[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 222254
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Sun Jul 23 2023

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
2300 UTC.

...SPECIAL FEATURES...

Newly upgraded Hurricane Don is centered near 40.1N 50.0W at
22/2100 UTC, or 420 nm SSE of Cape Race Newfoundland moving N at
10 kt. Estimated minimum central pressure is 988 mb. Maximum
sustained wind speed is 65 kt, with gusts to 80 kt. Seas 12 ft or
greater are evident within 90 nm of the center. Scattered moderate
to isolated strong convection is evident within 75 nm of the
center. Don's cloud pattern continued to become better organized
with convection wrapping around an elongated eye. Don strengthened
as it passed over the warmer waters of the Gulf Stream, however
it will move north of those warmer waters later this evening, and
Don has likely peaked in intensity. Don will turn northeastward
late tonight, then northeastward to east- northeastward until the
system dissipates in 2-3 days. Please read the latest HIGH SEAS
FORECAST issued by National Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest T.S.
Don Forecast/Advisory and Public Advisory at www.hurricanes.gov
for more details.

Central Tropical Atlantic (AL95):
Shower activity has become a little less organized since
yesterday, associated with a small area of 1012 mb low pressure
located near 12N43W. This is roughly midway between the Cabo
Verde Islands and the Lesser Antilles. Environmental conditions
are forecast to remain marginally conducive for some gradual
development, and this system could become a tropical depression
early next week while it moves westward across the tropical
Atlantic. Interests in the Lesser Antilles should monitor the
progress of this system. The disturbance has a medium chance of
development over the next 48 hours. Refer to the latest Tropical
Weather Outlook at www.hurricanes.gov for more details.

Gale Warning E of 35W:
The strong pressure gradient between a 1029 mb high pressure near
the Azores and lower pressures over NW Africa has induced fresh to
near gale-force northerly winds in the eastern Atlantic, mainly
north of 17N and east of 25W. The strongest winds are present off
the coast of Morocco and Western Sahara and in the water passages
of the Canary Islands. Seas in the affected area are 7-10 ft.
Meteo-France is forecasting frequent gusts to gale force and rough
to very rough seas in the Agadir Marine Zone through 23/0000 UTC
and Canarias Marine Zone until 23/0300 UTC. Please read the High
Sea Forecast and Warning at https://wwmiws.wmo.int for more
details.

...TROPICAL WAVES...

An eastern Atlantic tropical wave was added to the analysis near
20W between 05N to 18N, moving westward at 10-15 kt. Scattered
moderate convection is noted from 14N to 18N between 21W and 24W.

An eastern Atlantic tropical wave has its axis along 35W from
05N to 19W. It is moving westward at 10-15 kt. No significant
convection is noted in association with this wave.

A western Caribbean tropical wave has its axis along 82W and
south of 19N. It is moving westward at 10-15 kt. The interaction
between the wave axis and the eastern Pacific monsoon trough is
producing scattered showers and a few thunderstorms south of 11N
between 78W and 82W, to the coast of Panama.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis reaches the Atlantic through the coast of
Mauritania near 19N16W, and continues southwestward to 11N25W,
then to the low pressure near 12N43W and ending near 08N47W. No
significant convection is evident beyond what was described in the
Special Features section.

...GULF OF MEXICO...

Scattered moderate showers and thunderstorms are active over the
north-central Gulf from 25N to 28N between 90W and 93W, associated
with a trough extending from 29N88W to 26N90W. A few thunderstorms
are also active over the northeast Gulf, near an upper trough in
that area. Additional showers and thunderstorms are active along a
trough moving off weak the west coast of the Yucatan peninsula.
Elsewhere, a surface ridge extends from the Straits of Florida to
the lower Texas coast. This pattern is supporting generally gentle
to moderate breezes and slight seas across the basin.

For the forecast, the weak ridge will remain dominant into early
next week. This will support mainly gentle to moderate winds,
except over the eastern Bay of Campeche where winds will be
enhanced by a daily trough that will emerge off the Yucatan
Peninsula daily during the overnight hours.

...CARIBBEAN SEA...

Please see the Tropical Wave section above for convection in the
western Caribbean. The remainder of the basin is under the
influence of a subtropical ridge positioned near the Azores.
Saharan dust covers most of the eastern and central Caribbean,
resulting in drier conditions, above normal temperatures and
reduced visibility.

The pressure gradient between the ridge and lower pressures in NW
South America continue to sustain fresh to strong easterly trade
winds in the south-central Caribbean as seen by a recent
scatterometer. In the remainder of the basin, moderate or weaker
winds prevail. Wave heights are in the 8-10 ft range over the
central Caribbean and much lower in the 2-6 ft range elsewhere.

For the forecast, the pressure gradient between the Bermuda High and
lower pressure over Central America and northern South America
will maintain strong trades across the central Caribbean into Sun.
Winds should diminish slightly to fresh to strong Sun night into
Wed. Fresh to locally strong trades will develop over the Gulf
of Honduras Sun through Mon. Low pressure, AL95, well east of
the region is forecast to move into Atlantic waters E of the
Lesser Antilles early next week, possibly as a tropical cyclone.
Expect increasing wind and seas over these waters in association
with this low pressure system.

...ATLANTIC OCEAN...

Please see the Special Features section for information on
Hurricane Don in the north-central Atlantic, gale winds in the
eastern Atlantic, and INVEST 95L in the central Atlantic.

Scattered showers and a few thunderstorms are active from 25N to
28N between 65W and 70W. This activity is related to divergence
aloft caused by an upper trough that extends 31N55W to 23N58W. At
the surface, the pattern is dominated by a surface ridge extending
from 1029 mb high pressure near the Azores, southeastward to the
central Bahamas. This pattern is supporting gentle to moderate
breezes and 4 to 6 ft combined seas west of 45W, and moderate to
fresh winds and 5 to 8 ft seas east of 45W, except for the strong
to near-gale force winds and 6 to 10 ft seas off northwest Africa
described in the Special Features section.

For the forecast west of 55W, weak high pressure will dominate
through early next week. Fresh trades may pulse nightly N just N
of Hispaniola and over the Windward Passage starting Sun.
Elsewhere across forecast waters, winds will be moderate or weaker
into early next week.

$$
Christensen
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