[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 311022
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Tue Aug 31 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
1000 UTC.

...SPECIAL FEATURES...

Tropical Depression Ida is centered near 34.1N 88.9W at 31/0900
UTC or 130 nm NNE of Jackson Mississippi moving NE at 10 kt.
Estimated minimum central pressure is 998 mb. Maximum sustained
wind speed is 25 kt with gusts to 35 kt. Little change in strength
is forecast during the next 48 hours. Considerable heavy rain and
flood threat will continue to spread from the Tennessee and Ohio
Valleys into the central and southern Appalachians and mid-Atlantic
through Wed. Ida is forecast to be a post-tropical cyclone by Wed
night, then becoming extratropical on Thu. Please read the latest
WPC Public Advisory at:
https://www.wpc.ncep.noaa.gov/tropical/tropical_advisories.php?storm=IDA
and Storm Summary Message at:
https://www.wpc.ncep.noaa.gov/discussions/nfdscc4.html for more
details.

Tropical Storm Kate is centered near 23.0N 50.9W at 31/0900 UTC
or 710 nm ENE of the Leeward Islands moving N at 4 kt. A northwestward
motion is forecast to begin tonight and continue into Wednesday.
Estimated minimum central pressure is 1006 mb. Maximum sustained
wind speed is 35 kt with gusts to 45 kt. Peak seas are 8 to 11 ft.
Kate remains poorly organized and is moving slowly over the central
Atlantic. Little change in strength is forecast during the next
few days. 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.

A well-defined low pressure system is located over the far eastern
tropical Atlantic more than 175 nm southwest of the coast of
Guinea. Associated shower and thunderstorm activity is beginning
to show some signs of organization, and environmental conditions
are conducive for additional development of this system. A tropical
depression is likely to form during the next day or so while the
low moves westward to west-northwestward at 10 to 15 kt. There is
a high chance of tropical cyclone formation within the next 48
hours. Refer to the latest Tropical Weather Outlook at:
www.hurricanes.gov for more details.

...TROPICAL WAVES...

An active tropical wave is along 17W/18W from 19N southward, moving
W at 5 to 10 kt. A cluster of moderate to strong convection is
along the wave axis and covers the waters from 10N-14N between
18W-22W.

A weak tropical wave is near 37W from 20N southward, moving W at
10 to 15 kt. Scattered showers are near the southern end of the
wave axis.

Another weak tropical wave is along 48W from 17N southward moving
slowly W near 5 kt. No significant convection is associated with
this wave.

A Caribbean tropical wave is near 66W, extending from Puerto Rico
to central Venezuela, moving W at 10 to 15 kt. The wave is enhancing
some shower activity over Venezuela.

Another Caribbean tropical wave is along 88W, crossing northern
Central American. The wave extends southward into the E Pacific
Ocean, moving W at 15 to 20 kt. Likely enhanced by the eastern
end of the Pacific monsoon trough, numerous moderate to isolated
strong convection is present offshore El Salvador and Nicaragua
on the Pacific side.

...MONSOON TROUGH/ITCZ...

A monsoon trough exits the coast of Africa near the border of
Guinea-Bissau and Guinea at 11N15W through a low pressure system
at 09N17W to 13N30W to 11N46W. Scattered moderate convection is
evident from 08N to 10N between 20W and 26W, and near 11N45W.

...GULF OF MEXICO...

Refer to the Special Features section above for information on
Tropical Depression Ida located over northern Mississippi. Fresh
to strong SW winds and seas in the 8-10 ft range are still noted
over the NE Gulf in association with the cyclonic circulation of
Ida. Elsewhere gentle to moderate winds and seas of 3-5 ft prevail
under the influence of a ridge. Narrow bands of showers with
embedded thunderstorms associated with Ida continue to affect the
northern Gulf waters, mainly N of 28N. A pair of these bands are
over SE Louisiana.

For the forecast, fresh to strong S to SW winds associated with
the circulation of Ida will continue to affect the NE Gulf of
Mexico through tonight. Then, fresh SW to W winds will persist on
Wed over the NE Gulf ahead of a frontal boundary. Elsewhere, a
ridge will dominate the Gulf region producing mainly gentle to
moderate southerly winds through Fri. Pulsing fresh winds are
expected NW of the Yucatan Peninsula at night through Sat night.

...CARIBBEAN SEA...

Recent satellite derived wind data show gentle to moderate winds
across most of the region, with moderate to fresh trades over the
south-central Caribbean. Seas are generally 3-5 ft with the
exception of 4-7 ft in the SW part of the basin, and 1-3 ft over
the eastern Caribbean E of 68W and in the lee of Cuba, including
also the waters in the Windward passage and between eastern Cuba
and Jamaica. Clusters of moderate to isolated strong convection
are noted over the SW Caribbean, particularly S of 13N between
73W-83W. Two tropical waves are moving westward across the basin.
Please, see Tropical Waves section for more details.

For the forecast, the pressure-gradient between a ridge east of
Florida and lower pressure over northern Colombia will support
moderate to fresh trade winds over the south-central Caribbean.
Similar wind speeds are expected in the Gulf of Honduras at night.
A broad area of low pressure is forecast to develop over the SW
Caribbean Sea in a couple of days. Environmental conditions appear
to be somewhat conducive for slow development by the end of the
week, as long as the system remains over water. This system is
expected to move gradually west-northwestward or northwestward at
5 to 10 kt toward Central America. This could will bring some
increase in winds and seas first in the SW Caribbean, then in the
NW Caribbean Wed through Fri.

...ATLANTIC OCEAN...

Three tropical waves are moving westward between the W coast of
Africa and the Lesser Antilles. Please, see Tropical Waves
section for more details. Also, see the Special Features section
for details on Tropical Storm Kate located over the central
Atlantic.

A weak high pressure center of 1015 mb is located E of NE Florida
near 30.5N78W. This is producing a weak pressure gradient across
the SW N Atlantic where mainly light and variable winds prevail.
Seas are 2-4 ft E of the Bahamas, and 1-2 ft between the Bahamas
and Cuba. A cold front enters the forecast area near 31N45W and
extends SW to near 28N55W. Then, a dissipating stationary front
continues westward to near 30N69W. Scattered showers are along the
frontal boundary. Another weak high pressure center of 1018 mb is
located near 29N28W, and extends a ridge toward the Madeira and
the Canary Islands. Outside of tropical cyclone Kate and the
developing tropical system near the coast of Africa, gentle to
moderate winds are seen per scatterometer data across most of the
Atlantic forecast region. Moderate to fresh SW winds are ahead of
the above mentioned cold front N of 29N. Moderate to fresh
northerly winds are also observed from 20N-23N E of 20W to the W
coast of Africa.

For the forecast west of 65W, a weak pressure gradient will prevail
through tonight with mainly light to gentle winds. Fresh to strong
SW winds are expected just off NE Florida on Wed ahead of a frontal
boundary forecast to clip the NW waters late Thu into Fri.

$$
GR
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