[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 012327
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Sat Sep 2 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...

Post-Tropical Cyclone Idalia is centered near 32.0N 66.5W at
01/2100 UTC or 85 nm W of Bermuda, moving ESE at 13 kt. Estimated
minimum central pressure is 1000 mb. Maximum sustained wind speed
is 45 kt with gusts to 55 kt. Gale force winds are currently
occurring north of 30N between 65W and 71W. Seas are peaking
around 20 ft near 31N69W. Strong to near gale force winds,
along with seas of 12 ft or greater currently cover waters north
of 27N between 63W and 75W. A gale warning is in effect through
Sat afternoon, with gale force winds expected N of 30N between
63W and 71W during that time. A cold front in the area extends
from 31N64W to 28N66W, and a surface trough continues to the NW
Bahamas. Scattered moderate convection is within 150 nm to the
south of the surface trough, including over the NW Bahamas. A
general ESE trajectory at a slower forward speed is expected
through early Saturday. A turn toward the east and then northeast
is forecast over the weekend. On the forecast track, the center of
Idalia will move near or to the south of Bermuda on Saturday.
Little change in strength is expected during the next few days.
Idalia could transition to a tropical or subtropical storm on
Saturday. Swells generated by Idalia will affect the southeastern
U.S. coast and Bermuda during the next couple of days. These
swells are likely to cause life-threatening surf and rip current
conditions.

Gert has strengthened to a tropical storm, centered near 27.8N
54.4W at 01/2100 UTC or 605 nm ESE of Bermuda, moving ESE at 4
kt. Estimated minimum central pressure is 1006 mb. Maximum
sustained wind speed is 35 kt with gusts to 45 kt. Peak seas are
11 ft near the center. Numerous moderate isolated strong
convection is noted within 60 nm N semicircle and 180 nm S
semicircle. A slow generally eastward motion is expected tonight.
A slightly faster northeastward motion is expected to begin by
Sunday. Some slight additional intensification is possible
tonight or tomorrow. Weakening is likely by Sunday, and Gert is
expected to dissipate by Monday.

Tropical Storm Jose is centered near 39.4N 49.1W at 01/2100 UTC
or 875 nm NE of Bermuda, moving NNE at 28 kt. Estimated minimum
central pressure is 996 mb. Maximum sustained wind speed is 45 kt
with gusts to 55 kt. Jose is expected to become absorbed by
Franklin by tonight or early Saturday.

Tropical Depression Twelve is centered near 20.8N 28.7W at
01/2100 UTC or 390 nm NW of the Cabo Verde Islands, moving NNW at
10 kt. Estimated minimum central pressure is 1006 mb. Maximum
sustained wind speed is 30 kt with gusts to 40 kt. Seas near the
center are around 11 to 12 ft. Scattered moderate to isolated
strong convection is seen within 270 nm of the center in the E
semicircle. Scattered moderate convection is also within 90 nm NW
quadrant. A generally northwestward motion with a decrease in forward
speed is expected through Monday. Some strengthening is possible,
and the depression could become a tropical storm tonight or on
Saturday. Weakening is expected to begin by early Sunday, and the
system could degenerate into a remnant low by late Sunday.

Franklin has become a powerful post-tropical cyclone near 39.5N
53.8W, or 685 nm NE of Bermuda, as of 01/2100 UTC moving NE at 15
kt. Estimated minimum central pressure is 979 mb. Maximum
sustained wind speed is 70 kt with gusts to 85 kt. Franklin is no
longer affecting the waters south of 31N and will continue moving
farther away.

See hurricanes.gov for public advisories on the active systems
and for the latest NHC Tropical Weather Outlook. See
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for the latest
High Seas Forecast.

...TROPICAL WAVES...

A strong tropical wave has been added to the analysis with axis
along the west coast of Africa near 15W from 18N southward,
moving W at 10-15 kt. Numerous moderate scattered strong
convection is seen from 07N to 16N between 14W and 21W. Conditions
appear conducive for gradual development during the early and
middle parts of next week, and a tropical depression could form
while it moves westward to west-northwestward over the eastern
and central portions of the tropical Atlantic. There is a low
chance of tropical cyclone formation within the next 48 hours and
medium chance within the next 7 days.

