[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 031203
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
803 AM EDT Tue Jul 3 2018

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
1145 UTC.

...TROPICAL WAVES...

A tropical wave has an axis extending from 16N33W to 04N34W and
is moving W around 10 kt. The wave coincides with a surge of
moisture as noted in the TPW product, but African dust surrounds
the northern side of the wave and is inhibiting convection there.
Scattered moderate convection is seen within the moister southern
portion of the wave from 01N to 08N between 30W and 36W.

A tropical wave extends from 19N52W to 05N53W. This feature is
moving W around 10 kt. The low level cloud field associated with
this wave exhibits an inverted-V signature. This wave shows up
well in the TPW animation where a pronounced bulge of moisture is
observed. This wave remains surrounded by Saharan dust which is
limiting convection in the vicinity of this wave. Only a small
cluster of moderate convection is noted E of the wave axis from
09N to 11N between 49W and 51W. Moisture associated with this wave
will begin reaching the Windward Islands early this afternoon and
bring a modest increase in chances for showers and thunderstorms
for this area during the next day or so.

A tropical wave has an axis extending from the eastern Cuba near
21N76W to the coast of Colombia 08N77W, moving westward at around
20 knots. The wave is well depicted in the moisture product. The
monsoon trough extends E over the SW Caribbean from Costa Rica to
northern Colombia near 10N74W. The tropical wave is interacting
with the trough to generate numerous moderate and isolated strong
convection from 11N to 13N between 81W and 84W. Scattered moderate
and isolated strong convection is found elsewhere within 120 nm
of a line from 08N75W to 14N83W. Model guidance indicates that the
abundant moisture associated with this wave will spread W from
the SW Caribbean over Nicaragua and Honduras this afternoon and
tonight.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic Ocean from the coast of
Senegal near 14N17W, then extends SW to 04N37W. The ITCZ continues
from 04N37W to 04N45W to the coast of French Guiana near 05N53W.
Aside from the convection associated with the tropical waves,
cloudiness and isolated moderate convection is observed within 150
nm of a line from 11N16W to 07N28W and within 120 nm of a line
from 03N38W to 07N46W.

...DISCUSSION...

GULF OF MEXICO...

A trough curves SSW from a weak 1014 mb surface low centered near
the mouth of the Mississippi to near 24N90W. Scattered moderate
convection is noted from 28N to 30N between 87W and 92W. This
system is forecast to weaken and slowly move W toward NE Texas
through Wed.

The remainder of the Gulf remains under the influence of a weak
ridging curving W over the basin from the Atlantic. The ridge is
manifested over the western Gulf in the form of two weak 1017 mb
high pressure centers located near 27N94W and near 23N97W. The
area of high pressure is producing mainly light to gentle
anticyclonic flow and seas of 1-3 ft across much of the Gulf
waters. This pattern will change little through mid week. A
surface trough will emerge off the Yucatan Peninsula each evening
through the end of the week and generate moderate to fresh
nocturnal winds over the SW Gulf.

CARIBBEAN SEA...

Satellite-derived wind data from 02Z this morning indicates
moderate to fresh trades in the central and eastern Caribbean Sea,
while surface observations show winds are light in the western
Caribbean Sea. Winds are forecast to increase across the central
Caribbean Sea beginning tonight, as high pressure to the north
builds. Forecast models suggest that the wind speeds will be in
the 25-30 kt range in the south central Caribbean Sea, with seas
building to 10 to 12 feet by early Wednesday morning.

Convection continues to flare up over the SW Caribbean Sea mainly
in the vicinity of the monsoon trough. This pattern will remain
in place for the next several days, even after the tropical wave
departs.

The Cuba-to-Panama broad tropical wave will enter the western
Caribbean Sea on Wednesday, and arrive across Central America and
the Yucatan Peninsula on Thursday morning. The next tropical wave
to affect the Caribbean is in the tropical Atlantic Ocean along
52W/53W. This wave will move across the tropical N Atlantic Ocean,
and enter the eastern Caribbean Sea this afternoon, reaching the
central Caribbean Sea on Thursday and into the western Caribbean
Sea on Friday. Fresh winds in the central Caribbean Sea will
become strong from Wednesday through Friday night. Near gale
force NE winds are possible near the coast of Colombia on
Thursday night and Friday night.

ATLANTIC OCEAN...

An upper level cyclonic circulation center is near 29N73W, about
270 nm to the NNE of the NW Bahamas. Upper level cyclonic wind
flow that is moving around the 29N73W center covers the Atlantic
Ocean and the Gulf of Mexico from 23N northward between 65W and
85W. A surface trough is along 31N69W, to a 1015 mb low pressure
center that is near 27N71W, with the trough curving to Andros
Island in the Bahamas. Precipitation: isolated moderate to locally
strong rainshowers cover the Gulf of Mexico and the Atlantic
Ocean from 20N to 32N between 65W and 86W. Widely scattered
moderate to isolated strong rainshowers are in the Atlantic Ocean
from 24N northward between 58W and 65W.

The low pressure center that is near 27N71W has weakened the
surface ridge that covers the western Atlantic Ocean. The low
center will move SW toward the Bahamas today and tonight. The
high will rebuild and strengthen from Wednesday through Saturday
night, as the low weakens into a trough and tracks across the NW
Bahamas and over Florida on Wednesday and Wednesday night. The wind
speeds to the N of Hispaniola will pulse to strong each day
during the afternoon and evening beginning on Wednesday.
Generally tranquil marine conditions are expected in the
remainder of the area through the period.

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

$$
CAM/MT
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