[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 172359
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 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 1800 UTC surface analysis and satellite imagery through
2300 UTC.

...SPECIAL FEATURES...

Tropical Storm Fiona is centered near 16.6N 64.9W at 17/0000 UTC
or 70 nm S of St. Croix moving WNW at 7 kt. Estimated minimum
central pressure is 998 mb. Maximum sustained wind speed is 50 kt
with gusts to 60 kt. Peak wave heights are reaching 18 ft. Seas
12 ft or greater are within 120 nm of center, expect 90 nm SW
quadrant. Numerous moderate to strong convection is noted within
270 nm SE semicircle. On the forecast track, the center of Fiona
will move south of the U.S. Virgin Islands this evening, approach
Puerto Rico tonight, and move across Puerto Rico by Sunday
afternoon. Then, Fiona will be offshore of the Dominican Republic
on Monday and near or to the east of the Turks and Caicos
Islands on Tuesday. Strengthening is forecast, and Fiona is
expected to become a hurricane before reaching the southern coast
of Puerto Rico on Sunday. Additional strengthening is expected
on Monday and Tuesday while Fiona moves over the southwestern
Atlantic. NOAA buoy 42060 east-southeast of Fiona's center
recently reported a sustained wind of 45 mph (72 km/h) and a gust
to 51 mph (83 km/h). A station at Teagues Bay, St. Croix,
recently reported a sustained wind of 36 mph (57 km/h) and a gust
to 44 mph (70 km/h). Heavy rain associated with Fiona are likely
to produce life-threatening flash flooding and urban flooding,
along with mudslides in areas of higher terrain, particularly in
portions of Puerto Rico and the eastern Dominican Republic. Very
heavy rains and flooding have occurred over portions of the
Leeward Islands since Friday. A station at St. Claude Matouba
Irfa, in the mountains in southwestern Guadeloupe, recently
measured a 24-hour rainfall total of 19.85 inches (504.2 mm).
Swells generated by Fiona are affecting the Leeward Islands, the
northern Windward Islands, the Virgin Islands, Puerto Rico, the
northern coast of the Dominican Republic, the Turks and Caicos
Islands, and the southeastern Bahamas. These conditions could
cause life- threatening surf and rip current conditions. Please
consult products from your local weather office.

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...

A tropical wave is along 34W from 04N-16N, moving westward at
10-15 kt. Scattered showers are noted near the wave axis.

A second tropical wave is along 47W from 07N-21N, moving
westward about 10-15 kt. An area of disorganized showers and
thunderstorms is near the northern end of the wave axis. Some
slow development of this system is possible during the early or
middle part of next week while it moves generally northward at
about 10 kt. 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
Mauritania near 17N16W and continues to 12N25W. The ITCZ extends
from 12N25W to 11N32W. Aside from convection related to the
tropical waves described above, scattered moderate convection is
noted from 08N-12N E of 17W to the coast of Africa.

GULF OF MEXICO...

High pressure over the SE CONUS extends a ridge across the Gulf
waters. Since yesterday, convection has diminished across the
basin, and currently isolated showers and thunderstorms are
noted. However, showers and thunderstorms continue to flare up
over Florida. A shortwave trough over the eastern Gulf is
enhancing this convective activity. Gentle to moderate winds
prevail across the Gulf region with seas generally in the 1-3 ft
range. Winds and seas may be locally higher in and near
thunderstorms.

For the forecast, high pressure over the southeastern U.S. will
maintain gentle to moderate easterly breezes and slight seas the
next few days.

CARIBBEAN SEA...

Please see the Special Features section for information on
Tropical Storm Fiona currently located over the northeastern
Caribbean.

Outside of Fiona, an area of low level convergence is enhancing
convection from Haiti to near Cabo Gracias a Dios, Nicaragua,
particularly from 15N-19N between 70W-85W. Another area of
scattered moderate convection is noted N of the monsoon trough
from 09N-12N between 73W-83W. Fresh to locally strong NE winds
ahead of Fiona are noted per scatterometer data across the Mona
Passage and just S of Dominican Republic. Elsewhere gentle to
moderate winds prevail. Seas are generally 3-5 ft, except 5-7 ft
in the Mona Passage and just S of Dominican Republic to near Cabo
Beata.

For the forecast, Fiona will move to 17.3N 65.5W Sun morning,
strengthen to a hurricane near 18.1N 66.7W Sun afternoon, 19.0N
68.0W Mon morning, 20.1N 69.0W Mon afternoon, 21.4N 69.8W Tue
morning, and 22.7N 70.5W Tue afternoon. Fiona will change little
in intensity as it moves to 25.4N 70.7W Wed afternoon.

ATLANTIC OCEAN...

Please see the Special Features section for information on
Tropical Storm Fiona, forecast to reach the Turks and Caicos
Islands on Tuesday.

Abundant moisture prevails across the western Atlantic supporting
scattered to numerous showers and thunderstorms mainly N of 24N
and W of 75W, including the NW Bahamas. A frontal boundary enters
the forecast waters near 31N60W and continues SW to near 28N65W.
A few showers are along the front. The remainder of the Atlantic
is under the influence of a ridge, with a 1021 mb high pressure
located near 33N53W. Under the influence of the ridge, mainly
light and variable winds are noted roughly N of 25N. Winds
increase between Fiona and the ridge to the N, with an area of
moderate to fresh NE-E winds S of 22N between 64W-70W based on
scatterometer data. An area of fresh to strong NE winds, with
seas of 7-9 ft, is near the coast of Mauritania from 18N to 21N
E of 20W.

For the forecast west of 55W, Tropical Storm Fiona will move to
17.3N 65.5W Sun morning, strengthen to a hurricane near 18.1N
66.7W Sun afternoon, 19.0N 68.0W Mon morning, 20.1N 69.0W Mon
afternoon, 21.4N 69.8W Tue morning, and 22.7N 70.5W Tue afternoon.
Fiona will change little in intensity as it moves to 25.4N 70.7W
Wed afternoon. Scattered showers and thunderstorms are expected
over the far western part of the area through early next week as
the trough lingers offshore the Florida coast.

$$
GR
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