[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 162329
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
729 PM EDT Fri Jun 16 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
2315 UTC.

...TROPICAL WAVES...

A tropical wave extends its axis from 11N21W to 03N21W moving
westward at 10 to 15 kt. A cluster of moderate to strong
convection is noted on the east side of the wave axis, covering
the area from 07N to 09N between 17W and 21W. Scattered moderate
to isolated strong convection is noted elsewhere from 02N to 09N
between 22W and 29W. The wave shows up pretty well in the TPW
product and 700 streamline analysis.

A tropical wave extends its axis from 10N33W to a 1012 mb low
pressure located near 06N34W to 00N33W moving westward at about 10
kt. Cloudiness and showers associated with this system have
become better organized since yesterday. Additional slow
development is possible during the next few days while the wave
moves westward over the tropical Atlantic. Satellite imagery
indicates scattered moderate convection from 03N to 09N between
30W and 36W. Latest Tropical Weather Outlook gives this system a
low chance of development during the next 48 hours, and a medium
chance of development through 5 days.

A tropical wave extends its axis from 14N41W to 06N42W. A small
cluster of showers is within about 90 nm west of the wave's axis
and along 10N. The wave is well defined in the TPW animation and
700 streamline analysis.

A tropical wave is over the central Caribbean and extends its
axis from the Windward Passage to the coast of Colombia near
11N75W. This wave is moving across an area where a diffluent flow
aloft is enhancing scattered to numerous moderate convection,
currently extending across the west Caribbean mainly west of 75W.
The wave is very well depicted in the moisture product and 700 mb
streamline analysis. This wave will become absorbed in a broad
area of low pressure forecast to form over the NW Caribbean during
the upcoming weekend.

...MONSOON TROUGH/ITCZ...

The Monsoon Trough extends from the coast of west Africa near
10N15W to 06N32W. The ITCZ extends from 08N43W to 07N57W. Three
tropical waves are embedded within the Monsoon Trough/ITCZ. Most
of the convective activity is associated to these features.

...DISCUSSION...

GULF OF MEXICO...

A weak ridge dominates the Gulf region, anchored by a 1016 mb high
centered near 26N88W. This high is forecast to remain nearly
stationary over the next 24 hours. Under the influence of this
system, mainly gentle to moderate anticyclonic flow prevails
across the basin. Water vapor imagery indicates the presence of
an upper-level trough extending from Louisiana, across the
western Gulf to near Veracruz, Mexico. A short-wave trough is
near western Florida. Upper-level diffluence on the east side of
the trough combined with a moist and humid SE flow at low levels,
will continue to support the showers and thunderstorms over parts
of Florida, Cuba and the Bahamas. Plenty of moisture is expected
to persist over the southeast Gulf and the Yucatan Peninsula
through the weekend. This weather pattern will be associated with
a broad area of low pressure forecast to form over the northwestern
Caribbean Sea and the Yucatan Peninsula during the next day or
two. Conditions appear to be favorable for gradual development of
this system while it moves slowly northwestward into the southern
Gulf of Mexico early next week. The latest Tropical Weather
Outlook gives this low pressure a medium chance of development
through 5 days.

CARIBBEAN SEA...

A tropical wave is moving across the central Caribbean. Please
refer to the section above for details. Convection is on the
increase across the western Caribbean as a diffluent flow aloft
prevails over the area mainly west of 75W. A surface trough was
analyzed over the northwest Caribbean from 20N84W to 17N84W. A
broad area of low pressure is expected to form in this area during
the next day or two. Scatterometer data show moderate to fresh
winds in the wake of the tropical wave. Mainly gentle to moderate
winds are over the northwest Caribbean. Experimental GOES-16
satellite imagery hints the presence of a low-level circulation
near the coast of Honduras, along the aforementioned surface
trough. 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 area and the Atlantic ridge. Plenty of moisture and
very active weather is also expected with this low, likely
affecting the western and central Caribbean Sea, Central America,
and most of Cuba during the weekend. Locally heavy rain and gusty
winds could occur over these areas.

...HISPANIOLA...

A tropical wave combined with the local effects and a diffluent
flow aloft will continue to produce scattered showers and
thunderstorms through tonight. On Saturday, moisture is forecast
to diminish across the island as the tropical wave continues to
move away from the area. So, expect scattered showers and isolated
thunderstorms in association with the local effects, and mainly
during the afternoon and evening hours this weekend.

ATLANTIC OCEAN...

Three tropical waves are moving westward across the basin. Please
refer to the Tropical Waves section above for details. A surface
trough remains over the Atlantic ocean and extends from 30N56W to
24N57W. This trough is a reflection of an upper-level low located
near 26N55W, with a trough extending southwest across the Leeward
Islands into the eastern Caribbean. Isolated showers are observed
along the surface trough. Elsewhere, a broad high pressure covers
the Atlantic from the Azores to the Florida Peninsula, with a
1020 mb high pressure near 26N65W, and the main center of 1026 mb
located southwest of the Azores near 35N28W. 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 41W, as noted in the Saharan Air
Layer from CIMSS.

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

$$

ERA

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