[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 250537
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
137 AM EDT Thu Oct 25 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...

A broad 1010 mb low is analyzed near 20N48.5W. A trough runs
through the low from 22N47W to the low to 18N57W. Numerous
moderate with isolated strong convection is seen from 20N-24N
between 43W-48W with scattered weaker activity from 17N-20N
between 43W-46W. The system is gradually becoming better
organized. This low is expected to move northward over the next
couple of days into an area where upper-level winds are forecast
to be conducive for further development, and a tropical or
subtropical storm is likely to form on Friday or Saturday. After
that time, the system is forecast to turn westward well to the
north or northeast of the Lesser Antilles through early next
week. The system has a medium chance of formation during the next
48 hours.

...TROPICAL WAVES...

An Atlantic tropical wave is along 40/41W from 12N southward
moving west at 15-20 kt. Scattered showers and thunderstorms are
seen from 03N-12N between 32W and the wave axis.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of
Sierra Leone near 08N13W, to 06N18W. The ITCZ continues from
06N18W to 05N25W to 06N38W. The ITCZ then continues west of a
tropical wave from 06N44W to 06N51W. There is a discontinuity in
the ITCZ near 52W. The ITCZ is analyzed to be along 10N between
53W-61W. Aside from the showers mentioned above associated with
the tropical wave, numerous moderate with isolated strong
convection is located from 02N-06N between 24W-30W. Scattered
showers and isolated thunderstorms are noted elsewhere from 01N-
07N between 22W-32W. An area of scattered moderate convection is
noted near and within 60 nm north of the monsoon trough and ITCZ
between 16W-22W. Another area of scattered moderate convection is
seen from 01N-04N between 14W-19W. Farther west, isolated showers
are along and just south of the ITCZ between 44W-47W. Enhanced
cloud cover with light showers are in the vicinity of Trinidad.

GULF OF MEXICO...

A dissipating stationary front extends from Marco Island Florida
to 27N89W. A warm front extends from that point to a 1010 mb low
just off the coast of Texas near 28N96W. A stationary front
extends southward from the low to 23N96W. National Weather Service
Doppler Radar indicates scattered to numerous showers and
thunderstorms are along the Texas and western Louisiana coasts
from Houston to Lake Charles and extending inland. Scattered
showers and isolated thunderstorms extend offshore of Texas and
Louisiana north of 28N.

An upper level cyclonic circulation center is over the southern
Gulf of Mexico near 19N92W. Upper level cyclonic wind flow covers
the area that is from 22N southward between 89W and 96W. GOES-16
water vapor channels indicate relatively dry air over the
southwest Gulf, and mostly clear to partly cloudy skies are
present.

The low pressure in the NW Gulf will drift N early this morning,
then move E-NE across the northern Gulf through Fri, dragging a
cold front across the Gulf. The front will be nearly stationary
from central Cuba to the SW Gulf by Sat night.

CARIBBEAN SEA...

The monsoon trough over the far southwest Caribbean extends along
10N west of 75W from the N coast of Colombia to Costa Rica and
into the East Pacific. The monsoon trough combined with an area
of weak upper-level diffluence in the SW corner of the Caribbean
Sea is enhancing scattered showers and isolated thunderstorms from
08N-13N between 75W-84W. Scattered moderate to isolated strong
convection has been increasing during the last few hours over N
Colombia and NW Venezuela from 07N-11N between 70W-78W. Aside from
the southwest Caribbean, the remainder of the Caribbean is free
of significant convection at this time.

Gentle to moderate trades will prevail across the Caribbean Sea
through Sat. A cold front crossing the Gulf of Mexico will become
stationary across Yucatan Channel Sat night and Sun. Expect fresh
trade winds over the S central Caribbean early next week.

Some enhanced rainfall is possible through the remainder of the
work week over the southwest Caribbean and the southern half of
Central America from Nicaragua southward due to an active monsoon
trough in the region.

ATLANTIC OCEAN...

See sections above for information on convection associated with
the tropical wave, monsoon trough/ITCZ and the low discussed in
the special features section.

A cold front enters the forecast area at 32N70W and extends SW to
29N79W to the east coast of central Florida. At 03Z, the front was
changed to a stationary front west of 76W. A N-S surface trough
is also analyzed from 28N79W southward through the NW Bahamas to
24N77W. A 1010 mb low is located near 29N61W with a cold front
extending SW from there to the central Bahamas. This front has
weakened and will likely be dropped and changed to a trough for
the upcoming 06Z map. Scattered to numerous showers are north of
24N between 54W-64W. Isolated showers with abundant cloud clover
are from 22N-26N between 64W-74W. Scattered to broken low clouds
are along the front east of northern Florida.

A 1008 mb low near 34N25W extends scattered moderate convection
north of 29N between 18W-25W.

The cold front east of north-central Florida will continue to
weaken early this morning as it becomes stationary before
transitioning to a warm front later today. SE winds will
increase E of Florida tonight and Fri as a low pressure system
moves across the SE U.S. A trailing cold front from this low will
reach from Bermuda into the NW Bahamas on Sat, then stall and
weaken from 30N70W to central Cuba on Sun.

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

$$
Hagen
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