[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 290045 AAA
TWDAT

Tropical Weather Discussion...Update
NWS National Hurricane Center Miami FL
0005 UTC Sun Aug 29 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 1800 UTC surface analysis and satellite imagery through
0000 UTC.

Updated Special Features section below

...SPECIAL FEATURES...
Hurricane Ida, now a Category 2 on the Saffir-Simpson Hurricane
Wind Scale, is centered near 26.6N 87.5W at 29/0000 UTC or 175 nm
SSE of the mouth of The Mississippi River and moving NW at 14 kt.
Estimated minimum central pressure is 969 mb. Maximum sustained
wind speed is 90 kt with gusts to 110 kt. The maximum sea heights
are 34 ft. Numerous moderate to strong convection is noted near
the center from 25N to 28N between 85W and 89W. Outer rainbands
with scattered moderate to isolated strong convection are found
across the N central, NE and SE Gulf; including the Florida Keys.
On the forecast track, the center of Ida will continue moving NW
at similar forward speed through landfall on Sun afternoon, then
slow down while turning toward the N Sun evening. Landfall is
expected in Louisiana, with Ida moving through portions Louisiana
and Mississippi Mon. Rapid intensification has begun and is likely
to continue through Sun morning, and Ida is expected to become an
extremely dangerous major hurricane later tonight, and will
likely be a Category 4 hurricane at landfall Sun. Weakening is
expected after Ida makes landfall. 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.

Tropical Depression Ten is centered near 16.2N 49.9W at 29/0000
UTC or 670 nm E of the Leeward Islands moving N at 7 kt.
Estimated minimum central pressure is 1007 mb. Maximum sustained
wind speed is 30 kt with gusts to 40 kt. Numerous moderate to
isolated strong convection is seen from 14N to 18N between 45W
and 50W. On the forecast track, the depression will continue in a
general northward motion over the next several days. Some slight
strengthening is forecast, and the depression is expected to
become a tropical storm on Sun. Please read the latest NHC Public
Advisory at https://www.nhc.noaa.gov/text/MIATCPAT5.shtml and
Forecast/ Advisory at
https://www.nhc.noaa.gov/text/MIATCMAT5.shtml for more details.

Showers and thunderstorms continue to show signs of organization in
association with an area of low pressure located over the central
Atlantic.  Although environmental conditions remain only marginally
conducive for further development, only a slight increase in
organization would result in the formation of a tropical depression
later tonight or on Sunday.  In a couple of days, the system is
forecast to be absorbed by a frontal system.  The disturbance is
expected to drift eastward through tonight, then accelerate
northeastward Sunday toward the central north Atlantic. 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.

...TROPICAL WAVES...

An Atlantic tropical wave is noted along 20W from 19N southward,
moving W at 15 to 20 kt. Scattered moderate convection is noted
from 11N to 16N E of 20W.

An Atlantic tropical wave is along 36W from 17N southward, moving
W at 15 kt. No significant convection is associated with this
wave.

Another Atlantic tropical wave has moved farther away from
Tropical Depression Ten, described in the Special Features section
above, and is now along 56W, from 18N southward. It is moving W
at 15 kt. Aside from convection primarily associated with the
tropical depression, scattered moderate convection is noted from
07N to 15N between 53W and 61W.

A Carribbean tropical wave is along 74W from Haiti to Colombia,
moving W at 15 kt. No significant convection is currently
associated with this wave.

...MONSOON TROUGH/ITCZ...

A monsoon trough passes through the coast of Guinea near 15N17W
to 11N27W. The ITCZ has developed from 11N27W to 11N33W. The ITCZ
is also noted from 07N39W to 12N49W. Aside from convection related
to the tropical waves described in the section above, scattered
moderate convection is noted along the ITCZ from 03N to 09N
between 38W and 49W.

...GULF OF MEXICO...

See Special Features section above for information on Category Two
Hurricane Ida, which is forecast to become a major hurricane over
the central Gulf.

A deep-layer trough extends from 28N93W to 20N91W. Convection
previously associated with this trough has diminished. While Ida
is impacting most of the eastern Gulf, light to gentle E to ESE
winds and seas at 1 to 3 ft prevail for the western Gulf. In the
southeast Gulf including the Straits of Florida SE winds are
moderate to fresh with seas 7 to 10 ft.

For the forecast, hurricane Ida near 26.2N 87.0W 976 mb at 5 PM
EDT moving NW at 14 kt. Maximum sustained winds 90 kt gusts 110
kt. Ida will move to 27.5N 88.6W Sun morning, 29.1N 90.4W Sun
afternoon, inland to 30.5N 91.3W Mon morning, move inland and
weaken to a tropical storm near 32.2N 91.2W Mon afternoon, move
inland and weaken to a tropical depression near 34.0N 90.1W Tue
morning. Light to gentle variable winds are expected in the SW
gulf and far western basin through Mon. Otherwise, moderate to
locally fresh return flow will establish across most of the basin
Tue and Wed.

...CARIBBEAN SEA...

Refer to the Tropical Waves section above for details on the
tropical wave moving across the Caribbean Sea.

Scattered moderate convection extends southward in a rainband
from Gulf of Mexico Hurricane Ida, described in the Special
Features section above, N of 20N between 82W and 86W, including
portions of western Cuba. Seas across the N central and NW
Caribbean Basin are in the range of 6 to 8 ft, including the
Yucatan Channel.

Aside from this rainband, dry conditions prevail over the
Carribbean with generally moderate trades and seas of 4 to 6 ft.

For the forecast, moderate to fresh winds are expected through
the forecast period, 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 Tue.

...ATLANTIC OCEAN...

Please see Special Features section above for information on T.D.
Ten and the low pressure east of Bermuda that has the potential
for tropical development.

Scattered moderate convection is noted over the NW Bahamas and
adjacent portions of the Gulf Stream. High pressure extends across
much of the western Atlantic north of 25N, anchored by a 1024 mb
center SE of North Carolina and a 1021 mb high near 32N25W. This
is leading to generally gentle wind and seas of 5 ft or less N of
25N. interrupting the ridging is a weak surface trough that
stretches from 31N29W to 26N37W. Moderate to fresh trades and
seas of 5 to 7 ft are present from 10N to 18N between 54W and the
Lesser Antilles, and also near the Canary Islands N of 18N between
the NW African coast and 22W. Moderate to fresh SE winds and seas
at 6 to 7 ft exist from the Equator to 06N between 35W and the S
American coast. Light to gentle winds and seas of 4to 6 ft prevail
elsewhere across the Atlantic Basin.

A tropical wave is expected to emerge off the coast of west Africa
by the middle of next week, and this wave has some potential for
tropical development thereafter.

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 weak pressure gradient will
prevail through the remainder of the forecast period, which will
result in light to gentle variable winds. Otherwise, fresh to
locally strong winds are expected to pulse N of Hispaniola during
the evening hours through tonight.

$$

Chan
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