Tropical Weather Discussion
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000
AXNT20 KNHC 201804
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 PM EDT Mon Mar 20 2017

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
1745 UTC.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough axis extends from the African coast near
07N11W to 00N18W to 01S28W. The Intertropical Convergence Zone
axis extends from 01S28W to the South American coast near
03S42W. Scattered moderate to strong convection is from 03S-03N
between 00W-06W. Scattered moderate/isolated strong convection
is from 03S-03N between 06W-10W. Scattered moderate convection
is occurring from 01N-04N between 10W-17W, and from the equator
to 03N west of 45W.

...DISCUSSION...

GULF OF MEXICO...

As of 1500 UTC, a 1025 mb high is analyzed over the north
central Gulf of Mexico near 27N91W. Buoy observations show
anticyclonic flow throughout consisting of 10-15 kt, except for
lighter winds of 5-10 kt near the high center. Water vapor
imagery shows very strong subsidence aloft along with strong
zonal flow in the wake of yesterday`s cold front. This is
keeping conditions very dry throughout. Mostly clear skies are
north of 23N east of 92W, while scattered to broken low clouds
are west of 92W, and south of 23N east of 92W. The 1025 mb high
is forecast to shift slightly eastward through Tuesday, then
move westward back to the north-central waters on Wednesday.
Little overall change is forecast for the basin through
Wednesday.

CARIBBEAN SEA...

A weakening frontal trough extends from eastern Cuba southwest
to just offshore the coast of the border between Honduras and
Nicaragua near 15N83W. Scattered showers are within 90 nm
northwest and 60 nm se of trough, respectively. The trough is
forecast to dissipate tonight. Buoy observations and a few ship
reports show 15-20 kt northeast winds to the northwest of the
trough. 10-15 kt northeast to east trades are over the remainder
of the Caribbean, with the exception of within 90 nm of the
coast of Colombia where trades are in the 20-25 kt range due to
the pressure difference between low pressure over northwest
Colombia and stronger high pressure over the northwest Caribbean.
Satellite imagery depicts pockets of scattered showers moving
westward over portions of the central and eastern Caribbean
waters. Similar activity is observed across portions of the
Leeward Islands, Puerto Rico, south-central Hispaniola, Jamaica,
and eastern Cuba. Scattered showers are also over sections of
northern Honduras and over the interior of Nicaragua. Isolated
showers moving northwestward are over the northeast Caribbean
and near the Windward Islands. Over areas not currently being
affected by low-moisture and shower activity, dry condtions
aloft due to strong subsidence is allowing for only scattered to
locally broken clouds to generally mostly clear over those
areas. A weak surface trough over the eastern Caribbean will
reach the central Caribbean waters by Wednesday. This will
introduce additional low-level moisture over that portion of the
sea along with the possibility of increasing chances for
scattered showers. Scattered showers are expected to persist
along and inland the coasts of eastern Honduras and Nicaragua
through Wednesday.

...HISPANIOLA...

Scattered showers are presently over some sections of the
central portions of the island as well as over northwest and
southwest Haiti due to low level moisture lingering over much of
the island in combination with ongoing daytime heating. Little
change is expected during the next 24 hours, then the
possibility for increasing scattered showers increases
afterwards as low-level moisture increases with the approach of
a surface trough.

ATLANTIC OCEAN...

As of 1500 UTC, a dissipating cold front is over the western
Atlantic from 32N62W to 23N69W, where it becomes a dissipating
stationary front to the eastern tip of Cuba. A fast moving cold
front is behind this front along a position from 32N64W to
23N73W to along the northern coast of central Cuba. Strong to
near gale force west to northwest winds with seas of 8-14 ft are
behind this front. A narrow line of cumulus clouds defines the
front on satellite imagery. Broken patches of stratocumlus
clouds moving southward denoting a drier air mass are observed
to the north of 25N west of 70W, and north of 26N between the
front and 70W. Isolated showers are possible with these clouds.
Patches of low-level moisture with scattered showers are seen
northeast of Puerto Rico from 19N-22N between 63W-66W. A 1028 mb
high is centered over the eastern Atlantic near 33N28W, with a
ridge southwest to near 23N56W. In the upper levels, an upper
level trough is noted over the western Atlantic north of about
24N between 60W-76W supporting the fast moving cold front, and
producing upper level diffluence across the northern portion of
the dissipating cold front. This is helping to aid scattered
moderate/isolated strong convection north of 27N east of the
first front to 58W. An elongated upper level low is centered
over the tropical Atlantic near 22N22W. Isolated showers moving
westward are noted from 17N to 22N between 22W-40W. The
aforementioned cold front extending from 32N64W to 23N73W and to
along the coast of central Cuba will merge with the dissipating
front tonight, with the merged front forecast to become
stationary from near 22N65W to the Windward Passage on Tuesday
before it begins to drift to the north on Wednesday while
weakening. Scattered showers and is to isolated thunderstorms
are expected along and near the merged front.

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

$$
Aguirre



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