AXNT20 KNHC 231647
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1247 PM EDT Fri Jun 23 2017
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 that extends from
18N25W to 06N27W, moving westward at 20 kt. This wave is
accompanied by Saharan dust over the northern portion, with
scattered moderate convection over the southern portion from 07N
to 11N between 24W and 28W.
A central Atlantic tropical wave has an axis that extends from
13N46W, through a 1012 mb low near 09N47W to 03N47W, moving
westward at 15 to 20 kt. This wave is accompanied by scattered
moderate convection within 120 nm of either side of the wave axis.
A tropical wave just crossed the Windward Islands last night and
is now over the eastern Caribbean with an axis extending from
17N63W to 08N63W. Dry air at the mid to upper levels is inhibiting
deep convection over much of the wave, with mainly scattered
showers noted within 240 nm of either side of the wave axis north
A tropical wave extends from the NW Caribbean near 21N87W to
central America near 15N88W, to the eastern Pacific near 11N88W.
This wave is interacting with an upper low to support scattered
thunderstorms within 300 nm of the wave axis north of 16N.
The monsoon trough crosses the western Africa coast near 14N16W
and extends to 09N25W. The ITCZ axis extends from 07N29W to
04N45W. Aside from convection associated with an eastern and
central Atlantic tropical wave, scattered moderate convection is
within 150 nm of either side of the ITCZ axis.
GULF OF MEXICO...
High pressure centered over the western Atlantic has a ridge axis
that extends across the northern Gulf of Mexico, supporting
moderate to fresh south to southeast winds and mainly fair weather
over the basin today. The only exception is a band of moisture
from the SW Gulf to near the mouth of the Mississippi, and
moisture streaming northwest over over the SE Gulf producing
scattered showers. Over the next 24 hours the northern portion of
a tropical wave will interact with an upper low to produce
scattered thunderstorms over the south central and southwest Gulf
tonight and Saturday.
An upper level low is interacting with a tropical wave over the NW
Caribbean to support scattered showers and thunderstorms, while
another tropical wave has just entered the eastern Caribbean.
Please see the tropical waves section for more details. Scattered
thunderstorms south of 11N over the southwest Caribbean are
associated with the monsoon trough. Mainly moderate to fresh trade
winds cover the Caribbean today, except light winds south of 11N
over the southwest Caribbean. Over the next 24 hours the western
Caribbean wave will exit the basin. The eastern Caribbean wave
will approach the central Caribbean with scattered showers.
Scattered showers in a band of low level moisture are passing
across the island today. Another batch of showers are poised to
reach the island tonight, with additional showers possible late
Saturday as a tropical wave passes south of the island.
There are two tropical waves crossing the tropical north Atlantic
basin. Please refer to the tropical waves section for more
details. A surface trough extending from 28N57W to 24N55W is a
surface reflection of an upper low centered near 25N53W. These
features support scattered showers and thunderstorms from 22N to
27N between 49W and 57W. A dissipating stationary front void of
convection extends from 31N35W to 30N44W. High pressure of 1021 mb
centered near 30N67W has a ridge axis that extends west across
north Florida, and northwestward from the high to another high
centered near the Azores. This ridge dominates the remainder of
the Atlantic discussion waters. Little change is expected over the
next 24 hours.
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