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Atlantic Tropical Weather Discussion

AXNT20 KNHC 271757

Tropical Weather Discussion 
NWS National Hurricane Center Miami FL 
205 PM EDT TUE SEP 27 2016

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 wave along 52W/53W from 6N-18N with a 1008 mb low along
the wave near 11N53W moving west-northwest near 15 kt over the
past 24 hours. Wave shows that it is well organized and a
tropical depression or tropical storm could form later today or
tonight. Scattered moderate to isolated strong convection is
within 60/75 nm of a line from 12N50W to 15N52W. Scattered
showers and isolated thunderstorms dot the area from 10N-17N
between 49W-57W. Regardless of tropical development, heavy rains
and strong gusty winds, possibly to tropical storm force, are
expected to spread over portions of the Lesser Antilles
beginning tonight and continuing into Wednesday. Please see the
Tropical Weather Outlook under AWIPS/WMO headers MIATWOAT/ABNT20
KNHC for more details. 


Tropical wave in the east Tropical Atlantic extends along 23W-
24W from 3N-14N moving west near 25 kt over the past 24 hours.
Wave coincides with a 700 mb global model low and trough and
remains embedded within an area of moisture as seen on the Total
Perceptible Water imagery. No associated deep convection is

Tropical wave in the Caribbean extends along 71W/72W from 10N-
19N moving west at 10 to 15 kt over the past 24 hours. Wave is
trailing a weak 700 mb global model trough and remains embedded
within an area of moisture as seen on the Total Perceptible
Water imagery. Wave is beneath an upper trough partially masking
the satellite signature. No associated deep convection is noted. 


The Monsoon Trough extends across Africa into the east Tropical
Atlantic near 14N17W then along 7N23W 8N34W to 10N42W. The ITCZ
is again disrupted by the tropical wave in the special features
above. Clusters of scattered moderate to isolated strong
convection are from 5N-8N between 11W-15W, 3N-7N between 19W-
22W, within 150/180 nm north of the monsoon trough between 24W-
41W, and within 210/240 nm south of the monsoon trough 28W-42W. 



An upper trough over the east CONUS is supporting a stationary
front along the coast of southwest Louisiana and Texas. A
surface trough is just offshore extending from 29N94W along
24N96W 21N96W into the Bay of Campeche to the coast of Mexico
near 18N94W. Scattered to numerous showers and isolated
thunderstorms are south of 28N west of 92W. This front and
trough are beneath an upper ridge that is anchored over central
Mexico and covers the Gulf west of 84W. An upper trough covers
the Florida peninsula extending from the west Atlantic across
Florida near Cape Canaveral to the Florida Keys generating
scattered to numerous showers and scattered thunderstorms from
23N-26N east of 83W through the Straits of Florida and over the
Florida Keys. The west Gulf surface trough will drift west and
weaken through Wednesday night. A cold front will enter the
north Gulf Thursday, becoming stationary from central Florida to
the southwest Gulf Friday. 


The upper ridge over the Gulf of Mexico covers the far west
Caribbean west of 80W. Isolated showers and thunderstorms dot
the northwest Caribbean north of 20N between 80W-85W. An upper
low north of the Hispaniola extends an upper trough through the
Mona Passage along 15N70W to east Panama generating scattered
showers and isolated thunderstorms north of 15N to over the
Leeward/Virgin Islands between 61W-67W. The monsoon trough
extends along 10N from over Colombia to across Costa Rica
generating scattered showers and isolated thunderstorms south of
13N west of 77W. The tropical wave will continue west and move
through the west Caribbean through Friday. The 1008 mb low along
the tropical wave in the special features, is expected to become
a tropical cyclone before it moves across the Windward Islands
with Gale force winds north of the low as it crosses the Lesser


Currently skies are mostly clear across the island this
afternoon. The upper trough through the Mona Passage will shift
west of the island by late Wednesday. Afternoon/evening showers
and thunderstorms will continue through Wednesday. Thursday will
bring an increase of moisture to the Dominican Republic when the
tropical wave in the special features moves into the eastern
Caribbean. This will increase the showers and thunderstorms
especially across the south portion of the island through the end
of the week. 


The upper low is centered in the west Atlantic near 30N80W with
an upper trough extending across Florida to over the Florida
Keys and supporting a surface trough that extends from a 1012 mb
low near 31N80W along 28N79W to over Florida near Fort
Lauderdale. A second upper low is centered north of Hispaniola
near 23N69W. Between these upper lows is wedged an upper ridge
providing diffluence aloft to generate scattered showers and
isolated thunderstorms from 22N-28N west of 71W and north of 28N
between 70W-76W. A surface ridge covers the northwest and
north/central Atlantic anchored by a 1024 mb high 36N60W. An
upper trough extends over the north/central Atlantic to 30N
supporting a cold front that extends through 32N43W to 30N50W
becoming stationary to 50N58W where it dissipates to 29N58W.
Scattered showers and possible isolated thunderstorms are within
120 nm of the front east of 56W. The remainder of the Atlantic
east of the above front is dominated by a surface ridge anchored
by a 1033 mb high east of the Azores. Winds and Seas will
increase over the west Tropical Atlantic Wednesday then north of
the Puerto Rico and Hispaniola on Friday as the low/tropical
wave in the special features moves into the Caribbean.  

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