[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 130004
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
803 PM EDT Mon Jun 12 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 1800 UTC surface analysis and satellite imagery through
2300 UTC.

...TROPICAL WAVES...

An eastern Atlantic tropical wave has an axis that extends from
14N27W to 05N27W, and is moving westward around 20 kt. This wave
is associated with broad 700 mb troughing between 25W and 38W. TPW
satellite imagery shows this wave is embedded in deep-layer
moisture. Scattered moderate convection is found from 03N to 05N
between 19W and 25W.

Another eastern Atlantic tropical wave has an axis that extends
from 12N35W to 04N36W, and is moving westward around 20 kt. This
wave is also associated with broad 700 mb troughing between 25W
and 38W. TPW satellite imagery shows this wave is encountering dry
air to the north of 10N. Scattered moderate convection is
observed from 04N to 06N between 32W and 36W.

A central Atlantic tropical wave has an axis that extends from
14N48W to 05N50W, and is moving westward around 15 to 20 kt. TPW
satellite imagery shows this wave is associated with a local
maximum in the poleward extent in moisture, but is only associated
with weak 700 mb troughing. Isolated moderate convection is seen
from 09N to 12N between 49W and 54W.

An eastern Caribbean tropical wave has an axis extending from
15N69W to 06N70W, and is moving westward around 20 kt. This wave
is associated with weak 700 mb troughing. An upper-level trough
that passes over the eastern Caribbean from Puerto Rico to central
Venezuela is producing subsidence in the vicinity of the wave
which is limiting moisture and inhibiting deep convection.

A western Caribbean tropical wave has an axis extending from
17N82W to 08N82W, and is moving westward around 10 kt. This wave
is associated with weak 700 mb troughing. The wave is also
interacting with the Monsoon Trough, which passes over the SW
Caribbean. However, upper-level ridging from the Gulf of Honduras
to the central Caribbean is producing subsidence over this wave
which is inhibiting deep convection.

...MONSOON TROUGH/ITCZ...

The Monsoon Trough extends over the Atlantic Ocean from the coast
of Senegal in west Africa near 16N17W to 08N24W to 08N35W. The
ITCZ extends from 08N38W to 09N49W, then resumes west of a
tropical wave near 10N51W to the coast of Venezuela near 09N61W.
Aside from convection discussed in the tropical waves section,
scattered moderate and isolated strong convection is noted from
03N to 09N between 11W and 18W.

...DISCUSSION...

GULF OF MEXICO...

An upper-level trough passes over the Gulf of Mexico from near
the Mouth of Mississippi to the Yucatan Peninsula. Divergent
upper- level winds on the east side of the trough are interacting
with deep-layer moisture over the central and eastern Gulf to
trigger isolated showers and thunderstorms over the Gulf east of
90W. Upper-level convergence and subsidence on the west side of
the trough is putting the damper on convection over the Gulf west
of 90W. A surface trough passes over the Bay of Campeche from
22N95W to 20N94W to 18N93W. Showers and thunderstorms associated
with this trough remain over southeastern Mexico. High pressure
over the Atlantic ridges westward from the Carolinas to Texas.
This ridge generally supports east-southeast wind flow over the
Gulf, except where winds are become strong and gusty in and near
thunderstorms. During the next 24 hours showers and thunderstorms
will continue primarily overthe eastern half of the basin as the
upper-level trough over the Gulf slowly shifts eastward.

CARIBBEAN SEA...

Two tropical waves are passing over the Caribbean. Please see the
tropical waves section for more details. The pressure gradient
between Atlantic high pressure and lower pressure associated with
the Monsoon Trough is generating moderate to fresh east to east-
southeast winds over the Caribbean basin. Winds are strongest over
the Gulf of Honduras and along the northern coast of Colombia.
Upper-level ridging from the Gulf of Honduras to the central
Caribbean is combining with an upper-level trough passing over the
eastern Caribbean from Puerto Rico to central Venezuela to create
a subsident environment over the basin which is inhibiting deep
convection.

...HISPANIOLA...

An upper-level trough extending southward over Puerto Rico into
the Caribbean is inhibiting convection somewhat. However, colder
air aloft is providing the instability for showers and isolated
thunderstorms mainly over the mountains during the afternoon and
early evening through Tuesday.

ATLANTIC OCEAN...

Three tropical waves are moving westward between the coast of
Africa and the Lesser Antilles. Please refer to the Tropical Waves
section above for details. A weak surface trough off the Florida
East Coast from 28N80W to 31N79W is supporting isolated showers
and thunderstorms along the Florida coast west of 78W. This trough
is expected to persist during the next 24 hours. A surface trough
located over the central Atlantic from 28N52W to 20N58W has no
deep convection associated with it. A weakening 1019 mb surface
low is centered SW of the Azores near 29N38W. No deep convection
is noted. Otherwise, broad high pressure covering the Atlantic
from the Azores to the Carolinas is generating moderate trades
north of the ITCZ to 22N between the Windward Islands and 30W.

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

$$
McElroy
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