[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201727
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
127 PM 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 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...SPECIAL FEATURES...

Tropical Storm Fiona is centered near 20.3N 47.8W at 20/1500 UTC
or about 817 nm east-northeast of the Leeward Islands, moving
west-northwest at 12 kt. Estimated minimum central pressure is
1008 mb. Maximum sustained wind speed is 35 kt with gusts to 45
kt. Scattered moderate convection is from 19N-25N between 44W-
48W. 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...

A tropical wave extends across the central Atlantic with axis from
17N34W to a 1009 mb low near 11N35W to 05N36W, moving west at
about 15 kt within the last 24 hours. Intrusion of Saharan dry
air and dust across the eastern portion of the wave is inhibiting
convection in this area while scattered moderate convection
prevails west of the wave's axis from 06N-14N between 37W-42W. 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.

A tropical wave is moving across the eastern Caribbean with axis
extending from 19N68W to 11N69W, moving west 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 are limiting convection
development at this time.

A tropical wave is moving across the western Caribbean and Central
America with axis from 19N85W to 09N86W, moving west at 20-25 kt
within the last 24 hours. TPW imagery depicts the wave embedded
in a moist environment, however, strong dry air subsidence from
aloft and unfavorable deep-layer wind shear limits the convection
to isolated showers mainly south of 10N.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends across Africa into the east Tropical
Atlantic near 14N17W through the 1009 mb low/tropical wave
described above near 11N35W. The ITCZ begins near 11N35W to
10N57W. Aside from the convection associated with the tropical
wave, scattered moderate convection prevails from 07N-13N between
14W-21W.

...DISCUSSION...

GULF OF MEXICO...

Weak surface ridging prevails across the Gulf waters N of 22N,
anchored by a 1017 mb high near 28N85W. The ridge provides a gentle
variable flow across the E-NE basin while E-SE gentle to moderate
flow prevails elsewhere. A surface trough extends across the Bay
of Campeche from 21N93W to 19N94W with isolated convection. An
elongated upper-level trough centered over the Bahamas and extending
across the SE Gulf supports isolated showers and thunderstorms across
the Florida straits. Dry air subsidence and unfavorable deep-layer
wind shear support fair weather elsewhere. Little change is
expected through the next 24 hours.

CARIBBEAN SEA...

Two tropical waves are moving across the basin. Please refer to
the section above for details. Scattered moderate convection
prevails across the southern Caribbean south of 10N between 79W-
84W as the Monsoon Trough extends north of Panama and over Costa
Rica. Fair weather prevails elsewhere. Scatterometer data depicts
moderate to fresh trades across the basin except fresh to strong
winds from 11N-14N between 73W-78W. Expect for the waves to
continue moving west with minimal convection. Little change is
expected elsewhere.

...HISPANIOLA...

Moisture associated with the passage of a tropical wave and
divergent flow aloft will support cloudiness across the island
today with a few showers. After that, fair weather is expected for
the entire island through the next 24 hours.

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 details. A tropical wave is also moving across the
eastern Atlantic. Please refer to the section above for details.
Over the wester Atlantic; an elongated upper-level low is
centered over the Bahamas near 25N77W. With this, cloudiness and
isolated convection prevails over this area. To the east; a
surface trough extends from 30N67W to 28N68W with isolated showers.
The remainder of the basin is dominated by a surface ridge
anchored by a 1017 mb high near 24N66W and a 1021 high centered
near 28N34W.

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

$$

ERA
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