[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192318
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 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 1800 UTC surface analysis and satellite imagery through
2300 UTC.

...SPECIAL FEATURES...

Tropical Storm Bret has formed in the central Atlantic. Interest
in the Lesser Antilles should monitor this system. At 19/2100
UTC, Bret is centered near 11.3N 42.2W or about 1125 nm E of the
Southern Windward Islands moving W at 18 kt. Estimated minimum
central pressure is 1008 mb. Maximum sustained wind speed is 35
kt with gusts to 45 kt. Satellite imagery continues to show that
the system is becoming better organized, with convective banding
and a dense central overcast. On the forecast track, the system
should be approaching the Lesser Antilles late this week. Bret is
forecast to strengthen and move across the Lesser Antilles as a
hurricane on Thursday and Friday, bringing a risk of flooding
from heavy rainfall, hurricane-force 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.

A tropical wave (AL93) located several hundred miles south-
southwest of the Cabo Verde Islands continues to produce a large
area of disorganized showers and thunderstorms. Its axis is along
29W S of 15N moving W at 10 to 15 kt. A 1012 mb low pressure is
analyzed along the wave axis near 08.5N29W. A cluster of moderate
convection is within about 150 nm NW quadrant of low center.
Another cluster of moderate to strong convection is to the W
covering the area from 08N to 11N between 32W-34W. Environmental
conditions appear favorable for further development of this
system, and a tropical depression could form in a couple of days
while the system moves westward across the eastern and central
tropical Atlantic. The latest Tropical Weather Outlook gives this
system a medium chance of tropical cyclone formation in the next
48 hours, as well as over the next seven days. Refer to the
latest NHC Tropical Weather Outlook at www.hurricanes.gov for
more details.

...TROPICAL WAVES...

A tropical wave is along 51W S of 16N moving W at 10-15 kt. A small
area of moderate convection is near the northern end of the wave
axis.

A tropical wave is along 74W/75W S of 15N, extending inland across
western Colombia and moving W at 10-15 kt. Currently, no significant
convection is occurring near this wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 16N16W to
1012 mb low pressure located near 08.5N29W to 10N36W. No ITCZ is
currently present. Aside from the convection associated with the
tropical waves and Tropical Storm Bret, no significant convection
is noted.

GULF OF MEXICO...

The Atlantic ridge extends across Florida into the Gulf waters.
The pressure gradient between the ridge and lower pressure inland
Mexico supports moderate to fresh southerly winds across the
western half of the Gulf, and a gentle to moderate anticyclonic
flow across the eastern half of the Gulf. Seas are generally 3-5
ft W of 85W and 1-3 ft elsewhere. A short-wave trough is helping
to induce showers and thunderstorms over South Florida. A diffluent
pattern aloft is also enhancing convection along the coastal
waters between Alabama and the Florida Big Bend. 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 medium concentration.

For the forecast, high pressure extending from the Straits of
Florida to the upper Texas coast will generally persist through
the week. 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 most recent satellite derived wind data provide observations
of fresh to strong trade winds across the south-central Caribbean.
Seas are 8-9 ft within these winds. Seas of 6-8 ft dominate the
waters from 10N-17N between 70W-82W. Moderate to fresh winds are
noted in the Gulf of Honduras with seas of 3-5 ft. Gentle to
moderate winds prevail elsewhere except in the lee of Cuba where
light to gentle winds are seen. Showers and thunderstorms have
flared-up over northern Nicaragua and NE Honduras and regional
waters. A surface trough is noted across this area along 84W.
Similar convective activity is also noted over parts of the
Greater Antilles.

For the forecast, 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. Recently upgraded
Tropical Storm Bret will move to 11.7N 44.8W Tue morning, 12.2N
47.7W Tue afternoon, 12.7N 50.3W Wed morning, strengthen to a
hurricane near 13.2N 52.9W Wed afternoon, 13.7N 55.5W Thu
morning, and 14.3N 58.3W Thu afternoon. Bret will change little
in intensity as it moves to 15.5N 63.6W Fri afternoon.

ATLANTIC OCEAN...

Please refer to the Special Features section for information on
Tropical Storm Bret.

A surface trough is an analyzed E of Florida and runs from 31N75W
to South Florida near 25N81W. gentle to moderate winds are on
either side of the trough. Showers and thunderstorms have developed
over South Florida under a southwesterly flow ahead of a mid-upper
level trough extending across the eastern CONUS. This convective
activity is also affecting the NW Bahamas. The Bermuda-Azores
high dominates the remainder of the Atlantic forecast waters with
a 1027 mb high center near 32N48W. The pressure gradient between
the high pressure and T.S. Bret is resulting in an area of fresh
NE winds roughly from 14N-23N between 40W and 50W. Gentle to
moderate anticyclonic flow is noted elsewhere with light to
gentle winds near the high pressure center. Outside of Bret, and
E of 70W, seas are generally 4-6 ft, and 2-4 ft W of 70W and E
of the Bahamas.

For the forecast W of 55W, the Bermuda high will continue to
dominate the forecast are 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. Recently upgraded Tropical Storm Bret will
move to 11.7N 44.8W Tue morning, 12.2N 47.7W Tue afternoon, 12.7N
50.3W Wed morning, strengthen to a hurricane near 13.2N 52.9W
Wed afternoon, 13.7N 55.5W Thu morning, and 14.3N 58.3W Thu
afternoon. Bret will change little in intensity as it moves to
15.5N 63.6W Fri afternoon.

$$
GR
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