AXNT20 KNHC 190530
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 AM EDT Tue Jun 19 2018
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 0000 UTC surface analysis and satellite imagery through
A tropical wave axis extends along 21W from 05N to 14N, moving W
of Africa at 15 kt in a low vertical shear environment. GOES-16
Dust RGB imagery show the wave is being affected by dry air and
dust, especially in the northern part. No deep convection and
minimal tropical showers are associated with the wave.
A tropical wave axis in the central Atlc extends from 12N33W to
03N34W, moving W at 15-20 kt in a low shear environment. It is
being affected by dry air and dust, and no deep convection is
associated with this wave.
A tropical wave axis in the west-central Atlc extends from
14N49W to 06N51W, moving W at 10-15 kt. GOES-16 RGB imagery
shows dry air and dust intrusion in the wave environment, which
along with strong wind shear is inhibiting deep convection.
A tropical wave axis crossing the Windward Islands extends from
15N61W to 07N62W, moving W at 15 kt. This wave is within a very
moist environment and upper level diffluent flow, supporting
scattered moderate convection south of 15N between 59W and 63W.
A tropical wave axis in the central Caribbean extends from
21N77W to 09N78W, moving W at 10-15 kt in a strong wind shear
environment. GOES-16 middle and lower level water vapor imagery
show very dry air in the region. These two factors are hindering
the development of deep convection at the time.
The monsoon trough extends from the coast of Africa near 09N13W
to 05N21W. The ITCZ continues from 04N22W to 07N50W. Scattered
showers are from 02N to 07N between 20W and 29W and from 06N to
10N between 50W and 56W.
GULF OF MEXICO...
Scattered to numerous showers and thunderstorms are over the NW
Gulf of Mexico, associated with an upper level low interacting
with a surface trough near the Texas coast. Development of this
system is not anticipated. However, heavy rainfall and flash
flooding across portions of southern and southeastern Texas are
likely to continue the next few days. The pressure gradient
between the area of low pressure and a ridge across the SE CONUS
extending into the NE Gulf supports fresh to strong SE to S
winds N of 22N between 91W and 95W. The ridge will weaken by Tue
evening, winds diminishing to below 20 kt. Gentle to moderate
return flow will dominate the basin thereafter through Wed
night, with strongest winds being west of 90W.
Strong trades across the S central Caribbean will gradually
decrease in areal coverage this morning as high pressure in the
SW N Atlc shifts east. Fresh to strong winds will pulse at night
in the Gulf of Honduras through early Wed morning. Otherwise, a
tropical wave passing west of the Windward Islands will move
across the E Caribbean today along with showers. The wave will
move S of Puerto Rico, then into the central Caribbean on Wed.
A weakening stationary front extends from a 106 mb low near
31N56W to east of the Bahamas near 25N75W. Weak surface ridging
north of the front supports light to gentle NE to E winds and
mostly fair weather. Lingering moisture is associated with the
front. A mid-level trough continues to support widely scattered
showers within 150 nm ahead of the front. Latest scatterometer
data shows fresh winds near the low center. The remainder of the
Atlantic is under the influence of the Azores subtropical ridge
anchored by a 1029 mb high NE of the Azores Islands. The front
will weaken today then dissipate tonight. Surface ridging will
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