[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261734
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
134 PM 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 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...SPECIAL FEATURES...

Hurricane Lorenzo is centered near 15.4N 40.2W at 26/1500 UTC or
920 nm W of the Southernmost Cabo Verde Islands moving WNW at 11
kt. Estimated minimum central pressure is 949 mb. Maximum
sustained wind speed is 115 kt with gusts to 140 kt. Numerous
strong convection is within 90 nm of the center. Scattered
moderate to isolated strong convection is elsewhere from 11N-20N
between 33W-45W. Lorenzo is forecast to turn toward the northwest
later today, and this motion should continue through Friday. A
turn toward the north is expected Friday night and Saturday.
Lorenzo is a category 4 hurricane on the Saffir-Simpson Hurricane
Wind Scale. Additional strengthening is possible today, and
fluctuations in intensity are expected tonight through Friday
night. 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 26.6N 63.3W at 26/1500 UTC
or 350 nm SSE of Bermuda moving NNE at 12 kt. Estimated minimum
central pressure is 1004 mb. Maximum sustained wind speed is 40
kt with gusts to 50 kt. Numerous strong convection is from 25N-
28N between 63W-66W. Scattered moderate to isolated strong
convection is elsewhere from 24N-29N between 60W-67W. Karen is
forecast to make a slow clockwise loop, ultimately moving
westward by early Sunday. Weakening is forecast by the weekend,
and Karen is expected to become a remnant low by Sunday. 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 23W from 14N southward,
moving W at 10 kt. Widely scattered moderate convection is from
05N-12N between 18W-27W.

A central Atlantic tropical wave is along 53W, from 20N
southward, moving W at 10 kt. Scattered showers are within 90 nm
of the wave axis.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of Senegal
near 14N17W to 10N20W to 08N28W. The monsoon trough resumes west
of Hurricane Lorenzo near 12N43W to 08N50W. Besides the convection
mentioned in the tropical wave section, scattered moderate to
isolated strong convection is along the coast of W Africa from
04N-11N between 08W-18W.

GULF OF MEXICO...

A 1009 mb low is centered over NE Yucatan Peninsula near 19N91W. A
surface trough extends NW from the low to the NW Gulf of Mexico
near 27N94W. Scattered showers are within 90 nm of the trough. A
1015 mb high is centered over the NE Gulf near 28N85W. 5-10 kt
surface winds are noted throughout the Gulf. In the upper levels,
an upper level trough is over the NE Gulf.

The surface trough 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, relatively
weak high pressure centered over the northeast Gulf will be
reinforced by stronger high pressure that builds south-
southwestward from the western Atlantic Fri through early next
week. The resultant gradient will increase winds to fresh speeds
over the NE Gulf beginning late Sun.

CARIBBEAN SEA...

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

Radar imagery shows scattered showers over Puerto Rico and the
Virgin Islands. A surface trough extends from NE of Jamaica near
19N75W to SW of the Cayman Islands near 18N84W. Scattered moderate
convection is within 60 nm of the trough. Further S, scattered
moderate to isolated strong convection is over the SW Caribbean
from 11N-15N between 77W-82W.

A weak pressure pattern allowing for generally light and variable
winds and low seas will be replaced by somewhat stronger high
pressure that builds southward over the western Atlantic beginning
on Fri. This will lead to trades increasing over much of the
central and western Caribbean through early next 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 east of the region will propagate through the tropical N Atlc
and eastern 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.

A 1016 mb high is centered over the W Atlantic near 32N74W. A
surface trough extends from the S Bahamas near 24N72W to E Cuba
near 20N75W. Isolated moderate convection is within 60 nm of the
trough. Of note in the upper levels, an upper level low is
centered over the central Bahamas near 23N75W enhancing
convection. Another upper level low is centered over the E
Atlantic near 31N43W also enhancing convection.

Tropical Storm Karen near 26.6N 63.3W 1004 mb at 11 AM EDT
moving NNE at 12 kt. Maximum sustained winds 40 kt gusts to 50
kt. Karen will maintain intensity as it moves to near 27.6N 62.5W
this evening, then weaken slightly early on Fri near 28.1N 61.1W,
reach to near 28.0N 60.4W Fri evening, then weaken to a tropical
depression near 27.8N 60.6W Sat morning and reach to near 27.6N
61.9W Sat evening. Karen is forecast to become a remnant low and
move to near 27.3N 63.5W Sun morning. Karen will change little in
intensity as it moves to near 27.1N 66.5W early on Mon, and
continue to near 27.0N 69.0W early on Tue. Meanwhile, high
pressure will build down from off the eastern seaboard to the
Bahamas this weekend and 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.

$$
Formosa
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