[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150554
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
154 AM EDT Mon Oct 15 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 0000 UTC surface analysis and satellite imagery through
0515 UTC.

...SPECIAL FEATURES...

Shower and thunderstorm activity has increased overnight in
association with a broad area of low pressure over the
southwestern Caribbean Sea centered near 14N80W. Scattered
moderate convection prevails over the W Caribbean from 12N-16N
between 78W-82W. The monsoon trough extends NE from the low to
16N77W and W from the low over Central America to 14N83W to
16N90W. An area of upper-level diffluence over Central America is
enhancing convection over Central America. Satellite imagery shows
scattered moderate isolated strong convection over southern and
western Nicaragua, southern Honduras, El Salvador and the south
coast of Guatemala. Scattered thunderstorms are also noted over
the Mexican states of Chiapas, Oaxaca and Veracruz. The broad low
is moving slowly west-northwestward, and some additional
development is possible before it moves inland over Central
America tonight or Tuesday. Regardless of development, locally
heavy rainfall, which could cause flash flooding, is possible
across portions of Central America for much of the week. In
addition to the potential for heavy rain over Central America,
these rains could spread to the Yucatan Peninsula and portions of
southern Mexico this week.

...TROPICAL WAVES...

A low amplitude tropical wave extends its axis along 44W from
01N-12N, moving west at 15-20 kt. A 700 mb trough is shown by
model analyses with this wave. TPW imagery indicates abundant
moisture in its environment. Scattered moderate to strong
convection is occurring from 06N-14N within 180 nm of the wave
axis.

A tropical wave extends its axis along 51/52W from 08N-21N,
moving west at 10-15 kt. A 700 mb trough is depicted by model
analyses with the wave, and there is a local maximum in TPW. A
recent ASCAT pass shows that the tropical wave is well-defined at
the surface with 25-30 kt winds from 16N-18N within 60 nm of the
wave axis. Scattered moderate to strong convection is noted from
15N-18N between 48W-52W. Scattered showers are noted from 19N-
22N between 46W-50W and along the wave's axis south of 13N. It is
likely that the tropical wave along 44W will be merging with this
wave over the next 24 hours. Expect plenty of convective activity
near and in between both waves. Moisture associated with these
waves is likely to enhance showers and thunderstorms over the
Lesser Antilles Tuesday into Wednesday, and this activity will
spread to the eastern Caribbean Sea during the middle of the
week.

A tropical wave extends its axis along 62W from 08N-21N moving
west at 10 kt. Scattered showers are noted just north of the
northern Leeward Islands and Virgin Islands. Additional scattered
showers and storms are seen from 11N-14N between 55W-60W. The
northern end of the wave is moving into an area of diffluent flow
aloft this morning. Enhanced showers and thunderstorms are
possible today for the Leeward Islands, Virgin Islands, and
Puerto Rico. This wave is expected to continue weakening into
Tuesday as it moves toward the central Caribbean.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the eastern Atlantic from the coast of
Africa near 13N17W and extends to 07N23W to 07N28W. The ITCZ
extends from 07N28W to 08N35W to 08N41W. Scattered moderate
convection is seen along and within 180 nm south of the ITCZ between
28W-32W. Another area of scattered moderate convection is noted
from 03N-06N between 18W-21W.

GULF OF MEXICO...

An upper-level anticyclone over central Mexico extends an upper-
level ridge over the western and north-central Gulf of Mexico. A
surface ridge prevails across the northeastern and north-central
Gulf. With this, dry air covers most of the basin. A cold front will
enter the far NW and W central Gulf by Tue morning. Ahead of the
front, numerous showers and thunderstorms are expected over the
far NW and W central Gulf beginning late this morning and
increasing this afternoon. This front will slowly shift southward
over the western Gulf through Wed night. Fresh to strong northerly
winds behind the front will increase to minimal gale force in the
W central and SW Gulf behind the front Tue night through Thu
night. Winds will diminish below gale force by Fri.

Due to the combination of the front with the broad low mentioned
in the Special Features section, expect enhanced shower and
thunderstorm activity over the southwestern Gulf of Mexico Tue
into Wed.

CARIBBEAN SEA...

Two tropical waves will affect the Lesser Antilles over the next
few days. See the Tropical Waves section for more details. See
Special Features section for information relating to the broad low
in the western Caribbean.

A mid to upper level trough extends from 23N66W to the Mona
Passage. An area of scattered moderate convection extends from
the north coast of western Puerto Rico to 21N between 66W-68W.
Isolated showers prevail from 14N-17N between 65W-69W. Elsewhere,
scattered showers are within 60 nm of the northwest coast of
Venezuela and the northeast coast of Colombia.

ATLANTIC OCEAN...

The three tropical waves in the Tropical Atlantic and Lesser
Antilles region have been described above in the Tropical Waves
section.

A cold front extends across the west Atlantic from 32N59W to
30N66W, where it becomes a stationary front. The stationary front
extends from that point to 28N74W, where it becomes a dissipating
stationary front. The dissipating stationary front extends from
that point to near 27N79W. Isolated showers are along and within
60 nm SE of the front.

A 1025 mb high is centered near 30N46W, leading to relatively
quiet weather elsewhere.

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

$$
Hagen
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