[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040556
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 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 0000 UTC surface analysis and satellite imagery through
0545 UTC.

...SPECIAL FEATURES...

Tropical Storm Gert is centered near 35.4N 50.7W at 04/0300 UTC
or 730 nm ENE of Bermuda, moving N at 19 kt. Estimated minimum
central pressure is 1000 mb. Maximum sustained wind speed is 45
kt with gusts to 55 kt. Scattered moderate convection is evident
mainly in the southern semicircle within 80 nm of the center of
Gert, while the center partially exposed. Seas 12 ft or greater
are noted within 150 nm in the southeast semicircle of the
center, and within 60 nm of the northwest semicircle. A faster
northward to north-northwestward motion is expected on Monday
while Gert moves around Post-Tropical Cyclone Idalia. Little
change in strength is forecast before Gert dissipates on Monday.
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 27.1N 33.4W at
04/0300 UTC or 850 nm NW of the Cabo Verde Islands, moving WNW
at 5 kt. Estimated minimum central pressure is 1007 mb. Maximum
sustained wind speed is 30 kt with gusts to 40 kt. The
depression is moving slowly west-northwestward.  A slow west-
northwestward to northwestward motion is expected for about
another day before the system reverses course and drifts
southeastward. West-southwesterly vertical wind shear and dry
air should continue to weaken Katia, and this system will likely
become a remnant low in 12 to 24 hours.  Dissipation is expected
in 3 to 4 days. 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.

Invest 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 kt over the central and western portions of the tropical
Atlantic. The chance of formation into a tropical cyclone during
the next 49 hours is medium, but high through the next seven
days. Please refer to the website: www.hurricanes.gov for more
details.

Large swell event: Large northerly swell with wave heights of 8
to 12 ft and 12 second periods persists over the western
Atlantic north of 24N and west of 45W. This swell is the result
of earlier winds associated with Idalia and Gert, and it may
cause rough surf near the Bahamas this evening. The swell will
decay through Mon.

...TROPICAL WAVES...

An Atlantic tropical wave is along 29.9W from 03N to 18N, moving
west at 15 kt. The Invest AL95 low pressure is centered along the
tropical wave where it intersects the monsoon trough 10.7N29.9W
with a pressure of 1010 mb. Scattered moderate convection is
depicted from 07N to 15N between 27W and 35W

A Caribbean Sea tropical wave was relocated based on satellite
imagery and now is near 71W, from 19N southward, moving westward
5 to 10 kt. No significant convection is evident near the wave
axis over the waters at this time. However, convection is
depicted over Puerto Rico and Dominican Republic and their
coastal waters.

A Caribbean Sea tropical wave is near 85W, from 19N southward,
moving westward 10 knots to 15 knots. Scattered moderate
convection is depicted near the wave axis south of 19N.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from 14N17W to the 1010 mb low
pressure near 10.7N29.9W to 13N41W. The ITCZ continues from
13N41W to 11N48W to 10N55W. Aside from the convection already
mentioned in the TROPICAL WAVE section, scattered moderate
convection is depicted  from 08N to 14N between 45W and 55W.

The eastern portion of the East Pacific Monsoon Trough is
producing scattered moderate convection in the offshore waters
of Nicaragua and Costa Rica.

...GULF OF MEXICO...

A weak stationary cold front extends from western Cuba to
southeast Louisiana/Alabama border. Isolated moderate convection
is depicted in the central Gulf in association with this front.
An area of similar convection is depicted drifting westward into
the Bay of Campeche from the Yucatan Peninsula. This area of
convection is associated with a surface trough. Moderate winds
and 2 to 4 ft are noted east of the front, and gentle to
moderate with 1 to 3 ft seas are evident elsewhere.

For the forecast, high pressure over the SE CONUS will support
gentle to moderate E to SE winds across the basin N of 22N
through mid- week. Dissipating high pressure will lead to a
weaker pressure gradient afterward, thus resulting in light to
gentle variable winds the remainder forecast period.

...CARIBBEAN SEA...

Please refer to the TROPICAL WAVES and MONSOON TROUGH/ITCZ
sections above for information on convection in the Caribbean
Sea. Moderate to fresh SE winds and 4 to 6 ft seas are evident
over the eastern Caribbean following the tropical wave over the
central part of the basin. Gentle winds and 1 to 3 ft are noted
elsewhere.

For the forecast, moderate to fresh trade winds 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 will
prevail elsewhere. Seas will be moderate in the eastern half of
the basin and slight elsewhere.

...ATLANTIC OCEAN...

Please read the SPECIAL FEATURES section for details about T.S.
Gert, T.D. Katia, Invest AL95 and the large swell over the
western Atlantic. For convection in the tropical Atlantic,
please read the MONSOON TROUGH/ITCZ section above. In addition,
an area of isolated moderate convection is depicted near 25N and
49W.

Along with the immediate winds and seas related to Gert, the
remnant low of Idalia is still causing fresh to strong SW to W
winds and rough seas south and southwest of Bermuda, as far south
as 28N. An associated cold front reaches from 31N54W to eastern
Cuba. No significant convection is depicted in association with
the front. Gentle to moderate breezes and 4 to 6 ft seas are
noted elsewhere across the basin.

For the forecast west of 55W, the aforementioned cold front,
attached to the remnant low of Idalia, extends 31N54W to eastern
Cuba. Fresh to strong winds are on either side of the front
mainly N of 29N. Rough seas generated by the remnant low of
Idalia continues to affect the NE waters. These seas will
gradual subside through mid-week. The front will move eastward
over the next couple of days while dissipating.

$$
KRV
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