[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 161745
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
145 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 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...TROPICAL WAVES...

A tropical wave extends from 11N20W 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 07N between 21W and
25W. The wave shows up pretty well in the TPW product and 700
streamline analysis.

A tropical wave extends from 11N32W to a 1012 mb low pressure
located near 05N33W to 02N33W moving westward at near 10 kt.
Cloudiness and showers associated with this tropical 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 low a low chance of development
in 48 hours, and a medium chance of development through 5 days.

A tropical wave extends from 14N41W to a 1012 mb low pressure near
08N41W to 06N41W. Visible satellite imagery shows a swirl of low
clouds associated with the low center forecast to dissipate in
about 24 hours. A small cluster of moderate convection is within
about 90 nm NW of the low center. The wave is well defined in the
TPW animation and 700 streamline analysis.

Another tropical wave is over the central Caribbean and extends
from Haiti to the coast of Colombia near 11N74W. Scattered showers
and thunderstorms are near the southern end of the wave axis. 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.

The tropical wave, that was previously moving across the SW
Caribbean, has been already absorbed by a developing broad area
of low pressure located over the NW Caribbean.

...MONSOON TROUGH/ITCZ...

The Monsoon Trough extends from the coast of west Africa near
10N14W to 08N21W to 06N32W. The ITCZ extends from 06N43W to
06N56W. Three tropical waves are embedded within the Monsoon
trough/ITCZ. Most of the convective activity is associated with
these tropical waves.

...DISCUSSION...

GULF OF MEXICO...

A weak ridge dominates the Gulf region. A weak 1015 mb high
pressure is analyzed near 26N88W and it is forecast to remain
nearly stationary over the next 24 hours. Under the influence of
this system, mainly gentle to moderate anticyclonic flow prevails.
A thermal trough, that normally develops during the evening hours
over the Yucatan Peninsula and moves across the SW Gulf during
the overnight and early morning hours, extends along 94W south of
22N. Moderate to fresh E to SE winds are noted per scatterometer
data on the east side of the trough axis. Water vapor imagery
indicates the presence of an upper-level trough extending from SE
Louisiana, across the central Gulf to near Veracruz, Mexico. A
short-wave trough is near SW Florida. Upper diffluence on the
east side of the trough combined with a moist and humid SE flow at
low levels, will continue to support the development of showers
and thunderstorms over parts of Florida, Cuba and the Bahamas.
Plenty of moisture is expected to persist over the SE 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.
Latest Tropical Weather Outlook gives this low pressure a medium
chance of development through 5 days.

CARIBBEAN SEA...

Convection is on the increase across the western Caribbean. Satellite
imagery indicates clusters of moderate to strong convection, more
concentrated, from 13N to 18N between 78W and 83W. Similar convection
is also noted south of 12N between 73W and 80W. As of 1500 UTC, a
surface trough is analyzed over the NW Caribbean and goes from
21N85W to 16N85W. A diffluent pattern aloft, associated with the
above mentioned upper-level trough over the Gulf of Mexico, is
helping to induce all this convective activity. 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 that extends from Haiti to the coast of
Colombia. Mainly gentle to moderate winds are over the NW Caribbean.
Experimental GOES-16 visible 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 parts of Cuba, the
Yucatan Peninsula and Central America.

...HISPANIOLA...

A tropical wave, currently leaving Haiti, combined with the local
effects will produce scattered showers and tstms this afternoon
and early evening. 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.

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 surface trough remains over the
Atlantic ocean and extends from 31N54W to 22N59W. This trough is
a reflection of an upper-level low located near 25N55W, with a
trough extending SW across the Leeward Islands into the eastern
Caribbean. The low is generating scattered showers and isolated
thunderstorm. The most recent scatterometer pass shows the wind
shift associated with the trough. Otherwise, broad high pressure
covers the Atlantic from the Azores to the Florida Peninsula, with
a 1020 mb high pressure near 25N65W, and a main center of 1027 mb
located SW 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

$$
GR
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