[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261033
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
633 AM EDT Thu Sep 26 2019

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
1045 UTC.

...SPECIAL FEATURES...

Hurricane Lorenzo is centered near 15.2N 39.3W at 26/1000 UTC or
995 nm W of the Southernmost Cabo Verde Islands, moving WNW at 13
kt. Estimated minimum central pressure is 955 mb. Maximum
sustained wind speed is 100 kt with gusts to 120 kt. Numerous
moderate strong convection extends 250 nm in the east semicircle
and 280 nm in the west semicircle from the center of Lorenzo.
Scattered moderate convection is seen in the outer bands extending
out to 400 nm on the E semicircle and 350 nm west semicircle.
Lorenzo is forecast to turn toward the northwest and begin moving
at a slightly slower speed later today. A turn toward the north
is then anticipated on Saturday. Lorenzo is a category 3 hurricane
on the Saffir-Simpson Hurricane Wind Scale. Additional strengthening
is possible today. Please read the latest NHC forecast/advisory
under AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC or
www.hurricanes.gov for more details.

Tropical Storm Karen is centered near 25.5N 63.5W at 26/0900 UTC
or 475 nm S of Bermuda moving NNE at 13 kt. Estimated minimum
central pressure is 1004 mb. Maximum sustained wind speed is 35
kt with gusts to 45 kt. Numerous moderate to strong convection
is seen from 23N-26N between 62W-66W. Scattered showers and
tstorms are seen along a line from 20N67W to 22N63W to 25N61W.
A northeastward to eastward motion with a decrease in forward
speed is expected through Friday. Karen, or its remnants, are
then expected to slow down and make a clockwise loop over the
southwestern Atlantic into the weekend. Little change in strength
is forecast during the next few days. Please read the latest NHC
forecast/advisory under AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC
for more details.

...A heavy rain event in Central America and Southeastern
Mexico...

Southwesterly monsoonal flow is pushing abundant moisture from
the tropical Pacific Ocean toward Central America. Heavy rainfall
is expected in Central America, through the weekend. The greatest
threat for heavy rainfall will migrate northwestward to areas
from southern Guatemala to southern Mexico, including in the
Mexican states of Chiapas, Oaxaca and Guerrero. It is possible
that the heavy rains may lead to flash floods and mudslides,
especially in areas of mountainous terrain and areas near the
Pacific coast.

...TROPICAL WAVES...

An east Atlantic tropical wave is along 21W from 13N southward,
moving around 10 kt. Scattered moderate convection is seen along
the wave axis from 04N-10N between 19W-25W.

A central Atlantic tropical wave extends its axis along 50W,
from 19N southward, moving W at around 10 kt. Scattered showers
are noted along the wave axis.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of Senegal
near 12N16W to 10N29W, resumes west of Hurricane Lorenzo near
10N43W to 08N48W. Scattered showers are seen in the vicinity of
the boundary.

GULF OF MEXICO...

A surface trough extends from the west central Gulf into the Bay
of Campeche from 20N90W to 26N93W with scattered moderate to
strong convection from 21N-23N between 90W-92W. A trough in the
Yucatan Peninsula is producing scattered moderate to strong
convection inland and along the Yucatan Channel and the Gulf of
Honduras. Surface ridging prevails across the remainder of the
basin, anchored by a 1015 mb high centered over the eastern Gulf
coast.

A surface trough over the Central Gulf and Yucatan Peninsula will
move slowly westward across the southwestern Gulf of Mexico
during the next few days before it reaches the northeast coast of
Mexico Sat. Elsewhere, high pressure will prevail.

CARIBBEAN SEA...

A heavy rainfall event is expected in Central America and
southeastern Mexico. Please read the Special Features section
above for more details.

An upper level trough extends from a 24N73W upper level cyclonic
circulation center, into the waters that are between Jamaica,
Cuba, and Haiti. A surface trough is analyzed from the Windward
Passage near 20N73W across Jamaica near 18N78W to NW Caribbean
Sea near 19N85W. Scattered moderate convection prevails along and
south of the trough from 16N-18N between 74W-85W. To the east,
the southern periphery of T.S. Karen is enhancing convection
across Puerto Rico and adjacent waters. Scatterometer data depicts
light to gentle winds across the whole basin.

A fairly weak pressure pattern with light and variable winds and
low seas will prevail across the western and central Caribbean
through this afternoon, with more typical conditions and trades
returning by the end of the week. A tropical wave will move across
the tropical N Atlc on Fri, then through the eastern to central
Caribbean this weekend, reaching the western Caribbean early next
week. Swells from Hurricane Lorenzo which will remain E of the
region will propagate through the tropical N Atlc and E Caribbean
passages this weekend into early next week.

ATLANTIC OCEAN...

Refer to the sections above for details on the tropical wave,
Hurricane Lorenzo and T.S. Karen.

An upper-level trough extends across the west Atlantic from a
cyclonic circulation center that is near 23N49W. This trough is
enhancing scattered showers mainly in the vicinity of the trough
axis from 24N-31N between 37W-48W. Surface ridging prevails
across the remainder of the basin.

Tropical Storm Karen will become a remnant low as it moves to
27.0N 65.2W early Mon, and continue to near 26.8N 67.4W early Tue.
Meanwhile, high pressure will build down from off the Carolinas
to the Bahamas this weekend into early next week tightening the
pressure gradient. Winds and seas will increase and build by the
end of the weekend into early next week as a result.

$$
NATIONAL HURRICANE CENTER
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