[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 212355
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Thu Jun 22 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: Tropical Storm Bret is centered near
13.4N 54.6W at 22/0000 UTC or 285 nm E of Barbados, moving W at
13 kt. Estimated minimum central pressure is 1000 mb. Maximum
sustained wind speed is 55 kt with gusts to 65 kt. Seas 12 ft or
greater are observed within 120 NM NE quadrant, 60 NM SE
quadrant, 30 NM SW quadrant, and 90 NM NW quadrant with seas to
16 ft. On the forecast track, the center of Bret is expected to
approach the Lesser Antilles on Thursday, move across the Lesser
Antilles late Thursday and Thursday night, and then move westward
across the eastern and central Caribbean Sea Friday and Saturday.
Little change in strength is forecast during the next day
or so while Bret approaches the Lesser Antilles.  Weakening is
anticipated to begin Thursday night or Friday after Bret passes the
Lesser Antilles, and the system is likely to dissipate over the
central Caribbean Sea by Saturday. Bret is forecast to move
across the Lesser Antilles as a strong tropical storm, bringing a
risk of flooding from heavy rainfall, strong winds, and
dangerous waves along the coast. Given the uncertainty in the
track and intensity forecasts, it is still too early to specify
the exact location and magnitude of where Bret's associated
hazards could occur. Through Saturday, storm total rainfall
amounts of 3 to 6 inches with maximum amounts of 10 inches are
possible across portions of the Lesser Antilles from Guadeloupe
south to St. Vincent and the Grenadines, including Barbados. The
heavy rainfall could lead to flash flooding, especially across
areas of higher terrain. Urban flooding is also possible. Swells
generated by Bret are expected to begin affecting portions of the
Lesser Antilles on Thursday. These swells are likely to cause
life-threatening surf and rip current conditions.

Please read the latest HIGH SEAS FORECAST issued by National
Hurricane Center at website
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): Recent satellite-derived wind data indicate
the area of low pressure located about midway between the west
coast of Africa and the Lesser Antilles has an elongated surface
circulation with maximum sustained winds of about 30 mph. This
area of low pressure is along a tropical wave with axis near 39W.
Showers and thunderstorms continue to show signs of organization,
and environmental conditions appear conducive for further development.
Therefore, a tropical depression will likely form during the next
day or so while the system moves westward to west-northwestward
at 10 to 15 kt across the central tropical Atlantic through the
early part of the weekend. The latest Tropical Weather Outlook
gives this system a high 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 new tropical emerged off the coast of west Africa. Its axis is
along 17W south of 14N moving W at 5 to 10 kt. Scattered moderate
convection is noted near the wave axis while a cluster of moderate
to isolated strong convection is ahead of the wave affecting the
waters from 08N to 11.5N between 21W and 25W.

A tropical wave is over the eastern Caribbean with axis along
63W/64W and extends into eastern Venezuela. This system is moving
W at 10 to 15 kt. The wave is helping to induce scattered
showers with embedded thunderstorms across the waters between the
Lesser Antilles and 68W.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near the city
of Banjul in Gambia, through Invest Area AL93 to 10N43W. No ITCZ
is currently present in the Atlantic. Scattered moderate
convection is depicted from 11N-13N between 30W and 36W.

...GULF OF MEXICO...

Numerous showers and thunderstorms are noted over the NE Gulf and
across most of the Florida Peninsula ahead of a frontal boundary
that extends over the the SE of US. Similar convective activity
is also flare-up over the north-central Gulf and SE Louisiana. This
unsettled weather is associated with an upper-level low spinning
over the SE CONUS. Elsewhere, the Atlantic ridge extends across
Florida into the Gulf waters. The pressure gradient between the
ridge and lower pressure inland Mexico supports moderate to
locally fresh southerly winds across the western the Gulf S of
26N while gentle to moderate anticyclonic flow prevail elsewhere
across the Gulf waters. Stronger winds are noted near the
convective activity over the NE Gulf. Seas are generally 4-6 ft
based on altimeter data, except 1-3 ft over the SE Gulf.

For the forecast, high pressure extending from the Straits of
Florida to the upper Texas coast will change little through Thu
night, then lift N through the 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. A
nearly stationary trough over the NE Gulf waters will continue
to bring scattered thunderstorms to those waters through Thu.
Smoke from agricultural fires in Mexico will continue to result
in haze over sections of the far western Gulf through at least
the next couple of days.

...CARIBBEAN SEA...

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

The most recent satellite derived wind data provide observations
of fresh to strong trade winds across the central Caribbean.
Seas are 8-10 ft within these winds based on altimeter data.
Moderate to fresh trades dominate the eastern Caribbean with seas
of 4-6 ft. Moderate to locally fresh E 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. Numerous showers and thunderstorms are
noted over Central America, but mainly from Costa Rica to
Guatemala. Convection is on increase over the NW Caribbean. A
diffluent pattern aloft is helping to induce this convective
activity. Scattered showers and thunderstorms are over the
Greater Antilles.

For the forecast, Tropical Storm Bret will maintain intensity as
it moves to near 13.5N 54.8W late tonight, to near 13.8N 58.5W
early Thu afternoon and track west-northwest to near 14.2N 61.7W
by late Thu night as it begins to weaken. Bret is forecast to
reach near 14.5N 65.2W by early Fri afternoon, to near 14.7N
68.7W by late Fri night with maximum sustained winds 45 kt gusts
55 kt, then to near 14.9N 72.2W by early Sat afternoon and
dissipate by early Sun afternoon. The remnant trough will
continue westward to the western Caribbean into early next week
accompanied by fresh east to southeast winds. Low pressure that
is currently over the eastern Atlantic may move across the
tropical N Atlantic waters this weekend as a possible tropical
cyclone. Otherwise, the pressure gradient between the Bermuda
High and the Colombian Low will support fresh to strong trade
winds across the central Caribbean through late Fri night.
Moderate to fresh E to SE winds in the Gulf of Honduras will
continue through early Thu, then increase to fresh to strong,
reaching near gale Thu night and diminish back to fresh to strong
Fri into early Sat.

...ATLANTIC OCEAN...

Please refer to the Special Features section for information on
Tropical Storm Bret and Invest Area AL93.

Broad high pressure dominates the entire Atlantic forecast waters
with a 1021 mb center located near 30N52W. A band of multi-layer
clouds, with embedded showers and isolated thunderstorms extends
across Cuba and the Bahamas toward the NE to near Bermuda. These
clouds are ahead of an upper-level trough extending over the
eastern Gulf and the far NW Caribbean. Moderate to fresh southerly
winds are depicted per scatterometer data north of 29N between
79W and the coast of Florida with seas and seas of 4 to 6 ft.
Gentle to moderate anticyclonic winds and 3 to 5 ft are noted
under the influence of the ridge N of 20N. Winds increase to
moderate to fresh between the southern periphery of the ridge
and the tropical systems over the tropical Atlantic. Moderate to
fresh E to SE winds are also noted N of Hispaniola to about 23N.
Seas of 5-7 ft dominates most of the waters S of 20N outside of
Bret.

For the forecast W of 55W, broad high pressure ridging extending
southwest across the area will continue to control the weather
regime during the rest of the forecast period. Fresh to locally
strong southwest winds offshore NE Florida will diminish by early
Fri. Otherwise, mainly gentle to moderate anticyclonic winds
will prevail the next several days, locally fresh offshore N
Hispaniola and offshore N Florida. Low pressure that is currently
over the eastern Atlantic may move across the tropical N
Atlantic waters this weekend as a possible tropical cyclone.

$$
GR
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