Tropical Weather Discussion
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AXNT20 KNHC 171029

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
529 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 0600 UTC surface analysis and satellite imagery through
1015 UTC.


A 993 mb low is centered near 40N41W with an associated cold
front extending SW from the low to 37N39W to 31N44W. A surface
trough continues SW from 31N44W to 27N53W. 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 41W-43W, with seas from 10-16 ft. See the latest
NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02
KNHC for more details.


The monsoon trough extends from the African coast near 10N14W to
06N23W to 06N28W. The Intertropical Convergence Zone axis extends
from 06N28W to 04N38W to the South American coast near 06N54W.
Isolated moderate convection is from 04N-11N E of 42W.



A 1025 mb high is centered over Ohio near 40N84W. 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 21N94W to
17N94W. 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 Hispaniola at 20N70W to Panama at
09N79W. Two 1008 mb lows are embedded on the trough axis at
17N73W and 13N76W. 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 31N70W to 27N74W. A trough extends from 26N73W through the
central Bahamas to central Cuba at 23N80W. Scattered showers are
within 45 nm of the trough. Another surface trough is N of the
Leeward Islands from 25N62W to Hispaniola at 20N70W. 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 1020 mb high is centered over the E Atlantic
near 28N30W. The tail end of a surface trough is over the E
Atlantic from 31N19W to 27N23W. Scattered moderate convection is
W of the Canary Islands from 28N-31N between 18W-20W. 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

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