Tropical Weather Discussion
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AXNT20 KNHC 181748

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 AM EDT TUE OCT 18 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.


A non-tropical 1004 mb surface low is centered northeast of the
Turks and Caicos near 23N70W with a surface trough extending
from 26N65W through the low then across the Turks and Caicos to
northeast Cuba near 20N75W. Clusters of scattered moderate to
isolated strong convection are from 25N to the Greater Antilles
between 60W-72W. The low is expected to slowly intensify as
upper level winds become more conducive, and a subtropical or
tropical cyclone could form during the next couple of days.
There is a medium chance of tropical formation in the next 48
hours as the low moves northeast today, then toward the north
and northwest later in the week. Please see the Tropical Weather
Outlook under AWIPS/WMO headers MIATWOAT/ABNT20 KNHC for more


Tropical wave in the east Atlantic extends along 28W/29W from 7N-
15N moving west 5 to 10 kt over the next 24 hours. Wave
coincides with a weak 700 mb trough and is embedded within a
surge of moisture. Scattered moderate to isolated strong
convection is from 9N-12N between 25W-30W.


The Monsoon Trough extends across Africa into the east Tropical
Atlantic near 11N16W then along 8N20W 8N27W to 5N39W. The ITCZ
has been disrupted across the Atlantic basin. Scattered moderate
convection is from 4N to the equator between 18W-22W.



An upper ridge is anchored over central Alabama moving into
central Georgia and extends a ridge axis south into the
northeast Gulf to 27N88W. A second upper ridge extends from the
northwest Yucatan to the central Texas coast. Strong subsidence
and dry, stable air aloft dominates much of the Gulf this
afternoon. A surface ridge extends over the Gulf from northeast
to southwest anchored by a series of 1020 mb highs. One high is
in the west Atlantic near 35N68W, with a second over South
Carolina and a third over central Georgia. The southerly surface
flow around the surface ridge is bringing isolated showers
within 45/60 nm of 90W north of 25N to inland over southeast
Louisiana. The remainder of the Gulf is under fair weather this
afternoon. The surface ridge will persist through Wednesday then
shift east ahead of a cold front that will move into the
northwest Gulf Thursday. The front will race east reaching from
central Florida to the Yucatan peninsula by Friday night.


A broad upper ridge anchored over Honduras extends an upper
ridge axis east to over the Leeward Islands covering the
Caribbean with near zonal westerly flow aloft. A mid to lower
level trough extends from the west Atlantic to over the west
Caribbean supporting a surface trough that extends at 18/1500
UTC from 19N81W through a newly developed 1010 mb near 16N81W
then along 13N80W to 11N80W. Scattered showers and isolated
thunderstorms are within 120 nm east of the surface trough. The
mid level trough is generating scattered to numerous showers and
scattered thunderstorms are within 120 nm of line from 13N79W to
across Hispaniola and Puerto Rico near 18N67W. The surface
trough and low will persist through the end of the week. A cold
front will move into the northwest Caribbean this weekend from
the Gulf of Mexico.


The mid to lower level trough over the west Atlantic extends
into the north Caribbean between 70W-85W covering the island
with diffluent flow to generate isolated to scattered showers
over the island of Hispaniola with possible isolated
thunderstorms developing later this afternoon. This could give
the island showers and possible thunderstorms through the end of
the week.


A deep layered trough extends over the west Atlantic from 65W-
80W supporting the low and surface trough in the special
features above. The upper ridge over the Caribbean extends into
the central Atlantic from the Leeward Islands near 18N63W along
24N54W to beyond 32N52W. This is providing difflunce aloft to
enhance the activity associated with the special features
low/trough. A deep layered trough over the east/central
Atlantic is supporting a remnant stationary front that extends
through 32N36W 25N43W to 21N49W. Isolated showers are possible
within 60 nm either side of the front north of 26N. A surface
ridge dominates most of the east Atlantic with a weakness in the
vicinity of a 1018 mb low near 29N24W. The west Atlantic,
special features low will move northeast today, then toward the
north and northwest later in the week. Fresh to near gale force
winds will occur mainly on the northwest side of the low. A cold
front will move into the west Atlantic this weekend.

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