[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 070930
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
530 AM EDT Sat Oct 7 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 0600 UTC surface analysis and satellite imagery through
0930 UTC.

...SPECIAL FEATURES...

Hurricane Nate is centered near 24.5N 87.0W at 07/0900 UTC or
about 297 nm south-southeast of the mouth of the Mississippi
river. Nate is moving north-northwest at 19 kt. Estimated minimum
central pressure is 987 mb. Maximum sustained wind speed is 70 kt
with gusts to 85 kt. Numerous strong convection is from 23N-25N
between 85W-88W. Scattered moderate to isolated strong convection
and tstms are elsewhere from 17N-29N between 82W-92W. See the
latest NHC Intermediate Public Advisory under AWIPS/WMO headers
MIATCPAT1/WTNT31 KNHC and the full Advisory/Forecast under
AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC for more details.

...TROPICAL WAVES...

A tropical wave came off the coast of Africa this morning. Its
axis extends from 11N15W to 01N14W expected to move W at 10 kt
during the next 24 hours. Satellite derived date indicate the
wave is in a low vertical shear region while the CIRA LPW imagery
show abundant low level moisture in the wave environment. This
combined with upper level divergent flow support numerous moderate
convection and scattered tstms from 02N-12N between 11W-18W.

A tropical wave is in the central Atlc associated with a 1011 mb
low located near 06N43W, which is expected to move NW towards
10N46W within the next 24 hours. The wave axis extends from 14N40W
to the low center to 05N43W, and has been moving W at 10 kt. The
wave is in a region of strong vertical wind shear and is experiencing
dry air intrusion to its environment as indicated by CIRA LPW
imagery at the lower levels. This is limiting convection to
scattered moderate from 06N-14N between 39W-46W just underneath
middle to upper level divergent flow.

A tropical wave is in the central Atlc with axis extending from
19N48W to 08N53W, moving west at 5-10 kt. The wave is in a region
of strong vertical wind shear, however CIRA LPW imagery show
abundant moisture in the wave environment at the lower levels
mainly E of the wave axis where scattered moderate convection is
from 13N-17N between 46W-53W just underneath middle level
divergent flow.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the African coast near 13N17W to
08N20W to 04N26W. The ITCZ extends from there to 03N30W to
04N36W. For information about convection see the tropical waves
section.

...DISCUSSION...

GULF OF MEXICO...

The main feature in the basin is hurricane Nate located several
nm NNE of the Yucatan Peninsula. Additional strengthening is
expected through Saturday up until the time Nate makes landfall
along the northern Gulf coast Saturday night. In Mexico, a storm
surge will raise water levels by as much as 1 to 3 feet above
normal tide levels along the immediate coast in areas of onshore
winds on the Yucatan Peninsula and the adjacent islands. Near the
coast, the surge will be accompanied by large and destructive
waves. Nate is expected to produce rain accumulations of 6 inches
in the Eastern Yucatan and western Cuba through Monday. For
further details, see special features. Scatterometer data show a
surface trough NW of Nate over the NW Gulf along 28N94W to 23N93W
producing scattered showers and tstms within 15 nm either side of
its axis.

CARIBBEAN SEA...

Scattered moderate to isolated strong convection along with
scattered tstms prevail across the NW Caribbean W of 80W,
including the Yucatan channel and W Cuba. This precipitation
activity is associated with hurricane Nate centered over the SE
Gulf of Mexico. Refer to the special features section above for
details. Nate is a broad tropical cyclone, which outer rainbands
continue to affect the Cayman Islands, Jamaica and, central and
eastern Cuba. Isolated showers extends over Hispaniola and are
also being enhanced by a surface trough over SW N Atlc waters.
Water vapor and CIRA LPW imagery show dry air over the central and
eastern Caribbean, which is resulting in mainly clear skies and
fair weather conditions. Gentle to moderate E-SE winds are
expected to prevail E of 80W through the weekend. Heavy rainfall
is expected to continue across the NW Caribbean as Nate tracks
northward.

...HISPANIOLA...

Isolated showers are over Hispaniola associated with the outer
rain bands of Hurricane Nate centered over SE Gulf of Mexico
waters. These showers are also being enhanced by a surface trough
over SW N Atlc waters N of the Mona Channel. Similar conditions
are expected through the weekend with showers increasing Sunday
morning due to closer proximity of the surface trough to the
Dominican Republic.

ATLANTIC OCEAN...

Three tropical waves are moving across the basin. Refer to the
section above for details. In the SW N Atlc waters, a surface
trough underneath middle to upper level diffluent flow is
generating scattered heavy showers and isolated tstms from 19N to
30N between 63W and 79W. In the north-central Atlc waters, a
stationary front extending from 30N37W to 25N46W continues to
weaken and is expected to become a remnant surface trough tonight.
SE of this front a pre-frontal trough extends from 25N38W to
17N44W. The remainder of the basin is under the influence of a
surface ridge, anchored by a 1026 mb high centered near 35N53W.

For additional information please visit
http://www.hurricanes.gov/marine

$$
Ramos
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