[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111730
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
130 PM EDT SUN SEP 11 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 1200 UTC surface analysis and satellite imagery through
1745 UTC.

...SPECIAL FEATURES...

A vigorous tropical wave is in the central Atlantic associated
with a 1009 mb low pressure centered near 16N47W. The wave
extends from 10N to 23N with axis near 47W, moving W at 5 kt
within the last 24 hours. Scattered showers and isolated tstms
are from 10N to 23N between 40W and 51W. Gale force winds are in
the NE quadrant of the low center.Please see the latest NWS High
Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for
more details. There is a high chance of tropical development
later today or on Monday before upper-level winds become less
conducive for development. The low is expected to move NW over
the central Atlantic Ocean during the next few days. Please see
the latest NWS Tropical Weather Outlook under AWIPS/WMO headers
MIATWOAT/ABNT20 KNHC for more details.

...TROPICAL WAVES...

A tropical wave in the E Atlantic extends from 10N to 20N with
axis near 20W, moving W at 5 kt within the last 24 hours. A moderate
moist environment from the surface to 850 mb, favorable deep
layer wind shear and diffluent flow aloft support scattered
showers and tstms from 10N to 15N E of 25W.

A tropical wave in the E Atlantic extends from 09N to 17N with
axis near 29W, forecast to move W at 15 kt within the next 24
hours. The wave is in a region of favorable deep layer wind shear,
however Saharan dry air and dust in the northern wave environment
limit the convection to scattered showers from 07N to 10N between
25W and 33W.

A tropical wave is in the W Caribbean extending from 10N to 21N
with axis near 84W moving W at 10 kt within the past 24 hours. A
moderate moist environment from the surface to 850 mb, favorable
deep layer wind shear in the SW basin and diffluent flow aloft
support scattered showers and tstms from 09N to 15N W of 79W.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends across Africa into the east Tropical
Atlantic near 14N17W and continues along 09N30W to 11N41W. Aside
the convection associated with the tropical waves discussed above,
scattered moderate convection is from 04N to 10N E of 18W and from
03N to 07N between 32W and 38W.

...DISCUSSION...

...GULF OF MEXICO...

Surface low pressure is present in the SE and SW portions of the
basin. In the SE Gulf, a 1015 mb low is centered near 23N85W with
associated trough extending from 26N85W to the low to 21N85W. Dry
air subsidence from aloft, low moisture and neutral to unfavorable
deep layer wind shear in that portion of the basin limit the
convection to scattered showers and tstms within 90 nm from the
low center. Scatterometer data show gentle variable wind
associated with the low and gentle E wind in the NE Gulf. North to
northeasterly gentle flow linked to a broad surface ridge covering
the central U.S. and central Mexico dominates the basin W of 90W.
Aloft, the base of an upper trough reaches the NW basin and along
a ridge to the east generate diffluent flow that support scattered
heavy showers and tstms within 210 nm off the SE Louisiana,
Mississippi and Alabama coasts between 86W and 91W. Lastly, a surface
trough in the SW basin extends from 21N93W to 16N95W supporting
scattered showers in the Bay of Campeche W of 92W. A tropical wave
currently over the W Caribbean will enter the Yucatan Peninsula
near sunrise Monday and then will move across the Bay of Campeche
through Tuesday.

...CARIBBEAN SEA...

The main feature in the basin is a tropical wave moving across the
W Caribbean. Aloft, an upper ridge anchored over Southern Mexico
extends E to the NW Caribbean and along with an upper level low
over Hispaniola generate diffluent flow in the SW basin to support
the convection associated with the tropical wave. See tropical
waves section for further details. A 1012 mb low is off the coast
of Colombia connected to the E Pacific monsoon trough, which is
supporting scattered showers within 60 nm of the low center. The
upper low over Hispaniola and a broad area of low pressure moving
across the southern Bahamas support isolated showers and tstms
over Hispaniola. The remainder basin is under the influence of dry
air subsidence from aloft. which is supporting fair weather. In
terms of winds, generally moderate trades prevail across the
basin. The tropical wave will move to the Yucatan Peninsula near
sunrise Monday. Showers across Hispaniola are expected through
early Tuesday morning.

...HISPANIOLA...

An upper-level low centered over the Island and a broad area of
low pressure moving across the southern Bahamas support isolated
showers and tstms over Hispaniola. This shower activity is
expected to continue through early Tuesday morning.

...ATLANTIC OCEAN...

The primary feature of concern in the basin is invest area AL94
located in the central tropical Atlantic. This disturbance
associated with a tropical wave has a high chance of become a
tropical cyclone later today or tomorrow. Currently, there is a
gale warning due to it. Please see the special features section
for details. A second area of disturbed weather is in the SW N
Atlantic waters with scattered heavy showers and tstms over the
Bahamas, Turks and Caicos Islands and the Great Bahamas Bank.
There are no signs of a surface circulation, and conditions do
not appear conducive for significant development of this
disturbance while it moves NW. Heavy rainfall is possible over
portions of the Bahamas through Monday. Surface ridging anchored
by a 1025 mb high N of the area dominate the remainder Atlantic
waters.

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

$$
RAMOS
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