[Tropical] Tropical Weather Discussion

EMWIN Server emwin at nashvilleweather.net
Sun Sep 5 04:10:51 CDT 2021


AXNT20 KNHC 050910
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Sun Sep 5 2021

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 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
0930 UTC.

...SPECIAL FEATURES...

Category Three Hurricane Larry is centered near 18.8N 49.0W at
05/0900 UTC moving NW at 12 kt. Estimated minimum central
pressure is 958 mb. Maximum sustained wind speed is 105 kt with
gusts to 130 kt. The eye diameter is 45 nm on IR satellite
imagery. Numerous moderate to strong convection is noted within
180 nm of the center all quadrants, except 120 nm in the SW
quadrant. Seas of 12 ft or higher extend within 300 nm in the N
semicircle and 270 nm in the S semicircle, with seas as high as 43
ft. Hurricane Larry is expected to continue to move NW through
Tue, gradually slowing in forward speed. Little change in
strength is forecast during the next few days, although
fluctuations in intensity are possible. Larry is expected to
remain a major hurricane into Thu. Swell generated by Larry are
expected to reach the Lesser Antilles today, and will spread
westward to portions of the Greater Antilles, the Bahamas, and
Bermuda Monday and Tuesday. Significant swells will likely reach
the east coast of the United States and Atlantic Canada around
midweek. Please read the latest High Seas Forecast issued by the
National Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest NHC
Forecast/Advisory and Public Advisory at www.hurricanes.gov for
more details.

...TROPICAL WAVES...

An east Atlantic tropical wave has an axis along 20W from 03N to
20N, moving W around 10 kt. Scattered moderate convection is noted
from 06N to 14N between 14W and 20W.

An Atlantic Ocean tropical wave has an axis along 37W from 05N to
19N, moving W at 10 kt. The wave is situated at the leading edge
of a Saharan dust plume. As a result of the dry Saharan air, no
significant convection is noted with the wave at this time.

A Caribbean Sea tropical wave has an axis along 76W, stretching
from eastern Cuba to NW Colombia, moving W at 10 to 15 kt.
Scattered moderate convection is noted in and near the Windward
Passage as well as northern Colombia. Fresh E winds are occurring
E of the wave axis in the southern Caribbean.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of southern Mauritania
near 17N16W to 06N27W. The ITCZ is from 06N27W to 05N34W, then
continues W of a tropical wave from 05N38W to the coast of
Venezuela near 10N61W. Aside from the convection mentioned in the
Tropical Waves section above, scattered moderate convection is
noted within 150 nm either side of the ITCZ between 38W and 46W.

GULF OF MEXICO...

A previously stationary front is weakening and beginning to lift
north early this morning, extending from the Florida Big Bend to
the coast of Mississippi. No convection is occurring along this
boundary. A pair of 1015 mb high pressure centers are located near
27N92W and 25N83W, and are the dominant weather features in the
Gulf of Mexico this morning. A surface trough stationary along the
west coast of the Yucatan Peninsula is inducing scattered moderate
convection in the extreme eastern Bay of Campeche, while another
trough along the western coast of the Bay of Campeche is producing
similar convection in that vicinity. More numerous and stronger
convection is located well inland over Guatemala. Light to gentle
winds and slight seas encompass the basin, except over in the SW
Gulf, where moderate E winds are occurring.

For the forecast, the surface trough over the Yucatan Peninsula,
combined with a weak upper level low, will continue to produce
locally heavy rainfall today. The trough is forecast to move NW
into the SW Gulf of Mexico later today, then move slowly N or NE
over the western or central Gulf of Mexico. Upper- level winds are
forecast to be only somewhat conducive for tropical formation,
but some slow development is possible through mid week. There is a
low chance of tropical formation over the next 5 days. Elsewhere,
a weakening front over the NE Gulf will dissipate today, while
high pressure dominates much of the remainder of the basin.

CARIBBEAN SEA...

See the Tropical Waves section above for details on a tropical
wave in the central Caribbean.

An upper level trough N of the area is inducing scattered moderate
convection N of 19N between 75W and 83W, mainly between Jamaica,
Cuba, and the Cayman Islands. Otherwise, significant convection is
not occurring in the basin. Moderate to fresh E winds are ongoing
over most of the central and eastern Caribbean as well as in the
Gulf of Honduras, with gentle to moderate winds elsewhere. Seas
are 4 to 6 ft, except 2 to 4 ft in the NW Caribbean.

For the forecast, Major Hurricane Larry will remain well N and E
of the area, then move N and away from the area by midweek.
Associated rough seas are entering the region this morning, and
will reach the Leeward Islands and Atlantic entrances by early
Mon, then subside mid week. Elsewhere, gentle to moderate trade
winds will persist, pulsing to fresh winds off Colombia mainly at
night.

ATLANTIC OCEAN...

See Special Features section above for details on Major Hurricane
Larry.

A weak stationary front extends from 32N72W to near Cape
Canaveral, Florida. A 1013 mb low pressure center is located along
this boundary near 28N78W. Scattered moderate convection is noted
E of these features, N of 23N and W of 63W. Otherwise, high
pressure dominates most of the basin, outside of the influence of
Hurricane Larry. This is leading to gentle to moderate winds
across the basin. Farther to the east, some locally fresh NE to E
trades are occurring around the Cabo Verde Islands.

For the forecast, Major Hurricane Larry will move to 19.9N 50.4W
this afternoon, 21.2N 52.1W Mon morning, 22.4N 53.6W Mon
afternoon, 23.6N 55.0W Tue morning, 25.0N 56.4W Tue afternoon, and
26.5N 57.8W Wed morning. Larry will change little in intensity as
it moves SE of Bermuda early Thu. Large swell and rough seas
generated by Larry will continue to propagate across waters north
of the Leeward Islands spread W of 65W by early Mon, the perhaps
reach 70W by mid week.

$$
KONARIK
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