[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 171141
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Sat Sep 17 2022

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
1130 UTC.

...SPECIAL FEATURES...

Tropical Storm Fiona is over the northeastern Caribbean Sea near
near 16.4N 63.3W at 17/0900 UTC or 110 nm W of Guadeloupe moving
W at 11 kt. Estimated minimum central pressure is 1000 mb.
Maximum sustained wind speed is 50 kt with gusts to 60 kt. Peak
wave heights of 21 ft are near and northeast of the center. Seas
12 ft or greater extend as far as 240 nm from the center of
Fiona in the NE quadrant. Shear has decreased and the center is
now tucked into the convection. A large, almost symmetrical,
area of numerous moderate to scattered strong convection is
observed on latest satellite imagery from 13N to 20N and between
58W and 65W. A westward to west-northwestward motion with a
decrease in forward speed is expected through Sun night. A turn
toward the northwest is forecast early next week. On the
forecast track, the center of Fiona is expected to move near or
just south of the Virgin Islands and Puerto Rico today through
Sun, and approach the southern or eastern coast of the Dominican
Republic Sun night and Mon. Fiona is forecast to move across the
Dominican Republic Sunday night and Monday. Gradual
strengthening is forecast, and Fiona could be near hurricane
strength when it moves near moves near Puerto Rico and the
Dominican Republic this weekend.
Please read the latest HIGH SEAS FORECAST issued by the National
Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest T.S.
Fiona NHC Forecast/Advisory and NHC Public Advisory at
www.hurricanes.gov for more details.

...TROPICAL WAVES...

An eastern Atlantic tropical wave has its axis extending from
16N32W to 11N33W to 04N32W. It is moving westward at 15-20 kt.
Clusters of scattered moderate convection are evident from 09N to
13N between the wave axis and 36W. The southern part of this
convective activity appears to be weakening.

A central Atlantic tropical wave has its axis along 45W from 08N
to 25N, moving westward about 15 kt. An area of disorganized
scattered moderate is north and northeast of the northern part of
the wave from 19N to 26N between 40W-45W. Scattered showers and
thunderstorms are along the wave axis within 60 nm of 18N45W.
Overnight ASCAT data revealed fresh to strong easterly winds from
17N to 23N between 40W-47W. Wave heights with these winds are in
the 5-7 ft range. Some slow development of this system is possible
during the early or middle part of next week while it moves
slowly northwestward to northward. The latest Tropical Weather
Outlook gives this system a low chance of tropical cyclone
formation through five days.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis enters the Atlantic through the coast of
The Gambia near 13.5N16W and continues to 109N23W to 10N31W and
to 08N39W. Aside from convection related to the tropical wave
along 45W, scattered moderate to isolated strong convection is
seen within 180 nm south of the trough between 16W-24W.

GULF OF MEXICO...

A surface trough extends from near Destin, Florida to 28N89W and
to 25N90W, while an upper-level trough is moving through the
eastern Gulf. These features are acting upon very deep tropical
moisture that is present over the area, resulting in scattered
and thunderstorms over some areas of the eastern Gulf. A surface
trough is analyzed over the western Bay of Campeche. Scattered
to numerous showers and thunderstorms are noted over the Bay of
Campeche south of 21N between 93W-96W. Isolated showers and
thunderstorms are elsewhere over the Gulf south of 26N. Weak
high pressure over the area supports gentle to moderate easterly
winds. Wave heights of 3-4 ft are over he northern Gulf,
especially N of 27N. Lower wave heights of 1-3 ft are noted
elsewhere in the basin.

For the forecast, high pressure over the southeastern U.S. is
maintaining gentle to moderate easterly breezes and slight seas.
This will continue through the next few days. Abundant deep
tropical moisture in place over the eastern Gulf along with an
upper trough over the eastern Gulf. This should continue to
support scattered showers and thunderstorms over the eastern
Gulf through the rest of the weekend.

CARIBBEAN SEA...

Please see the SPECIAL FEATURES section for information on
Tropical Storm Fiona currently over the northeastern Caribbean.

