[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 021033
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
633 AM EDT Tue Jul 2 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
1145 UTC.

...TROPICAL WAVES...

A far eastern Atlantic tropical wave with axis along 21W from 05N
to 22N is moving westward at 10-15 kt. Satellite imagery indicates
a possible mid-level circulation near 14N21W. Scattered showers
and thunderstorms are seen within 180 nm either side of the wave
axis from 05N to 10N.

An eastern Atlantic tropical wave with axis along 40W from 02N to
17N is moving westward at estimated speed of 20-25 kt. A trade
wind surge trails the wave. Model diagnostics depict this wave.
The total precipitable water (TPW) imagery shows a maximum in
moisture content across the wave axis from 04N to 11N and between
35W-42W. Scattered showers and isolated thunderstorms are noted
from 06N to 10N between 38W and 42W. This wave is forecast to
impact the eastern Caribbean Sea Thu through Fri.

A central Caribbean Sea tropical wave with axis along 71W south
of 16N is moving westward at about 20 kt. Latest TPW imagery shows
moisture concentrated to the south of 15N and between 70W and
77W. The wave is moving through an area of broken to overcast
multilayered clouds and upper-level strong southwest winds that
are in advance of an upper-level trough and low over the western
Caribbean. Isolated showers and thunderstorms are south 14N
between 67W and 71W.

A western Caribbean tropical wave with axis roughly along 81W is
moving westward at about 17 kt. This wave is passing underneath
an area of subsidence and dry air present north of 13N in
association with a western Caribbean upper-level trough and low.
The only moisture content with this wave is found in the usual far
southwestern Caribbean area primarily south of 13N between 76W
and 81W, where isolated showers and thunderstorms are occurring.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from the coastal of southwestern
Senegal near its border with Guinea-Bissau at 12N17W and continues
to 10N23W, where latest scatterometer data indicates that it
transitions to the ITCZ and continues to 08N31W and to 06N38W. It
resumes to the west of the tropical wave along 40W at 06N41W and
to 04N51W. Aside from shower and thunderstorm activity associated
with tropical waves as described above, only scattered moderate
convection is within 150 nm south of the ITCZ between 31W-37W.

GULF OF MEXICO...

An upper-level low over central Mexico is embedded within a
broad trough that stretches from Missouri to Texas and to the
central region of Mexico. Strong upper-level southerly winds to
the east of the trough and low expand eastward to the western
Gulf. These winds are spreading upper-level moisture in the form
of mostly broken high clouds across the western and north-central
Gulf areas. The total precipitable water imagery depicts abundant
moisture over the much of the western and central Gulf, and is
spreading northward. Scattered showers and isolated thunderstorms
are noted west of 91W, and also north of 25N between 85W and 91W.
The majority of the activity over the SW Gulf and Bay of Campeche
moved offshore from the southeast section of Mexico, and is being
steered northward by the strong upper-level southerly flow.
Isolated showers and thunderstorms over the far eastern Bay of
Campeche and along the coast of the Yucatan Peninsula are also
tied to the nocturnal Yucatan Peninsula trough.

With this moisture in place and along with atmospheric conditions
becoming more unstable today, expect for the shower and thunderstorm
activity to further increase through tonight and into Wed over
the western and north-central Gulf waters. Some of this activity
may be accompanied by strong gusty winds and rough seas. Isolated
showers and thunderstorms are expected elsewhere over the Gulf
through Wed. The upper level-low over central Mexico is forecast
to lift northeastward toward central Texas tonight and Wed while
shearing out in a northeast to southwest fashion.

A weak 1018 mb high center is analyzed over the extreme southern
part of the eastern Gulf near 25N85W, with associated
anticyclonic flow, as depicted in the latest Ascat pass, covering
much of the Gulf. The weak high pressure will change little
through the upcoming weekend. As referenced above in relation
to isolated showers and thunderstorms over the far eastern Bay of
Campeche, the same culprit trough will develop over the Yucatan
Peninsula each afternoon and move offshore across the Bay of
Campeche during the evening hours, bringing fresh to locally
strong northeast to east winds to the SW Gulf of Mexico.

CARIBBEAN SEA...

An upper-level trough extends from the central Atlantic near
28N44W southwestward to the Mona Passage and eastern Dominican
Republic, and from there it continues southwestward to a rather
ill-defined upper-level low at 16N78W and to a base at 10N81W.
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 across the
south-central and eastern Caribbean. Isolated showers and
thunderstorms are south of 13N and between 67W and 65W. 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.

Scattered moderate to isolated strong convection over northwestern
Colombia is being aided by the eastern extension of the E Pacific
monsoon trough. This activity is moving westward and has recently
crossed to over the southern part of Panama and to just inland the
Pacific coast of Colombia.

The pressure gradient, between N Atlantic high pressure and lower
pressures in northern Colombia, will support strong to near gale-
force winds, pulsing each night off the coast of Colombia and near
the Gulf of Venezuela through Sat. High pressure will build north
of the region Fri through Sat night, with the associated pressure
gradient to bring strong east winds and building seas across much
of the central Caribbean. Moderate to fresh trade winds will
prevail elsewhere over the Caribbean waters.

A tropical wave, currently over eastern Atlantic as described
above, is expected to move across the Windward Islands and
far eastern Caribbean on Thu and across the rest of the eastern
Caribbean on Fri. It will be accompanied by scattered showers and
thunderstorms. Strong gusty winds can be expected with this
activity.

ATLANTIC OCEAN...

A cold front dipping southward extends from 32N61W to 30N68W and
northwestward to north of the area at 32N75W. A surface rough out
ahead of it extends from near 30N66W to 25N73W. These features are
being driven by a broad deep-layer trough that is gradually
sliding eastward north of 26N and between 54W and 71W. Scattered
showers and isolated thunderstorms are seen within 90 nm either
side of a line from 32N59W to 28N63W to 25N68W. Increasing
scattered showers and thunderstorms are within 120 nm either side
of a line from 32N57W to 29N61W and within 75 nm either side of
a line from 29N61W to 25N68W. The deep-layer trough will shift
eastward through the next 24 to 48 hours, while the cold front
will reach from near 32N59W to 28N68W by early this evening and
become stationary and dissipate by early Wed evening. Fresh to
locally strong southwest winds will precede the cold front today.
Isolated showers and thunderstorms are present from 25N to 27N
between 70W and 75W and also south of 29N W of 75W.

Elsewhere, broad scale high pressure is the main feature. It is
forecast to change little through the next 48 hours. The associated
gradient between it and relatively lower pressure to the south,
over the Caribbean Sea, will allow for east winds to pulse to
fresh to locally strong speeds between the southeastern Bahamas
and Hispaniola in the late afternoons and evenings through the
upcoming weekend.

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

$$
Aguirre
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