[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101109
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
709 AM EDT Mon Jul 10 2017

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 tropical wave is in the eastern Atlantic southwest of the Cabo
Verde Islands with axis extending from 13N30W to 05N30W, moving
west at 15 kt. Abundant moisture prevails within this wave, as
noted in TPW imagery. Model guidance shows this wave staying
fairly consistently active and fast in the deep tropics over the
next several days, possibly forming a weak low pressure in the
next 24 to 48 hours. Scattered moderate convection is along the
southern portion of the wave axis, close to where it intersects
the monsoon trough, from 07N to 13N between 25W and 30W.

Another tropical wave is over the far eastern Atlantic with axis
extending from 15N42W to 05N42W, moving west at 10 kt. A sharp
upper trough is observed just west of the tropical wave along 45W.
Deep layer moisture is pooling along the tropical wave under the
divergent area aloft on the east side of the upper trough,
extending well north into the subtropics to 25N. A large area of
Saharan dust is noted to the east of the moisture plume. The wave
is slower and higher latitude than the faster and lower latitude
more to the east. Model guidance suggests these feature may almost
come into phase at different latitudes over the next couple of
days. Scattered moderate to isolated strong convection is noted
closer to the monsoon trough, from 04N to 07N between 40W and 42W.

A broad area of lower to mid level cyclonic turning is noted in
satellite derived winds farther west, with an axis along roughly
48W to 50W. This is likely a mid latitude trough that intruded
into the tropics over the eastern Atlantic. While scatterometer
and buoy data hint of a very broad trough at the surface, this
feature is on the drier subsident side of the sharp upper trough,
and little to no sensible weather is noted, other than a few
showers along the monsoon trough. The trough will across the
Leeward and Windward Islands late Tuesday, but with little impact
anticipated at this time. Model guidance also suggests this
feature will dampen out over the central Caribbean later in the
week, but spawn a weak trough into the subtropics.

A tropical wave is analyzed over the central Caribbean. The 00
UTC sounding data from St Maarten, San Juan, and Santo Domingo
indicate the main wave axis was crossing Puerto Rico, the Mona
Passage and into the eastern portion of Hispaniola. The tropical
wave will stay on the southeast quadrant of a broad upper low
currently centered over the western Caribbean as it shifts
westward through late week.

A tropical wave is analyzed from far western Panama through
eastern Nicaragua and Honduras to near the Isle of Youth and
western Cuba, moving west at 10 kt. 00Z sounding data from Grand
Cayman provided evidence the axis of the wave passed through. The
trough is in an area of dry subsident area on west side of an
upper low. Aside from scattered to numerous moderate to strong
convection off Panama and Costa Rica in the far southwest
Caribbean, little sensible weather is noted with this trough.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from 15N17W to 08N25W to 07N40W. The
intertropical convergence zone extends from 08N43W to 06N55W.
No significant convection noted other than as described in the
tropical wave section.

...DISCUSSION...

GULF OF MEXICO...

Earlier scatterometer data indicated a weak trough emerging off
the west coast of the Yucatan peninsula, supporting a few showers
and thunderstorms near Ciudad del Carmen. A few showers extended
farther north through the western Gulf, supported by divergence
aloft related to an upper trough over south Texas. Weak ridge
extended from the western Atlantic across the Florida peninsula
into the eastern Gulf. Light to gentle winds and slight seas were
noted across the region as a result, with the exception of
moderate to fresh east winds in the Straights of Florida where
scattered showers and a few thunderstorms persist.


CARIBBEAN SEA...

Two tropical waves are moving across the Caribbean. See above.
A small area of strong convection is ongoing between southwest
Haiti, Jamaica and southeast Cuba, on the divergent eastern side
of an upper trough centered over the western Caribbean. The
pressure gradient related to ridging sandwiched between the
tropical waves is supporting strong trade winds over the south
central Caribbean where seas are building to 7 to 9 ft.

...HISPANIOLA...

The interaction of an approaching tropical wave with an upper low
over the western Caribbean will maintain scattered showers and
thunderstorms across eastern Hispaniola through this morning.
Daytime heating will add another impetus for convection, mainly
across the mountainous interior areas.

ATLANTIC OCEAN...

Two tropical waves are analyzed over the tropical Atlantic. See
the section above for details. A broad 1033 mb surface high is
centered north of our area near 37N41W with fair weather. An
extensive area of African Saharan dust is situated over the
central Atlantic and is gradually shifting westward.

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

$$
Christensen
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