the northwest Caribbean is becoming better
organized this morning. The low is centered near 17N84W, and has
an estimated pressure of 1006 mb. Strong, rotating convection is
building near the center of the low, and a large band is observed
within 180 nm to the northeast of the center. The low pressure
developed along a tropical wave, currently moving into Central
America. Environmental conditions are favorable enough to support
a high chance for the low pressure to develop into a tropical
depression or a tropical storm today or Saturday as it moves
slowly to the northwest into the northeastern Yucatan peninsula.
The low may emerge into the south central Gulf of Mexico by
Sunday, then shift westward through early next week. Regardless of
development, the slow moving low pressure will likely bring heavy
rains, with possible flash flooding, to portions of southeastern
Mexico, Central America, and western Cuba during the next several
days. Seas will build over the far northwestern Caribbean and
Yucatan Channel through Saturday night, and in the south- central
Gulf through early next week.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 36W from 16N southward,
moving west at 10 to 15 knots. Scattered moderate convection is
noted near the wave axis and along the ITCZ from 06N to 11N
between 30W and 40W.

A Caribbean Sea tropical wave is along 66W from 19N southward,
moving west at 10 to 15 knots. Scattered moderate to isolated
strong convection is evident from 11N to 13N between 63W and 68W.

A Caribbean Sea tropical wave is along 84W south of 20N, moving
west at 10 to 15 kt. Showers and thunderstorms are described in
the Special Features section above.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of
Senegal near 12N16W to 11N20W. The ITCZ continues from 11N20W to
10N34W, and from 08N38W to 06N57W. Scattered moderate convection is
noted from 06N to 11N between 30W and 40W.

GULF OF MEXICO...

A dissipating stationary front extends from southwest Florida to
the north central part of the Yucatan peninsula. Scattered
moderate convection is noted within 75 nm north of the front. A
scatterometer pass from 03 UTC indicated fresh to strong NE winds
over much of the south-central Gulf to the north of the front, and
ahead of the developing low pressure nearby in the northwest
Caribbean. Fresh to strong NW to N winds are also evident over the
far southwest Gulf of Mexico, south of 20N, where a recent
altimeter pass indicated seas of 6 to 8 ft. Farther north, a
reinforcing cold front is moving through the norther Gulf,
reaching from the Florida Big Bend area to central Texas. Buoy and
platform observations indicate fresh northerly winds are following
the front from the western Florida Panhandle to the north Texas
coast. Elsewhere, gentle to moderate winds and 3 to 5 ft seas are
noted.

For the forecast, the low pressure is expected to move into the
Yucatan peninsula and south central Gulf through Sat, possibly as
a tropical depression, supporting strong to near-gale force winds
and building seas across the south central Gulf into early next
week. Meanwhile farther north, a reinforcing front over the
northern Gulf will move across the northeast Gulf today,
eventually stalling and dissipating across southern Florida and
the southeast Gulf through Sat.

CARIBBEAN SEA...

Please see the Special Features section above for information on
the developing low pressure in the northwest Caribbean.

Elsewhere across the Caribbean, a broad mid to upper trough north
of Puerto Rico is bringing dry and stable air across the Dominican
Republic and the Mona Passage. Divergent flow aloft on the
southeast periphery of the upper trough is enhancing the shower
and thunderstorm activity over the eastern Caribbean, near the
tropical wave along 66W. Fresh to strong trade winds persist over
the eastern and central Caribbean, between the Bermuda high to the
north and the lower pressure over the western Caribbean, and seas
are generally 6 to 9 ft.

Winds and seas will gradually subside across the entire Caribbean
basin early next week as the low moves farther to the northwest
and the ridge north of the area weakens and shifts eastward.

ATLANTIC OCEAN...

A stationary front passes through 32N74W, to the NW Bahamas, to
26N80W in south Florida. The front is under a sharp upper ridge
extending to the northeast of the broad upper anticyclone covering
the developing low in the northwest Caribbean. Convergent
southeast flow into the front along with divergence along this
upper ridge is supporting clusters of showers and thunderstorms
along and within 120 nm of the front. Gentle to moderate winds and
3 to 5 ft seas are observed over the waters north of 22N and west
of 65W. Moderate to fresh trade winds and 5 to 7 ft seas south of
22N.

For the forecast west of 65W, the stationary front extending from
32N74W to southeast Florida will gradually dissipate through late
today. A reinforcing cold front will move into the waters off NE
Florida late today, before also stalling from near 31N79W to
central Florida by Sat afternoon, and then retreating northward as
a warm front on Sun. Meanwhile, the Bermuda High north of the
area and lower pressure in northwest Caribbean will support
moderate to fresh trades south of 22N, occasionally pulsing to
strong north of Hispaniola during the overnight hours through Sun
night. Looking ahead, a third weak front will move over the
Atlantic waters east of NE Florida late Sun and dissipate by early
Tue.

Farther east, 1034 mb high pressure is centered near 41N38W. A
couple of weak troughs are noted south of the high pressure, north
of 22N along roughly 40W and 50W. Fresh E winds and seas to 8 ft
persist near the trough along 40W, but winds and seas are expected
to subside today. Generally moderate trades persist farther south
into the tropics, with 5 to 7 ft seas. Fresh to strong NE winds
with 6 to 9 ft seas are noted off North Africa.

$$

Christensen
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