[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 152342
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
742 PM EDT Thu Jun 15 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
2330 UTC.

...TROPICAL WAVES...

A strong tropical wave was added to the 1200 UTC surface map near
the west coast of Africa based on visible satellite imagery and
the Hovmoller Diagram. Its axis extends now from 11N16W to
04N16W. Scattered moderate convection extends from 03N-11N between
14W-21W.

A tropical wave located several hundred miles south-southwest of
the Cabo Verde Islands extends from 10N30W to a 1012 mb low
pressure located near 06N30W to 00N30W. This wave is producing
disorganized showers and thunderstorms from 03N-08N between 30W-
34W. Development, if any, of this system should be slow to occur
during the next few days while the wave moves westward near 20 kt
over the tropical Atlantic.

The tropical wave situated along 39W on the 1200 UTC surface map
was re-located farther east based on a recent ASCAT data. At this
time, the axis extends from 14N37W to 07N38W, moving westward at
around 10 kt. The wave remains embedded within an area of deep-
layer moisture as depicted on the TPW product. The wave also
coincides with an inverted trough at 700 mb. Satellite imagery
show isolated convection with some cyclonic turning along the
wave's axis.

A tropical wave is over the eastern Caribbean and extends from
western Puerto Rico to the coast of central Venezuela. Scattered
showers and thunderstorms are observed across the northern half of
the wave affecting the area north of 15N. The wave is very well
depicted in the moisture product and 700 streamline analysis. This
wave is forecast to move across Hispaniola through Friday.

Another tropical wave is drifting westward across the SW Caribbean
with axis from 17N82W to the coast of western Panama. Scattered
moderate convection is seen on either side of the wave axis
supported by a diffluent flow aloft that covers the western
Caribbean mainly west of 76W. This wave will reach central
America tonight, and will be absorbed by the complex low pressure
system forecast to develop over the northwestern Caribbean Sea and
the Yucatan Peninsula this weekend.

...MONSOON TROUGH/ITCZ...

The Monsoon Trough extends from the coast of west Africa near
08N18W to 07N28W. The ITCZ extends from 10N44W to 09N60W. Three
tropical waves are embedded within the Monsoon trough/ITCZ. Most
of the convective activity is associated to these waves.

...DISCUSSION...

GULF OF MEXICO...

A surface ridge extends from the western Atlantic, across Florida
into the Gulf of Mexico producing gentle to moderate E to SE
winds across the area. A thermal trough, that normally develops
during the evening hours over the Yucatan Peninsula and moves
across the southwest Gulf during the overnight and early morning
hours, extends along 90W south of 22N. Scattered to numerous
showers and thunderstorms are observed along the Yucatan Peninsula
near the trough. Water vapor imagery continues to reveal the
presence of an upper-level low spinning over the southeast Gulf,
with a trough that extends southwest across the northern Yucatan
Peninsula into the eastern Bay of Campeche. Upper diffluence on
the east side of the low combined with a moist and humid southeast
flow at low levels will continue to support the development of
scattered to numerous showers and thunderstorms over parts of
the Florida Peninsula, the Florida Keys and the southeast Gulf.
Abundant moisture is expected to persist over the southeast Gulf
and the Yucatan Peninsula through the weekend. This weather
pattern will be associated with a complex area of low pressure
forecast to form over the northwestern Caribbean Sea and the
Yucatan Peninsula this weekend. Conditions appear to be favorable
for gradual development of this system while it moves slowly
northwestward toward the southern Gulf of Mexico by early next
week.

CARIBBEAN SEA...

Two tropical waves are moving across the Caribbean Sea. Please
see the Tropical Waves section above for more details. These
tropical waves will become absorbed in a broad area of low
pressure forecast to form over the northwest Caribbean during the
upcoming weekend. Experimental GOES-16 visible satellite imagery
is already hinting the presence of a low-level circulation over
eastern Honduras. This system will bring increasing winds and
building seas across the central and western Caribbean during the
upcoming weekend due to a tight pressure gradient between the
developing low pressure and the Atlantic ridge. Plenty of moisture
and very active weather is also expected with this low affecting
the western and west and central Caribbean Sea as well as Central
America during the weekend. Locally heavy rain could occur over
parts of Cuba, the Yucatan Peninsula and Central America.
At this time, scatterometer data show moderate to fresh trades
across the east and central Caribbean. Gentle to moderate winds
prevail over the northwest Caribbean. This wind pattern will
continue through Saturday.

...HISPANIOLA...

A tropical wave, currently over western Puerto Rico, will move
across Hispaniola this evening through Friday supporting scattered
showers and thunderstorms as it moves through.

ATLANTIC OCEAN...

Three tropical waves were analyzed across the basin. Please refer
to the Tropical Waves section above for details. A surface trough
extends from 30N55W to 26N62W. This surface feature is the
reflection of an upper-level low centered near 28N57W, with a
trough extending southwest towards Puerto Rico. Isolated showers
are observed along this trough. Elsewhere, a broad high pressure
covers the remainder of the basin anchored by a 1020 mb surface
high centered near 27N68W and a 1026 mb surface high near 35N25W.
Moderate to locally fresh trades are around the southern periphery
of the ridge between the Windward Islands and the coast of
Africa. A surge of African dust continues to spread westward in
the wake of the tropical wave located along 38W as noted in the
Saharan Air Layer from CIMSS.

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

$$

ERA
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