Tropical Weather Discussion
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AXNT20 KNHC 270532

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
132 AM EDT Tue Jun 27 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 0000 UTC surface analysis and satellite imagery through
0530 UTC.


A tropical wave was introduced in this map, extending its axis
over Africa from 19N12W to 11N13W. This wave was found using
satellite imagery and model diagnostics. Scattered moderate
convection prevails along the northern portion of the wave mainly
north of 14N between 12W-17W.

A tropical wave extends its axis from 10N28W to 01N28W, moving
westward at 15 kt. The wave is embedded within a rather moist
environment, however Saharan dry air and dust is intruding some
around the northern segment of the wave. Isolated showers are
observed within 150 nm west of the wave`s axis.

A tropical wave extends over the central Atlantic with axis from
11N48W to 04N52W, moving westward at 10-15 kt. The wave is in an
area of moderate moisture and a diffluent flow aloft. These
features are supporting scattered showers and thunderstorms north
of 06N between 45W-57W.

A tropical wave is over the central Caribbean with axis from
19N72W to 08N73W, moving westward at 15-20 kt. The wave is in a
region of limited moisture at low to mid-levels. Isolated showers
are north of 15N and west of the wave`s axis between 72W-75W.

A tropical wave is over the western Caribbean with axis from
21N86W to 10N86W, moving westward at about 15 kt. The southern
portion of the wave is very near to the eastern Pacific monsoon
trough. The wave marks the leading edge of deep tropical moisture
that trails the wave east to near 83W. Clusters of moderate
convection are located within this area of deep moisture south of
17N between 83W-91W.


The monsoon trough extends from the coast of Africa near 15N17W
southwest to near 05N28W. The Intertropical Convergence Zone then
begins from that point to 06N42W. Isolated showers are within 180
nm on either side of the ITCZ.



A broad upper-level trough extends from eastern United States
to the extreme northeast portion of the Gulf waters, then becomes
a narrow trough south to near 25N84W. This feature supports a
stationary front that is analyzed from 29N83W to 29N90W. Isolated
showers are noted along the portion of the front near Louisiana
affecting the adjacent waters north of 28N between 89W-93W. This
frontal boundary is forecast to gradually become diffuse through
Tuesday afternoon, with the remnants possibly lifting back north
as a warm front. The portion of the front along the Florida coast
may sag some to the south through Tuesday as high pressure to its
north builds in from the northwest. To the west, a pair of surface
troughs extend across the Bay of Campeche. The first extends from
25N93W to 20N93W while the second is located from 25N97W to
19N94W. Isolated showers are observed along these troughs.


The main features in the basin are two tropical waves already
discussed in the section above. Latest scatterometer data depicts
fresh to strong winds in the vicinity of the waves south of about
17N. These winds are expected to increase to near gale across the
Gulf of Venezuela by Tuesday night. Elsewhere, scattered showers
and thunderstorms are developing over the Windward Passage, north
of Jamaica, and over Cuba. Another tropical wave currently over
the central tropical Atlantic is expected to enter the eastern
Caribbean on Tuesday night, and reach the central Caribbean late
on Wednesday. This wave will be accompanied by scattered showers
and thunderstorms, some of which may contain gusty winds.


Upper-level moderate to strong southwest to west winds continue
to advect deep level moisture over the island and surrounding
waters as the northern portion of a tropical wave moves across
southwestern Haiti. Expect scattered showers and thunderstorms to
be on the increase over much of the island through the next day
or so.


Two tropical waves are moving across the basin. Please refer to
the section above for details. A surface high pressure covers the
basin, with the parent 1025 mb anticyclonic center located just
north of the area at 34N45W. A broad upper- level trough along the
United Stated eastern seaboard supports a stationary front that
extends from a 1015 mb low pressure center near 33N77W southwest
to inland northeast Florida. Isolated showers are observed along
the front. This activity is expected to continue through late
Tuesday as the surface boundary begins to drift southward, and
upper-level dynamics provide further support to maintain it

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