Tropical Weather Discussion
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AXNT20 KNHC 181017

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
517 AM EST Sat Nov 18 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.


The monsoon trough extends from the African coast near 09N13W to
08N20W. The Intertropical Convergence Zone axis extends from
08N20W to 06N24W to 08N36W, then resumes west of a surface trough
near 07N40W to the South American coast near 07N58W. Isolated
moderate convection is from 04N-11N between 12W-24W. Scattered
moderate convection is from 08N-11N between 38W-45W.



A 1021 mb high is centered over North Carolina near 35N78W. A
surface ridge axis extends SW from the high to the central Gulf of
Mexico near 25N90W. 10-15 kt surface winds are over the base of
the ridge axis. Radar imagery shows isolated showers over the
Straits of Florida between 81W-83W. Fair weather is over the
remainder of the Gulf of Mexico. In the upper levels, a large
upper level high is centered over central Mexico near 23N102W
producing northerly upper level flow and strong subsidence over
the entire Gulf of Mexico. 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 N Colombia
at 07N75W. Two 1008 mb lows are embedded on the trough axis at
18N72W and 11N74W. Scattered showers and clusters of scattered
moderate convection are within 360 nm E of the trough axis, to
include Puerto Rico. In the upper levels, an upper level trough is
over the NW Caribbean with axis from central Cuba near 22N80W to
the Gulf of Honduras near 16N89W. Upper level diffluence E of the
trough is enhancing the showers and convection over the central
Caribbean Sea. Expect the area of convection to drift E and
persist for the next 48 hours.


Scattered showers are over the island, and will continue through
the weekend. Expect convection to be heaviest over E Hispaniola
in the afternoon and evening hours during maximum heating.
Localized flooding is also possible during this time.


A 1007 mb low is centered over the central Atlantic near 26N57W.
A surface trough extends SW from the low to Hispaniola near
20N70W. Scattered moderate to isolated strong convection is N of
the Leeward Islands from 19N-23N between 59W-67W. Scattered
showers are elsewhere within 120 nm of the trough. A quasi-
stationary front enters the central Atlantic near 31N38W and
extends to 27N50W to the central Atlantic low near 26N57W.
Scattered showers are within 120 nm of the frontal system. A 1019
mb high is centered over the E Atlantic near 27N28W. Of note in
the upper levels, a large upper level trough is over the W
Atlantic enhancing the central Atlantic with upper level
diffluence. Another upper level trough is over Morocco.

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