[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081156
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0805 AM EDT Tue May 8 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
1100 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of Sierra
Leone near 09N13W to 04N15W. The ITCZ continues from 04N15W to
01N37W to 03S45W along the coast of Brazil. Scattered moderate
convection is noted from 01N to 03N between 13W and 18W, and from
01N to 03N between 35W and 50W.

...DISCUSSION

GULF OF MEXICO...

A very broad mid-latitude trough continues to move across the
southeastern U.S. and is shifting SE across the northern coastal
waters. The main impact of the trough is north of the region,
limiting mid/upper support for a stalling and dying frontal
boundary reaching from South Florida to the south central Gulf.
1020 mb high pressure is centered over the northwest Gulf behind
the front near 27N94W, maintaining generally gentle to light
winds and slight seas. Moderate to fresh northerly winds are
noted over the far eastern Gulf between the high pressure and
lower pressure off the Georgia coast, supporting 2 to 4 ft seas.
No significant shower activity is observed.

The high pressure will shift east toward the northeast Gulf
through Fri, then into the Atlantic Sat. This will maintain
moderate NE to E winds and 2 to 4 ft seas across the eastern Gulf
through the period. High daily temperatures over the Yucatan
peninsula will set up a weak thermal trough each evening, which
will move over the eastern Bay of Campeche during the morning
then dissipate during the afternoon each day beginning Wed.

CARIBBEAN SEA...

A sharp elongated trough reaches from central Cuba to the
southwest Caribbean near 14N80W. Ridging over the central
Atlantic is supporting moderate to fresh E to SE winds across
the basin east of the trough axis. Buoy observations and
altimeter satellite data show 5 to 7 ft west of the trough.
Generally gentle to light northerly winds are noted across the
Caribbean. Moderate to fresh trade winds are noted across the
tropical north Atlantic waters west of 55W, south of the main
ridge. Seas are reaching 8 ft, but this includes a decaying NE
to E swell. Regional radar mosaics indicate a few warm topped
showers south of the central Cuba and Jamaica near the trough,
supported by a broad mid/upper level trough south of the
Caymans. A few fast moving trade wind showers are observed
moving off the Atlantic into the Windward and Leeward Islands
and across the NE Caribbean. Otherwise, no significant weather
is noted.

The trough is expected to drift westward and weaken through mid
week, but will remain the focus for showers and a few
thunderstorms through late today as the supporting mid/upper
trough lifts northeast and dampens out. Trade wind flow will
increase over the south central Caribbean by Fri night as
ridging builds north of the region. Little change otherwise in
the forecast.

ATLANTIC OCEAN...

A cold front reaches from weak 1013 mb low pressure centered
north of the area, approximately 210 nm southeast of Cape
Hatteras, NC, ahead of a positively tilted mid/upper trough
reaching from the southern Appalachians to the central Gulf of
Mexico coastal waters. Scattered moderate to isolated strong
convection is active from 180 to 240 nm east of the frontal
boundary. The front is making very slow progress eastward as
most of the supporting dynamics aloft are lifting northward.
Fresh to strong southerly winds persist ahead of the front north
of 27N between 70W and 75W, between the low pressure off the
Carolinas and the main subtropical ridge centered farther east
over the central Atlantic.

Buoy observations and an altimeter satellite pass from 01 UTC
indicated 5 to 7 ft seas in open waters. Higher seas and stronger
gusts are possible near the aforementioned stronger thunderstorms
ahead of the front.

The winds ahead of the front will diminish to gentle to moderate
by Wed as the low pressure lifts north. High pressure ridging
extending east to west along 31N Fri through Sat night will
generate gentle to moderate E to SE winds over the forecast
waters, except that fresh to locally strong winds will pulse
between the southeast Bahamas and the coast of Hispaniola.

Farther east, a large mid/upper trough reaches from the Azores
to near 17N55W. Despite upper support on the east side of the
mid/upper trough, no significant moisture is noted north of the
ITCZ as deep layer moisture remains limited. A front over the
eastern Atlantic is keeping the subtropical ridge fairly weak
east of 40W, and latest scatterometer satellite passes indicated
generally moderate trade wind flow as well, except for the fresh
trades west of 55W which is south of 1031 mb high pressure
centered near 35N44W. Concurrent altimeter passes indicate seas
are generally 5 to 7 ft over central and eastern portions of the
tropical and subtropical North Atlantic.

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

$$
Stripling
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