[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191037
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 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 0600 UTC surface analysis and satellite imagery through
1045 UTC.

...SPECIAL FEATURES...

Hurricane Nigel is centered near 29.6N 53.6W at 19/0900 UTC or
600 nm ESE of Bermuda, moving NW at 11 kt. Estimated minimum
central pressure is 979 mb. Maximum sustained wind speed is 75
kt with gusts to 90 kt. Seas are peaking to near 34 ft near and
just northwest of the center. Satellite imagery shows that Nigel
has a rather large eye feature. Numerous moderate to isolated
strong convection is seen within 120 nm of the center in the
SE quadrant and 90 nm of the center in the NE quadrant. Scattered
moderate convection is 90 nm of the center in the NW quadrant,
and from 26N to 29N between 49W-52W. Nigel is forecast to turn
northward late today, and then accelerate rapidly northeastward
through the rest of the week. Nigel is forecast to strengthen
some through early Wed, with weakening likely on Thu and Fri.
Nigel is forecast to become a strong post-tropical cyclone on
Fri. Swells generated by Nigel are expected to reach Bermuda
later today. These swells are likely to cause life-threatening
surf and rip current conditions. Please consult products from your
local weather office.

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 far eastern Atlantic tropical wave has its axis along 23W from
04N to 19N. It is moving westward around 10 kt. Scattered
moderate convection is within 120 nm west of the wave from 04N to
07N.

A central Atlantic tropical wave has its axis along 43W from
02N to 13N. It moving westward at 10-15 kt. Numerous moderate
convection is within 180 nm west of the wave from 07N to 10N, and
within 120 nm east of the wave from 07N to 10N.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis enters the Atlantic near the Gambia-
Guinea Bissau border near 13N17W and continues west-southwestward
to 09N26W and to 10N34W to 07N48W. The ITCZ extends from 07N48W
to 07N54W. Other than the convection described in the TROPICAL
WAVES section above, scattered moderate to isolated strong
convection is within 240 nm north of the trough between 30W-40W,
also within 240 nm south of the trough between 35W-42W, within 120
nm south of the trough and the ITCZ between 46W-49W and south of
the trough from 04N to 07N between 26W-30W. Scattered moderate
convection is within 60 nm of the ITCZ between 49W-53W.

...GULF OF MEXICO...

A stationary front extends from extreme South Florida to near
25N91W. Satellite imagery shows increasing showers and
thunderstorms along and near the stationary frontal boundary. A
trough is over the far eastern Bay of Campeche. Isolated showers
and thunderstorms are near the trough. Moderate northeast winds
are north of the stationary boundary, with mainly gentle winds
elsewhere. Seas are 2-4 ft north of the boundary and 1-2 ft
elsewhere outside of any convection.

For the forecast, the stationary front will slowly dissipate
through this evening. 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 rather relaxed gradient is present over the area. Fresh
northeast to east trade winds and 4-6 ft seas are in the south-
central part of the sea. Light to gentle trade winds and seas of
1-3 ft are in the northwest part of the basin. Gentle monsoonal
winds with seas at 3 to 4 ft exist offshore from Costa Rica and
Panama. Gentle to moderate northeast to east trade winds are over
the rest of the basin, except for fresh to strong trades offshore
northern Colombia and northwest Venezuela. Seas are 4-6 ft there,
and 3-5 ft across the remainder of the waters.

Scattered showers and thunderstorms are confined to the
southwestern Caribbean. Similar activity is along and near the
northeast part of Honduras, also over Haiti and the Windward
Passage.

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 on Hurricane
Nigel.

A stationary front stretches southwestward from 31N72W to
South Florida. Scattered showers and thunderstorms are along
and within 60 nm northwest of the stationary front. Mainly gentle
winds are behind and just north of the front along with seas of
4-6 ft seas. Outside the direct impact of Hurricane Nigel, a
broad area of fresh to strong trade winds is present from 20N-27N
between the coast of Africa and 41W along with 8-11 ft seas per
recent altimeter data. Gentle to moderate trade winds and 5-8 ft
seas are found elsewhere north of 10N and east of 45W, with mainly
gentle winds and 5-7 ft seas across the remainder of the tropical
Atlantic waters.

An area of scattered showers and a few thunderstorms moving
quickly westward is from 18N to 22N and between 30W-36W. This
activity is behind a surface trough that extends from near 20N37W
to 15N35W.

For the forecast W of 55W, Hurricane Nigel is near 29.6N 53.6W at
5 AM EDT, and is moving northwest at 11 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 31.2N 54.5W this afternoon with maximum sustained winds 85
kt gusts 105 kt, then to north of the forecast waters to near
33.8N 54.8W late tonight with maximum sustained winds 90 kt gusts
110 kt. Nigel will then begin to accelerate northeastward and well
away from the area through the rest of the week while weakening.
A weak stationary front extending from near 31N72W to South
Florida will change little 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. Gale-force
northeast to east winds are expected off the southeastern U.S.
coast Fri and Fri night.

$$
Aguirre
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