AXNT20 KNHC 211020
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
620 AM EDT Wed Aug 21 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 0600 UTC surface analysis and satellite imagery through
An eastern Atlantic tropical wave has an axis along 34W S of 19N,
moving W around 20 kt. TPW imagery continues to show the wave
accompanied by a large area of high moisture content. Scattered
moderate showers are seen from 05N-07N between 29-33W.
A central Atlantic tropical wave extends from 23N57W to 12N59W and
is moving W at 15-20 kt. Isolated light showers are seen within
90 nm of the wave axis from 15N-21N.
The monsoon trough extends from the coast of The Senegal near
13N17W to 10N31W to 07N42W. The ITCZ extends from 07N42W to 09N53W
to 07N59W. Aside from the convection mentioned with the tropical
waves, numerous moderate to scattered strong convection is seen
over west Africa and just offshore from 10N-15N between 13W-18W.
Scattered moderate convection is from 05N-08N between 10W-15W.
GULF OF MEXICO...
The northern end of a tropical wave is over the eastern Bay of
Campeche from 24N90W to 18N91W. Numerous moderate to scattered
strong convection is over the Yucatan Channel from 20N-23.5N
between 84W-88W. Scattered showers and tstorms are off the W coast
of the Florida peninsula.
The tropical wave over the eastern Bay of Campeche will persist
as a mid-level trough, bringing enhanced shower and thunderstorm
activity to much of the central and southwest Gulf today and
Thursday. Fresh to locally strong winds are forecast in the SW
Gulf tonight and Thursday. The mid-level trough will migrate
northward late in the week, enhancing convection for the
northwestern and north-central Gulf Thursday night into Friday.
Elsewhere, weak surface ridging will persist, leading to mainly
gentle to moderate E to SE winds through Sunday.
Moisture from a tropical wave along with upper-level diffluence
are leading to numerous moderate to scattered strong convection
over the Yucatan Channel from 19N-23N between 84W-88W. Scattered
showers and isolated tstorms are farther S in the Gulf of
Honduras, and farther E between the Windward Passage and the E
coast of Jamaica. The eastern half of the Caribbean is drier,
although scattered light showers are seen in some areas in
advance of the tropical wave, which is expected to move through
the Lesser Antilles later today and tonight. In the SW Caribbean,
scattered moderate to strong convection is over N Colombia, Costa
Rica and over water within 30 miles of Costa Rica. The latest
ASCAT pass from Tuesday evening shows strong trades in the
central Caribbean between Jamaica and NE Colombia.
The tropical wave over the W Yucatan Peninsula and Guatemala will
continue to support scattered showers and thunderstorms over the
NW Caribbean through this evening. Strong winds will affect the
Gulf of Honduras at night tonight and Thu. Fresh to strong trades
will persist over the south-central Caribbean through the
next five days. The next tropical wave will move across the
Lesser Antilles Wed night, reach the central basin on Thu night
and enter the western Caribbean Fri night.
Enhanced upper-level divergence in between an upper trough and an
upper ridge as well as abundant low-mid level moisture are over
the SE and central Bahamas. Scattered moderate convection is to
the east of the Bahamas from 23N-28N between 71W-76W. Scattered
showers and isolated tstorms are elsewhere from 20N-29N between
68W-80W. An upper-level low near 32N69W is inducing scattered
showers and isolated tstorms from 26N-32N between 64W-71W. The
remainder of the Atlantic is being influenced by an E-W high
pressure ridge along 31N, anchored by a 1024 mb high near 32N50W.
A middle-level low over the SW forecast waters will continue to
support scattered showers and thunderstorms over the Bahamas
through Sat. Surface high pressure will prevail elsewhere along
with gentle to moderate E to SE winds. Otherwise, fresh to locally
strong trades are expected at night between Hispaniola and the
Turks and Caicos Islands. In the far E Atlantic, strong to near
gale force N to NE winds will persist today offshore of Morocco
and Western Sahara as well as near the Canary Islands.