AXNT20 KNHC 230555
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
155 AM EDT Sun Sep 23 2018
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
Tropical Storm Kirk centered near 9.0N 26.4W at 23/0300 UTC, or
370 nm SSW of the Southernmost Cabo Verde Islands, moving WNW at
14 kt. Estimated minimum central pressure is 1006 mb. Maximum
sustained wind speed is 35 kt with gusts to 45 kt. Some
strengthening is forecast through Sunday, with little change in
intensity expected on Monday and Tuesday. Scattered moderate to
strong convection is observed from 08N-11N between 24W-31W. See
the latest NHC forecast/advisory under AWIPS/WMO headers
MIATCPAT2/WTNT32 KNHC for more details.
Tropical Depression Eleven centered near 13.8N 54.5W at 23/0300
UTC, or 380 nm E of the Windward Islands, moving NW at 3 kt.
Estimated minimum central pressure is 1008 mb. Maximum sustained
wind speed is 25 kt with gusts to 35 kt. The depression is expected
to weaken to a remnant low on Sunday and dissipate by Sunday
night east of the Lesser Antilles. Scattered moderate convection
is noted from 12N-15N between 51W-55W. See the latest NHC
forecast/advisory under AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC
for more details.
Satellite imagery indicates that a frontal non-tropical low
pressure system is located about 1000 nm west-southwest of the
Azores. Conditions are expected to become conducive for this low
to acquire subtropical or tropical characteristics during the next
day or so, and a subtropical or tropical cyclone is likely to
form by early next week while the low meanders over the central
Atlantic Ocean. The system has a medium chance of tropical cyclone
formation within the next 48 hours. Please refer to the latest
Tropical Weather Outlook under AWIPS/WMO headers MIATWOAT/ABNT20
KNHC for more information.
A cold front extends from a 1004 mb low pressure located N of the
area near 34N44W to 31N41W to 25N50W to 28N59W. The most recent
scatterometer data provide observations of minimal gale-force
winds N of 29N and within 60 nm south of the front. Seas of 11 to
13 ft are within the area of these winds. These conditions are
expected through Sunday morning.
A tropical wave has its axis along 44W from 03N-16N and is moving
west at 10-15 kt. The wave corresponds nicely with a maximum in
TPW imagery. Model analyses depict an associated 700 mb trough
along 44W. Scattered showers are located near and east of the
wave axis from 10N-13N between 38W-44W.
A western Caribbean tropical wave has its axis along 87W from
09N-21N, moving west around 10 kt. The 700 mb trough associated
with this wave is well depicted in model guidance, and TPW imagery
shows abundant moisture in its environment. Scattered moderate
convection is noted south of 20N between 85W-90W. Moisture
associated with this wave will continue to spread inland across
Central America through the weekend, enhancing similar convection
across this area.
The monsoon trough extends from the African coast near 18N16W to
17N21W. It continues west of T.S. Kirk near 06N28W to 05N33W. The
ITCZ begins near 05N33W to 05N43W, then resumes near 06N46W to
11N53W. Aside from the convection associated with the tropical
wave and cyclones across the area, scattered showers are located
along and within 75 nm on either side of the monsoon trough
GULF OF MEXICO...
An upper-level cyclonic circulation is centered near 28N87W. This
feature is enhancing convection across the eastern Gulf waters
mainly along 84W. To the west, a surface trough is analyzed along
91W from 24N-29N. Scattered showers are noted along the trough. A
cold front is entering the northwest Gulf enhancing convection
north of 25N and west of 95W. This front is likely to stall and
dissipate today. Gentle to moderate E to SE winds and seas 3 ft or
less will prevail across most of the Gulf of Mexico through the
middle of next week. A surface trough will develop over the
Yucatan peninsula each evening, shift W over the SW Gulf each
night, then dissipate by morning. Moderate to fresh winds will
accompany this trough.
A tropical wave is moving across the far western Caribbean, and a
portion of this wave is entering Central America. Please see the
Tropical Waves section for more details.
The eastern Pacific monsoon trough combined with diffluence aloft
continues to enhance convection over portions of Panama and the
waters of the southwest Caribbean from the coasts of Panama and
Costa Rica northward to 13N and eastward to 78W. Plenty of
moisture will persist over the extreme southwest Caribbean, Panama
and Costa Rica through the weekend. Elsewhere, fresh to strong
winds prevail over the central Caribbean. These winds will
diminish across most of the basin by tonight.
Currently, there are two tropical cyclones and a tropical wave
between the west coast of Africa and the Lesser Antilles. Please
see the Special Features and Tropical Waves sections for more
A broad 1010 mb low is centered 200 nm south of Bermuda. A
surface trough runs through the low from 30N62W to the low near
29N64W to 26N70W. Scattered showers are noted along the trough and
near the low. Unfavorable upper-level winds and dry air are expected
to limit development tonight and Sunday, but conditions could
become more conducive for some development of this system on
Monday or Tuesday while it moves westward and west-northwestward
over the southwestern Atlantic Ocean. By the middle of next week,
strong upper-level winds are likely to limit additional
development as the system turns northward and moves closer to the
southeastern coast of the United States. This feature has a low
chance of tropical cyclone formation during the next 48 hours.
The remainder of the basin is under the influence of a surface
ridge, anchored by a 1027 mb high centered near 39N20W.
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