[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 110556
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
156 AM EDT Tue Jul 11 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 0000 UTC surface analysis and satellite imagery through
0515 UTC.

An area of showers and thunderstorms reaching 500 nm to the southwest
of the coast of Guinea-Bissau may be indicative of a tropical wave
emerging into the eastern Atlantic. This will be evaluated for
addition to the next surface map at 06 UTC.

An Atlantic Ocean tropical wave is along 33W/34W from 05N to 14N
southward, moving westward 15 knots. This tropical wave remains
well defined in satellite derived wind fields. Scattered moderate
convection is noted from 09N to 13N between 33W and 37W.

An Atlantic Ocean tropical wave is along roughly 44W from 06N to
15N, moving westward around 10 knots. A fairly well defined and
amplified surface trough is noted in satellite derived winds to
the north of the tropical wave, while the tropical wave itself
remains poorly defined. This feature continues to move slowly
west, and will likely come in phase with the more rapid moving
tropical wave farther east in the deep tropics. No significant
convection is noted with this tropical wave.

A trough along roughly 53W remains fairly well defined in the
lower to mid levels of the atmosphere, and to a lesser extent at
the surface, moving west at 10 to 15 kt. This feature emerged out
of the mid latitude areas of the eastern Atlantic a few days ago,
and will continue westward in the deep tropics toward the
Windward and Leeward Islands into the eastern Caribbean later
today. This feature exhibits no deep layer moisture or sensible
weather at this time.

A tropical wave reaches across the central Caribbean Sea from the
Guajira peninsula of northeast Colombia to central Hispaniola and
is moving west at 10 to 15 kt. Fairly dry air follows this wave
across the eastern Caribbean. No significant convection is noted
with it.

A tropical wave in the far northwest Caribbean and Gulf of
Honduras and is moving onshore along the coast of Belize and the
Yucatan peninsula. No significant convection is observed.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough passes through Senegal near 14N16W, to 07N33W,
09N40W. The ITCZ extends from 09N45W to 07N55W. Scattered moderate
to isolated strong convection is observed from 05N to 11N east of
25W, likely associated with a tropical wave moving off the
African coast. Scattered moderate convection is noted 02N to 05N
between 30W and 50W.

...DISCUSSION...

...THE GULF OF MEXICO...

Broad ridging reaches from the Big Bend area of Florida in the
northeast Gulf through the coast of south Texas. The northern
extent of a tropical wave is moving into the Yucatan peninsula,
and will move across the far southwest Gulf through mid week,
enhancing resident overnight troughing. This will support moderate
to fresh overnight winds across the southwest Gulf will clusters
of showers and a few thunderstorms. A broad upper low over the
north central Gulf will continue to support showers and
thunderstorms across the Straits of Florida, where moderate to
fresh east winds persist south of the ridge. Elsewhere, gentle
winds and slight seas will persist.

...THE CARIBBEAN SEA...

Strong trade winds persist over the south central Caribbean ahead
of and in the wake of a passing tropical wave. The area of strong
trade winds is shrinking slightly however as high pressure north
of the region weakens. Trade wind convergence continues to
support clusters of showers and thunderstorms along the monsoon
trough over the southwest Caribbean. Little convection is noted
elsewhere with moderate trade wind flow.

...HISPANIOLA...

A few overnight showers are forming off the northern coast of the
Dominican Republic. However, showers and thunderstorms from the
late afternoon and evening appear to have dissipated completely at
the end of daytime heating, despite a tropical wave moving across
the region. This is due in part to diminishing divergence aloft
as an upper low west of the area weakens. Scattered showers and a
few thunderstorms are likely once again later today over interior
areas with afternoon heating.

...THE ATLANTIC OCEAN...

Showers and thunderstorms associated with the remnants of T.D.
Four near 22N65W are weakening. Weak 1014 mb low pressure was
analyzed at 00 UTC near 22N65W. Since that time, while there
appears to be lingering circulation at least in the lower to mid
levels of the atmosphere, Buoy 41043 on the southwest quadrant of
the circulation shows southeast winds. Supported by recent
scatterometer data, this indicates there is no longer a closed
circulation at the surface, and is in fact a trough. Farther
northeast, an upper low is centered near 28N58W, supporting
possible scattered showers from 25N to 29N between 54W and 57W.
Elsewhere, broad ridging dominates the Atlantic Ocean north of
22N.

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

$$
Christensen
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