[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301754
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Wed Jun 30 2021

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 1200 UTC surface analysis and satellite imagery through
1710 UTC.

...SPECIAL FEATURES...

Broad low pressure of 1008 mb located where a tropical wave
intersects the monsoon trough near 09N42W, about midway between
the African coast and the Lesser Antilles is producing scattered
moderate to isolated strong convection from 06N to 10N between 40W
and 48W. Peak winds are near 30 kt and highest seas around 10 ft.
Environmental conditions appear generally favorable for
development, and a tropical depression is likely to form during
the next few days while the system moves WNW at 15 to 20 kt.
Interests in the Windward and Leeward Islands should closely
monitor this system as it will likely be moving through that
region on Friday. Please read the latest Tropical Weather Outlook
at www.hurricanes.gov, for more information.

...TROPICAL WAVES...

An Atlantic tropical wave is along 27W from 12N southward and
moving W near 15 kt. Scattered moderate convection is seen from
the Equator to 08N between 21W and 33W. The wave has a weak trough
noted at the surface.

Another Atlantic tropical wave is near 41W from 17N southward and
moving W at 15 to 20 kt. Please see Special Features section above
for more information on convection and the potential for this
wave to develop into a tropical cyclone.

A third Atlantic tropical wave is along 58W from 18N southward and
moving W at 20 to 25 kt. Scattered moderate to isolated strong
convection is found from 10N to 18N between 58W and 65W over the
Lesser Antilles. The tropical wave displays a sharp trough at the
surface. Significant development of this system is unlikely while
it moves quickly west. This wave will pass through the Lesser
Antilles this evening and then across the eastern and central
Caribbean Sea over the next few days. Regardless of development,
this system could bring locally heavy rainfall to the Lesser
Antilles, especially the Windward Islands during the next couple
of days.

A Caribbean tropical wave is over eastern Cuba and the central
Caribbean and moving W near 10 kt. Scattered showers and isolated
thunderstorms are present near the Windward Passage. The tropical
wave is only identifiable from GFS- and ECMWF-based 700 mb trough
diagnositics.

Another Caribbean tropical wave is near the western end of Cuba
and the western Caribbean, moving W at 5 to 10 kt. Scattered
moderate to isolated strong convection is noted near the Yucatan
Channel and basin. The tropical wave is only identifiable from
GFS- and ECMWF-based 700 mb trough diagnositics.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 17N16W
to 08N29W to a low pressure near 08N41W to 06N44W. The ITCZ then
continues from 06N47W to near the Suriname/Brazil border. All
convection in the vicinity of these features is related to
tropical waves described in the sections above.

GULF OF MEXICO...

An upper-level trough curves S from the Florida panhandle to near
the Yucatan Peninsula. Scattered showers and isolated
thunderstorms are occurring over the eastern Gulf. A 1011 mb low
pressure system is located at the Bay of Campeche near
19N94W. Aided by divergent flow W of the upper low, Numerous
moderate to strong convection is flaring up over the Bay of
Campeche within 80 nm of 20N94W. Scattered moderate to isolated
strong convection is evident farther N from 21N to 25N between
94W and the Mexican coast. Gentle to moderate E to SE winds and
seas of 2 to 4 ft are found across the Gulf. Locally fresh winds
and seas up to 5 ft are expected in areas of strong convection.

For the forecast, a ridge will dominate the Gulf waters over the
next several days producing mainly moderate E to SE winds. Fresh
east to southeast winds are expected at night near the western
Yucatan Peninsula through Fri due to local effects induced by a
thermal trough. Another trough will persist over the SW Gulf over
the next several days producing showers and thunderstorms. Winds
and seas may be higher near thunderstorms.

CARIBBEAN SEA...

See Tropical Wave section above for details on convection near the
Lesser Antilles.

Strong to near gale E trades are present over the S central and SW
Caribbean this morning. Seas are from 8-13 ft. Gentle to moderate
trade winds and seas of 3 to 5 ft prevail across the eastern
basin. While moderate to fresh trades and seas of 6 to 9 ft are
seen across the northwestern basin.

For the forecast, a tropical wave located just east of the Lesser
Antilles is quickly moving west to west-northwestward. It will
pass through the Lesser Antilles today, then across the eastern
and central Caribbean Sea later this week. Locally heavy rain from
disorganized showers and thunderstorms can be expected over
portions of the Lesser Antilles during the next day or two.
Farther east, a broad low pressure associated with a tropical wave
midway between the west coast of Africa and the Windward Islands
is producing a large area of showers and thunderstorms that
continue to show some signs of organization. Conditions appear
favorable for development and a tropical depression is likely to
form during the next few days while the system moves WNW at 17 kt.
The system will likely move through the Windward and Leeward
islands on Fri.

ATLANTIC OCEAN...

See Tropical Wave section above for details on convection across
the tropical Atlantic Basin.

An upper-level trough reaches WSW from a low near Bermuda at
32N64W to near the Bahamas at 28N72W, then turns WNW to N Florida.
Scattered showers are found north of 29N from 58W to 63W.
Divergent flow south of these upper features is triggering scattered
showers and thunderstorms from the Bahamas northwestward to
Florida. Otherwise, a surface ridge extending WSW from a 1025 mb
high near 28N48W dominates the mid Atlantic Basin. Gentle winds
and seas of 3 to 5 ft are N of 23N, while moderate to fresh E winds
and seas of 6 to 8 ft are present from 06N to 23N. Gentle to
moderate E winds and seas of 4 to 6 ft are seen elsewhere.

For the forecast W of 65W, the Atlantic ridge will build westward
and dominate the forecast waters the remainder of the week. Fresh
to strong winds are expected just north of Hispaniola Thu night
through Sun night due to the pressure gradient between the
Atlantic ridge and a couple of tropical wave passages over the
Caribbean Sea.

$$

Chan/Landsea
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