[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 071749
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
148 PM EDT Tue Aug 7 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 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...SPECIAL FEATURES...

...Sub-tropical Storm Debby has developed...
The center of Debby is located near 38.9N/48.5W as of 1500 UTC.
Its estimated minimum pressure is 1008 mb, and it is moving north
at 14 kt. Maximum sustained winds are 35 kt with gusts to 45 kt.
Its general motion will decrease in forward speed is expected
during the next 24 hours. A gradual turn to the northeast is
anticipated thereafter. See the latest NHC Forecast/Advisory under
AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details.

...Caribbean Gale Warning...
A Gale Warning is in effect for the south-central Caribbean. A
strong Atlantic ridge is tightening the pressure gradient over
this area. A similar weather pattern will prevail through the next
48 hours, therefore, gale-force winds are forecast through this
period. Please see the Atlantic High Seas Forecast under AWIPS/WMO
headers MIAHSFAT2/FZNT02 KNHC for further details.

...TROPICAL WAVES...

A tropical wave axis in the eastern Atlantic extends from 19N40W
to 07N42W, moving W at 10-15 kt. Scatterometer data depicts a
wind shift along the convergence zone axis west of the wave and
latest satellite imagery shows the inverted V pattern very well.
The northern part of the wave is affected by Saharan dry air
intrusion, limiting convection to the area south of 16N between
38W-45W.

A tropical wave in the equatorial central Atlantic extends from
07N-19N along 54W, moving W at 10-15 kt. The wave continues to be
affected by intrusion of Saharan dry air and dust. Shallow
moisture in the vicinity of the ITCZ supports scattered showers
mainly S of 08N.

A tropical wave axis in the west-central Caribbean extends south
of 21N along 77W, moving W at 15-20 kt. The wave is in a moist
environment at the lower levels as indicated by LPW and water
vapor imagery, and under a diffluent environment between an
elongated upper-level low over the central basin and S-SW flow to
the east, which is supporting scattered showers N of 18N between
70W-73W.

A tropical wave is in the western Caribbean with axis S of 21N
along 85W, moving W at 5-10 kt. Shallow moisture is present in
the vicinity of the wave, and combined with the interaction with
the monsoon trough, supports scattered moderate convection mainly
S of 17N between 80W-86W.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the eastern Atlantic near 17N17W and
extends southwestward to 13N24W then westward to 13N40W. The ITCZ
begins W of a tropical wave near 12N44W and continues to 08N52W.
Aside from the convection related to the tropical waves,
scattered showers are observed along the ITCZ.

...DISCUSSION...

GULF OF MEXICO...

A broad area of high pressure extends from the western Atlantic
into Gulf waters. A surface trough extends from 25N82W to 27N80W
with scattered showers affecting southern Florida and adjacent
waters. An upper-level low centered over the northwest Caribbean
is enhancing convection across the Florida Straits and Yucatan
Channel. A mid-level trough extends across the northwest Gulf
enhancing convection west of 90W.

Expect convection to fire up again across the basin later today.
A nocturnal thermal trough that will emerge off the Yucatan
Peninsula each night, and enhance the NE winds off the W Yucatan
Peninsula. A tropical wave will move across the Yucatan Peninsula
in 48 hours enhancing convection over the Bay of Campeche.
Surface ridging will prevail elsewhere through Sat.

CARIBBEAN SEA...

Two tropical waves are moving across the basin. Refer to the
section above for details. A Gale Warning is in effect for the
south-central Caribbean. Please check the Special Features section
above for details.

Enhanced satellite imagery continues to show a thin layer of
Saharan dust moving across most of the basin where deep-layer
wind shear prevails. This environment continues to suppress the
development of significant convection across most of the basin.
The monsoon trough in the SW Caribbean supports moderate
convection south of 13N and west of 80W. This pattern will
continue through the midweek. The next tropical wave will enter
the basin within the next 48 hours.

ATLANTIC OCEAN...

Sub-tropical storm Debby has developed int he central Atlantic.
Refer to the section above for details. Two tropical waves are
moving across the basin. See the section above for details. An
upper- level low is reflected at the surface as a trough, that
extends from 31N67W to 28N66W. Scattered moderate convection
prevails along the trough. The remainder of the basin is under the
influence of a broad area of high pressure supporting fair
weather.

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

$$

ERA
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