[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 300409
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 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 0000 UTC surface analysis and satellite imagery through
0400 UTC.

...SPECIAL FEATURES...

Low pressure of 1009 mb has developed where a tropical wave
intersects the monsoon trough, near 08N37.5W. Scattered moderate
isolated strong convection is noted from 03N to 10N between 35W
and 45W. Environmental conditions appear generally favorable for
development, and a tropical depression could form during the next
few days while the system moves west-northwestward at about 20
mph. 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...

The axis of a tropical wave is near 37W/38W from 19N southward,
moving W at 15 to 20 kt. Scattered moderate and isolated strong
convection is noted from 03N to 10N between 35W and 45W. Scattered
moderate convection is noted from 00N to 12N between 33W and 46W.
Low pressure is centered where the wave intersects the monsoon
trough, near 08N37.5W. Please see Special Features section above
for more information on the potential for this low to develop into
a tropical cyclone.

The axis of a tropical wave is near 52W/53W from 19N southward,
moving W at around 20 kt. Scattered moderate isolated strong
convection is noted from 12N to 15N between 52W and 56W. A 1011 mb
surface low is analyzed along the tropical wave near 13N52.5W.
There is a low probability that this low will develop into a
tropical cyclone. Development, if any, of this system should be
slow to occur as the tropical wave moves quickly westward to west-
northwestward at 20 to 25 mph, passing through the Lesser
Antilles on Wednesday and then across the eastern and central
Caribbean Sea later this week. Regardless of development, this
system could bring locally heavy rainfall to portions of the
Lesser Antilles during the next couple of days.

The axis of a tropical wave is near 73/74W south of Haiti. There
is no significant convection associated to this wave.

The tropical wave previously analyzed near 85W has been
repositioned to near 82W, south of Cuba. Scattered moderate
convection is along the wave axis.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 15N17W
to 12N20W to low pres near 08N37.5W to 08N47W. Aside from
convection noted in the tropical waves section, scattered moderate
isolated strong convection is noted from 00N to 07N between 22W
and 30W.

GULF OF MEXICO...

An upper-level trough extends from the Florida panhandle to near
the Yucatan Peninsula. Upper level divergence east of the trough
axis is helping generate scattered moderate and isolated strong
convection over the eastern Gulf. The latest scatterometer pass
indicates moderate to locally fresh winds just north and west of
the Yucatan Peninsula, with gentle to moderate winds elsewhere.
Seas are in the 4-7 ft range over the western half of the Gulf and
2-4 ft over the eastern half of the Gulf.

For the forecast, a ridge will dominate the Gulf waters over the
next several days producing mainly moderate E to SE winds. Fresh E
to SE fresh 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
2 or 3 days producing showers and thunderstorms. Winds and seas
could be higher near thunderstorms.

CARIBBEAN SEA...

High pressure prevails north of the area. The pressure gradient
between this area of high pressure and climatological low pressure
over Colombia is supporting fresh to strong winds over the central
Caribbean. Fresh to strong winds are also noted over the Gulf of
Honduras. Moderate to fresh winds prevail elsewhere. Seas are in
the 7-10 ft range over the central Caribbean, highest just north
of Colombia. Seas are in the 6-8 ft range over the NW Caribbean,
and 4-6 ft elsewhere.

For the forecast, low pressure along a tropical wave a few
hundred miles E of the Lesser Antilles has the potential for slow
development as the wave moves quickly W to WNW at 20 to 25 kt,
passing near the Lesser Antilles Wed then across the eastern and
central Caribbean later this week. Heavy rain is possible in the
Lesser Antilles over the next couple of days, regardless of
development. Broad low pressure has formed in association with a
tropical wave midway between the west coast of Africa and the
Windward Islands. Gradually development of this system is also
possible over the next few days and the system is showing signs of
organization.

ATLANTIC OCEAN...

Ridging dominates the waters west of 65W with moderate to locally
fresh E-SE flow. Seas are 3 to 5 ft across this area east of the
Bahamas. Scattered showers and thunderstorms are occurring west of
76W/77W, as well as from 20N to 27N between 65W and 71W due to
mid-upper level divergence.

To the east, a stationary front extends from 31N35W to 28N54W to
30N58W. Isolated showers are possible near this feature. High
pressure ridging prevails both north of and south of the front.
Light to moderate anticyclonic winds prevail north of 25N and east
of 65W, along with mainly 3 to 5 ft seas. Moderate to locally
fresh trades are south of 25N and north of the convergence zone,
except fresh to strong from 12N to 16N between 48W and 54W near a
vigorous tropical wave and attendant low pressure area. Seas are
mainly 5 to 7 ft across this area, except 7 to 9 ft near the area
of fresh to strong winds. Fresh to strong N-NE winds are also
noted west of the coast of Africa to 20W, north of 19N due to a
locally tight pressure gradient, where seas are 6 to 9 ft.

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 N 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.

$$
AL
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