[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210603
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
203 AM 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 0000 UTC surface analysis and satellite imagery through
0545 UTC.

...SPECIAL FEATURES...

Tropical Storm Fiona is centered near 21.7N 50.1W at 21/0300 UTC
or about 717 nm east-northeast of the Leeward Islands, moving
northwest at 13 kt. Estimated minimum central pressure is 1004 mb.
Maximum sustained wind speed is 45 kt with gusts to 55 kt.
A cluster of heavy showers is from 20N-23N between 47W-50W.
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 wave is just off the west coast of Africa extending from
06N-19N with axis near 16W. There is a 1011 mb low near 12N16W
associated with the wave, which is expected to move at 10-15 kt
within the next 24 hours. The wave is within a moderate moist
environment and it is in a region of favorable to neutral deep
layer wind shear that favors scattered heavy showers and isolated
tstms from 06N-15N E of 21W. Environmental conditions appear
conducive for gradual development, and a tropical depression is
likely to form in a few days while the system moves westward and
then northwestward over the eastern tropical Atlantic Ocean.

...TROPICAL WAVES...

Tropical wave is in the central Atlantic extending from 05N-18N
with axis near 39W, moving W at 15-20 kt within the last 24
hours. There is a 1009 mb low near 12N39W associated with the
wave. Intrusion of Saharan dry air and dust to the wave
environment continue to limit the convection to scattered showers from
05N-17N between 35W and 49W. Any development of this system
during the next couple of days should be slow to occur due to its
large size and proximity to dry air. Environmental conditions are
forecast to be more conducive for development beyond a couple of
days, and a tropical depression could form by the middle of next
week while the system moves westward and then west-northwestward across
the tropical Atlantic Ocean, through the eastern Caribbean Sea,
and then near the Greater Antilles.

Tropical wave in the central Caribbean extends from 09N-19N with
axis near 71W, moving W at 10 kt within the last 24 hours. Even
though the wave is in a region of favorable to neutral deep layer
wind shear, strong dry air subsidence from aloft inhibits convection
at the time.

Tropical wave across the Yucatan Peninsula and northern Central
America extends from 09N-22N with axis near 88W, moving W at
20 kt within the last 24 hours. CIRA LPW imagery from surface to
850 mb show mainly dry air in the wave environment. However, satellite
derived data indicate the wave is in a region of mainly unfavorable
deep layer wind shear. These two factors combined support the lack
of convection in the NW Caribbean and Yucatan Peninsula.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends across Africa into the east Tropical
Atlantic near 12N17W to 10N30W through the 1009 mb low near
12N39W to 08N48W. The ITCZ begins near 08N48W to the coast of
Venezuela near 08N61W. For convection information, see the
tropical waves section.

...DISCUSSION...

GULF OF MEXICO...

Weak surface ridging dominates across the Gulf waters N of 22N,
being anchored by a 1016 mb high near 26N84W. The ridge continue
to provide gentle variable flow across the east basin and E-SE
gentle to moderate flow elsewhere. A tropical wave is movingacross the Yucatan Peninsula supporting cloudiness and providing NE
moderate to fresh wind across the eastern Bay of Campeche. Dry
air subsidence and unfavorable deep layer wind shear support fair
weather elsewhere. Mostly gentle to moderate E-SE winds are
expected through late Sunday. Fresh to strong winds are forecast
to develop over the Bay of Campeche Monday before sunrise.

CARIBBEAN SEA...

Water vapor imagery continue to show very dry and stable air across
the Caribbean, thus supporting fair weather basin-wide. The
exception are isolated heavy showers and tstms within 90 nm off
the coasts Costa Rica and Panama associated with the proximity of
the east Pacific monsoon trough. Two tropical waves remain the
main features across the basin, the westernmost wave moving
across Central America and the second one moving across the
central basin. For more details about the waves see the tropical
waves section. The tropical wave in the central Caribbean has
amplified the area of fresh to strong trades to S of 18N between
68W and 80W. These winds are forecast to prevail through near
Tuesday sunrise.

...HISPANIOLA...

A tropical wave is moving across the central Caribbean, however
very dry air subsiding from aloft is supporting fair weather
conditions across the entire Island. These favorable weather
conditions are forecast to prevail through Monday near sunrise.

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. The remainder of the basin is dominated
by a surface ridge anchored by a 1022 mb high near 29N35W.

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

$$
RAMOS
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