Outside of Fiona, a weak surface trough along 73W from 15N to 20N
is underneath an upper-level trough. Divergence east of the
upper-level trough is supporting scattered showers and a few
thunderstorms over the north-central Caribbean Sea from 15N
to 18N between 70W-76W. Scattered showers and thunderstorms are
noted from 13N to 16N west of 77W to the along the coasts of
Honduras and Nicaragua. Similar activity is over the southwestern
Caribbean, where the eastern extension of the eastern Pacific
monsoon trough is analyzed. Isolated showers are elsewhere north
of 16N and west of 82W. Moderate to fresh trade winds are
occurring in the north-central Caribbean, Windward Passage and
Gulf of Honduras per overnight ASCAT data passes. Wave heights
with these winds are in the 4-6 ft range. Gentle to moderate trade
winds along with lower wave heights of 2-4 ft are elsewhere.

For the forecast, Tropical Storm Fiona near 16.4N 63.3W 1000 mb,
or about 110 nm west of Guadeloupe at 5 AM EDT and moving W at 11
kt, with maximum sustained winds 50 kt gusts 60 kt will move to
near 16.8N 64.8W this afternoon, to near 17.1N 66.3W late tonight
with maximum sustained winds 60 kt gusts 75 kt, to near 17.7N
67.7W Sun afternoon, then strengthen to a hurricane as it
approaches the northeast coast of the Dominican Republic late Sun
night with maximum sustained winds 65 kt gusts 80 kt. Fiona is
forecast to maintain intensity as it reaches near 19.7N 69.9W Mon
afternoon, to near 20.8N 70.6W late Mon night, and continue to
strengthen as it moves northward over the Atlantic and farther
from the Caribbean Sea. Residual swell from Fiona will linger over
the northeastern Caribbean.

ATLANTIC OCEAN...

Please see the SPECIAL FEATURES section for information on
Tropical Storm Fiona.

A surface trough is analyzed from near 29N76W to the eastern
part of the Straits of Florida. Scattered showers and
thunderstorms moving eastward are to the northwest of the
trough, reaching to north of the area between 75W-80W. Isolated
showers are elsewhere near the trough. Moderate to fresh west-
northwest winds behind a frontal boundary are north of about 30N
and between 65W-69W. Wave heights are in the range of 3-6 ft over
the waters west of 67W. Farther south, moderate to fresh
trade winds are south of 21N and between 71W-77W, with related
wave heights of 4-7 ft. The remainder of the basin is dominated
by a large ridge over the central Atlantic maintaining fairly
tranquil weather conditions.

In the eastern Atlantic, overnight partial ASCAT data depicts
fresh to strong north to northeast winds from 17N to 23N and
east of 30W, with the strongest winds occurring off northern
Mauritania. Similar winds are evident off Morocco and Western
Sahara and the waters surrounding the Canary Islands. Wave heights
are 6-9 ft north of 16N and east of 25W. Elsewhere, moderate or
lighter winds winds are present along with wave heights of 4-6 ft.

For the forecast west of 55W, Tropical Storm Fiona over the
northeastern Caribbean Sea near 16.4N 63.3W 1000 mb at 5 AM EDT
moving W at 11 kt, with maximum sustained winds 50 kt gusts 60
kt is forecast to move near or just south of Puerto Rico through
Sun, and strengthen to a hurricane as it nears the northeast coast
of the Dominican Republic late Sun night with maximum sustained
winds 65 kt gusts 80 kt. It is forecast to maintain intensity as
it reaches near 19.7N 69.9W Mon afternoon, to near 20.8N 70.6W
late Mon night, and strengthen as it reaches near 23.0N 71.5W late
Tue night with maximum sustained winds 75 kt gusts 90 kt and to
near 26.0N 71.5W late Wed night with maximum sustained winds 80 kt
gusts 90 kt. Scattered showers and thunderstorms are expected
over the far western part of the area through early next week
as a trough lingers offshore the Florida coast.

$$
Aguirre
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