[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 031030
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
630 AM EDT Wed Jul 3 2019

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 0600 UTC surface analysis and satellite imagery through
1115 UTC.

...TROPICAL WAVES...

A far eastern Atlantic tropical wave with axis along 27W/28W from
04N-20N is moving westward at 10-15 kt. Satellite imagery shows
an apparent northern mid-level vorticity on the wave near 14N26W.
The latest TPW imagery animation continues to depict increasing
moisture east of the wave's axis in an inverted-V shape. However
since the wave is moving through stable environment, the observed
moisture is rather capped allowing for only isolated showers and
thunderstorms within 150 nm either side of the wave axis from 06N-
09N.

A central Atlantic tropical wave with axis along 48W from 03N-
19N has become better defined in its satellite signature during
the overnight hours. It is moving westward near 20 kt. Model
diagnostics depict this wave very well. The TPW satellite
animation shows a very deep moisture area, also in an inverted-V
shape, behind this wave from 04N-16N and between 40W-53W. Deep
convection consisting of the scattered moderate to isolated
intensity is increasing behind the wave from 06N-10N and between
41W-45W. In addition, a trade wind surge trails this wave. This
wave is forecast to impact the eastern Caribbean by Thu through
Fri, bringing enhanced showers and thunderstorms with gusty winds.

The previous analyzed western Caribbean tropical wave with axis
along 80W is presently not identifiable. as it has lost its
signature.

The earlier tropical wave that was analyzed over Central America
has advance into the eastern Pacific along 85W. Its northern
portion extends inland to northern Costa Rica and central
Nicaragua. Scattered showers and thunderstorms have increased
during the overnight hours over the central portion of Nicaragua,
and are moving westward. Isolated showers and thunderstorms are
along the coast of central and southern Nicaragua.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from coast of border between
Mauritania and Senegal near 16N16W and continues south-
southwestward to 08N26W. Latest scatterometer data indicates that
it transitions to the ITCZ west of the tropical along 28W and
continues to 05N47W. Aside from shower and thunderstorm activity
associated with tropical waves as described above, scattered
moderate convection that moved offshore Africa in advance of the
next tropical wave is seen within 270 nm south of the monsoon
trough between 16W-21W. Scattered moderate convection is within
60 nm either side of the ITCZ between 36W-41W.

GULF OF MEXICO...

An upper-level elongated trough extends from northern Texas to
an upper-level low over north-central Mexico. Associated upper-
level strong southwest winds cover far western Gulf. These winds
continue to advect abundant moisture northward over the western
Gulf. The earlier observed scattered moderate convection over the
northwest Gulf weakened and diminished in coverage during the
evening and overnight hours. Scattered showers and isolated
thunderstorms are seen north of 26N between 87W-94W. Isolated
showers and thunderstorms are elsewhere west of 90W. Expect for
scattered showers and thunderstorms to develop again today over
much of the western and north-central Gulf as deep moisture
remains in place. This activity is expected to decrease some
tonight and Thu as the aforementioned upper-level trough shear
out and weakens.

A weak 1015 mb high center is over the eastern Gulf at 25N86W.
Weak high pressure is over the area, and is generally expected to
change little through the upcoming weekend, resulting in mainly
gentle to moderate winds across the Gulf, with the exception of
the far western Gulf where southeast to south winds are mainly in
the fresh range. These winds will diminish beginning on Fri. A
trough will develop over the Yucatan Peninsula each day and move
across the Bay of Campeche during the evening, bringing fresh to
locally strong winds to the SW Gulf through Thu night.

CARIBBEAN SEA...

An upper-level trough extends from well northeast of the
Caribbean to across the northeastern Caribbean, then to a weak
upper-level low moving westward at 17N72W, and from there it
stretches southwestward and westward as a shear axis to across
northern Nicaragua. Strong upper-level southwest to west winds
are southeast of the trough. These winds are advecting abundant
upper- level moisture in the form of broken high clouds east-
northeastward to the south-central and eastern Caribbean.
Isolated showers and thunderstorms are south of 12N and between
77W-83W. Dry sinking air is situated to the northwest of the
upper-level trough to near 82W, where skies are relatively cloud
free except for small pockets of scattered low clouds. This
section of the Caribbean remains under the SE periphery of mid to
upper-level ridging present over the central Gulf of Mexico.

The gradient between high pressure over the central Atlantic and
low pressure in Colombia will support strong to near gale force
winds each night off the coast of Colombia and Gulf of Venezuela
through Sat. Moderate to fresh trades will continue elsewhere
across the Caribbean the next several days. A tropical wave is
forecast to impact the eastern Caribbean by Thu through Fri,
likely reaching the central Caribbean from Fri night into Sat. It
will be accompanied by scattered showers and thunderstorms. Strong
gusty winds can be expected with this activity.

ATLANTIC OCEAN...

A cold front was analyzed at 06Z along a position from near
32N54W to 29N60W, where it transitions to a dissipating
stationary front to 28N66W and to 29N70W. A rather sharp upper
trough/shear axis is over this cold front. A pre-frontal trough
extends from near 29N59W to 26N68W. Scattered moderate convection,
mainly as a result from the upper trough dynamics, are moving
east-northeast within 30 nm of a line from 32N56W to 30N59W.
Isolated showers and isolated thunderstorms are within 30 nm
of the stationary front and also within 30 nm of the trough
between 62W-68W.

Farther south, a surface to low-level trough is approaching the
Leeward Islands along a position from near 20N59W to 16N60W.
Isolated showers are within 60 nm either side of the trough.
Elsewhere, a 1028 mb high pressure center located well north
of the area at 35N34W has an associated ridge stretching
southwestward to 32N42W to 27N52W, then narrows as it reaches
to near 23N60W. An overnight Ascat pass nicely captured the
anticyclone flow associated with this ridge. A weak 1015 mb high
is centered at 28N74W. High pressure covers the Atlantic basin
outside the tropical waves.

The cold front and stationary front is forecast to dissipate
by early this evening. High pressure will build over northern
waters Thu through Sat night, which will support pulsing fresh to
strong winds north of Hispaniola each evening through Sat.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Aguirre
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