[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 212342
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
742 PM EDT SUN AUG 21 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...

A tropical Storm Fiona is centered near 23.4N 54.9W at 21/2100
UTC or about 543 nm northeast of the Leeward Islands, moving west-
northwest or 290 degrees at 15 kt. Estimated minimum central
pressure is 1007 mb. Maximum sustained wind speed is now 35 kt
with gusts to 45 kt. Fiona has is still a tropical storm now but
it is forecast to become a tropical depression tonight due to
strong westerly shear affecting the system. A cluster of moderate
convection is noted from 23N-25N between 50W-54W. Please see
latest NHC Forecast/Advisory under the AWIPS/WMO headers
MIATCMAT1/WTNT21 KNHC for more details.

A tropical wave is just off the west coast of Africa extending
from 17N20W to 1008 mb low near 12N21W to 08N20W. Scattered
moderate convection is noted from 14N-16N between 20W-30W.
Environmental conditions are conducive for development, and a
tropical depression is likely to form during the next day or two
while this system moves westward and then northwestward over the
eastern tropical Atlantic. The Tropical Weather Outlook gives
this system a high chance of tropical cyclone development through
the next 48 hours.

...TROPICAL WAVES...

A tropical wave is in the central Atlantic extending from 20N44W
to a 1010 mb low near 14N45W to 10N44W. Convection is limited in
association with this wave due to the presence of Saharan dust
based in the current SAL analysis. Visible satellite imagery shows
a large swirl of mainly low clouds related to the low pressure.
The proximity of this system to dry air is expected to inhibit
significant development during the next few days while the
disturbance moves westward at 15 to 20 kt. Environmental
conditions could become more conducive for development late this
week when the system is expected to be near Hispaniola and the
southeastern Bahamas. Moisture associated with this system is
expected to reach the Leeward Islands and part of the Windward
Islands by Tuesday evening or night.

A tropical wave is over central Caribbean with axis that extends
from Haiti to the coast of Colombia along 74W, moving west at 10
kt within the last 24 hours. No deep convection is associated with
the wave as Saharan dust and dry air prevails across most of the
Caribbean basin inhibiting significant convection. This feature
is enhancing the trade wind flow across the central Caribbean. The
wave will continue to move westward across the western Caribbean
through Tuesday night.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends across Africa into the east Tropical
Atlantic near 15N18W to 09N25W to 12N38W. The ITCZ begins near
10N46W to the coast of Venezuela near 10N61W. Aside from the
convection related to the tropical wave/low described in the
Special Features section above, scattered moderate convection
prevails within 100 nm south of the ITCZ between 48W-52W.

...DISCUSSION...

GULF OF MEXICO...

A 1019 mb surface high is located over the NE Gulf near 28N85W
dominating the basin. At upper-levels, a low pressure is centered
just north of western Cuba near 24N85W supporting isolated
moderate convection across the Florida Straits, the Florida
Peninsula, and eastern Gulf waters mainly east of 85W. To the
southwest; a thermal surface trough is over the Bay of Campeche
along 94W. Scatterometer data depicts a gentle to moderate
anticyclonic flow across the basin. Expect through the next 24
hours for the surface high to move west towards the Mississippi
delta through Tuesday. The Bay of Campeche's trough will support
fresh to strong NE-E winds just off the NW coast of the Yucatan
peninsula and across the SW Gulf tonight and then again Monday
night.

CARIBBEAN SEA...

A tropical wave is moving westward across the central Caribbean.
Please see the tropical waves section for details. The only area
with scattered moderate convection continues to the the south-
central mainly south of 10N between 79W-82W due to the presence
of the Monsoon Trough currently extending over Costa Rica and
Panama. There are a few showers developing over Cuba supported by
an upper-level low centered just northwest of the island.
Scatterometer data depicts moderate to fresh trades across the
basin except fresh to strong winds south of 16N between 72W-80W.
Expect for the wave to continue moving west through the next 24
hours. Little change is expected elsewhere.

...HISPANIOLA...

Fair weather prevails across the island at this time. Moisture is
forecast to increase across the island within the next 24 hours as
a surge of moisture reaches Hispaniola. This moisture combined
with the local effects will support scattered showers and isolated
thunderstorms.

ATLANTIC OCEAN...

T.S. Fiona is moving across the central Atlantic. Please see the
Special Features section above for more details. Attention remains
focused on the tropical waves and associated lows located over
the eastern and central Atlantic. The wave along 14N is expected
to move across the north-eastern Caribbean by early next week and
then move northwest reaching the southern Bahamas by the end of
the week. There is a low chance for this wave to become a tropical
system within the next 48 hours but conditions could become more
conducive for some slow development during the next 5 days. The
wave along 21N is discussed in the Special Features section above.
The remainder of the area is dominated by a surface ridge anchored
by a 1022 mb high centered near 31N54W and a 1022 mb high near
29N37W.

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

$$

ERA
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