AXNT20 KNHC 221804
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 AM EST Fri Nov 22 2019
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
Tropical Storm Sebastien is centered near 25.2N 55.3W at 22/1500
UTC or 600 nm NE of the Northern Leeward Islands moving ENE at
13 kt. Estimated minimum central pressure is 1000 mb. Maximum
sustained wind speed is 45 kt with gusts to 55 kt. Numerous
moderate with isolated strong convection is from 25N to 30N
between 49W and 55W. An ENE to NE motion is expected during the
next few days. Continued gradual weakening is anticipated and
Sebastien is forecast to dissipate by early next week. The
Public Advisories for Sebastien are available via AWIPS/WMO
headers MIATCPAT5/WTNT35 KNHC. The Forecast/Advisories for
Sebastien are available via the AWIPS/WMO headers
A tropical wave is in the central Atlc from 01N to 10N with axis
near 36W, moving W at 10-15 kt. Scattered moderate isolated
strong convection is from 0N to 11N between 25W and 38W.
A tropical wave is to the SE of the Windward Islands from 06N to
14N with axis near 56W, moving W around 10 kt. Isolated showers
are S of 10N between 51W and 60W.
The monsoon trough passes through the coastal plains of Sierra
Leone near 07N12W to 07N14W. The ITCZ continues from 07N14W to
05N20W to 05N32W, then continues W of a tropical wave from
02N37W to 01N46W to 0N50W. For information on convection, see
the Tropical Waves section.
GULF OF MEXICO...
Except for isolated showers and patchy fog along the NW Gulf
coast, the remainder basin is under fair weather conditions
being supported by a deep-layered anticyclone centered near the
Yucatan Peninsula in the middle to upper levels. At the surface,
the ridge is anchored by a 1022 mb high over the SW N Atlc and
provides gentle to fresh return flow to the gulf as seen in the
latest ASCAT pass.
The surface ridge will prevail across the area through today. A
cold front will move off the Texas coast and into the NW Gulf
this evening, cross the northern and central waters this
weekend, then weaken and stall over the southern Gulf Sun night
into Mon. Another cold front may move into the NW Gulf by Tue
A surface trough, remnants of a former tropical wave, is over
the NW Caribbean waters extending from 19N82W to Nicaragua
adjacent waters. Isolated showers are in the vicinity of this
trough. The remnants of a former cold front are analyzed as a
shearline extending from Guadeloupe SW to 15N67W to 14N73W.
Scattered to isolated showers are within 60 nm either side of
the shearline. This line of showers and tstms will gradually
move SSE through Sat and then dissipate. Otherwise, the pressure
gradient between T.S. Sebastien in the central Atlc and high
pressure building over the SW N Atlc waters is supporting a
swath of fresh winds N of 14N between the Mona Passage and the
Dominican Republic. These winds will diminish Sat as Sebastian
is expected to continue a NE track, which will weaken the
Easterly trades will freshen across the south-central Caribbean
early next week, increasing to strong Tue into Tue night.
Please, see the Special Features section above for details on
A cold front is just west of T.S. Sebastien extending from
22N61W to near Puerto Rico. The front will continue moving
eastward and steer Sebastien into the north-central Atlantic.
Surface high pressure is over the SW N Atlc waters and will
prevail through Sat, then shift eastward Sat night. The next
cold front will cross the region Sun through Mon, weakening near
70W Tue and Tue night. Otherwise, surface ridging domintes the
northeastern Atlc waters.