[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 070004
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
804 PM EDT Sun May 6 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 1800 UTC surface analysis and satellite imagery through
2300 UTC.

...SPECIAL FEATURES...

A broad upper level cyclonic circulation center is on top of the
SW Bahamas, along 72W/73W. Upper level cyclonic wind flow that is
moving around the circulation center covers the area from SW
corner of the Caribbean Sea to 28N in the Atlantic Ocean between
68W in the Caribbean Sea and 70W in the Atlantic Ocean and 84W in
the Gulf of Mexico. A surface trough is along 80W/81W from 20N
northward, and from 20N81W to 15N80W and 11N77W. Precipitation:
widely scattered moderate to isolated strong rainshowers cover the
areas from 15N in the Caribbean Sea to 25N in the Atlantic Ocean
between 70W and 80W. Isolated moderate rainshowers are elsewhere
from 14N southward from 74W westward in the SW part of the
Caribbean Sea, and elsewhere from 15N northward in the Caribbean
Sea and in the Atlantic Ocean from 68W westward. This feature was
forecast by the computer models at the beginning of the week. The
GFS model forecast, for 250 mb and 500 mb, shows that the current
cyclonic circulation center will stay on top of Cuba, weaken into
a trough, and then move eastward. An upper level trough will move
across the Gulf of Mexico toward Florida. The GFS model, from the
surface to 700 mb, shows that a broad trough will remain in the
area between 70W in the Atlantic Ocean and 85W in the Gulf of
Mexico, including in the Caribbean Sea, during the next few days.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of Sierra
Leone near 08N13W to 02N20W and 01N26W. The ITCZ continues from
01N26W, crossing the Equator along 27W, to 03S32W and 04S38W.
Precipitation: scattered moderate to strong rainshowers are from
01N to 04N between 20W and 26W. isolated moderate to locally
strong rainshowers are elsewhere from the line 08N12W 07N30W
07N53W southward. Scattered moderate to strong rainshowers are
from 07W eastward.

...DISCUSSION...

GULF OF MEXICO...

A cold front passes through the NE corner of the Gulf of Mexico,
into the central sections, to the west central Gulf, and the coast
of Mexico near 24N98W. north central and NW corner of the Gulf of
Mexico. Precipitation: Broken to overcast multilayered clouds and
possible rainshowers are within 150 nm on either side of the line
that passes through 29N81W in Florida, to 25N90W and 25N98W.

The current cold front will move east of the Gulf tonight. High
pressure building over the Gulf in the wake of the front will
support gentle to moderate north to northeast winds through Tue
night. Winds over the basin will become northeast to east Wed
through early Thu, except for southeast to south winds over the
far western gulf in return flow as high pressure in the wake of
the front shifts to the northeast gulf. On Fri, the high will have
moved into the western Atlantic, with a ridge extending westward
across the northern gulf waters. This will allow for mainly
moderate east to southeast winds to exist over the basin. A weak
thermal trough will move off the Yucatan Peninsula and over the
eastern Bay of Campeche during the mornings and dissipate in the
early afternoons beginning Wed.

CARIBBEAN SEA...

Please read the SPECIAL FEATURES section for more infomation about
the upper level cyclonic circulation and surface trough near Cuba
and the Bahamas and Florida.

The southern portion of a surface trough that
extends from western Cuba south to 19N83W will linger through Wed
night while gradually dissipating. The gradient between it and
strong central Atlantic high pressure that ridges southwestward
across the eastern and central Caribbean will maintain fresh to
strong east to southeast winds over the Caribbean E of 75W through
late tonight, then diminish to mainly fresh winds through the
rest of the period. A large upper-level low centered over eastern
Cuba will gradually shift east-southeastward through tonight as it
weakens to a trough into Mon. This trough will move eastward
across the central and eastern Caribbean through Tue night.
Scattered showers and isolated thunderstorms can be expected ahead
of the trough.

ATLANTIC OCEAN...

Please read the SPECIAL FEATURES section for more infomation about
the upper level cyclonic circulation and surface trough near Cuba
and the Bahamas and Florida.

An upper level trough extends from a 30N15W cyclonic circulation
center, just to the north of the Canary Islands, through 25N28W,
to a 19N48W to 19N58W. Precipitation:
isolated moderate to locally strong rainshowers cover the area
that is from 22N to 25N between 40W and 50W.

The surface trough that moved across the basin the
past few days has moved to the eastern Gulf of Mexico as central
Atlantic high pressure continues to build westward across most of
the area. A weak cold front over the far northwest waters will
slowly move southeastward reaching from near 31N78W to the Straits
of Florida early Mon, from near 31N77W to western Cuba by early
Mon afternoon, then from near 31N74W to the central Bahamas and
stationary to west-central Cuba early Tue. The cold front portion
will then become stationary later on Tue. Fresh to strong southerly
winds will precede the front north of about 27N through late Mon
afternoon. The front will weaken through Thu night and dissipate
Fri, with its remnants lifting northwest to near 29N on Fri as a
high pressure center moves off the southeastern United States
coast to near 31N75W Thu night and to near 31N70W Fri with a
ridge extending to near 30N80W.

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

$$
MT
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