[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 012355
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
755 PM EDT Sun Jul 1 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
2345 UTC.

...TROPICAL WAVES...

The tropical wave has an axis extending from 15N25W to 04N25W and
is moving W at around 15-20 kt. Scattered moderate convection is
noted from 04N to 08N between 21W and 31W. A total precipitable
water surge coincides with this wave.

A tropical wave has an axis extending from 18N46W to 04N47W. This
wave is moving W at around 20-25 kt. This wave is well defined in
model 700 and 850 mb fields and coincides with an inverted-V
signature in total precipitable water data. This wave is
surrounded by Saharan dust which is inhibiting deep convection.

A tropical wave has an axis extending from 20N63W to 04N63W,
moving westward at 15 to 20 knots. This wave is clearly defined
with an inverted-V signature evident in visible satellite imagery.
Scattered moderate convection prevails across the portion of the
wave over South America. Saharan dust surrounds the northern
portion of this wave. Tropical moisture associated with this
feature will continue to spread west over the southeast and south-
central Caribbean, well ahead of the actual wave axis.

A tropical wave has an axis extending from 19N87W to 07N87W.
Infrared and visible satellite imagery as well as total
precipitable water data confirm the location of this wave. The
wave will continue across central America tonight, enhancing
shower and thunderstorm activity.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean from the coast of
Senegal near 14N16W and extends to 09N22W to 06N30W. The ITCZ
extends from 06N30W to 05N43W, then resumes west of a tropical
wave near 05N47W to 08N58W. Aside from the convection associated
with the tropical waves, scattered moderate convection is observed
from 06N to 10N E of 20W, and within 90 nm of the monsoon trough
and ITCZ axis.

...DISCUSSION...

GULF OF MEXICO...

A surface trough extends over the northeastern Gulf from a 1015
mb low near 31N87W to 28N89W. Abundant cloudiness and numerous
showers and thunderstorms are associated with the low/trough
affecting mainly the waters N of 27N and E of 89W. The low is
dissipating today, and the trough will drift northwestward through
tonight. Scattered showers and thunderstorms will continue over
much of the NE and north- central Gulf waters through at least Mon
associated with this system.

The remainder of the basin is under the influence of a weak high
pressure center located over the west Atlantic. This system is
producing light to gentle anticyclonic flow and seas of 1-3 ft
over the eastern half of the Gulf, and gentle to moderate SE to S
winds and seas of 3-5 ft over the western half of the Gulf. This
weak high pressure pattern will change little through mid-week. A
surface trough will emerge off the Yucatan Peninsula each evening
through Wed, enhancing nocturnal winds over the SW Gulf through
this period.

CARIBBEAN SEA...

Two tropical waves are moving across the eastern Caribbean and
central America. Please see the Tropical Waves section for
details. Scatterometer data depicted fresh to strong winds across
the south-central Caribbean south of 14N between 70W and 78W,
while moderate to fresh trades prevail across the remainder of the
basin S of 18N and E of 82W. Light to gentle winds are noted over
the NW Caribbean. A surface ridge will remain north and northeast
of the Caribbean and Tropical N Atlantic waters through the next
few days. Fresh to strong winds across the south-central Caribbean
will gradually diminish through Tue before strengthening again on
Wed.

Convection continues to flare up over the SW Caribbean mainly in
the vicinity of the monsoon trough, which is just north of Panama.
An upper-level low, currently just south of central Cuba, will
drift westward across the NW Caribbean through Mon, and will
enhance convection across the extreme western Caribbean waters
and over land areas across the NW Caribbean.

ATLANTIC OCEAN...

Two tropical waves are moving across the waters between the coast
of West Africa and the Lesser Antilles. Refer to the Tropical
Waves section above for details. A weak surface high center of
1019 mb is located near 28N75W. A surface trough is just E of this
high, and extends from 32N64W to 26N67W. Numerous showers and
scattered thunderstorms are from 25N to 30N between 62W and 73W,
and elsewhere within 90 nm of the trough axis. The high will
weaken as this trough moves westward across the NW Bahamas Tue,
and inland Florida Wed. Enhanced shower and thunderstorm activity
is expected to continue in the vicinity of the trough.

Another surface trough is over the central Atlantic and extends
from 32N51W to 26N52W. Light winds are on either side of the
trough axis based on scatterometer data from this morning. This
trough is a surface reflection of an upper-level low spinning near
29N52W. Scattered showers and thunderstorms are associated with
this system from 27N to 32N between 45W and 54W. Surface high
pressure located NW of the Azores is in control of the remainder
of the central and eastern Atlantic discussion waters.

GOES-16 RGB Geocolor imagery continues to show an extensive area
of African dust that extends from the west coast of Africa to the
eastern Caribbean this morning. The Saharan dust occasionally
obscures sky conditions near the Caribbean islands. The dust turns
skies hazy, reducing visibility and can result in poor air
quality.

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

$$

ASL/ERA
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