Tropical Weather Discussion
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AXNT20 KNHC 261758

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
158 PM EDT Tue Sep 26 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
1630 UTC.


Hurricane Maria is centered near 33.8N 73.1W at 26/1800 UTC or
about 143 nm southeast of Cape Hatteras North Carolina, moving
north at 6 kt. Minimum central pressure is 974 mb. Maximum
sustained winds are 65 kt with gusts to 80 kt. Maria is a very
large cyclone with hurricane-force winds extending outward up to
90 nm from the center. Scattered moderate convection is within
360 nm of this system in the eastern semicircle. Stable air on the
western semicircle is resulting in mainly showers within 300 nm
west of the center. Buoy data indicates seas of 15 ft extending
over 150 nm south of the center, with 8 ft seas about 300 nm south
of the center. See the latest NHC Forecast/Advisory under
AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC for more details.

Hurricane Lee is centered near 29.9N 53.7W at 26/1500 UTC or
about 585 nm east of Bermuda. Lee is moving to the west at 9 kt.
Estimated minimum central pressure is 975 mb. Maximum sustained
winds are 90 kt with gusts to 110 kt. Lee is a small cyclone with
numerous moderate and isolated strong convection confined to
within 75 nm of the center. Lee is forecast to remain a hurricane
the next couple of days as it continues west today, then moving
toward the west- northwest by Wednesday. See the latest NHC
Forecast/Advisory under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC
for more details.


A tropical wave is exiting the coast of Africa with an axis
extending from around 13N16W to 04N13W, moving westward at around
15 to 20 kt. Scattered moderate convection is associated with a
squall line within about 150 nm west of the wave axis, south of

A tropical wave extends along 40W from 20N to 06N, moving west at
10 to 15 kt. This wave is well defined in 700 mb wind fields.
However, aside from the southern portion of the wave, most of
this wave is embedded within a fairly dry and stable environment
per recent SSMI TPW imagery. Scattered moderate convection is
south of 11N between 37W and 44W.

A tropical wave is in the eastern Caribbean along 70W/72W, from
20N to 08N, moving west at 10 to 15 kt. The wave is embedded
within a weak 700 mb trough. Isolated moderate convection is
within 90 nm of the wave axis north of 15N, and is partially due
to upper level diffluence over the region.


The monsoon trough extends from the coast of Africa near 15N17W
to 10N23W to 08N38W. The Intertropical Convergence Zone extends
from 08N43W to 09N60W. Aside from convection associated with the
tropical waves, scattered moderate to strong convection is from
08N to 14N between 50W and 56W. Widely scattered moderate
convection is within 90 nm of the monsoon trough between 22W and
38W, and the ITCZ axis west of 56W.



A surface trough extends over the southwest Gulf from 23N95W to
18N93W, and is void of deep convection. An upper low over the
eastern Gulf supports scattered thunderstorms south of 28N, east
of 89W. Weak ridging extends from Ohio Valley high pressure,
southwestward over the northern Gulf, supporting gentle to
moderate winds over the basin outside of thunderstorm activity.
Over the next 24 hours thunderstorms will continue over the
southeast Gulf.


A tropical wave is over the E Caribbean. Please refer to the
tropical waves section for details. A surface trough extends from
21N82W to 13N83W and is located under a broad upper level
anticyclone that is supportive of scattered moderate convection
from 14N to 20N between 79W and 83W. Widely scattered
thunderstorms are elsewhere north of 12N between 75W and 86W. A
ridge of high pressure over the SW N Atlantic supports moderate to
locally fresh trades over the Caribbean, except gentle winds over
the southwest Caribbean near the E Pacific monsoon trough. Little
change is expected over the next 24 hours.


A tropical wave is crossing the island today. However, dry air is
limiting shower and thunderstorm activity to mainly isolated in
coverage. Little change is expected through Wednesday.


Two tropical waves are moving across the basin. Please refer to
the tropical waves section above for details. Hurricanes Maria
in the western Atlantic and Lee in the central Atlantic are
discussed in the special features section above. A plume of
moisture is being pulled northeast across the bahamas and
surrounding waters by an upper low over the eastern Gulf of
Mexico. This plume combined with upper level diffluence from the
upper low supports numerous showers and scattered thunderstorms
from 22N to 28N, west of 74W. Low level convergence well to the
southeast of Maria, combined with upper level diffluence from an
upper low to the east is supporting scattered showers and
thunderstorms N of 22N between 63W and 70W. Elsewhere, surface
ridging prevails across much of the remainder of the central and
the eastern Atlantic, anchored by a 1021 mb high centered near

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