AXNT20 KNHC 282322
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
722 PM EDT FRI OCT 28 2016
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
Tropical wave extends from 09N49W to 17N48W moving W at 10-15 kt.
The wave remains low-amplitude and relatively difficult to track
as a result. Subtle 700 mb trough is noted in global model fields
between 46W-52W. Isolated moderate convection remains within
close proximity to the ITCZ axis from 07N-12N between 41W-51W and
continues to be enhanced by the base of an upper level trough with
axis extending from 16N47W to 08N53W.
Tropical wave extends from 10N73W to 18N71W moving W at 10-15 kt.
The wave coincides with 700 mb troughing between 70W-74W and is
expected to merge with a broad area of lower pressure across the
NW Caribbean Sea by Saturday night into Sunday. Widely scattered
moderate convection is from 10N-19N between 70W-75W.
The Monsoon Trough extends from near 15N28W into a 1011 mb low
near 13N35W to 10N39W. The Intertropical Convergence Zone axis
extends from 10N39W to 08N55W. Scattered moderate and widely
scattered strong convection is from 07N-12N between 09W-15W.
Isolated moderate convection is from 01N-06N between 10W-25W...
and from 11N-16N between 22W-33W.
GULF OF MEXICO...
A middle to upper level low is noted on water vapor imagery
centered near 26N93W with axis extending from over the lower
Mississippi River valley through the upper level low to another
upper level low centered over the eastern Pacific waters near
15N100W. This troughing aloft is inducing a weak surface trough
analyzed across the SW Gulf from 24N97W to 19N94W providing focus
for scattered showers and isolated tstms generally within 90 nm
either side of the trough axis. Elsewhere to the east of the
upper level troughing...south-southwesterly flow aloft prevails
with plenty of cloudiness covering much of the central and
eastern Gulf waters...southern Florida peninsula and Florida
Straits this evening. Scattered showers and isolated tstms are
occurring generally from 23N-29N between 85W-93W...and S of 26N E
of 83W...including the Florida Straits. Aside from convection...a
strengthened pressure gradient exists between higher pressure
across the SE CONUS and an area of low pressure across the NW
Caribbean Sea. Fresh to strong easterly winds are expected across
central and eastern portions of the basin through Saturday night
with slightly weaker winds...moderate to fresh E-NE winds
occurring across western portions of the basin through Saturday.
Southerly flow aloft prevails between an upper level trough over
the western Gulf of Mexico and an upper level anticyclonic
circulation centered over the central Caribbean near 16N71W.
Within the western periphery of the upper level ridging...a 1010
mb surface low is centered in the NW Caribbean near 19N84W with a
surface trough analyzed S-SE from the low to 16N81W to 12N81W. As
the wind shear across this region remains unfavorable for
organized deep convection in the vicinity of the low...scattered
showers and isolated strong tstms are occurring to the NE of the
low from 19N-25N between 74W-84W...including much of Cuba. Other
isolated showers and tstms are occurring across the north-central
Caribbean N of 15N between 68W-77W in association with the upper
level diffluent environment...along with the presence of a
tropical wave along 73W. Otherwise...outside of the influence of
the area of lower pressure across the western portion of the
basin...light to gentle trades are expected to persist through the
weekend into Monday.
Upper-level anticyclonic wind flow prevails across the island with
widely scattered showers and isolated tstms occurring across the
southern and western adjacent coastal waters this evening. This
moisture...cloudiness...and precipitation is expected to move
across Hispaniola overnight into Saturday.
Upper level south-southwesterly flow prevails aloft over much of
the SW North Atlc this evening. Moisture and cloudiness stretch as
far E as 55W on the northern periphery of an upper level
anticyclonic circulation centered over the central Caribbean Sea
near 16N71W. A slowly dissipating stationary front is analyzed
from 28N56W W-SW to 27N65W to 25N68W then becomes a shear line to
eastern Cuba near 21N76W and providing the primary focus for
sustained convection this evening. Scattered showers and tstms are
noted on satellite imagery mainly S of 26N W of 65W and within 120
nm either side of the stationary boundary between 55W-65W.
Isolated showers and possible isolated tstms are elsewhere S of
30N W of 55W. Aside from the ongoing convection...fresh to strong
E-NE winds continue generally north of the frontal boundary W of
65W. Farther east...the remainder of the front E of 55W is
analyzed as a stationary front from 33N43W to 28N56W with isolated
showers possible within 90 nm either side of the boundary.
Finally...across the NE portion of the discussion area...a 1006 mb
low is centered SE of the Azores near 36N25W with a surface trough
analyzed from the low to 33N21W to 28N24W to 25N32W. Isolated
showers and tstms are occurring mainly from 30N-37N between 16W-
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