[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131203
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
803 AM EDT Sat Oct 13 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 0600 UTC surface analysis and satellite imagery through
1145 UTC.

...SPECIAL FEATURES...

Hurricane Leslie centered near 36.2N 16.7W at 13/0900 UTC or 500
nm E of the Azores moving ENE at 33 kt. Estimated minimum
central pressure is 980 mb. Maximum sustained wind speed is 65
kt with gusts to 80 kt. A Tropical Storm Warning is in effect for
Madeira Island. A fast motion toward the east-northeast is
expected to continue through Sunday. On the forecast track, the
center of Leslie will pass north of Madeira Island this morning,
approach the southwestern portion of the Iberian Peninsula today,
and move inland over portions of Portugal and Spain tonight and
Sunday. Leslie is expected to transition into a hurricane-force
post-tropical cyclone later today. Weakening is forecast after
Leslie moves inland over the Iberian Peninsula tonight, and the
post-tropical cyclone is expected to dissipate by Sunday
night/early Monday. Scattered moderate convection extends outward
to 180 nm from the center in the eastern semicircle and to 60 nm
in the northwest quadrant. See the latest NHC forecast/advisory
under AWIPS/WMO headers MIATCPAT3/WTNT33 KNHC for more details.
Interests in Portugal and Spain should monitor the progress of
Leslie. Additional information on this system can be found in
products from the Portuguese Institute for Sea and Atmosphere at
www.ipma.pt. Interests in Spain should refer to products from the
State Meteorological Agency at www.aemet.es.

...TROPICAL WAVES...

A low amplitude tropical wave has been introduced to this
analysis, extending its axis along 34W from 02N-10N, moving west
at 5-10 kt. At this time, scattered to numerous showers and
thunderstorms prevail from 02N-10N between 30W-38W.

Another tropical wave has been introduced to this analysis, with
axis extending along 40W from 08N-21N, moving west at 10-15 kt.
This wave is what was previously called Nadine. Scattered moderate
convection is noted from 18N-20N between 35W-40W.

The tropical wave extends its axis along 55W from 07N-20N based
on satellite imagery and model diagnostics. Movement is westward
at 5-10 kt. A slight maximum in Total Precipitable Water is noted
with the wave. Scattered showers are noted from 16N-20N between
54W-60W. Isolated showers extend to 120 nm west of the wave axis
from 15N-18N.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the eastern Atlantic from the coast of
Senegal near 14N17W and extends to 07N22W. The ITCZ extends from
07N22W to 05N32W, then resumes west of a tropical wave from 05N36W
to 06N53W. Aside from the convection related to the tropical wave
along 34W, scattered moderate convection is noted within 180 nm
south of the ITCZ between 20W-30W.

GULF OF MEXICO...

A frontal boundary extends from 26N81W to 22N88W to 25N98W. No
significant convection is currently occurring with the front, and
dry air prevails north of it covering the majority of the basin.
Scattered showers cover the southern portion of the Bay of
Campeche south of 20N between 90W- 94W. The front will continue
to weaken and wash out as it drifts slowly southward today. High
pressure is building in over the northern Gulf in the wake of the
front. Another cold front will approach the NW Gulf by Mon night,
but will stall across the western Gulf through Wed night. Behind
the front, expect fresh to strong northerly winds and building
seas, with near-gale force winds likely along the coasts of
Tamaulipas and Veracruz.

CARIBBEAN SEA...

An upper-level trough extends from 25N65W to Haiti to Jamaica. To
the southeast of this upper-trough, ample moisture is present
along with persistent shower and thunderstorm activity. These
showers and thunderstorms are affecting eastern portions of the
Dominican Republic, Puerto Rico and the Virgin Islands. Scattered
showers and thunderstorms extend across the eastern Caribbean from
the coast of Venezuela to Puerto Rico between 63W-70W.

A Central American Gyre has formed in the southwest Caribbean.
GOES-16 Total Precipitable water clear shows large scale rotation
associated with the gyre. A surface trough is analyzed through the
developing gyre from 18N79W to a 1009 mb low near 13N80W.
Scattered showers and isolated thunderstorms are noted from 10N-
18N between 70W- 84W, although little to no showers are occurring
north of 15N and west of 80W. This gyre, will slowly shift W
toward central America through early next week. Enhanced showers
and thunderstorms are expected to persist over the southwest
Caribbean. Another surface trough is located from northwestern
Honduras to northern Belize. Scattered showers and thunderstorms
are over Belize, northern Guatemala and the Yucatan Peninsula.

To the south, the monsoon trough extends over the SW Caribbean Sea
from 12N73W to 12N80W to the coast of central Nicaragua. Scattered
moderate convection is occurring over Nicaragua and waters west of
81W and south of 14N.

Expect moderate trade winds to prevail across the eastern
Caribbean Sea through tonight. Mainly moderate to fresh trades
will prevail across the basin for the start of next week. The
tropical wave associated with the remnants of Nadine is expected
to reach the Lesser Antilles early next week.

ATLANTIC OCEAN...

Refer to the sections above for information on Hurricane Leslie,
the remnants of Nadine (now a tropical wave) and the tropical
waves along 34W and 55W.

A cold front extends across the west Atlantic from 32N70W to
26N80W. Scattered showers prevail about 300 nm ahead of the
front. To the east, a surface trough is analyzed north of La Mona
Passage from 24N65W to 21N67W. The trough is helping to enhance
showers and thunderstorms over Puerto Rico to 23N between 61W-
69W.

Farther east, a cold front extends from 32N26W to 30N43W. A
surface trough extends from 28N23W to 26N28W with scattered
showers.

A 1021 mb high is centered near 30N46W, leading to relatively
quiet weather from 25N-32N between 43W-53W.

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

$$

AH/ERA
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