AXNT20 KNHC 300604
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
204 AM EDT TUE AUG 30 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
Hurricane Gaston is centered near 31.6N 54.6W at 30/0300 UTC or
about 520 nm east of Bermuda and about 1400 nm west of the Azores
moving northeast at 5 kt. Estimated minimum central pressure is
968 mb. Maximum sustained wind speed is 90 kt with gusts to 110
kt. Scattered to numerous moderate convection is from 29N-34N
between 51W-56W. See latest NHC Forecast/Advisory under the
AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC for more details.
Tropical Depression Eight is centered near 33.8N 74.1W at 30/0300
UTC or about 110 nm southeast of Cape Hatteras North Carolina
moving northwest at 4 kt. Estimated minimum central pressure is
1011 mb. Maximum sustained wind speed is 30 kt with gusts to 40
kt. Scattered moderate convection is observed within 120 nm in the
northeast semicircle of the center. See latest NHC Intermediate
Public Advisory under AWIPS/WMO headers MIATCPAT3/WTNT33 KNHC and
the full Forecast/Advisory under the AWIPS/WMO headers
MIATCMAT3/WTNT23 KNHC for more details.
Tropical Depression Nine is centered near 23.9N 85.5W at 30/0300
UTC or about 210 nm west of Key West Florida and about 175 nm
west-northwest of Havana Cuba moving west at 6 kt. Estimated
minimum central pressure is 1003 mb. Maximum sustained wind speed
is 30 kt with gusts to 40 kt. Scattered moderate convection is
observed within 90 nm in the southwest semicircle of the center. See
latest NHC Forecast/Advisory under the AWIPS/WMO headers
MIATCMAT4/WTNT24 KNHC for more details.
A tropical wave is analyzed from 09N34W to 18N34W moving west at
10 to 15 kt. The tropical wave is well represented on animated
precipitable water imagery and GOES high density winds for the
lower and mid levels of the atmosphere. Aside from mid level
cloudiness, no significant sensible weather is associated with
this tropical wave. There is , and there is little evidence of
this feature at the surface at this time, although that cannot be
ruled out. Global models indicate the tropical wave will continue
west although remain fairly weak at the surface, possible bringing
a few showers into the Leeward and Windward Islands by Thursday.
A tropical wave emerging off the African coast reaches from
08N15W to 1008 mb low pressure near 15.5N16.5W to 20N16W. The
gradient bewteen the tropical wave and high pressure to the north
is enhancing northeast flow across the Canary Islands. Scattered
moderate showers and thunderstorms are evident off the coast of
Gambia and Senegal. The tropical wave is expected to stay intact
as it tracks westward across the Atlantic over the next several
days, accompanied by areas of strong winds, seas to 8 ft and
scattered showers and thunderstorms.
The Monsoon Trough extends from 10N20W to 08N27W to 10N40W to
08N45W. The Intertropical Convergence Zone axis extends from
08N45W to 07N55W. Scattered moderate convection is evident within
120 nm south of the monsoon trough and ITCZ axes.
GULF OF MEXICO...
The primary concern is Tropical Depression Nine centered in the
southeast Gulf under an upper level anticyclonic circulation
allowing slow and gradual strengthening during the next several
days. Buoy observations and an earlier scatterometer pass
indicated easterly winds of 20 to 30 kt across much of the eastern
Gulf north T.D. Nine and east of 85W. A weak trough remains in
place over the northwest Gulf reaching from a 1009 mb low pressure
system centered near 27N97W to 25N94W. Moderate to fresh northeast
to east winds are noted north of the trough axis and west of 90W.
Convergence of these winds is supporting scattered showers and
thunderstorms in the same vicinity. Earlier shower and
thunderstorm activity over the northeast Gulf has diminished.
Light to gentle breezes are noted elsewhere. Looking ahead, T.D.
Nine is expected across central portions of the basin and will
begin re- curving to the northeast and in the general direction of
the Florida Big Bend region, reaching the Florida coast Thursday
Divergent flow aloft between an upper anticyclone over T.D. Nine
in the southeast Gulf and an upper low east of the Bahamas is
supporting scattered showers and thunderstorms over the north
central Caribbean this morning, north of 15N between 75W and 85W.
The normally dominant subtropical ridge north of the area is
temporarily weakened due to the presence of T.D. Nine and a
persistent trough north of Hispaniola, resulting in only moderate
to fresh trade wind flow across the southwest Caribbean this
morning. Clusters of thunderstorms over Central America earlier in
the evening have weakened and shifted to the Pacific coast.
Recent sounding data from Trinidad indicated a low latitude trough
moved into the far southeast Caribbean early Saturday. Slightly
stronger trade wind flow is noted across the southeast Caribbean
currently, reaching as far west as Curacao where winds to 25 kt
are noted. Trade winds will increase across much of the south-
central Caribbean through mid week as high pressure builds north
The scattered showers and thunderstorms from earlier this
afternoon have dissipated as daytime heating as decreased. The
showers and thunderstorms were enhanced in part by divergence
aloft related to an upper low centered north of the area. The
pattern will be similar through mid week.
Aside from active tropical cyclones, scattered showers and
thunderstorms are noted across the Bahamas and adjacent waters
including north of the Bahamas associated with an upper low
centered over the coast of Georgia. Another upper low centered
near 24N68W, supporting scattered moderate convection from 23N to
26N between 65W and 70W. Elsewhere, the remainder of the central
and eastern Atlc is under the influence of a surface ridge
anchored by a 1022 mb high centered near 31N42W. A surface trough
is evident into the ridge from 20N43W to 27N41W.
For additional information please visit