[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 200842
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Tue Jun 20 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
0730 UTC.

...SPECIAL FEATURES...

Tropical Storm Bret: As of 09 UTC, Tropical Storm Bret is
centered near 11.7N 44.7W at 20/0900 UTC or 980 nm E of the
Southern Windward Islands moving W at 15 kt. Estimated minimum
central pressure is 1008 mb. Maximum sustained wind speed is 35 kt
with gusts to 45 kt. Seas 12 ft or greater extend up to 60 nm in
the N semicircle with peak seas of 13 ft. As Bret interacts with
subtropical high pressure to the north, strong winds and rough
seas in excess of 8 ft reach as far north as 17N. Numerous
moderate with isolated strong convection is observed from 09N to
14N between 41W and 51W. Although Bret remains a well-organized
tropical cyclone on satellite imagery, its overall appearance has
changed little since yesterday evening. The cloud pattern
consists of a developing CDO with some banding features mainly
over the eastern portion of the circulation. On the forecast
track, the system should be approaching the Lesser Antilles by
late this week. Bret is forecast to initially strengthen and then
move across the Lesser Antilles near hurricane intensity on
Thursday and Friday, bringing a risk of flooding from heavy
rainfall, strong winds, and dangerous storm surge and waves.
Given the larger than usual uncertainty in the track forecast, it
is too early to specify the location and magnitude of where these
hazards could occur. However, everyone in the Lesser Antilles,
Puerto Rico, and the Virgin Islands should closely monitor updates
to the forecast for Bret and have their hurricane plan in place.
Please read the latest HIGH SEAS FORECAST issued by National
Hurricane Center at wed-site
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest T.S.
Bret Forecast/Advisory and Public Advisory at www.hurricanes.gov
for more details.

Invest Area (AL93): A tropical wave in the Eastern Atlantic
extends along 31W/32W from 02N to 15N, moving W at around 15 kt.
A 1011 mb low pressure is analyzed along the wave axis near
08.5N31.5W. Winds are currently fresh to locally strong north of
the low-pressure center, generating 5-7 ft seas. Scattered
moderate with isolated strong convection is observed from 04N to
12N between 30W and 39W. Environmental conditions appear favorable
for further development of this system, and a tropical depression
will likely form later this week while the system moves westward
at 10-15 kt across the eastern and central tropical Atlantic.
The current tropical weather outlook assigns a medium (60%)
probability of formation through the next 48 hours, and a high
(70%) probability over the next seven days. Please refer to the
latest Tropical Weather Outlook at www.hurricanes.gov, for more
details.

...TROPICAL WAVES...

An Atlantic tropical wave extends along 56W from near central
Suriname at 01N to 16N, moving west at 20-25 kt. The northern
portion of the wave has passed NDBC buoy 42058, which is currently
reporting 20 kt NE winds and 5 ft seas. Associated convection
remains isolated and weak.

A tropical wave is moving from the central to the western
Caribbean Sea, extending along 78W S of 15N to across eastern
Panama and into the eastern tropical Pacific Ocean, moving west
at around 25 kt. No significant convection is occurring near
this wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 16N16W
to Invest Area 93L near 08.5N31.5W to 10N39W. No ITCZ is
currently present. All significant convection is described in the
Special Features section.

GULF OF MEXICO...

The subtropical Atlantic ridge extends across the Straits of
Florida to the NW Gulf waters. Scattered showers and
thunderstorms are noted in the north-central and NE Gulf,
particularly within 180 nm of the coast. The pressure gradient
between the ridge and lower pressure over Mexico and the southern
US, along with a surface trough located offshore of the western
Yucatan Peninsula is supporting moderate to fresh anticyclonic
winds across the basin, except gentle to moderate in the SE Gulf
through the Straits of Florida. Seas are mainly 3-5 ft per recent
buoy observations, locally higher near the convection, and except
1-3 ft in the SE Gulf. Smoke due to agriculture fires over Mexico
may be reducing visibilities along the coast of Mexico and the
western Bay of Campeche where the latest SAB analysis indicates a
low to medium concentration.

For the forecast, high pressure extending from the Straits of
Florida to the upper Texas coast will generally persist through
the week and into the upcoming weekend. Fresh winds will pulse
north of the Yucatan peninsula each night through the forecast
period as a diurnal trough develops and moves offshore. Elsewhere,
gentle to moderate winds will prevail, locally fresh at times.
Smoke from agricultural fires in Mexico will produce hazy skies
over the central and western Gulf for at least the next day or
two.

CARIBBEAN SEA...

Please refer to the Special Features section for information on
Tropical Storm Bret, which is forecast to approach the Lesser
Antilles late this week.

The gradient between subtropical high pressure and lower
pressure over the SW Caribbean is supporting strong easterly
trade winds in the central Caribbean, where seas are in the 6-10
ft range. Fresh SE winds are noted in the Gulf of Honduras.
Gentle winds are noted in the lee of Cuba and approach to the
Windward Passage, where seas are 1-3 ft. Winds are moderate to
fresh elsewhere, with 3-6 ft seas.

For the forecast, Tropical Storm Bret is currently near 11.7N
44.7W 1008 mb at 5 AM EDT moving W at 15 kt. Maximum sustained
winds 35 kt gusts 45 kt. Bret will move to 12.1N 46.9W this
afternoon, 12.6N 49.7W Wed morning, 13.1N 52.4W Wed afternoon,
strengthen to a hurricane near 13.5N 55.0W Thu morning, 13.9N
57.8W Thu afternoon, and weaken to a tropical storm near 14.3N
60.4W Fri morning. Bret will change little in intensity as it
moves to 15.0N 65.8W early Sat. Otherwise, the pressure gradient
between the Bermuda High and the Colombian Low will support fresh
to strong E trades across the central Caribbean through early Thu.
Moderate to fresh E winds are expected in the Gulf of Honduras.

ATLANTIC OCEAN...

Please refer to the Special Features section for information on
Tropical Storm Bret and Invest Area AL93 located in the eastern
Atlantic Ocean.

An unsettled weather pattern remains over the SW N Atlantic mainly
W of 74W where scattered showers and isolated thunderstorms are
occurring. Additional isolated activity is between 60W and 74W. A
1025 mb high pressure centered near 32N45W is the dominate
feature across the basin. North of 22N, anticyclonic winds are
gentle to moderate with 3-6 ft seas. South of 22N and outside of
the immediate impacts from Tropical Storm Bret, moderate to fresh
NE-E winds and 5-7 ft seas are observed, except for gentle winds S
of 10N and W of 35W with 3-5 ft seas.

For the forecast W of 55W, Tropical Storm Bret is currently near
11.7N 44.7W 1008 mb at 5 AM EDT moving W at 15 kt. Maximum
sustained winds 35 kt gusts 45 kt. Bret will move to 12.1N 46.9W
this afternoon, 12.6N 49.7W Wed morning, 13.1N 52.4W Wed
afternoon, strengthen to a hurricane near 13.5N 55.0W Thu morning,
13.9N 57.8W Thu afternoon, and weaken to a tropical storm near
14.3N 60.4W Fri morning. Bret will change little in intensity as
it moves to 15.0N 65.8W early Sat. Otherwise, Bermuda high
pressure extends a ridge SW through the central Bahamas to the SE
Gulf of Mexico, and will continue to dominate through mid-week. A
weak cold front off the SE US coast will linger and gradually
dissipate through the early part of the week with locally fresh
winds E of it tonight. Mainly gentle to moderate anticyclonic
winds will prevail the next several days, locally fresh offshore N
Hispaniola and offshore N Florida.

$$
Lewitsky
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