AXNT20 KNHC 161727
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Fri Apr 16 2021
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
Gulf of Mexico Gale Warning: A cold front is expected to move
off the Texas coast and enter the Gulf of Mexico very early
Saturday morning, between midnight and sunrise. The front will
move southward across the basin bringing strong winds and
building seas. An area of gale force northerly winds is
expected to develop offshore of the Tampico area Saturday night,
behind the front. Seas will build to 9 to 11 ft in that area.
Please read the latest NWS High Seas Forecast issued by the
National Hurricane Center at the website:
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details.
Eastern Caribbean Ashfall Advisory: An Ashfall Advisory is in
effect for La Soufriere Volcano on St. Vincent near 13.3N 61.2W.
A new eruption occurred early this morning around 1000 UTC.
GOES-16 Geocolor imagery at 1500 UTC this morning shows that
this plume is mainly spreading from St. Vincent towards the west
and northwest, over the eastern Caribbean, as far north as 15N,
and as far west as 63W. Through this evening, the plume of
volcanic ash is forecast to spread as far north as 17N and as
far west as 65W before it begins to thin out tonight. The
volcano remains in a very active state, and additional eruptions
and ash plumes are possible at any time. Mariners transiting the
nearby waters should exercise caution, and are encouraged to
report volcanic ash to the National Hurricane Center by calling
The monsoon trough enters the Atlantic ocean through the coast
of West Africa near 12N16W and continues SW to 06N19W. The ITCZ
continues from 06N19W to 03N26W to the coast of South America
near 01N50W. Scattered moderate convection is seen from 00N-07N
between 10W-52W. Similar convection is seen from 03S-00N between
GULF OF MEXICO...
Please see the Special Features section for details on the Gale
Warning in effect for the west-central Gulf of Mexico.
A cold front extends from Cedar Key Florida westward to the
28.5N88.5W, in the north-central Gulf, where it transitions to a
warm front that extends to near Freeport Texas. Scattered
moderate and isolated strong thunderstorms are occurring along
the coast of SE Louisiana and along the coast of the Florida
Panhandle, which is just north of the frontal boundary. Strong N
to NE winds are occurring in the convection. A recent ASCAT pass
indicates that moderate E winds are elsewhere north of the front
with moderate southerly winds south of the front, over the
eastern half of the Gulf. A weak 1005 mb low is along a trough
near Tuxpan Mexico. The trough extends along the coast from
Veracruz to Tuxpan, then inland to 25N100W. East of that trough,
fair weather prevails over the remainder of the SW and
south-central Gulf. TPW imagery shows lower moisture content
where the fair skies are located. GOES Geocolor imagery and
coastal surface observations from Mexico suggest that smoke or
haze is occurring over portions of the SW Gulf, mainly south of
26N and west of 93W, potentially reducing visibility to 3-5
miles. ASCAT shows fresh SE winds to the west of the Yucatan
Peninsula, south of 22N and east of 94W. Seas are 3-5 feet from
the central to SW Gulf, and 1-3 feet over the eastern Gulf.
For the forecast, the front will remain over the northern Gulf
into Saturday, before being overtaken by a cold front that will
stretch from the Florida Peninsula to Bay of Campeche by the end
of the weekend. Behind the front, gales will develop offshore
Tampico Mexico, Saturday night. Areas of smoke and haze in the
western Gulf will reduce visibility at times today.
An Ashfall Advisory is in effect for La Soufriere volcano on St.
Vincent. See the Special Features section above for details.
A surface trough extends from 17.5N66W east-northeastward to
beyond 20N58W. A line of broken clouds extends along the trough
axis with possible isolated showers. This thin line of scattered
to broken clouds continues WSW to near 16N77W with little
fanfare. The East Pacific monsoon trough is enhancing scattered
moderate convection in the SW Caribbean south of 12N between
76W-85W, including over portions of NW Colombia, eastern Panama,
NE Costa Rica and SE Nicaragua. Expect periods of moderate to
heavy rain to continue over portions of Panama and Costa Rica
this afternoon before becoming lighter this evening. A recent
ASCAT pass shows fresh trades over the south-central Caribbean
with moderate trades elsewhere, except for light to gentle winds
south of Cuba to the Cayman Islands. Fresh SE winds are also
likely occurring in the Gulf of Honduras. Seas of 4-6 ft prevail
over much of the basin, except 1-3 ft south of Cuba to the
Cayman Islands and Jamaica.
For the forecast, fresh to strong SE winds are expected in the
NW Caribbean this weekend, and then again Tue night. Fresh to
strong trade winds will prevail across the central Caribbean Sun
night through early next week.
A cold front extends from 32N71W to Daytona Beach Florida. A
surface trough is from 30N74W to 28N77W. Well ahead of the
front, scattered moderate convection is seen north of 28N
between 65W-75W. Isolated moderate showers are noted near the
surface trough and cold front. A recent ASCAT pass shows fresh
to locally strong SW winds ahead of the front, mainly north of
27N between 70W-78W, and mainly north of 29N between 62W-70W.
Seas of 6-9 ft are present in the area of fresh to strong winds.
The cold front will stall north of 28N through Sat then
dissipate as it lifts northward through Sun. A surface ridge
extends from a 1019 mb high pressure near 25N53W to 25N65W to
24N78W near Andros Island Bahamas. Mostly gentle wind speeds are
found from 18N-27N between 40W-80W, where seas are mainly in the
4-7 ft range. High pressure will continue to dominate this same
general area for the next few days.
Over the central Atlantic, a cold front extends from 32N38W to
25N46W, where it transitions to a dissipating stationary front
that continues to 23N49W. A surface trough continues from 23N49W
to the NE Caribbean near 18N65W. Scattered moderate convection
is along the cold front from 26N-28N between 41W-43W, and along
the surface trough from 19N-21N between 55W-59W. A secondary
cold front extends from 32N46W to 29N50W. Winds south of 30N are
mainly gentle, but some fresh winds are noted north of 30N. The
cold front from 32N38W to 25N46W will dissipate by early Sat. A
1026 mb high is near 32N28W. This high pressure is expected to
remain in the same general area during the next few days. Fresh
to locally strong trade winds are noted from 07N-20N between the
Cabo Verde Islands and 50W, where seas are 6-8 ft.