Tropical Weather Discussion
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451
AXNT20 KNHC 231121
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
721 AM EDT Sun Jul 23 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
1045 UTC.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 22W/23w from 16N
southward. Convective precipitation: scattered moderate to
isolated to widely scattered from 04N to 11N between Africa and
32W.

An Atlantic Ocean tropical wave is along 36W/37W from 21N
southward. Convective precipitation: isolated moderate from 04N
to 22N between 30W and 40W.

An Atlantic Ocean tropical wave is along 47W/48W from 17N
southward. Convective precipitation: isolated moderate from 11N
to 13N between 48W and 52W. isolated moderate elsewhere from
15N southward between 47W and 53W.

A Caribbean Sea NW-to-SE oriented tropical wave is along 22N68W,
across Puerto Rico, to 17N66W, to 11N65W. Convective
precipitation: isolated moderate to locally strong from 20N to
26N between 60W and 70W.

The position of a second Caribbean Sea tropical wave was adjusted
based on satellite imagery and tropical wave diagnostics, in
order to be along 77W/78W, from SE Cuba across Jamaica, to the
eastern part of Panama. Convective precipitation: scattered strong
in eastern sections of Honduras. isolated moderate in the coastal
waters of Honduras and Nicaragua.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough passes through the coastal sections of SW Senegal
near 12N17W, to 11N22W, to 13N36W and 10N52W. The ITCZ continues
from 10N52W to 09N61W in NE Venezuela. Convective precipitation:
isolated moderate elsewhere from 14N southward between Africa and
60W.

...DISCUSSION...

...THE GULF OF MEXICO...

An upper level cyclonic circulation center is near 25N90W. Upper
level cyclonic wind flow covers Florida and the Gulf of Mexico
from 85W eastward, with the 31N77W Atlantic Ocean cyclonic
circulation center. Upper level cyclonic wind flow covers the rest
of the Gulf of Mexico. Convective precipitation: isolated
moderate from 25N northward. rainshowers are possible from 24N
southward.

A surface ridge extends from Lake Okeechobee in south Florida,
into the central sections of the Gulf of Mexico, to 19N96W, into
the coastal plains of Mexico.

A thermal trough is in the Yucatan Peninsula.

...CURRENT CONDITIONS AND WEATHER, FOR THE OFFSHORE OIL PLATFORM
SITES, THAT ARE IN THE AREA WHOSE BOUNDARIES ARE FROM 27N
NORTHWARD AND FROM 88W WESTWARD, and FOR THE COASTAL PLAINS OF THE
U.S.A., FROM THE DEEP SOUTH OF TEXAS TO FLORIDA...

MVFR: at KEHC, KMDJ, and KMIS. Convective precipitation:
isolated moderate elsewhere from 25N northward from 85W westward.
TEXAS: MVFR in Edinburg. MVFR in Jasper. LOUISIANA: light rain in
Lafayette. MISSISSIPPI: LIFR in McComb. MVFR in the Hattiesburg
metropolitan area. ALABAMA: MVFR in parts of the Mobile
metropolitan area. FLORIDA: nearby rainshowers and thunder are in
multiple parts of the Pensacola metropolitan area. earlier rain
and thunder have ended for the moment in Milton. earlier rain and
drizzle have ended for the moment in Mary Esther. MVFR in Destin.
light rain in parts of the Panama City metropolitan area. nearby
rain and thunder in Perry and in Cross City. nearby rain and
thunder are in parts of the Tampa-St. Petersburg metropolitan
area, and in Sarasota.

...THE CARIBBEAN SEA...INCLUDING HISPANIOLA...

Upper level cyclonic wind flow covers the Caribbean Sea from 16N
northward between the Mona Passage and NW Cuba. Convective
precipitaiton: Scattered moderate to isolated strong from 16N to
21N between the Windward Passage and 82W in the Caribbean Sea.

A NW-to-SE oriented tropical wave is along 22N68W, across Puerto
Rico, to 17N66W, to 11N65W. Convective precipitation: isolated
moderate to locally strong from 20N to 26N between 60W and 70W.

The position of a second tropical wave was adjusted based on
satellite imagery and tropical wave diagnostics, in order to be
along 77W/78W, from SE Cuba across Jamaica, to the eastern part
of Panama. Convective precipitation: scattered strong in eastern
sections of Honduras. isolated moderate in the coastal waters of
Honduras and Nicaragua.

Upper level anticyclonic wind flow covers the area from NW corner
of the Caribbean Sea, into the SW corner of the Caribbean Sea.
Convective precipitation: scattered moderate to strong in parts of
eastern Honduras and its coastal waters.

Middle level to upper level anticyclonic wind flow covers the
easternmost part of the area, to the E and SE of the trough/
cyclonic wind flow.

The monsoon trough is along 10N/11N between 74W in Colombia and
beyond 86W in NW Costa Rica. Convective precipitation: numerous
strong is in Colombia from 08N to 10N between 74W and 78W,
including in the Gulf of Uraba of Colombia. Isolated moderate to
strong elsewhere from 11N southward.

24-hour rainfall totals in inches, for the period that ended at
23/0000 UTC, according to the PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...are: 0.40 in
Guadeloupe.

Hispaniola is on the eastern side of an upper level trough. The
trough extends from a 31N77W Atlantic Ocean cyclonic circulation
center. Upper level southerly wind flow is moving across the area.

SURFACE OBSERVATIONS...for Port-au-Prince in Haiti: MVFR. for the
DOMINICAN REPUBLIC: Santo Domingo/La Romana/Punta Cana: VFR.
Santiago/Puerto Plata: VFR.

The GFS MODEL forecast for 250 mb shows that either southerly wind
or cyclonic wind flow will cover Hispaniola during the first 24
hours or so of the 48-hour forecast period. A trough either will
be to the west of Hispaniola, or it will be on top of the area.
Anticyclonic wind flow will move across the area during day two.
The GFS MODEL forecast for 500 mb shows that Hispaniola will be
on the southern side of an Atlantic Ocean ridge. An inverted
trough will move across the area during day one. NE-to-E wind flow
will move across the area during day two. The GFS MODEL forecast
for 700 mb shows that E-to-SE wind flow will move across the
area, with Hispaniola on the southern side of an Atlantic Ocean
ridge.

...THE ATLANTIC OCEAN...

A western Atlantic Ocean upper level cyclonic circulation center
is about 240 nm to the east of the coast of Georgia. The cyclonic
wind flow that surrounds the cyclonic center covers the Atlantic
Ocean and the Bahamas, and parts of Cuba and Hispaniola and the
northern parts of the Caribbean Sea. Convective precipitation:
widely scattered moderate to isolated strong from 27N to 29N
between 78W and 80W, and in the coastal waters of the Florida west
coast in the Gulf of Mexico from 26N to 30N from 85W eastward.
isolated moderate elsewhere from 20N northward between 70W and
interior sections of Florida, and also in the rest of the coastal
waters of Florida in the Gulf of Mexico.

An upper level cyclonic circulation center and associated trough
are about 1525 nm to the west of the Western Sahara in Africa.
Convective precipitation: rainshowers are possible from 20N
northward between 40W and 50W, and from 23N northward between 50W
and 60W.

A surface ridge passes through 32N27W, to 28N40W, to a 1021 mb
high pressure center that is near 28N65W, to 27N78W just to the
north of the NW Bahamas,across south Florida, into the central
Gulf of Mexico.

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

$$
MT



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