[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041144
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
744 AM EDT Fri May 4 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.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from 10N14W to 00N34W. The intertropical
convergence zone continues from 00N34W to 01S48W. Scattered
moderate convection is ongoing from 04S to 04N between 24W and
30W.

...DISCUSSION...

GULF OF MEXICO...

A surface ridge extends east to west from the western Atlantic
along the northern Gulf coast to Texas. Strong peak winds reported
by NOAA buoy observations in the Florida Keys are evidence of
moderate to fresh easterly winds persisting across the Straits of
Florida, between the ridge to the north, a weak trough over the
far southeast Gulf, and a more developed trough to the east of the
area. Seas are likely reaching 8 ft in the Straits accordingly,
reaching as far west as the approaches to the Yucatan Channel, up
to a latitude of about 25N. Convergence of the fresh to strong
easterly flow out of the Bahamas is supporting scattered showers
across the Florida Straits, as noted in regional radar. Fresh SE
return flow and seas to 6 ft are noted over the far northwest
Gulf, between the ridge and lower pressure over south Texas. A
couple of platforms in the Texas coastal waters are report light
to moderate fog in the moist SE flow, but widespread fog or
significant restriction to visibility is not anticipated through
the day.

Farther south, a daily thermal low will develop inland inside the
Yucatan Peninsula, causing surges of fresh to occasionally strong
NE to E winds as the low strengthens and weakens over the coming
days.

For the forecast, winds over the southeast Gulf will diminish and
back more to the NE through early Sat ahead of the trough moving
from the western Atlc across Florida. Scattered showers and
thunderstorms will accompany the trough as it moves into the
eastern Gulf early Sun before stalling and weakening. The ridge
will weaken as well and high pressure will shift west through the
lower Mississippi Valley, allowing moderate northerly flow and 2ft
to 4 ft seas through mid week.

CARIBBEAN SEA...

A surface trough is developing from north of Hispaniola into the
north central Caribbean. E to SE winds will increase slightly from
the Tropical North Atlantic through the central Caribbean as high
pressure builds westward over the Atlantic in the wake of the
trough. This is already starting to happen as winds off Colombia
have diminished slightly from the last synoptic observations, as
they increase through the Windward and Leeward Islands. Scattered
thunderstorms are popping up in the Windward Passage as well, on
the south side of a prominent mid/upper low centered north of the
area, moving slowly to the west. Seas will build over tropical
north Atlantic and the eastern Caribbean to 6 to 9 ft through Sun.

This pattern will persist through Sun, then start to subside into
early next week as the trough moves farther westward and the ridge
weakens. Atmospheric instability associated with the mid/upper
level low will provide more thunderstorm potential to the north
central Caribbean through late Sat.

ATLANTIC OCEAN...

The main weather maker remains a prominent cold-core, mid/upper
level low centered over Great Exuma in the central Bahamas.
Divergence of the southeast side of this feature is supporting a
broad area of scattered showers and thunderstorms over the
southern Bahamas, Turks/Caicos Islands, and north of Hispaniola
and Puerto Rico. This is also supporting the development of a
amplifying surface trough extending from 28N68W through eastern Haiti
and into the north central Caribbean. Strong NE to E winds are
ahead of the trough east and across the Bahamas, with seas in
excess of 7 ft noted in an altimeter satellite pass at 0950 UTC.
Fresh to strong easterly winds are noted between 20N and 28N,
closer to the subtropical ridge axis. Buoy and scatterometer data
also show strong SE winds off the Leeward Islands in the Atlantic,
with buoys showing seas to 9 ft. This is related to ridging
building in the wake of the trough.


The trough will sharpen and elongate as it moves westward,
eventually moving into Florida Sat. Strong to near gale force
winds will accompany the trough, as well numerous showers and
scattered thunderstorms across the Bahamas through Sat. Scattered
thunderstorms are possible across the Bahamas and adjacent waters
into Sun as the upper low slowly drifts south-southwestward.
Winds and seas will start to diminish Sun through early next week
as through lifts northward to off the northeast coast of Florida
through Mon, and the ridge weakens, but hold in place along
roughly 28N/29N.

Farther east, the remainder of the Atlantic is under the
influence of a 1028 mb high pressure located near 33N57W. This
system is producing moderate to fresh trade winds across the deep
tropics, where seas are reaching 6 to 8 ft in NE to E swell.

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

$$
Manougian
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