[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041020
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Mon Sep 4 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
1000 UTC.

...SPECIAL FEATURES...

Tropical Storm Gert is centered near 37.6N 51.0W at 04/0900 UTC
or 750 nm ENE of Bermuda, moving N at 21 kt. Estimated minimum
central pressure is 1000 mb. Maximum sustained wind speed is 45 kt
with gusts to 55 kt. A small area of disorganized deep convection
has been persisting to the southeast of the center. Gert will
likely be absorbed by Post-Tropical Cyclone Idalia later today. A
faster north-northwestward to northwestward motion is expected
today while Gert moves around Idalia with little change in
strength. 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 Gert
NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov
for more details.

Tropical Depression Katia is centered near 27.7N 33.7W at 04/0900
UTC or 890 nm NW of the Cabo Verde Islands, moving NW at 6 kt.
Estimated minimum central pressure is 1008 mb. Maximum sustained
wind speed is 30 kt with gusts to 40 kt. The system is producing
a few puffs of deep convection over the northern portion of its
circulation. Weakening is forecast, and Katia is expected to become
a remnant low later today or tonight, and dissipate in a few
days. A generally northwestward motion is expected today, followed
by a slow southeastward to south-southeastward motion on Tuesday
and Wednesday. Seas to 12 ft are still noted within about 90 nm N
semicircle of center. 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 Katia
NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov
for more details.

Tropical Atlantic (AL95):
Showers and thunderstorms continue to show signs of organization
in association with a tropical wave located several hundred miles
southwest of the Cabo Verde Islands. Environmental conditions are
forecast to be conducive for further development, and this system
is expected to become a tropical depression in two or three days.
Additional strengthening is likely late this week while the system
moves westward to west-northwestward at 15 to 20 mph over the
central and western portions of the tropical Atlantic. This system
has a medium chance of tropical cyclone formation through 48
hours, and a high chance through 7 days. Please refer to the
latest NHC Tropical Weather Outlook at www.hurricanes.gov for
more details.

Atlantic Swell Event: rough seas generated by the remnant low of
Idalia and Tropical Storm Gert continue to propagate across the
Atlantic forecast waters mainly N of 25N between 45W and 74W.
Currently, seas are in the 8 to 12 ft range in northerly swell,
with the highest seas affecting the waters N of 29N between 55W
and 65W. This swell event will continue to subside through mid-
week.

...TROPICAL WAVES...

Looking ahead, a tropical wave is forecast to move off the African
coast in a couple of days. Environmental conditions could support
some slow development starting midweek while the wave moves to
the west-northwest at 10 to 15 kt over the far eastern tropical
Atlantic. This system has a low chance of tropical cyclone formation
through 7 days. Please refer to the latest NHC Tropical Weather
Outlook at www.hurricanes.gov for more details.

A tropical wave is along 31W moving west at 10 to 15 kt. A 1010 mb
low pressure (AL95) is analyzed along the wave axis near 11N. See
the Special Features section for more details.

A tropical wave is moving across the central Caribbean at 5 to 10
kt. Its axis is along 71W and extends from Hispaniola to western
Venezuela. The wave appears to enhance convection over Hispaniola
and regional waters as well as over western Venezuela and northern
Colombia.

Another tropical wave is over Central America with axis along 84W
moving W at 10 to 15 kt. Scattered showers and isolated thunderstorms
are noted along the wave axis, particularly over the eastern plains
of Nicaragua.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic through the coast of
Mauritania and continues SW to a 1010 mb low located near 11N31W
to 11.5N50W. The ITCZ extends from 11.5N50W to 10N60W. Aside from
the convection already mentioned in the Tropical Waves section,
scattered moderate convection can be found from 05N to 09N between
12W and 20W, within about 90 nm N of the monsoon trough/ITCZ
between 43W and 52W, and from 09N to 11N between 52W and 59W.

...GULF OF MEXICO...

High pressure of 1018 mb located over the SE CONUS dominates the
Gulf region. A weakening stationary front extends from western
Cuba to SE Louisiana. A few showers are along the frontal boundary.
Recent scatterometer data indicate gentle to moderate E to SE
winds across most of the Gulf waters, with the exception of
moderate to fresh winds across the offshore waters of W Florida
and in the Straits of Florida. Seas are 4 to 6 ft in the Straits
of Florida, 3 to 4 ft over the eastern Gulf and the E and central
Bay of Campeche, and 1 to 3 ft elsewhere.

For the forecast, high pressure over the SE CONUS will support
gentle to moderate E to SE winds across most of the basin through
mid-week. Afterward, a weak pressure gradient will result in
light to gentle winds and slight seas the remainder of the
forecast period, with the exception of gentle to moderate winds
just W of the Yucatan Peninsula.

...CARIBBEAN SEA...

Two tropical waves are moving westward across the basin. Please
refer to the Tropical Waves section for more details. Satellite
derived wind data provide observations of moderate to fresh trade
winds in the wake of the tropical wave located along 71W. Gentle
to moderate winds prevail elsewhere. Seas are generally 3 to 5 ft
E of 72W, 3 to 4 ft in the NW Caribbean, and 1 to 3 ft elsewhere.
Seas of 5 to 6 ft, in northerly swell, are seen in the Caribbean
passages E of La Mona Passage.

For the forecast, moderate to fresh trade winds and moderate seas
will continue in the central and eastern Caribbean the entire
forecast period, except for developing fresh to strong winds in
the south- central waters Tue night into Wed. Gentle to locally
moderate winds and slight seas will prevail elsewhere.

...ATLANTIC OCEAN...

Please read the Special Features section for details about T.S.
Gert, T.D. Katia, Invest AL95 and the Atlantic swell event.

A weakening cold front, attached to the remnant low of Idalia,
extends from 31N52W to eastern Cuba. A few showers and isolated
thunderstorms are along the frontal boundary. Fresh winds are on
either side of the front mainly N of 29N. A weak ridge is noted
between the Canary Islands and T.D. Katia. An upper-level low
spinning near 28N42W is generating an area of showers with isolated
thunderstorms ahead of the above mentioned front, mainly N of 23N
between 44W and 52W.

For the forecast west of 55W, the front will move eastward over the
next couple of days while dissipating. The swell event will gradual
subside through mid-week.

$$
GR
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