AXNT20 KNHC 201808
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
208 PM EDT Tue Aug 20 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
An eastern Atlantic tropical wave has an axis along 23W from 20N
southward, moving W around 15 kt. TPW imagery shows that the wave
is accompanied by a large area of high moisture content.
Scattered moderate convection is from 06N-13N between 22W-26W.
An Atlantic Ocean tropical wave is along 43W from 20N southward,
moving W at 10-15 kt. No significant convection is noted along
the wave axis due to SAL intrusion. This is limiting showers on
either side of the wave.
A tropical wave along 50W from 10N-23N originated from the
subtropics and continues to move westward at 15 kt. Isolated
showers are possible near the vicinity of the wave axis.
However, convection is currently limited due to dry air in
A western Caribbean tropical wave is along 84W from 21N southward,
moving W around 15 kt. Scattered moderate to strong convection is
seen within 180 nm of the wave axis from 15N-21W between 81W-87W
with some additional showers and tstorms between Jamaica and the
Windward Passage. Expect scattered to widespread showers and
tstorms to continue over the NW Caribbean through today.
The monsoon trough extends from the coast of Guinea-Bissau near
11N16W to 07N30W to 08N46W. The ITCZ extends from 08N46W to
06N56W. Aside from the convection mentioned with the tropical
waves, scattered moderate convection is from 05N-10N between
GULF OF MEXICO...
A 1021 mb surface high is in the Southeast Plains centered near
33N83W. Ridging extends across most of the Gulf with the exception
of the SE Gulf. A surface trough extends across Florida from
28N80W to the Florida Keys near 23N82W. Scattered showers and
tstorms are seen from 24N-25N between 81W-83W and in the northern
Gulf from 28N-30N between 85W-90W with cloudy conditions. In the
Bay of Campeche, a surface trough extends from 23N93W to 18N94W.
Scattered moderate convection is present 180 nm west of the
trough. Similar activity is seen over the Yucatan Channel.
A surface ridge extending across the northern Gulf from Bermuda
high pressure will maintain mainly gentle to moderate E to SE
winds across much of the Gulf through Sat. The passage of a
tropical wave and surface trough on Wed night will support fresh
to locally strong winds in the SW Gulf Wed night and Thu.
Convection over the NW Caribbean is associated with a tropical
wave in the area. See section above for details. Scattered
moderate to isolated strong convection is seen west of 77W to the
Yucatan Peninsula. Scattered showers and isolated tstorms are
seen across Colombia, Panama, Costa Rica and Nicaragua south of
12N. Drier air is over the E Caribbean E of 73W with little to no
significant showers. The latest ASCAT pass shows moderate to fresh
trades in the central Caribbean, with moderate trades over the
remainder of the central and NW Caribbean.
A tropical wave over the western Caribbean near 84W will exit the
basin by tonight. Bermuda high pressure north of the area will
maintain fresh to strong trade winds over the south-central
Caribbean through tonight. Winds will remain fresh to locally
strong in this region through Sat as the pressure gradient
persists between high pressure north of the region and low
pressure over Colombia. The next tropical wave will move across
the Lesser Antilles on Wed night, then continue moving westward
across the Caribbean through the rest of the week.
Broad upper-level troughing is over the W Atlantic. Scattered
to numerous moderate convection is over the Bahamas from 21N-26N
between 72W-78W. Scattered showers are present from 28N-31N
between 56W-60W. High pressure dominates the remainder of the
basin, anchored by a 1024 mb high near 31N52W.
Scattered showers and thunderstorms will persist into tonight
near the Bahamas and Great Bahama Bank as the remnants of a
surface trough move across southern Florida. A surface ridge
extending westward from Bermuda high pressure will dominate the
northern waters through Sat, with gentle to moderate E to SE winds
prevailing across much of the region. Fresh trades are expected
at night between the Turks and Caicos Islands and Hispaniola.