Tropical Weather Discussion
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AXNT20 KNHC 170602

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
102 AM EST Fri Nov 17 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
0515 UTC.


A 996 mb low is centered near 38N44W with the associated cold
front extending SW from the low to 31N47W. A surface trough
continues SW from 31N44W to 26N58W. The low is supported aloft by
an upper level trough between 35W-55W N of 30N. In forecast
waters, gale force S-SW winds are N of 29N E of the trough between
43W-45W, with seas from 10-16 ft. See the latest NWS High Seas
Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more


The monsoon trough extends from the African coast near 08N13W to
06N27W. The Intertropical Convergence Zone axis extends from
06N27W to 08N40W to the South American coast near 08N51W. Isolated
moderate convection is from 04N-12N E of 43W.



A 1026 mb high is centered over Indiana near 40N87W. A surface
ridge axis extends S from the high to the central Gulf of Mexico
near 26N90W. 10-15 kt surface winds are over the base of the
ridge axis. A surface trough is over the Bay of Campeche from
22N93W to 18N93W. Scattered showers are S of 21N between 92W- 97W.
Elsewhere, radar imagery shows scattered showers and isolated
thunderstorms over the Straits of Florida and W Cuba from 23N-25N
between 80W- 82W. Mostly fair weather is over the remainder of the
Gulf of Mexico. In the upper levels, a large upper level trough
is over the Gulf with axis from N Florida at 30N80W to the Yucatan
Peninsula at 20N90W. Very strong subsidence is over the Gulf. The
next cold front is expected to emerge off the Texas and Louisiana
coasts Saturday evening with showers. 25-30 kt N-NE winds will
follow in the wake of the front as it sweeps southeastward.


A surface trough extends from Haiti at 20N72W to W Panama at
09N82W. Two 1008 mb lows are embedded on the trough axis at 17N75W
and 14N78W. Scattered showers and clusters of scattered moderate
convection are within 420 nm E of the trough axis. In the upper
levels, upper level diffluence E of the Gulf of Mexico trough is
enhancing the showers and convection over the Caribbean Sea.
Expect conditions to persist for the next 48 hours.


Scattered showers and thunderstorms are over the island, and will
continue through the weekend, as deep moisture advects NE over
the region due to the upper level trough. Convection will likely
be heaviest in the afternoon and evening hours during maximum
heating. Localized flooding and life-threatening mud slides are
also possible during this time.


The tail end of a dissipating cold front is over the W Atlantic
from 31N73W to the N Bahamas at 27N79W. A prefrontal trough
extends from 29N72W through the central Bahamas to central Cuba at
23N80W. Scattered showers are within 45 nm of the trough. Another
surface trough is over the W Atlantic from 24N65W to Haiti at
20N72W. Scattered showers and clusters of scattered moderate
convection are within 360 nm E of the trough axis. A surface
trough with gale winds are over the central Atlantic. See above.
Scattered showers and clusters of scattered moderate convection
are within 240 nm E of this trough axis. A 1019 mb high is
centered over the E Atlantic near 31N33W. The tail end of a
surface trough is over the E Atlantic from 31N20W to 28N24W.
Scattered moderate convection is W of the Canary Islands from N of
28N between 17W-21W. Of note in the upper levels, a large upper
level trough is over the W Atlantic supporting the W Atlantic
front, and enhancing the central Atlantic with upper level
diffluence. Another upper level trough is over the E Atlantic
supporting the E Atlantic surface trough.

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