[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 280607
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Sat Aug 28 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 0000 UTC surface analysis and satellite imagery through
0430 UTC.

...SPECIAL FEATURES...

Hurricane Ida is centered near 23.0N 84.0W at 28/0300 UTC or 90
nm W of Havana, Cuba and moving NW at 13 kt. Estimated minimum
central pressure is 989 mb. Maximum sustained wind speed is 70 kt
with gusts to 85 kt. The maximum sea heights are 17 ft. Scattered
moderate to isolated strong convection is found mainly NW and N of
the center from 22N to 25N between 83W and 86W, including N coast
of W Cuba. Ida has entered into the SE Gulf of Mexico and will
continue on a NW track with a slight increase in forward speed
across the central Gulf on Sat night and then into the N Gulf on
Sun morning. On Sun night, Isa is expected to turn toward the N
and slow down while approach the US Louisiana and Mississippi
coastline. Strengthening, possibly rapid, is expected, and Ida is
forecast to become a major hurricane by Sat evening as it moves
into the central Gulf. Ida is forecast to be a major Category 4
hurricane at landfall along the northern Gulf coast Sun. A
dangerous storm surge is forecast for portions of the Louisiana,
Mississippi and Alabama coasts. Rainfall of 10 to 20 inches are
possible across SE Louisiana, and 4 to 10 inches across SW
Louisiana, central and S Mississippi and SW Alabama. 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.

A 1008 mb low pressure about 660 mb E of the Lesser Antilles is
found near 14N49W. Numerous moderate to strong convection is
flaring up from 13N to 16N between 47W and 49W. Additional
development of this system is expected, and a tropical depression
is likely to form Sat or Sat night before it moves into a less
favorable environment. The disturbance is forecast to move west-
northwestward through tonight, then turn northward on Sat. 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 is centered east of Bermuda
near 34N52W. Disorganized scattered moderate convection is noted
from 30N to 34N between 50W and 54W. Environmental conditions are
expected to be marginally conducive for development. However, a
tropical depression could still form by early next week. The
system is expected to drift eastward through Sat, then accelerate
northeastward Sun 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 tropical wave is along 31W from 18N southward and
moving W at 15 to 20 kt. Scattered moderate to isolated strong
convection is seen from 05N to 09N between 29W and 38W.

Another Atlantic tropical wave is near 50W from 18N southward and
moving W near 15 kt. This wave is in close proximity with the 1008
mb low pressure mentioned in the Special Features section above,
and the significant convection is related to the low.

A Caribbean tropical wave is along 68W from 20N southward across
the E coast of Hispaniola to N Venezuela, and moving W near 15
kt. Scattered moderate convection is present over central and N
Venezuela.

...MONSOON TROUGH/ITCZ...

A monsoon trough passes through the coast of Mauritania near
19N16W to 11N25W to 06N38W. The ITCZ then continues from 06N38W
to 06N47W, and from 12N52W to 10N60W just N of Venezuela-Guyana
border. Scattered moderate to isolated strong convection is
occurring near and S of the monsoon trough along the African coast
from 13N to 20N between 14W and 18W. Similar conditions are also
present along and up to 100 nm N of the W portion of the ITCZ.
Scattered moderate convection is found near the E portion of the
ITCZ from 04N to 07N between 44W and 48W.

...GULF OF MEXICO...

See Special Features section above for information on Hurricane
Ida, which is forecast to become a major hurricane over the
central Gulf on Sat night; before making landfall as a Category 4
Hurricane along the Louisiana-Mississippi coastline on Sun.

A surface trough extends southward from near Lake Charles,
Louisiana to the S central Gulf. Aided by an upper-level low over
the NW Gulf near 25N93W, scattered moderate convection is noted N
of 24N between 89W and 94W. Gentle to moderate ENE to E trades and
seas of 3 to 5 ft are evident across central and NE Gulf. Light to
gentle E to ESE winds and seas at 1 to 3 ft prevail for the rest
of the Gulf.

For the forecast, Hurricane Ida near 23.0N 84.0W 989 mb at 11 PM
EDT or 0300 UTC is moving NW at 13 kt. Maximum sustained winds are
70 kt gusts 85 kt. Ida will move to 24.4N 85.6W Sat morning, 26.1N
87.7W Sat evening, 27.8N 89.6W Sun morning, along the Louisiana
coast near 29.2N 90.8W Sun evening, move inland and weaken to a
tropical storm near 30.7N 91.0W Mon morning, and farther inland
over central Mississippi near 32.3N 90.6W Mon evening. Ida will
weaken to a tropical depression while moving inland over 34.9N
88.2W by late Tue. 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 the basin Tue
and Wed.

...CARIBBEAN SEA...

Convergent fresh to strong SE to S winds feeding toward Hurricane
Ida over the SE Gulf of Mexico are triggering scattered showers
and isolated thunderstorms across W and central Cuba, and just N
of Jamaica. Seas across the N central and NW Caribbean Basin are
in the range of 6 to 9 ft, including the Yucatan Channel. Please
see the Special Features section above for more information on
Ida.

Outside of the influence of Ida, dry conditions along with gentle
to moderate trades and seas at 4 to 5 ft prevail across much of
the basin. The exception is light to gentle winds and seas at 1
to 3 ft along the W edge of the basin.

For the forecast, Hurricane Ida has entered into the SE Gulf of
Mexico and its influence over the Caribbean Basin will steadily
decrease throughout Saturday. Weather and sea conditions across
the NW basin should gradually improve through Saturday evening.
Moderate to fresh winds are expected elsewhere 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 sections above for information on two
low pressures that have the potential for tropical development,
east of the Lesser Antilles and east of Bermuda, respectively.

Convergent E to ESE winds well NE of Hurricane Ida is triggering
scattered showers and isolated thunderstorms near the E Georgia-
Florida coast and the NW Bahamas. An upper-level trough SE of
Bermuda near 31N60W is coupling with a surface trough in the
vicinity to trigger scattered showers and a few thunderstorms N
of 30N between 57W and 68W. For additional convection, refer to
the Tropical Waves and Monsoon Trough/ITCZ section.

A surface ridge curves westward from a 1021 mb Azores high
near 31N23W to NE of the Georgia coast. Light to gentle winds and
seas at 4 to 5 ft are found N of 22n between 22W and 70W. Gentle
to moderate ESE to SE winds and seas at 5 to 6 ft are found N of
22N between 70W and the Georgia-Florida coast. Moderate to fresh
trades and seas of 5 to 7 ft are present from 10N to 22N between
45W 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 8 ft exist from the Equator to 06N between
35W and the S American coast. Light to gentle winds and seas of 4
to 6 ft prevail elsewhere across the Atlantic Basin.

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 Sat night.

$$

Chan
This weather bulletin was brought to you by:
www.nashvilleweather.net