Tropical Weather Discussion
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000
AXNT20 KNHC 181125
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
725 AM EDT Sun Jun 18 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.

...SPECIAL FEATURE...

A tropical wave is along 45W/46W from 11N southward. The wave is
moving westward 10 to 15 knots. A 1007 mb low pressure is along
the tropical wave near 06N. Widely scattered moderate to isolated
strong rainshowers are from 04N to 10N between 43W and 50W.
The chance of formation into a tropical cyclone during the next
two days is medium. Please read the latest NHC Tropical Weather
Outlook under AWIPS/WMO headers MIATWOAT/ABNT20 KNHC for more
details.

A 1007 mb low pressure center is about 45 nm to the east of the
northern part of the coast of Belize, near 17.5N87W. Numerous
strong rainshowers cover the area that is from 13N to 20N between
81W and 85W, in the coastal waters of Nicaragua and Honduras.
Widely scattered moderate to isolated strong rainshowers also
cover the area from 15N to the southern coast of Cuba between 77W
and 82W. This low pressure center is forecast to move slowly
northwestward across the Yucatan Peninsula on Sunday, and into the
southern or central Gulf of Mexico early next week. It is likely
that a subtropical or tropical cyclone may form. Heavy rains are
expected in parts of Central America, the Yucatan Peninsula,
Jamaica, the Cayman Islands, and western Cuba during the next
several days. An Air Force Reserve Hurricane Hunter aircraft is
scheduled to investigate this system on Sunday, if necessary. The
chance of formation into a tropical cyclone during the next two
days is medium. Please read the latest NHC Tropical Weather
Outlook under AWIPS/WMO headers MIATWOAT/ABNT20 KNHC for more
details.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 22W/23W from 12N
southward. Isolated moderate to locally strong rainshowers are
from 04N to 12N between 10W and 30W.

An Atlantic Ocean tropical wave is along 33W/34W from 11N
southward, moving westward 10 to 15 knots. Isolated moderate
from 10N southward between 30W and 40W.

An Atlantic Ocean tropical wave is along 53W/54W from 18N
southward moving westward 10 knots. Widely scattered moderate to
isolated strong rainshowers are from 12N southward between 50W
and 60W.

A Caribbean Sea tropical wave is along 81W/82W, from 20N
southward. This wave is moving into the area of weather that is
being influenced by the 1007 mb low pressure center that is just
to the east of Belize, from the Special Features section.

...MONSOON TROUGH/ITCZ...

The Monsoon Trough passes through the coastal border sections of
Senegal and Mauritania near 16N16W, to 08N23W, 06N40W, and
06N43W. The ITCZ continues from 06N43W to 07N52W, to the border of
Guyana and Suriname near 06N57W. Convective precipitation:
Isolated moderate to locally strong elsewhere from 10N southward
from 60W eastward.

...DISCUSSION...

...THE GULF OF MEXICO...

A NE-to-SW oriented upper level trough cuts through the Florida
Panhandle, to 19N98W in southern Mexico, just to the west of the
Isthmus of Tehuantepec. A surface ridge passes through 27N/28N in
Florida, into the central Gulf of Mexico, to the coast of Mexico
near 20N97W. Comparatively drier air in subsidence is apparent in
water vapor imagery, within 120 nm to 180 nm on either side of
the line that passes through the Florida Big Bend, into the
central Gulf of Mexico, to the Mexico coast near 21N97W.

...CURRENT CONDITIONS AND WEATHER, FOR THE OFFSHORE OIL
PLATFORM SITES, FROM 27N NORTHWARD AND FROM 88W WESTWARD...

LIFR: none.

IFR: none.

MVFR: KGHB.

CURRENT CONDITIONS AND WEATHER, FOR THE COASTAL PLAINS OF THE
U.S.A., FROM THE DEEP SOUTH OF TEXAS TO FLORIDA...

Texas: MVFR, from interior sections of the Lower Valley to
Victoria. Some occasional MVFR ceilings have been reported during
the last few observations in the Houston metropolitan area and
surrounding smaller communities. LOUISIANA: MVFR in Baton Rouge.
Occasional IFR-to-MVFR ceilings around the northern side of Lake
Pontchartrain during the last few observations. MISSISSIPPI: LIFR
in Natchez. FLORIDA: rain and thunder and occasional MVFR ceilings
have ended for the moment from Pensacola to Milton. MVFR in Perry,
and at the Tampa Executive Airport.

...THE REST OF THE CARIBBEAN SEA...

Upper level anticyclonic wind flow covers the area from 66W
westward. The rest of the Caribbean Sea is just to the west of the
Atlantic Ocean 26N55W-to-08N60W trough.

The Monsoon Trough is along 09N74W in Colombia, through 10N80W in
the SW corner of the Caribbean Sea, into El Salvador. Widely
scattered moderate to isolated strong rainshowers from 10N to 13N
between 75W and 78W, in the coastal waters of Colombia.

24-hour rainfall totals that are listed for the period that ended
at 18/0000 UTC...according to the PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...are 0.04 in
Guadeloupe, and a trace in Tegucigalpa in Honduras.

...HISPANIOLA...

Upper level NW wind flow is moving across Hispaniola.

SURFACE OBSERVATIONS...for Port-au-Prince in Haiti: VFR. for the
DOMINICAN REPUBLIC: Santo Domingo: VFR. earlier rain and MVFR
ceilings have ended for the moment. Punta Cana: VFR. Santiago:
light rain. MVFR. ceiling 1600 feet. Puerto Plata: VFR.

The GFS MODEL forecast for 250 mb shows that NW wind flow will
move across the area during the first 24 hours of the 48-hour
forecast. N wind flow will continue for the next 24 hours. A
N-to-S oriented trough develops directly on top of Hispaniola at
the end of the forecast period, and for the start of day three.
The GFS MODEL forecast for 500 mb shows that anticyclonic wind
flow, with a N-to-S oriented ridge, will move across Hispaniola
during much of the first 24 hours of the forecast. The ridge will
be followed by an inverted trough at the end of day one. The
inverted trough remains across Hispaniola during the first two-
thirds of day two. The ridge slides westward during the rest of
the time of the day two forecast period. The GFS MODEL forecast
for 700 mb shows that SE wind flow will move across the area
during the next 48 hours, with Hispaniola being on the southern
side of an E-to-W oriented Atlantic Ocean ridge.

...THE ATLANTIC OCEAN...

An upper level central Atlantic Ocean trough is anchored by a
cyclonic circulation center that is about 760 nm to the NE of
Puerto Rico, and that ends near NE coastal Venezuela and northern
sections of Guyana near 08N60W. Scattered to numerous strong
rainshowers are from 08N to 10N between 59W and 61W, near
Venezuela and Guyana. A cold front/stationary front is along
32N/33N between 38W and 54W. Broken to overcast multilayered
clouds and possible rainshowers cover the area from 30N northward
between 33W and 70W. A surface trough is along 30N55W 29N58W
26N61W. Isolated moderate rainshowers cover the Atlantic Ocean
from 10N northward between 45W and 70W.

A NE-to-SW oriented upper level trough, from 20N northeastward,
is within 300 nm to 600 nm to the west of Africa. No significant
deep convective precipitation is apparent in satellite imagery.

Surface anticyclonic wind flow covers the Atlantic Ocean from 20N
northward from 53W eastward. A 1024 mb high pressure center is
near 30N42W.

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

$$
MT



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