[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190535
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Tue Sep 19 2023

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 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0000 UTC surface analysis and satellite imagery through
0545 UTC.

...SPECIAL FEATURES...

Hurricane Nigel is centered near 28.6N 52.7W at 19/0300 UTC or
660 nm ESE of Bermuda, moving NW at 10 kt. Estimated minimum
central pressure is 979 mb. Maximum sustained wind speed is 75
kt with gusts to 90 kt. Seas are peaking near 31 ft near and
just northwest of the center. Numerous moderate to isolated
strong convection is found near and up to 150 nm in the SE
semicircle and 90 nm in the NW semicircle. Nigel is forecast to
turn northward late Tuesday, and then accelerate northeastward
through the rest of the week. Additional strengthening is
forecast during the next day or so. Gradual weakening is
expected to begin by late Wednesday.

Please read the latest HIGH SEAS FORECAST issued by the
National Hurricane Center at website -
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest
Nigel NHC Forecast/Advisory and Public Advisory at
www.hurricanes.gov for more details.

...TROPICAL WAVES...

A tropical wave is off the Africa coast near 21W from 18N
southward, and moving west around 5 to 10 kt. Scattered moderate
convection is found from 03N to 07N between 19W and 29W.

A central Atlantic tropical wave was relocated based on wave
diagnostics and satellite imagery and it is now near 42W from
12N southward. Widely scattered moderate convection is noted
from 05N to 12N between 33W and 46W.

...MONSOON TROUGH/ITCZ...

A monsoon trough enters the Atlantic near the Gambia-Guinea
Bissau border near 13N17W then extends west-southwestward across
08N24W to 07N46W. The ITCZ continues from 07N46W to 07N53W.
Other than the convection described in the TROPICAL WAVES
section above, scattered moderate isolated strong convection is
evident from 06N to 10N between 46W and 53W.

The eastern end of the East Pacific monsoon trough is producing
scattered showers and thunderstorms across the Caribbean waters
north of Costa Rica, Panama and northwestern Colombia.

...GULF OF MEXICO...

A cold front reaches west-southwestward from South Florida to
25N86W. Then a surface trough turns west-southwestward to
23N92W. Scattered showers and thunderstorms are depicted near
the frontal boundary and the trough. Another surface trough is
depicted over the Yucatan Peninsula producing scattered showers
and thunderstorms in the eastern and central Bay of Campeche.
Moderate NE winds are occurring N of the boundary with mainly
gentle winds elsewhere. Seas are 2 to 4 ft north of the boundary
and 1 to 2 ft elsewhere outside of any convection.

For the forecast, a weak cold front extends from extreme South
Florida to near 25N85W and to 22N93W. The front will become
stationary overnight tonight and dissipate Tue. Winds will be
moderate or weaker with slight seas through Thu, pulsing to
moderate to fresh offshore the W Yucatan in the evenings. Winds
may freshen in the NE Gulf by the end of the week due to
building high pressure north of the area with seas also building.

...CARIBBEAN SEA...

An upper-level trough runs from west of the Lesser Antilles
throughout the Greater Antilles and into the Gulf of Honduras.
This trough is producing scattered showers and thunderstorms
across the northwestern and north-central basin. Please refer to
the MONSOON TROUGH/ITCZ section for additional weather in the
Caribbean Basin.

A modest trade-wind pattern continues for much of the basin.
Fresh NE to E winds and 4 to 6 ft seas are present at the south-
central basin. Light to gentle winds and seas of 1 to 3 ft are
noted at the northwestern basin. Gentle monsoonal winds with
seas at 3 to 4 ft exist offshore from Costa Rica and Panama.
Gentle to moderate NE to E winds prevail for the rest of the
basin, except fresh to strong offshore N Colombia and NW
Venezuela. Seas are 4 to 6 ft there and 3 to 5 ft across the
remainder of the waters.

For the forecast, long period north to northeast swell will
impact the Caribbean passages and Tropical N Atlantic through
early Wed. Moderate to fresh trades will prevail in the central
Caribbean, locally strong at times offshore northern Colombia
and northwest Venezuela, with moderate or weaker winds elsewhere
through the week.

...ATLANTIC OCEAN...

Please read the SPECIAL FEATURES section for details about
Hurricane Nigel.

A cold front runs southwestward from 31N73W to near South
Florida. Scattered showers and thunderstorms are found south of
31N and west of 73W. Mainly gentle winds are behind and just N
of the front along with 4 to 6 ft seas. Please refer to the
MONSOON TROUGH/ITCZ and TROPICAL WAVES sections above for
additional convection in the Atlantic Basin. Outside the direct
impact of Hurricane Nigel, a broad area of fresh to strong
trades is noted from 20N to 29N between the coast of Africa and
41W along with 8 to 11 ft seas. Gentle to moderate trades and 5
to 8 ft seas are found elsewhere north of 10N and E of 45W, with
mainly gentle winds and 5 to 7 ft seas across the remainder of
the tropical Atlantic waters.

For the forecast W of 55W, Hurricane Nigel is near 28.6N 52.7W
at 11 PM EDT, and is moving northwest at 10 kt. Maximum
sustained winds are 75 kt with gusts to 90 kt, and the minimum
central pressure is 979 mb. Nigel will continue to strengthen as
it moves to near 29.9N 53.8W Tue morning with maximum sustained
winds 85 kt gusts 105 kt, to just north of the area near 32.1N
54.5W Tue evening, then begin to accelerate northeastward well
away from the area through the rest of the week while weakening.
A weak cold front extending from near 31N73W to extreme South
Florida will reach from near 31N72W to near West Palm Beach,
Florida early Tue, then stall over the northern forecast waters
through Thu. The boundary should begin to slowly lift northward
on Fri as low pressure develops along it to the east of northern
Florida. Winds and seas will likely increase in that area by the
end of the week as a tight pressure gradient develops between
the developing low pressure off the Carolinas and high pressure
inland over the U.S.

$$
KRV
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