[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201736
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
136 PM EDT Sat Oct 20 2018

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...

An Atlantic tropical wave is along 52W from 03N-15N, moving west
around 15 kt. Total Precipitable Water imagery shows moderate to
high moisture content in the wave's environment. Scattered
moderate convection is seen from 07N-10N between 49W-55W.
Scattered showers are also present from 10N-14N between 45W-50W.
The wave could help to enhance showers and thunderstorms over the
southern Windward Islands and southeast Caribbean late this
weekend into early next week.

A western Caribbean tropical wave is along 81W from 08N-18N,
moving west around 10 kt. The wave corresponds with a 700 mb
trough, as indicated by model analyses. Numerous moderate with
embedded isolated strong convection is noted south of 12N and
west of 79W, extending to the coasts of Panama and Costa Rica, where
the wave meets the monsoon trough. Upper-level divergence over the
southwestern Caribbean is also playing a significant role in
enhancing the convection.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast Africa near 14N17W
to 10N20W. The ITCZ extends from 10N20W to 06N25W to 04N46W.
Scattered to numerous moderate convection is seen from 09N-14N
between 16W-24W. Scattered moderate isolated strong convection is
occurring along and within 240 nm north of the ITCZ between 24W-
35W. Scattered showers and isolated thunderstorms are within 210
nm of the ITCZ between 35W-42W.

GULF OF MEXICO...

At 1500 UTC, a cold front extends from the Texas/Louisiana border
near 30N94W to 29N95W, where it becomes a stationary front, which
extends to 1017 mb low near 27N96W. A trough extends southward
from the low to 23N96W to 19N94W. Another surface trough is
analyzed from 29N92W to 25N93W. At upper-levels, diffluence is
occurring over portions of the western Gulf. Scattered moderate
convection is noted over the western Gulf from 18N-24N between
94W-97W, and from 24N-29N between 92W-96W. A 1019 mb high is
centered over northern Florida, leading to quiet weather east of
90W.

A surface trough will persist over the SW Gulf through early next
week. A cold front will reach the northern Gulf waters this
evening. It is expected to become stationary as it reaches from S
Florida to near 25N97W by Sun evening. Low pressure will develop
over the far western Gulf late Sun night along the surface trough
near 26N96W. It will lift north-northeastward through Mon night,
then east-northeastward across the north-central Gulf through Wed
as high pressure builds across the waters north of the front and
to the west of the low. A front will extend southwestward from the
low through Wed. Another cold front will approach the far NE Gulf
Wed. Fresh to strong winds and building seas are expected over
these waters through period. Numerous showers and thunderstorms
are likely over much of the western Gulf through Wed. Scattered
showers and isolated thunderstorms are expected over the north-
central Gulf.

CARIBBEAN SEA...

The East Pacific monsoon trough extends eastward along 10N from
Costa Rica to northern Colombia near 75W. Convection associated
with a tropical wave along 81W interacting with the monsoon
trough is described above in the tropical waves section. Farther
east, Total Precipitable Water imagery shows high moisture
content over northeastern Venezuela and the extreme southeastern
Caribbean. Weak upper-level diffluence is noted along the northern
coast of Venezuela. Scattered showers are occurring along the
northern coast of Venezuela extending to 13N, including Trinidad
and the southern Windward Islands. The remainder of the Caribbean
is experiencing relatively quiet weather.

Expect enhanced shower and thunderstorm activity to persist over
the southeast Caribbean, southern Windward Islands, Trinidad and
northern Venezuela into the middle of next week. Fresh to strong
winds are expected in the Windward Passage, south of Hispaniola,
and near the coast of Colombia today. Otherwise, moderate to fresh
trades will prevail across most of the region through Tue night.

ATLANTIC OCEAN...

A stationary front passes through 32N49W to 27N60W to 26N69W, with
a dissipating stationary front from that point to 26N73W. A
surface trough extends from 30N48W to 25N53W. Scattered moderate
convection prevails north of 25N between 46W-54W. Scattered
showers are seen from 23N-25N between 51W-57W. To the south,
another surface trough is located from 20N54W to 16N57W. Isolated
showers are noted east of the trough between 50W-53W. Another
surface trough is from 16N38W to 10N42W. Upper-level west winds
are pushing the convection well east of the trough axis. Scattered
moderate convection is seen from 10N-14N between 30W-36W and from
14N-17N between 30W-39W. Elsewhere, scattered showers are noted
from 18N-22N between 30W-40W. An area of numerous moderate to
strong convection is noted just east of Trinidad from 09N-12N
between 59W-61W. Scattered showers and thunderstorms are in
between that cluster and the tropical wave along 52W. For more
details on the moisture leading to the convection in this area,
see the Caribbean Sea section above.

The aforementioned stationary front well east of the northwest
Bahamas will dissipate by this evening west of 65W. A strong cold
front will move off NE Florida this evening, reach from near
31N70W to 27N75W to near West Palm Beach Sun afternoon, from near
31N64W to 26N72W to Miami late Sun night, and from 26N65W to the
NW Bahamas and the Florida Keys by Mon evening then become
stationary. Fresh to strong winds and building seas are expected
behind this front through late Mon before gradually subsiding Tue
into Wed.

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

$$
Hagen
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