[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271756
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Fri Aug 27 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 1200 UTC surface analysis and satellite imagery through
1700 UTC.

...SPECIAL FEATURES...

Ida has strengthened to a hurricane near 21.4N 82.4W as of
27/1710 UTC, or 25 nm ESE of the Isle of Youth moving NW at 13
kt. Estimated minimum central pressure is 987 mb. Maximum
sustained wind
speed is 65 kt with gusts to 80 kt. The maximum sea heights are
currently 18 ft. Numerous strong convection extends out 90 nm
from the center in the N semicircle and 45 nm S semicircle.
Scattered moderate to strong convection is elsewhere within 270
nm NE quadrant and 390 nm SE quadrant, including portions of
Cuba and Jamaica. On the forecast track, the center of Ida will
pass near or over the Isle of Youth and western Cuba later
today, and move over the southeastern and central Gulf of Mexico
tonight and Saturday. Ida is expected to strengthen to a major
hurricane in the northern Gulf before making landfall along the
U.S. northern Gulf Coast Sunday. A dangerous storm surge is
forecast for portions of the Louisiana, Mississippi and Alabama
coasts. Please read the latest NHC Public Advisory at
https://www.nhc.noaa.gov/text/MIATCPAT4.shtml and
Forecast/Advisory at
https://www.nhc.noaa.gov/text/MIATCMAT4.shtml for more details.
Refer to the NHC High Seas Forecasts at
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for marine impacts.

Showers and thunderstorms associated with a 1008 mb low pressure
near 13N 47.5W have become a little better organized today.
Scattered moderate isolated strong convection is from 11N-15N
between 44W-50W. The low is along a tropical wave with axis near
47/48W, from 04N-19N, moving W at 15 kt. Additional development
of this system is expected, and a tropical depression is likely
to form later tonight or Saturday before it moves into a less
favorable environment. The disturbance is forecast to move
west-northwestward today, then turn northward Saturday. This
system has a high chance of tropical cyclone formation during
the next 48 hours. Please refer to the NHC Tropical Weather
Outlook at www.hurricanes.gov for more details.

An elongated 1014 mb low pressure centered near 33N53W is along
a surface trough extending from 35N50W to 29N60W. Disorganized
scattered moderate convection prevails from 27N-34N between
50W-57W. Environmental conditions are expected to be marginally
conducive for development. However, a tropical depression could
still form over the weekend. The system is expected to drift
eastward through Saturday, then accelerate northeastward Sunday
toward the central north Atlantic. This system has a medium
chance of tropical cyclone formation during the next 48 hours.
Please refer to the NHC Tropical Weather Outlook at
www.hurricanes.gov for more details.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 27W from 18N southward,
moving W at 15 kt. Scattered moderate isolated strong convection
is seen from 04N-12N between 24W-34W.

A Caribbean Sea tropical wave is along 65W from 07N-20N, moving
W at 15 kt. No significant convection is related to the wave at
this time.

The Caribbean Sea tropical wave that was along 83W at 0600 UTC
has moved into Central America and has exited the basin.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coast of Mauritania near
18N16W to 11N22W to 14N37W to 13N48W. The ITCZ continues from
10N51W to 09N60W. Aside from the convection discussed in the
sections above, isolated moderate convection is noted from
12N-18N between 32W-41W.

GULF OF MEXICO...

A surface trough extends from 28N91W to the eastern Yucatan
Peninsula. Scattered moderate isolated strong convection is
noted over the north-central Gulf from 26N-31N between
87W-90.5W. Isolated moderate convection is also noted farther
south along the trough from 23.5N-25.5N. A recent ASCAT pass
shows fresh E to SE winds extending east of the trough to 85W,
from 25.5N northward to 30.5N. Seas are 4 to 6 ft in this area.
Another surface trough is along the coast of Texas. Scattered
moderate convection is seen from 26N-30N between 93W-98W. The
ASCAT data show gentle winds over the western Gulf of Mexico,
where seas are 1 to 3 ft. Scattered moderate convection from
Hurricane Ida and strong winds are over the Florida Straits.
Strong numerous convection with Ida over western Cuba is about
to emerge into the SE Gulf, and tropical storm force winds will
reach the SE Gulf later this afternoon.

Hurricane Ida will be located near or over western Cuba this
evening, then strengthen to a major hurricane Sun morning over
the north-central Gulf of Mexico near 27.5N 90W, then move
inland as a major hurricane Sun evening near 29N91W. Ida will
weaken to a tropical storm Mon morning inland near 30N91W, and
then weaken to a tropical depression Tue morning inland near
33N90W. Maximum significant wave heights are forecast to reach
39 ft near the center of Ida in the north-central Gulf of Mexico
Sun morning. For more details on Ida, please see the special
features section above.

CARIBBEAN SEA...

Hurricane Ida is currently affecting portions of the NW
Caribbean Sea. Please see the special features section above for
details.

The eastern Caribbean east of 74W is free of any significant
shower activity. Fresh trades prevail over the central
Caribbean, east of Jamaica. Gentle winds prevail in the SW
Caribbean, south of 16N and west of 78W.

Hurricane Ida will be located near western Cuba this evening,
then move to near 24N86W Sat morning and to near 26N88W Sat
evening. Tropical storm force winds will exit the NW Caribbean
Sea by early Sat morning. Seas in the Yucatan Channel will
diminish below 8 ft by Sat evening. Moderate to fresh winds are
expected elsewhere through Tue, except for locally strong winds
in the south-central Caribbean through the weekend. Otherwise,
fresh to strong winds will pulse at night in the Gulf of
Honduras Sun to Mon.

ATLANTIC OCEAN...

Refer to the section above for details on the Special Features
developing across the basin and the tropical waves.

An area of thunderstorms is occurring over Florida and the
adjacent Atlantic waters, from the northwest Bahamas northward
to 29N, between Florida and 77W. These thunderstorms, while not
directly related to Ida, are being enhanced by upper-level
anticyclonic outflow that is curving away from Ida. Farther
south, scattered moderate convection over the Florida Straits is
directly associated with Ida's outer rainbands. Strong winds
prevail in the Florida Straits. A surface trough extends from
28N67W to 23N72W. Isolated moderate convection is near and just
west of the trough. Moderate to fresh E to SE winds and seas of
4 to 6 ft prevail across much of the western Atlantic, west of
70W. A 1019 mb high pressure is near 26N60W. A ridge axis with
gentle winds extends from this high to another 1021 mb high near
34N36W. Farther east, a surface trough extends from 31N26W to
28N31W to 24N33W, with only moderate NE winds observed west of
the trough. A 1018 mb high is near 30N21W. ASCAT shows fresh NE
to E trades from 13N-22N between 43W-60W, where seas are 6 to 9
ft, but 8 to 10 ft closer to the 1008 mb low near 13N 47.5W,
mentioned above.

For the forecast west of 65W, surface ridging will extend
southward into the SW N Atlantic through Sun night supporting
gentle to moderate E to SE winds. A weaker pressure gradient is
expected early next week, which will result in light to gentle
variable winds. Otherwise, fresh winds are expected to pulse N
of Hispaniola during the evening hours through Sat night.

$$
Hagen
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