[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162353
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
753 PM EDT Mon Jul 16 2018

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
2315 UTC.

...SPECIAL FEATURES...

SW Caribbean Sea gale warning: The synoptic pattern set-up with
strong high pressure situated over the central Atlantic interacting
with broad low pressure over the SW Caribbean Seas and over
northern S America will allow for the ongoing strong to near gale
force NE to E strong winds near the coast of Colombia from 11N to
13N between 73W and 75W to again reach minimal gale force Tue
night and Wed night over the same area along with seas in the
range of about 9-12 ft. Please read the High Seas Forecast, under
the AWIPS/WMO headers HSFAT2/FZNT02 KNHC, for more details.

...TROPICAL WAVES...

A tropical wave is over W Africa along 12W from 04N-15N, moving W
at 15 kt. A well defined 700 mb trough is noted together with an
inverted-V convection signature. Widely scattered moderate
convection is from 07N-15N between 08W-18W.

An eastern Atlantic tropical wave axis stretches from near 21N40W
to 06N42W, moving westward at 15-20 kt. The wave is depicted on
GOES-16 RGB imagery as having a rather broad inverted-V shape
envelope of broken to overcast of mainly stratocumulus clouds
covering over an area from 09N-23N between 30W-50W. Scattered
moderate convection is behind the wave along and within 60 nm
either side of the ITCZ between 35W-40W. Scattered showers and
isolated thunderstorms are ahead of the wave from 06N-09N between
the wave and 44W. The GOES-16 RGB images along with visible images
of the far eastern Atlantic are depicting yet another massive
plume of Saharan dry air and associated dust following in behind
the wave from 09N-27N east of 36W to well inland Africa, where
even more intense Saharan dust is being captured by the GOES-16
imagery behind and around another tropical wave. Visibilities
within these areas of dust are expected to be sharply reduced.

An eastern Caribbean Sea tropical wave is tilted NE to SW with its
axis reaching from E Hispaniola to the coast of Venezuela at
10N71W, moving westward at about 20 kt. This wave continues to be
impinged upon by Saharan dust as observed in GOES-16 satellite
imagery. Scattered moderate convection is inland over most of
Hispaniola. This wave will move across the rest of the eastern
Caribbean Sea through by early Tue, then across the central
Caribbean Sea through Wed night and the western Caribbean Seas Thu
through Fri before moving inland Central America and the Yucatan
Peninsula Fri night. The Saharan dust in its wake will filter
across the eastern Caribbean and much of the central Caribbean
through Wed.

A western Caribbean Sea tropical wave has its axis along 87W S of
20N, moving westward at 10-15 kt. Scattered moderate isolated
strong convection is over the Yucatan Peninsula and Central
America from Guatemala to Panama. This wave will move west of the
area and into the eastern Pacific late Tue.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from W Africa near 15N17W to 08N30W.
The ITCZ continues to 08N30W to 08N40W to South America near
06N53W. Widely scattered moderate convection is is from 05N-09N
between 20W-48W.

...DISCUSSION...

GULF OF MEXICO...

A 1019 mb high centered over the central gulf waters near 27N92W,
and is the main feature that is influencing the synoptic pattern
across the basin. Its associated gradient is allowing for
generally light to moderate anticyclonic flow to exist over the
gulf waters. Current NWS mosaic radar shows scattered moderate to
isolated strong convection over the northern gulf north of 28N
and E of 92W. Similar convection is over the Florida Peninsula.
This activity is expected to remain active through at least the
next couple of days as upper-level disturbances move from E to W
around the eastern periphery of an upper-level anticyclone
centered over western Texas. Isolated showers and thunderstorms
moving westward are present over much of the eastern gulf waters
as well as over the eastern half of the central gulf. This
activity should continue through tonight and into Tue. Expect high
pressure to prevail across the northern waters through Thu. A
surface trough will move westward off the Yucatan Peninsula each
evening through Thu, enhancing nocturnal winds over the eastern
section of the SW Gulf.

CARIBBEAN SEA...

Please read the Special Features section for details about
pulsing gale force winds near the coast of Colombia. Aside from
the tropical waves mentioned above, an upper level low is noted
on water vapor imagery just to the south of the Yucatan Channel.
A rather dry and stable environment is only for isolated showers
moving quickly with the trade wind flow to occur across much of
the basin. Mainly fresh E winds will continue over the central
Caribbean Sea through Thu, with the exception of strong NE-E winds
in the SW and S central sections of the Caribbean outside the
near gale to minimal gale force wind area described above.

ATLANTIC OCEAN...

A weak surface trough extends from near 32N78W southwestward to
just east of NE Florida. Scattered showers and isolated
thunderstorms are seen north of 28N between 72W and 79W. Another
surface trough extends from near 32N60W to 29N67W and
northwestward to near 32N76W. Scattered moderate isolated strong
convection is along and within 90-120 nm SE of this trough
between 60W-64W while isolated showers and thunderstorms are along
and within 60 nm SE of the trough between 64W-75W. This trough
will slowly weaken through Tue as the supporting upper trough
lifts to the NE away from it. High pressure will build in the wake
of the trough. A large area of Saharan Air Layer (SAL) dust
that is currently over the central Atlantic from 08N-24N and
between 45W-60W will continue to translate westward through the
rest of the week. A weaker area of dust is visible from the SE
Bahamas to 60W and from 09N-27N, also translating in westward
motion.

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

$$
Formosa
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