[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 060003
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM EDT MON SEP 5 2016

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
2330 UTC.

...SPECIAL FEATURES...

Post-tropical cyclone Hermine is centered near 39.3N 69.5W,or
about 150 nm SE of the eastern tip of Long Island. Hermine is
moving west-northwest, or 300 degrees, 6 knots. The estimated
minimum central pressure is 997 mb. Maximum sustained winds are
60 knots with gusts to 75 knots. Scattered moderate convection
was noted within 180 nm in the NW semicircle of Hermine.
Regional radar imagery indicated scattered showers moving
westward across eastern Massachusetts, Rhode Island and eastern
Long Island.  As Hermine tracks over cooler waters it is
forecast to gradually weaken through the forecast period. Large
waves generated by Hermine will affect the U.S. east coast from
the mid-Atlantic states northward along the coast of southern
New England through at least Tuesday. These waves are likely to
cause life-threatening surf and rip current conditions, and
significant beach erosion. Please read the latest NHC
Intermediate Public Advisory under AWIPS/WMO headers
MIATCPAT4/WTNT34 KNHC and the Forecast/Advisory under the
AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details.

...TROPICAL WAVES...

A tropical wave is over the central Atlc was relocated earlier
and currently extends from 10N to 20N with axis along 37W/38W,
moving west at 10-15 kt. The wave is in a region of favorable
deep layer wind shear from 10N to 20N, however continuous
intrusion of Saharan dry air and dust into the wave environment
is hindering convection and any development at the time.

A tropical wave is over the eastern Caribbean Sea and extends
from 10N to 20N with axis along 65W/66W, moving W at 15 kt
within the last 24 hours. A 1009 mb center of low pressure is
associated with the wave, located near 15N66W and is expected to
move W to near 16N73W within 24 hours. Abundant moisture in the
vicinity of the wave along with a diffluent environment aloft
support scattered moderate to strong convection over the NE
Caribbean from 14N to 18N between 62W and 68W. San Juan radar
depicted a fairly well defined low to mid level circulation near
17N66W with scattered to numerous showers passing over and to
the south of the island with the potential for very heavy
rainfall into early Tuesday. The 12Z San Juan rawindsonde showed
winds of 40 kt at 800 to 825 mb.

A tropical wave moved over the Yucatan Peninsula, and northern
Central America into the NE Pacific waters. The wave extends
from 08N to 21N with axis near 90W, 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
scattered showers over western Yucatan and over Honduras
and Nicaragua.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends across Africa into the east Tropical
Atlantic near 17N16W to 10N21W to 07N25W to 10N30W to 11N37W.
Scattered moderate to isolated strong convection is from 04N to
08N between 24W and 31W.

...DISCUSSION...

...THE GULF OF MEXICO...

Weak surface ridging prevails across the Gulf waters, except for
the far southern portion of the basin where low level moisture
convergence associated with the tropical wave along 90W is
supporting scattered thunderstorms across the western Yucatan
peninsula into the far eastern Bay of Campeche. Surface
observations indicated moderate E to SE winds basin-wide with
seas generally 2 to 4 FT. Cloudiness and scattered showers and
thunderstorms over the N-central Gulf coast and adjacent waters
are associated with the remnants of a former surface trough. The
tropical wave moving across the Bay of Campeche over the next
few days supports enhanced activity there. Elsewhere surface
ridging will remain as the main feature the next two days.

...THE CARIBBEAN SEA...

The main concern for the basin is a vigorous tropical wave that
is moving across the eastern Caribbean and Puerto Rico. This
wave is supporting scattered showers and thunderstorms from 14N
to 18N between 62W and 68W. Locally strong winds to near gale
force as possible in some of the heavier squalls passing over
and to the south of Puerto Rico. This disturbance will continue
to produce locally heavy rainfall and gusty winds over portions
of Puerto Rico and spread over Hispaniola on Tuesday. The
concern here is for very heavy rainfall over Hispaniola. Please
refer to the tropical waves section for details. The monsoon
trough supports scattered heavy showers in the SW basin within
150 nm off the coasts from Honduras to Colombia. Fresh to
locally strong winds are noted elsewhere in the Caribbean from
11N to 17N between 61W and 79W.

...HISPANIOLA...

Increasing multilayered cloudiness is spreading across the
Dominican Republic in advance of the strong tropical wave along
66W. The potential for very heavy rainfall exists on Tue into
Wed across the island as the strong tropical wave continues
westward in the Caribbean. Drier weather is expected by Thursday
as the wave moves away from the island.

...THE 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 surface trough prevails in the SW N
Atlc waters from 30N71W to a 1016 mb low pressure near 28N73W to
near Andros Island, supporting isolated showers within 90 nm
either side of its axis. Another surface trough is over the N
central extending from a 1018 mb low near 29N51W to 24N58W. the
low was moving west at 15 kt.  Another low pressure area was
located near 23N38W with an associated trough extending NE to
near 28N35W. Convective activity was located well to the north
of this feature in shearing SW flow aloft, generally from 26N to
32N between 28W and 35W. Lastly, a 1012 mb low in the deep
tropics near 12N45W detached from the tropical wave to its east
supports scattered heavy showers and isolated tstms from 08N
to149N between 40W and 46W. The remainder of the basin is
dominated by a broad but weak surface ridge.

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

$$
COBB
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