AXNT20 KNHC 301748
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 PM EDT FRI SEP 30 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 1200 UTC surface analysis and satellite imagery through
Hurricane Matthew is centered near 13.6N 71.3W at 30/1800 UTC or
about 75 nm north of Punta Gallinas, Colombia and about 415 nm
southeast of Kingston, Jamaica moving west-southwest at 10 kt.
Maximum sustained winds are 105 kt with gusts to 130 kt.
Estimated minimum central pressure is 960 mb. Scattered moderate
to strong convection is from 12N-15N between 66W-73W including
the ABC Islands. Scattered moderate convection covers the
remainder of the area from 12N-18N between 64W-74W. Matthew is
expected to continue on a westerly track through late Saturday
before making a turn toward the northwest then north late in the
weekend. Please see the latest NHC Forecast/Advisory under
AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC and the Intermediate
Public Advisory under AWIPS/WMO headers MIATCPAT4/WTNT34 KNHC
for more details.
Tropical wave in the east Tropical Atlantic extends along 28W
from 10N-20N moving west-northwest 5 to 10 kt over the past 24
hours. Wave is in the vicinity of a broad 700 mb trough and a
surge of moisture. Clusters of scattered moderate to isolated
strong convection are within 90 nm of line from 17N27W to
Tropical wave in the west Tropical Atlantic extends along 49W
from 9N-21N moving west-northwest at near 10 kt over the past 24
hours. Wave is embedded within a broad upper trough and within a
surge of moisture. No associated deep convection is noted.
Scattered showers and isolated thunderstorms are within 90/120
nm of a line from 19N49W to 25N47W.
The Monsoon Trough extends across over Africa into the east
Tropical Atlantic near 13N16W then continues along 10N19W 13N27W
9N33W to 9N38W where the ITCZ begins and continues to east of a
tropical wave near 12N46W then resumes west of the wave near
11N52W to South America near 8N59W. Scattered moderate to
isolated strong convection is within 180 nm of a line from
12N51W to 19N41W and is due to an upper trough rather than the
ITCZ or tropical wave.
...GULF OF MEXICO...
A broad deep layered trough covers the Gulf of Mexico east of
90W with the upper low centered over southern Indiana and
extends an upper trough into the west Atlantic. This is
supporting a cold front that extends from the west Atlantic
across Florida from Saint Augustine into the Gulf between Cedar
Key and Tampa then along 26N90W to just off Mexico near 24N97W.
Scattered showers and isolated thunderstorms are within 90 nm
south of the front west of 88W. An upper ridge covers the west
Gulf anchored over central Mexico. A weak surface trough is in
the southwest Gulf extending from 24N93W along 21N93W to 19N92W.
Isolated showers and possible isolated thunderstorms dot the
remainder of the Gulf south of the front, leaving the skies
clear north of the front. The front will stall across the Gulf
later today through Saturday and dissipate Sunday as high
pressure builds in across the north Gulf.
The main concern this afternoon is Hurricane Matthew located in
the central Caribbean. Please see Special Features above. An
upper ridge dominates the Caribbean this afternoon with the
exception of the far northwest, where the upper trough over the
east Gulf of Mexico dips south to 16N west of 80W. This is
generating isolated showers and thunderstorms mainly from 16N-
20N west of 86W to just inland over the Yucatan peninsula, and
within 60 nm of the Isle of Youth off the south coast of Cuba.
Northerly surface flow combined with southerly flow aloft is
generating scattered to numerous showers and isolated
thunderstorms south of 11N to inland over Panama between 76W-80W
and south of 13N to the coast of Panama between 80W-83W. The
remainder of the activity in the Caribbean is associated with
Hurricane Matthew. Matthew is expected to continue on a westerly
track through late Saturday before making a turn toward the
northwest then north late in the weekend.
High clouds are moving across the island due to the outflow from
Hurricane Matthew. Isolated showers are possible across the
island through today. Matthew is expected to continue on a
westerly track through late Saturday before making a turn toward
the northwest then north late in the weekend. Moisture
associated with Matthew is expected to move toward the island
Saturday with showers and thunderstorms moving in Saturday
afternoon through the Sunday as Matthew makes the turn toward a
more northerly track. Please see Special Features above.
The deep layered trough over the east Gulf of Mexico extends
over the far west Atlantic west of 74W supporting a cold front
that extends through 32N80W then across the Florida peninsula
near Saint Augustine continuing into the Gulf of Mexico. Skies
are clear west of the front with scattered showers and isolated
thunderstorms north of 24N between 73W-80W. The remainder of the
Atlantic is dominated by a surface ridge west of 60W and is
anchored by a 1025 mb high in the central Atlantic near 35N57W
and a 1029 mb high northwest of the Azores. The west Atlantic
cold front will stall and weaken through Saturday. The surface
ridge will persist through the weekend as Matthew moves through
the Caribbean. The ridge will shift east as Matthew moves into
the west Atlantic early next week.
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