Tropical Weather Discussion
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AXNT20 KNHC 182352

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
744 PM 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 1800 UTC surface analysis and satellite imagery through
2330 UTC.


A non-tropical 1004 mb surface low is centered northeast of the
Turks and Caicos near 24N69W with a surface trough extending from
20N74W through the low then to 27N63W. Scattered moderate convection
is from 22N-26N between 64W-69W. The low is expected to acquire
some tropical characteristics as upper-level winds become more
conducive, and a subtropical or tropical cyclone will likely form
during the next few 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 details.


A tropical wave is moving across the east Atlantic with axis that extends
from 15N29W to 04N31W, moving west at 5-10 kt over the past 24 hours.
The wave coincides with a well defined 700 mb trough depicted by
model guidance and is embedded within a surge of moisture. Scattered
moderate convection is from 04N-14N between 25W-33W.


The Monsoon Trough extends across Africa into the east Tropical Atlantic
near 11N16W to 08N26W to 05N39W. Aside from the convection related to
the tropical wave, scattered moderate convection is from 05N- 08N between



A surface ridge extends across the basin anchored by a 1018 mb
high centered south of Georgia near 31N83W. With this, fair
weather prevails across the basin with a light to gentle
anticyclonic flow. Expect for a cold front to approach the
northwest portion of the basin by Thursday. This front will
continue moving south across the basin enhancing winds/convection.


A 1010 mb surface low is centered over the west Caribbean near
16N81W. A surface trough extends from 12N82W, to the low, to
19N81W. Scattered moderate convection is observed with the low and
in its vicinity mainly south of 17N between 73W-88W. A diffluent
flow aloft generated east of an upper-level trough that extends
across the western Atlantic is enhancing scattered to numerous
showers and thunderstorms across the eastern Caribbean east of
70W. This activity is mostly affecting the western portion of
Puerto Rico at this time, where flooded roads are reported and Rio
Guanajibo is out of its bank and is been monitored. Scatterometer
data depicts light to gentle easterly winds west of 70W while
gentle to moderate southeasterly winds prevail east of 70W. Expect
for a similar weather pattern to continue through the next
24 hours.


Isolated moderate convection is observed across the eastern
portion of the island induced by a diffluent flow aloft that
prevails just east of an upper-level trough that extends across
the western Atlantic. These conditions will prevail through the
next 24 hours, with a higher convection coverage in the afternoon
hours as this upper-level flow combines with daytime heating.


A tropical wave is moving across the basin. Please refer to the
section above for details. A surface ridge extends acros the far
west Atlantic anchored by a 1018 mb high centered south of
Georgia near 31N83W. To the east, the base of an upper-level
trough extends west of 65W, with a diffluent flow prevailing
south of 30N between 60W-65W. This flow is related to the 1004
mb surface low discussed in the Special Features section above.
Scattered to numerous showers and thunderstorms are across this
area and also affecting the eastern Caribbean. To the east, a
stationary front was analyzed from 22N48W to 32N37W. A surface
trough extends across the eastern Atlantic from 30N29W to 31N21W.
Little change is expected through the next 24 hours.

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