[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150005
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM EDT Sat Oct 14 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 1800 UTC surface analysis and satellite imagery through
2345 UTC.

...SPECIAL FEATURES...

Hurricane Ophelia is centered near 35.9N 23.7W at 14/2100 UTC or
about 200 nm SE of the Azores, moving NE at 24 kt. Estimated
minimum central pressure is 960 mb. Maximum sustained winds are
100 kt with gusts to 120 kt. Numerous moderate convection is from
34N-38N between 21W-25W. The core of Ophelia will pass to the
south and southeast of the Azores tonight. It is expected to be a
powerful extratropical cyclone with hurricane force winds as it
approaches Ireland. See the latest Forecast/Advisory under
AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC for more details.

A cold front will move off the coast of Texas Sunday night,
reach from the Florida Big Bend to 23N94W to the Bay of Campeche
late Mon, and then stall from Tampa Bay to 25N91W to 18N93W late
Tue night. Meanwhile a trough over the south central Gulf, on
the northern extent of a tropical wave, will drift into the SW
Gulf ahead of the front through Mon. The combination of a
slightly tighter pressure gradient along with cooler and drier
air associated with the front will allow winds funneling along
the coast of Mexico to reach minimal gale force from Tampico to
Veracruz Monday through late Tuesday, with seas reaching 8 to 13
ft.

...TROPICAL WAVES...

A tropical wave is in the central Atlc with axis extending from
13N35W to 02N35W, moving W at 20 kt. The wave is in a region of
strong vertical shear N of 10N. The wave lies underneath upper
level diffluent flow that along with shallow moisture support
isolated showers from 10N-14N between 32W-40W.

A tropical wave is in the central Atlc with axis extending from
15N44W to 04N46W and is expected to move at 10 kt within the next
24 hours. The wave was introduced based on satellite imagery and
the tropical waves diagnostic tool. The wave is in a region of
strong vertical shear. However, the CIRA LPW imagery show very
high concentration of moisture in the wave environment that along
with middle to upper level diffluence support scattered heavy
showers from 11N-14N between 40W-48W.

A tropical wave is in the E Caribbean with axis extending from
21N62W to 11N64W, moving W at 15 kt. The wave is mainly in a low
to moderate vertical shear environment and CIRA LPW show the
northern portion of the wave is in a region of abundant moisture
at the lower levels. Upper level diffluent flow supports numerous showers
and squalls mainly to the east of the wave axis from 16N-19N. This
activity is expected to spread over the Leeward Islands and the
Virgin Islands today and Sunday. Upper-level winds are expected to
remain unfavorable for development during the next couple of
days, but the environment could turn a little more favorable for
some development early next week when the system begins to move
northward and then recurves over the west-central Atlantic Ocean.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the African coast near 08N13W to
07N16W. The Intertropical Convergence Zone axis extends from
07N16W to 07N26W to 05N35W. The ITCZ then resumes near 05N37W to
06N44W...resuming again near 09N47W to 10N58W. Aside from the
convection associated with the tropical waves, scattered
moderate/isolated strong convection is from 10N-12N between 50W-
58W.

...DISCUSSION...

GULF OF MEXICO...

A broad surface trough being supported by a middle level inverted
trough is moving across the central Gulf along 27N88W to inland
Guatemala. Water vapor imagery show dry air aloft, which is
limiting the convection to isolated showers and tstms S of 28N E
of 95W. Winds S of 25N are variable gentle to light while N of 25N
a slightly tight pressure gradient between the trough and a ridge
anchored in the SE CONUS support moderate easterlies. The surface
trough will move over the W Gulf through through Sunday night when
it will shift E due to a cold front that races along Texas to
enter the NW Gulf waters early Monday morning with fresh to strong
winds behind it. Gale force winds will develop associated with
this front. See special features.

CARIBBEAN SEA...

A tropical wave moving across Honduras and Nicaragua into the EPAC
waters continue to support scattered showers and tstms in the NW
Caribbean W of 80W. Similar convection is in the SW basin, which
continue to be supported by the eastern extent of the E Pacific
monsoon trough. Otherwise, a tropical wave is moving across the E
Caribbean with a low pressure associated with it, which is
centered near 18N63W. Numerous showers and squalls are mainly to
the east of the low center from 16N-19N. Fresh to strong winds are
E of the wave axis with the strongest winds being in the NE low
quadrant. See tropical waves section. Similar winds are within
120 nm off the coast of Colombia. The wave will move over the
central Caribbean by Monday morning.

...HISPANIOLA...

Isolated showers and tstms are noted in the southern region of the
Island between Dominican Republic and Haiti. Showers are forecast
to increase in areal coverage and intensity starting Sunday
evening as the wave approaches the central Caribbean by Monday
morning.

ATLANTIC OCEAN...

A surface trough is NE of the Bahamas from 31N73W to 25N76W.
Isolated showers are within 30 nm of the trough. Further east, a
surface trough extends from 29N57W to 23N62W. Scattered moderate
convection is from 21N-30N between 55W-68W. Weak surface ridging
is elsewhere.

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

$$
Ramos
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