An eastern Caribbean tropical wave axis is along 63W, moving W at
10-15 kt. Isolated showers are along and within 180 nm east of
the wave axis to the south of 16N, affecting the Windward Islands.

A western Caribbean tropical wave is along 87W from 20N southward
across western Honduras and into the Pacific, moving W at 10-15
kt. Scattered moderate to strong convection is noted from 10N to
17N and between 82W and 90W. Localized heavy rainfall is likely
occurring across portions of Nicaragua, Honduras, El Salvador and
northern Costa Rica, and should spread into SE Guatemala during
the next few hours.

...MONSOON TROUGH/ITCZ...

The monsoon trough reaches the Atlantic through the coast of
Africa near 11N16W to 17N21W. The monsoon trough resumes from
16N32W to 09N50W. Aside from the convection mentioned in the
sections above, scattered showers are noted from 06N to 08N
between 42W and 45W.

...GULF OF MEXICO...

A weak stationary front is draped across the northern Gulf coast.
Scattered showers and tstorms are present over the NE Gulf. A
surface trough extends from the mouth of the Mississippi River to
the central Bay of Campeche. Isolated showers and tstorms are near
the west coast of Yucatan and the eastern Bay of Campeche. Winds
are moderate or weaker across the Gulf, except for fresh near the
N coast of the Yucatan Peninsula. Seas are 3 ft or less across the
basin.

For the forecast, a weak surface trough with moderate winds over
the central Gulf will drift westward as high pressure continues to
build over the Gulf waters. Winds and seas could be higher near
thunderstorms associated with the trough. Moderate to locally
fresh winds will pulse at night off the NW Yucatan Peninsula
through Sun night. Otherwise, gentle to moderate winds will
persist through early next week with slight seas.

...CARIBBEAN SEA...

Please read the TROPICAL WAVES section for details on the
convection affecting parts of the Caribbean Sea. Thunderstorms
leftover from afternoon heating of landmasses have drifted
offshore the south coast of Cuba, offshore the west coast of
Jamaica, and near the west coast of central Haiti.

Fresh easterly trade winds cover the central Caribbean, except for
strong within 120 nm of the coasts of NW Venezuela and NE Colombia.
Seas in these waters are 5-8 ft. Moderate to locally fresh
easterly breezes and seas of 3-5 ft are evident in the eastern
Caribbean and most of the NW Caribbean.

For the forecast, fresh to strong trades will pulse in the
central Caribbean through tonight with moderate seas. Meanwhile,
gentle to moderate winds will prevail in the western Caribbean
with moderate to fresh winds in the eastern Caribbean. Trades will
weaken this weekend as the pressure gradient relaxes, and these
conditions will continue through early next week.

...ATLANTIC OCEAN...

Please read the SPECIAL FEATURES section for details about Post-
Tropical Cyclone Idalia, Post-Tropical Cyclone Franklin, Tropical
Storm Jose, Tropical Storm Gert and Tropical Depression Twelve.

Outside of the systems mentioned in the SPECIAL FEATURES section,
high pressure dominates the remainder of the tropical Atlantic,
supporting fairly tranquil weather conditions, moderate or weaker
winds and slight to moderate seas.

For the forecast W of 55W, strong winds will prevail N of 26N and
E of 75W during the next couple days. Rough seas will prevail N
of 24N and E of 79W during the next couple days. Post-Tropical
Cyclone Idalia could transition to a tropical or subtropical storm
on Saturday. It will move to 31.7N 65.3W Sat morning, 32.2N 62.5W
Sun morning, 35.6N 59.0W Mon morning, and 37.8N 58.2W Mon
afternoon. Gale force winds and rough to very rough seas
associated with Idalia will impact the north waters through the
weekend. Tropical Storm Gert will move to 27.7N 53.9W Sat morning,
29.0N 52.7W Sun morning, become extratropical and move to 33.0N
51.2W Mon morning, and dissipate Mon afternoon. Gert will continue
to move away from the offshore forecast waters during the
upcoming weekend. Strong winds and moderate seas will impact the
eastern forecast waters due to Gert through this evening.

$$
Hagen
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