AXNT20 KNHC 130005 
Tropical Weather Discussion 
NWS National Hurricane Center Miami FL 
804 PM EDT Thu Oct 12 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. 
Hurricane Ophelia is centered near 30.4N 35.5W at 12/2100 UTC or 
about 620 nm SW of the Azores. Ophelia is currently stationary. 
Estimated minimum central pressure is 973 mb. Maximum sustained 
wind speed is 85 kt with gusts to 105 kt. Numerous moderate 
convection is from 29N-31N between 34W-36W. The center of Ophelia 
will remain south of the Azores through Saturday. See the latest 
Forecast/Advisory under AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC 
for more details. 
A tropical wave came off the coast the coast of Africa earlier 
today. Its axis extends from 16N21W to 04N22W expected to move at 
15 kt within he next 24 hours. The wave is in a region of strong 
vertical shear and IR enhanced imagery show the wave is being 
affected by Saharan dry air and dust. These environmental 
conditions are hindering convection at the time. 
A tropical wave is in the central Atlc with axis extending from 
18N52W to 09N56W, moving W at 20 kt. The wave is mainly in a low 
to moderate vertical shear environment and CIRA LPW show the wave 
is in a region of abundant moisture at the lower levels. Middle 
level diffluence and upper level divergence support numerous 
strong convection from 11N-15N between 50W-53W. Scattered moderate 
convection is elsewhere from 09N-19N between 45W-55W. 
A tropical wave is in the Caribbean with axis extending from 
13N77W to 04N77W, moving W at 5 kt. The wave is mainly in a low 
to moderate vertical shear environment and CIRA LPW show the wave 
is in a region of abundant moisture at the lower levels. Middle 
level diffluence support scattered heavy showers inland NW 
Colombia and isolated showers in the SW Caribbean S of 13N. 
The monsoon trough extends across inland Africa to 11N16W. The 
Intertropical Convergence Zone axis extends from 09N27W to 07N40W 
to 08N48W. Aside from the convection associated with the tropical 
waves...scattered moderate convection is from 04N-09N between 30W- 
A stationary front extends from the Florida panhandle near 30N86W 
W-SW to 25N95W to 19N96W. The portion of the front across the NE 
Gulf remains generally precipitation-free and relatively diffuse. 
However, fresh to strong northerly winds are noted S of 21N W of 
the front with scattered showers occurring S of 27N W of 90W. 
A surface trough is approaching the Florida Peninsula and is 
already generating scattered showers and tstms in the Florida 
Straits and the SE Gulf S of 26N E of 84W. Otherwise, gentle to 
moderate NE winds prevail across the basin E of the front. The 
front is expected to become diffuse through Thursday night and 
remain as a surface trough boundary across the SW Gulf Friday. 
A middle to upper level low is in the area from central Cuba and 
the northern Bahamas, which continue to provide an overall lower 
pressure regime and weak pressure gradient pattern across the 
basin. The low aloft reflects at the surface as a trough from 
28N72W to 26N77W to 21N82W, which is generating scattered showers 
and tstms N of 15N W of 76W. A tropical wave is moving across the 
SW Caribbean across Panama into the EPAC. Widely scattered 
showers are occurring in the vicinity of the wave S of 14N. 
Otherwise, latest scatterometer data depicts gentle to moderate 
trades across the basin. 
Trailing moisture associated with the surface trough over the SW N 
Atlc and Cuba is supporting isolated showers and tstms mainly 
across adjacent waters of the Island. A middle to upper level high 
will be over the Island through Saturday, thus supporting fair 
Hurricane Ophelia is detailed above. An upper level low is 
centered over the northern Bahamas providing support for a 
surface trough analyzed from 29N72W to 22N79W with scattered 
showers and tstms focused primarily west of 71W. Farther east, a 
weaker surface trough is noted from 27N53W to 19N58W and is 
generating isolated showers and tstms within 30 nm of its axis. 
The remainder of the eastern Atlc outside of the influence of 
Hurricane Ophelia...is under the influence of surface ridging 
anchored by a 1021 mb high centered near 37N17W. 
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