[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121034
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
634 AM EDT Sat Oct 12 2019

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
1045 UTC.

...SPECIAL FEATURES...

Subtropical Storm Melissa is centered near 38.1N 68.2W at 11/0900
UTC or 375 nm S of Nantucket Massachusetts moving SSE at 3 kt.
Estimated minimum central pressure is 998 mb. Maximum sustained
wind speed is 40 kt with gusts to 50 kt. Scattered moderate
convection prevails across the northeast quadrant. Sub-T.S.
Melissa is forecast to weaken during the next couple of days and
is expected to become a remnant low by Sat night or early Sunday.
See the latest NHC forecast/advisory under AWIPS/WMO headers
MIATCPAT4/WTNT34 KNHC for more details.

...Gulf of Mexico Gale Warning...

A cold front over the NW Gulf extends from 29N90W to 21N97W near
Tampico, Mexico. The front will reach from the mouth of the
Mississippi River to Veracruz by Sat afternoon. Behind the front,
strong to gale force northerly winds are expected along the
Mexican coastal waters today. Winds will diminish across the area
Sun morning. Refer to the High Seas Forecast product under
AWIPS/WMO headers HSFAT2/FZNT02 KNHC for more details.

...Heavy rainfall event for Central America...

A broad area of low pressure is expected to form over the SW
Caribbean Sea this weekend. This system is forecast to move
westward toward Central America early next week, and some
development is possible if the low remains over water while moving
near the coasts of Honduras, Guatemala, and Belize. As the low
tracks westward toward Central America by early next week it will
likely interact with a Central American gyre. Through the weekend,
heavy rainfall is likely across Colombia, Panama, Costa Rica and
eastern portions of Nicaragua and Honduras. By early next week,
the heavy rain will continue in those locations and spread
northwestward to the rest of Central America as well as southern
Mexico. These rains could cause life-threatening flash flooding
and mudslides.

...TROPICAL WAVES...

An eastern Atlantic tropical wave has an axis from 18N33W to
01N33W, moving W at 10 kt. This wave is well depicted in
satellite imagery and model guidance. Scattered showers are noted
along the northern portion of the wave mainly north of 10N and
near the monsoon trough from 01N-07N between 30W-36W.

A central Atlantic tropical wave has an axis along 51W from 09N-
21N, moving W at 10 kt. Scattered moderate convection is over the
northern portion of the wave from 18N-23N between 51W-54W. This
convection is enhanced by an upper level low centered to the
northwest of the wave well depicted by the ASCAT.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends SW from the coast of Africa near
17N16W to 07N35W. The ITCZ extends from 07N35W to 07N49W. Besides
the convection mentioned in the tropical wave section, isolated
moderate convection seen along the monsoon trough from 05N-08N
between 34W-37W, and scattered showers along the ITCZ from 05N-
10N between 41W- 49W.

GULF OF MEXICO...

Refer to the section above for details on the Gale Warning
currently in effect.

A cold front extends from 29N90W to 21N97W near Tampico, Mexico,
then continues as a cold front in Mexico until it transitions to a
stationary front through Northern Mexico. Scattered moderate
isolated strong convection is noted along the frontal boundary
from north of Veracruz near 20N-21N and west of 96W, and another
area of convection is seen from 22N-26N between 91W-96W. Gale
winds are present behind this front in the NW Gulf with a Gale
Warning in effect. Isolated strong tstorms are seen in the Bay of
Campeche from 19N-21N and west of 95W. A surface trough is noted
in the eastern Gulf with no significant convection. Surface ridge
prevails across the remainder of the basin.

A cold front in the NW Gulf will reach from Alabama to 25N95W to
the Bay of Campeche later today, then stall by this evening. The
front will then weaken and drift northward through Sun and quickly
dissipate over water. Gale force northerly winds are NW of the
front off the NE Mexico coast, and a brief period of minimal gales
is expected this afternoon near Veracruz.

CARIBBEAN SEA...

Refer to the sections above for details on the tropical wave over
the west Caribbean and the heavy rainfall event currently
occurring over Central America and the SW Caribbean.

TPW imagery depicts abundant moisture over the southern Caribbean
and northern South America. The Pacific monsoon trough extends
from Colombia westward across the SW Caribbean Sea into northern
Costa Rica and southern Nicaragua. Scattered moderate isolated
strong convection covers the SW Caribbean mainly south of 16N
and west of 71W.

A broad low pressure area centered east of Nicaragua will move
W-NW into Central America through early next week. Fresh to strong
winds are possible in the western Caribbean and offshore waters
of Central America Mon and Tue from this system.

ATLANTIC OCEAN...

Refer to the section above for details on the Sub-Tropical Storm
Melissa and tropical waves moving across the basin.

A stationary front extends south from a 1009 mb low pressure
centered near 35N61W in the W-central Atlantic. The front
extends south to 30N62W, then transitions to a cold front 25N67W
to 23N78W near the central Bahamas. Scattered showers are noted
along the front mainly 80 nm ahead of the front. Further east,
a surface low is in the NE of the Caribbean near 22N55W. A
surface trough extends south/southwest to 19N57W to 20N62W. This
is producing scattered showers and tstorms from 19N-22N between
53W-62W. Surface ridging prevails across the remainder of the
basin.

A weakening stationary front east of the Bahamas will gradually
dissipate through Mon. High pressure north of the front will
induce moderate to fresh winds across most of the forecast area.
Subtropical Storm Melissa well north of the area will continue to
generate large N swell over a large portion of the western
Atlantic through Sun.

$$
Torres
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