AXNT20 KNHC 101729
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
129 PM EDT Tue Sep 10 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
Gabrielle has become an extratropical cyclone, and the final
advisory was issued at 10/1500 UTC. At 10/1500 UTC, the center of
Post-Tropical Cyclone Gabrielle is near 43.9N 37.8W, or about 605
nm NW of the Azores, moving NE at 25 kt. The estimated minimum
central pressure is 998 mb. The maximum sustained winds are 45 kt
gusting to 55 kt. Scattered moderate rainshowers extend outward to
300 nm in the N semicircle. Please read the final NHC
forecast/advisory under AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC,
or the website hurricanes.gov for more details.
An Atlantic Ocean tropical wave is along 21W, from 20N southward,
moving W at 10 kt. Scattered moderate showers are near and within
210 nm E of the wave axis from 13N-19N. Scattered moderate showers
are also from 03N-08N between 15W-27W. The wave is expected to
move westward quickly during the next several days. Some slow
development is possible late this week and over the weekend when
the system is several hundred nm east of the Lesser Antilles, and
there is a low chance of tropical cyclone formation within the
next 5 days.
An Atlantic Ocean tropical wave is along 47W, from 20N southward,
moving W at 10-15 kt. A 1011 mb low is along the wave near 13N.
Scattered moderate showers are from 10N-15N between 43W-51W.
Although some slight development is possible today or tomorrow,
upper level winds are forecast to become unfavorable for tropical
cyclone formation by Thursday. There is a low chance of tropical
cyclone formation during the next 2 days. This disturbance is
expected to move slowly westward for the next several days.
A tropical wave is in the eastern Caribbean Sea along 64W from
17N southward, moving W around 15 kt. Scattered showers and
tstorms are mostly inland over NE Venezuela, with only isolated
showers seen over water east of the wave axis near the Lesser
A western Caribbean Sea tropical wave is along 83/84W, from 17N
southward, moving W around 10 kt. The wave is interacting with the
East Pacific monsoon trough to produce scattered moderate
convection from 08N-12N between 80W-83W.
A tropical wave is inland, along 91W, from 19N southward, moving
W at 10-15 kt. The wave passes through the western Yucatan
Peninsula, to western Guatemala and into the East Pacific basin.
Isolated showers are near the wave axis.
The monsoon trough passes through coastal sections of Senegal near
16N17W to 12N20W to 12N30W to 13N40W to a 1011 mb low near 13N47W
to 09N52W. The ITCZ extends from 09N52W to 09N60W. Scattered
showers are within 270 nm N and 180 nm S of the monsoon trough
GULF OF MEXICO…
Middle level to upper level cyclonic wind flow covers northeastern
Mexico, E Texas and the Gulf of Mexico from 22N northward between
93W-102W. A diurnally induced surface trough is over the central
Bay of Campeche. Scattered moderate convection is south of 24N
between 92W-96W. Scattered showers and isolated tstorms are seen
elsewhere S of 29N and W of 91W. Scattered showers and tstorms are
also noted over the eastern Gulf of Mexico from 24N-28N between
82W-87W due to enhanced moisture in the area. Scattered showers
and tstorms are also occurring in the Yucatan Channel. The latest
ASCAT pass shows mostly moderate wind speeds over the basin.
Weak high pressure will continue just north of the western and
central Gulf through this week maintaining gentle to moderate
easterly flow throughout. Stronger high will build in from the
northeast across Florida and the eastern Gulf through Fri allowing
for fresh northeast to east winds to exist over the eastern Gulf
and fresh to strong winds over the Straits of Florida. A surface
trough is expected to move across Florida from the Atlantic Fri
and Fri night and into the eastern Gulf of Mexico this weekend
accompanied by scattered to numerous showers and thunderstorms.
Environmental conditions could become conducive for slow
development when the trough moves through the Gulf of Mexico over
the weekend. There is a low chance of tropical cyclone formation
during the next 5 days over the Gulf of Mexico from this trough.
See section above for information on the tropical waves traversing
the basin. An upper level trough and a surface trough, both near
the eastern Bahamas, extend moisture southward to Haiti, the
Windward Passage and Jamaica. Scattered showers and isolated
tstorms are seen north of 17N between 72W-78W. Additional
scattered tstorms are in the NW Caribbean from 20N-22N between
80W-86W. In the SW Caribbean, the East Pacific monsoon trough is
inducing scattered moderate convection S of 12N and W of 78.5W.
Latest ASCAT pass shows strong trades in the south-central
Caribbean from 11.5N-13.5N between 71.5W-76W.
High pressure ridging will remain to the north and northeast of
area through the remainder of the week. The ridging will maintain
moderate trades, except pulsing to fresh to strong in the south-
central Caribbean and near the coast of Colombia through the next
few days. A tropical wave over the eastern Caribbean near 64W will
move into the central Caribbean by late Wednesday then enter the
western Caribbean Friday. A stronger tropical wave may approach
the tropical N Atlc and far eastern Caribbean by the end of the
upcoming weekend with gusty winds and squalls.
A surface trough axis extends from 26N69W to 18N72W. Numerous
moderate convection is from 21N-27N between 67W-74W, including
over portions of the SE Bahamas. Scattered showers and isolated
tstorms are elsewhere from 20N-30N between 66W-75W. An upper-level
cyclonic circulation center near 27N74W is enhancing convection.
The surface trough will track WNW across the Bahamas through Thu
night before reaching Florida Fri. The trough will be accompanied
by scattered to numerous showers and tstorms. Some of these
thunderstorms could be severe across the Bahamas, especially
Thursday into Friday. Heavy rainfall is likely in the SE and
Central Bahamas Wed and Thu, spreading to the Central and NW
Bahamas on Friday. The system has little to no tropical cyclone
formation potential before it reaches Florida, but environmental
conditions could become a little more conducive for development
over the weekend when the trough is located over the Gulf of
A surface trough extends from 31N53W to 27N54W. An upper level
low is just south of that, near 24N55W. Scattered moderate
convection is from 23N-26.5N between 50W-55W. Farther E, a surface
trough along 42W from 28N-31N is inducing scattered showers near
the trough axis. A large upper level low near 26N31W is producing
scattered showers and isolated tstorms from 26.5N-31N between
Strong high pressure centered north of the area will expand
eastward through Wed night, then weaken on Thu into Fri as the
surface trough moves through the Bahamas to Florida.