[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 041219 AAA
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
819 AM EDT SUN SEP 4 2016

AMENDED FOR UPDATE TO INFORMATION ABOUT HERMINE

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
1030 UTC.

...SPECIAL FEATURES...

Post-tropical cyclone Hermine is centered near 37.0N 70.0W at
04/1200 UTC, or about 260 nm to the south-southeast of the
eastern tip of Long Island, and about 255 nm to the east-
southeast of Ocean City, Maryland. The cyclone is moving east-
northeastward 10 knots. Estimated minimum central pressure is
999 mb. Maximum sustained wind speed is 55 kt with gusts to 65
kt. Scattered moderate convection is present mainly northeast of
the center from 36N to 42N between 58W and 70W. Please see the
latest NHC Intermediate Public Advisory under AWIPS/WMO headers
MIATCPAT4/WTNT34 KNHC and the full Forecast/Advisory under the
AWIPS/WMO headers MIATCMAT4/WTNT24KNHC for more details.

...TROPICAL WAVES...

A tropical wave is over the eastern Atlc extending from 10N to
21N with axis near 32W, moving west at 10 kt within the last 24
hours. A 1011 mb center of low pressure is associated with the
wave and is located near 18N32W, which is expected to move NW to
20N36W within the next 24 hours. The wave is mainly within a
favorable deep layer wind shear from 10N to 20N, however intrusion
of Saharan dry air and dust in the wave environment is hindering
deep convection north of 15N. Moist air associated with the
monsoon trough and a diffluent environment aloft support scattered
moderate convection from 07N to 13N between 25W and 40W.

A tropical wave is over the Atlantic waters east of the Lesser
Antilles extending from 09N to 19N with axis near 57W, moving
west at 15-20 kt within the last 24 hours. A 1009 mb center of
low pressure is associated with the wave and is located near
14N57W, which is expected to dissipate within the next 24 hours.
The wave has been entering a region of unfavorable deep layer wind
shear and convection around the low looks disorganized. Scattered
moderate to isolated strong showers are from 12N to 19N between
52W and 65W.

A tropical wave is over the western Caribbean extending from 09N
to 19N with axis near 82W, moving at 15 kt within the last 24
hours. The wave is in a favorable deep layer wind shear
environment that along with diffluent flow aloft support isolated
heavy showers within 120 nm either side of the wave axis.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends across Africa into the east Tropical
Atlantic near 13N17W to 12N30W to 10N40W to 11N49W. Aside from
the convection associated with the tropical waves, little
convection is observed in the vicinity of the monsoon trough.

...DISCUSSION...

GULF OF MEXICO...

A weak surface ridge dominates the Gulf waters east of 90W
supporting light variable wind flow. A surface trough, remnants of
a former frontal boundary, extends along the Florida Panhandle
coastal waters to 29N89W to 27N91W with isolated showers within
20 nm of its axis. Scattered heavy showers and tstms are in the SW
basin S of 24N west of 93W associated with a surface trough
extending from 24N97W to 18N94W. Gentle to moderate E to SE winds
are across the western basin. The surface trough generating
showers in the Bay of Campeche will move inland Mexico today and
surface ridging will become the main feature basin-wide, thus
providing moderate return flow the next three days.

CARIBBEAN SEA...

A weak tropical wave is over western Caribbean waters supporting
scattered heavy showers S of 20N between 80W and 85W. A second
tropical wave is over Atlantic waters east of the Lesser
Antilles. This system continues to produce a large area of
cloudiness and showers, and is likely producing winds to near
tropical storm force. Upper- level winds are forecast to become
less conducive for any significant development of this disturbance
while it moves westward through the Caribbean Sea this week.
Regardless of development, this disturbance will produce locally
heavy rainfall and gusty winds, possibly to tropical storm force,
over portions of the Lesser Antilles Sunday afternoon through
early Monday. Please refer to the tropical waves section for
details. Fresh to strong winds are in the NE Caribbean as well as
in the south-central basin.

...HISPANIOLA...

Fair weather prevails across the island due to strong subsidence
from aloft as indicated by water vapor imagery. Stable and fair
weather is expected to continue today. On Monday, a moist airmass
associated with a tropical wave will bring showers.

ATLANTIC OCEAN...

Post-tropical cyclone Hermine is N of forecast waters. Please
refer to the special features section for details. Two tropical
waves are moving across the basin. Please refer to the tropical
waves section for details. A 1017 mb low formed east of
Jacksonville from which a surface trough extends to 28N78W to
27N80W with isolated showers and tstms within 120 nm east of its
axis N of 29N. Another surface trough is moving across the
western Bahamas generating similar shower activity. The remainder
basin is dominated by a weak and broad surface ridge that will
prevail the next three days.

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

$$
RAMOS
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