Tropical Weather Discussion
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000
AXNT20 KNHC 181757
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 PM EDT MON JUL 18 2016

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 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...TROPICAL WAVES...

Tropical wave in the east Tropical Atlantic extends from 13N39W
to 4N35W moving west-southwest near 20 kt over the past 24
hours. Wave is becoming tilted and coincides with a well defined
700 mb trough as depicted in the global models and within a
surge of deep moisture as seen on the SSMI Total Precipitable
Water imagery. Clusters of scattered moderate convection are
within 330 nm east and 210 nm west of the tropical wave.

Tropical wave in the west Tropical Atlantic is broad with a mean
axis extending from 22N55W to 9N54W moving west near 10 kt over
the past 24 hours. Wave has become tilted with a southern
vorticity center near 12N54W moving closer to 5 kt over the past
24 hours. Wave coincides with a 700 mb trough south of 16N as
depicted in the global models and within a surge of moisture as
seen on the SSMI Total Precipitable Water imagery. Isolated
showers are within 75 nm of the wave from 11N-14N, otherwise no
associated deep convection.

Tropical wave in the west Caribbean extends along 82W/83W south
of 18N to across Costa Rica into the east Pacific region moving
west near 10 kt over the past 24 hours. Wave coincides with a
700 mb trough as depicted in the global models and is embedded
within a surge of deep moisture as seen on the SSMI Total
Precipitable Water imagery. Wave is enhancing the activity in
the southwest Caribbean.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends across Africa into the east Tropical
Atlantic near 19N16W and continues south of the Cape Verde
Islands along 12N24W 8N312W 7N36W to 5N40W where the ITCZ begins
and continues along 3N43W to South America near 2N51W. Scattered
moderate to isolated strong convection is within 90 nm along the
coast of Africa from 6N-10N. Clusters of scattered moderate
convection are within 120 nm of line from 8N15W to 6N26W.

...DISCUSSION...

GULF OF MEXICO...

An upper ridge anchored over Louisiana and Arkansas extends over
the Gulf waters this afternoon. An upper trough extends from an
upper low along the north coast of Cuba to the Yucatan
peninsula. This is producing a diffluent environment over the
east Gulf to generate scattered showers and isolated
thunderstorms north of 25N between 84W-90W with isolated showers
and possible thunderstorms south of 25N east of 89W through the
Straits of Florida. Lingering scattered showers and isolated
thunderstorms are in the west Bay of Campeche south of 20N
between 93W-96W. A surface ridge extends from the west Atlantic
across the southeast CONUS to central Texas. The surface ridge
will persist through the week.

CARIBBEAN SEA...

An upper low is centered along the north coast of Cuba near
23N78W and extends a trough axis westward over the north Yucatan
peninsula. Clusters of scattered showers and isolated
thunderstorms are north of 19N west of 75W to the coast of the
Yucatan peninsula and inland over Cuba. An upper ridge axis
extends from Guatemala southeast to Colombia. This is providing
difflunce aloft and coupled with the tropical wave along 82W/83W
and the monsoon trough that extends from Colombia to Costa Rica
along 9N/10N are generating scattered showers and isolated
thunderstorms south of a line from Nicaragua near 15N83W along
15N79W to Colombia near 11N75W. A surface trough extends along
63W from the central Atlantic to across the northern Leeward/
Virgin Islands near 17N. Isolated showers over the Leeward/
Virgin Islands are associated with the leading edge of a broad
tropical wave that the mean axis is east of the Lesser Antilles.
The tight pressure gradient between the west Atlantic surface
ridge and the lower pressure over South America is producing
fresh to strong trade winds across the south-central Caribbean
that will continue  through the week. The tropical wave in the
west Caribbean will move inland across Central America later
this afternoon. The tropical wave east of the Lesser Antilles
will enter the east Caribbean early Wednesday then into the
central Caribbean through early Thursday.

...HISPANIOLA...

Isolated showers and possible isolated thunderstorms are
developing over south portion of the island leaving clear skies
across the remainder of the island. Afternoon or evening showers
and thunderstorms will be possible through Thursday. The
tropical wave east of the Lesser Antilles will enter the
Caribbean early Wednesday and could bring more showers and
thunderstorms to the island Thursday and Friday.

ATLANTIC OCEAN...

The upper low is along the north coast of Cuba near 23N78W
covering most of the west Atlantic with cyclonic flow with an
upper ridge axis along 32W/33W. This is providing difflunce
aloft to generate scattered showers and isolated thunderstorms
north of 28N west of 70W to over the southeast CONUS. A surface
trough extends from 26N71W across the Turks and Caicos to 20N72W
with scattered showers and isolated thunderstorms within 90 nm
either side of the trough axis. A second surface trough is to
the southeast extending along 63W south of 24N to across the
Leeward/Virgin Islands. This appears to be a northern vorticity
center associated with the tropical wave just east of the Lesser
Antilles. Scattered showers and isolated thunderstorms are from
20N-23N west of the trough axis to 67W with isolated showers and
thunderstorms from 17N-22N east of the wave axis to 60W.
Otherwise, high pressure dominates the remainder of the Atlantic
with a surface ridge extending from a 1031 mb high in the
northeast Atlantic near 36N45W through 32N60W then west to
inland over the southeast CONUS. This surface ridge will persist
through the week. The surface trough along 71W/72W will reach
the northwest Bahamas by wednesday evening. The surface trough
along 63W will continue westward reaching the Turks and Caicos
by early Wednesday.

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

$$
PAW


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