[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201001
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
601 AM EDT SAT AUG 20 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 0600 UTC surface analysis and satellite imagery through
1000 UTC.

...SPECIAL FEATURES...

Tropical Storm Fiona is centered near 19.2N 46.7W at 20/0900 UTC
or about 869 nm east of the Leeward Islands, moving west-
northwest at 11 kt. Estimated minimum central pressure is 1008 mb.
Maximum sustained wind speed is 35 kt with gusts to 45 kt.
Convection has significantly reduced in the last couple of hours.
Scattered showers and isolated tstms are from 17N-22N between 43W-
47W. Please see the latest NHC Intermediate Public Advisory under
AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC and the full
Forecast/Advisory under the AWIPS/WMO headers MIATCPAT1/WTNT21
KNHC for more details.

...TROPICAL WAVES...

Tropical wave is in the central Atlantic extending from 05N35W to a
1009 mb low near 11N35W to 16N33W, moving W at 15 kt within the
last 24 hours. Intrusion of Saharan dry air and dust to the wave
environment continue to limit the convection to scattered showers
and isolated tstms from 05N-16N between 30W and 40W. Any
development of this system during the next couple of days should
be slow to occur due to its proximity to dry air. Environmental
conditions are forecast to be more conducive for development after
that time, and a tropical depression could form by the middle of
next week while the system moves westward across the tropical
Atlantic Ocean and into the eastern Caribbean Sea.

Tropical wave in the eastern Caribbean extends from 10N-18N with
axis near 67W, moving W at 20 kt within the last 24 hours. Even
though the wave is in a region of favorable deep layer wind shear,
strong dry air subsidence from aloft and Saharan dry air in the
wave environment hinder convection at the time.

Tropical wave in the western Caribbean extends from 08N-19N with
axis near 83W, moving W at 20-25 kt within the last 24 hours.
CIRA LPW imagery from surface to 850 mb show the wave is
associated with moderate moisture. However, strong dry air
subsidence from aloft and mainly unfavorable deep layer wind shear
limits the convection to isolated showers and tstms S of 17N W of
81W.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends across Africa into the east Tropical
Atlantic near 13N17W through the 1009 mb low to near 11N42W. The
ITCZ begins near 11N45W and continues along 09N55W to 10N62W. The
monsoon trough/ITCZ is disrupted by Tropical Storm Fiona. Aside
from the convection associated with the tropical wave, scattered
heavy showers and isolated tstms are from 05N-15N E of 22W.

...DISCUSSION...

GULF OF MEXICO...

Weak surface ridging prevails across the Gulf waters N of 22N,
being anchored by a 1017 mb high near 27N84W. The ridge continue
to provide gentle variable flow across the E-NE basin and E-SE
gentle to moderate flow elsewhere. The surface trough that was along
the western Yucatan Peninsula has moved to the E Bay of Campeche
waters where it extends from 21N90W to 17N92W and provide NE
moderate wind. The trough also generates isolated showers S of
21N E of 96W and across portions of the Yucatan Peninsula. An
elongated upper level trough extending across the SW and SE Gulf
support isolated showers and tstms across the Florida straits. Dry
air subsidence and unfavorable deep layer wind shear support fair
weather elsewhere. Mostly gentle to moderate E-SE winds are
expected through the weekend. The diurnal surface trough will form
each evening over the Yucatan peninsula supporting fresh winds
along the northwest coast of the Yucatan.

CARIBBEAN SEA...

Water vapor imagery continue to show mostly dry air and stable
conditions in the central and eastern Caribbean. Two tropical
waves are the main features in the basin. However, none represent
a threat in terms of winds and precipitation. Due to the presence
of divergent flow aloft, low level moisture and favorable deep
layer wind shear the westernmost wave is associated with isolated
showers and tstms S of 17N W of 80W. For more details about the
waves see the tropical waves section. The E pacific monsoon
trough support scattered showers and tstms in the SW basin S of
10N. Otherwise...fresh to strong trades are from 11N-14N between
73W and 78W with near gale force winds along the coast of
Colombia. These winds are forecast to prevail for the rest of the
weekend.

...HISPANIOLA...

Remnant moisture associated with the passage of a tropical wave
and divergent flow aloft support cloudiness across portions of
Haiti and the Windward Passage. Model guidance indicate showers
will develop across the western Island tonight. Fair weather for
the entire Island is forecast for Sunday.

ATLANTIC OCEAN...

The primary concern in the Atlantic waters S of 30N continue to be
Tropical Storm Fiona. Please see the Special Features section
above for more details. Over the SW N Atlantic, an elongated area
of low pressure is centered by a 1015 mb low near 28N69W. Farther
east, scattered showers and isolated thunderstorms are N of 28N
between 46W and 52W. The remainder of the basin is dominated by a
surface ridge anchored by a 1019 mb high near 28N33W.

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

$$
RAMOS
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