[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 302215
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
315 PM PDT Tue Jun 30 2020

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 32N. 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.

...TROPICAL WAVES...

A tropical wave is added to the 1800 UTC surface map along 25W/26W.
The Hovmoller Diagram clearly shows the westward propagation of
the wave, and it is also well depicted in the tropical wave
diagnostics. A cluster of moderate to isolated strong convection
is noted from 06N-10N between 20W-25W.

A low amplitude tropical wave is along 46W S of 11N, moving
westward at around 15-20 kt. The tropical wave was repositioned
westward today. Scattered moderate and isolated strong convection
is present from 05N-08N between 40W-46W.

A tropical wave is over the eastern Caribbean and eastern
Venezuela along 63W. The northern end of the wave has broken off
and now is analyzed as a surface trough over the Atlantic
waters. It extends from 23N52W to 14N55W. The wave is well-defined
at the surface based on scatterometer passes from this morning.
The wave is helping to induce some convective activity over the
Windward Islands and Venezuela.

A tropical wave extends in the central Caribbean from 20N
southward near 75W, moving westward around 15-20 kt. Weak
troughing is evident at the surface with this wave north of 15N
from scatterometer and station data. No significant deep
convection is evident in association with the wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from inland in Mauritania near 18N16W
to 10N20W to 08N27W. The ITCZ continues from 08N27W to 06N40W to
05N52W. Aside from the convection associated with the tropical
waves, scattered moderate convection is noted from 03N-08N
between 47W-51W.

GULF OF MEXICO...

During the summer, the Gulf of Mexico and the Caribbean Sea are
dominated by the Bermuda-Azores High, which is at its westernmost
position. Circulation around the high results in southerly winds
over the Gulf of Mexico and easterly winds over the Caribbean.
Today, this high pressure is located near 35N43W and extends a
ridge westward across Florida into the Gulf of Mexico. A 1018 mb
high pressure cell is over the NE Gulf. Under this pattern,
moderate to fresh SE to S winds are expected over the western
Gulf, with light to gentle winds over the eastern Gulf.

No significant convection is occurring today over the Gulf. Some
Saharan Air Layer/African dust continues to be advected into the
W Gulf and it is somewhat reducing visibility.

High pressure over the eastern Gulf will gradually drift southward
through Fri, then persist across the central Gulf through this
weekend. Moderate to fresh return flow over the western Gulf will
diminish late this week. Saharan dust will produce hazy conditions
over portions of the central and western Gulf through at least
Wed.

CARIBBEAN SEA...

Refer to the section above for details on the two tropical waves
moving across the basin.

A moderate high pressure ridge extends west-northwest to east-
southeast over the Bahamas. The resulting pressure gradient is
causing generally moderate to fresh E trades this morning, except
for strong ENE trades just north of Colombia as observed by
scatterometer this morning. The S half of the Caribbean is
covered by a moderate Saharan Air Layer/African Dust event, though
visibilities are only slightly inhibited. Aside from some
convection in the SW Caribbean in connection with a tropical wave
and the NE Pacific monsoon trough, only the S Windward Islands are
experiencing scattered showers.

High pressure persisting north of the region will maintain fresh
to strong trades in the south-central Caribbean through the
upcoming weekend. Elsewhere, gentle to moderate trades will
prevail for the next several days.

ATLANTIC OCEAN...

Refer to the section above for details on the tropical waves
moving across the area.

The 1030 mb Bermuda-Azores High is located near 36N41W with a
ridge extending westward over the Bahamas. The trades south of
the ridge are generally gentle to moderate with some fresh NE
trades from 05N-20N between 30W-45W. W winds north of the ridge
off of the SE United States coast are moderate to fresh. Some African
dust still remains north of 25N west of 70W. A second Saharan Air
Layer/African dust region extends from around 07N-25N between
West African and 60W. This region has some reductions in
visibility because of the dust.

A high pressure ridge will prevail across the central waters
through late this week. A low pressure trough will linger off the
SE U.S. coast through Thu. A weak cold front may move into the
northern waters and stall late Fri through Sat.

$$
GR
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