Tropical Weather Discussion
Issued by NWS
AXNT20 KNHC 231151 CCA
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
636 AM EDT TUE AUG 23 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
Tropical Depression Fiona is centered near 25.8N 63.4W at
23/0900 UTC or about 456 nm north of the northern Leeward
Islands, moving west-northwest at 11 kt. Estimated minimum
central pressure is 1010 mb. Maximum sustained wind speed is 30 kt
with gusts to 40kt. Scattered showers and isolated tstms are from
24N to 26N between 61W and 64W. Please see latest NHC
Forecast/Advisory under the AWIPS/WMO headers MIATCMAT1/WTNT21
KNHC for more details.
Tropical Storm Gaston is centered near 13.2N 32.4W at 23/0900 UTC or
about 474 nm west of the southernmost Cabo Verde Islands, moving
west at 17 kt. Estimated minimum central pressure is 1004 mb.
Maximum sustained wind speed is 45 kt with gusts to 55 kt.
Scattered showers are from 10N to 16N between 30W and 35W. Please
see latest NHC Forecast/Advisory under the AWIPS/WMO headers
MIATCMAT2/WTNT22 KNHC for more details.
A tropical wave is located about 348 nm east-southeast of the
Leeward Islands extending from 11N to 21N with axis near 55W. The
wave is associated with a 1009 mb low located near 16N55W and
has been moving west-northwest at 15-20 kt within the last 24
hours. Moisture has increased in the wave environment, which
along with favorable deep layer wind shear and upper level
diffluence support heavy showers and isolated tstms from 13N to
20N between 53W and 58W. Large-scale conditions could become
more conducive later this week while the system moves near
Hispaniola and then the southeastern and central Bahamas.
Despite of any tropical development, gusty winds, heavy rains,
and possible flash floods and mud slides could occur over these
areas. This system has a medium chance for tropical formation
within the next 48 hours.
A tropical wave is in the Bay of Campeche and southern Mexico. The
wave extends from 11N to 21N with axis near 94W and has been
moving west at 25-30 kt within the last 24 hours. Moisture
associated with the wave and diffluence aloft generated by an
upper level low NW of the Yucatan Peninsula support isolated heavy
showers and tstms S of 23N.
The Monsoon Trough extends across Africa into the east Tropical
Atlantic near 13N16W to 13N21W. It then resumes west of Tropical
Storm Gaston near 08N33W to 08N44W to 08N50W. The ITCZ begins
near 08N50W and continues to 06N57W. For convection information,
see the special features and tropical waves sections.
GULF OF MEXICO...
Isolated heavy showers and tstms are in the Bay of Campeche
associated with the passage of a tropical wave. The latest
scatterometer show fresh to strong NE winds east of the wave axis
to the Yucatan Peninsula coast. For further details see the
tropical waves section. A broad surface ridge covers the eastern
U.S. and extends south across the remainder Gulf of Mexico where
it is anchored by a 1021 mb high near 28N86W. This ridge provides
variable gentle flow to the NE basin and gentle to moderate E-SE
flow elsewhere N of 21N. Except for the SW Gulf, dry air
subsidence from aloft continue to support fair weather. Winds over
the eastern Bay of Campeche are forecast to diminish later this
morning. Mostly gentle to moderate E-SE winds are expected to
prevail elsewhere through Thursday.
Scattered heavy showers and tstms are over Costa Rica and Panama
coastal waters. These showers are associated with the east
Pacific monsoon trough. A moist airmass continues to move across
Hispaniola supporting isolated showers and tstms extending to
adjacent coastal waters. Unfavorable to neutral deep layer wind
shear covers most of the remainder basin, which along with strong
dry air subsidence from aloft support fair weather this morning.
The gradient between high pressure over the Atlantic and lower
pressure over northern Colombia continue to support fresh to
strong winds from 10N to 14N between 74W and 80W. Moderate trade
winds dominate elsewhere over the Caribbean basin. A tropical wave
and associated low are located about 348 nm east-southeast of the
Leeward Islands. Environmental conditions could become conducive for
development of this system late this week when the system is
expected to move near Hispaniola and the southeastern and central
Bahamas. See the tropical waves section for further details.
A moist airmass is moving across Hispaniola supporting isolated
showers and tstms extending to adjacent coastal waters. These
showers are expected to cease later this morning, however will
resume Tuesday night as another moist airmass moves across the
The main features of interest in the basin continue to be
Tropical Storm Gaston, Tropical Depression Fiona and the
tropical wave discussed in the Special Features section above.
The remainder of the area is dominated by a surface ridge
anchored by two high pressure centers just N of the area.
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