[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201054
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Tue Sep 20 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
1030  UTC.

...SPECIAL FEATURES...

Hurricane Fiona is centered near 21.3N 70.9W at 20/0900 UTC or 20
nm SE of Grand Turk Island moving NNW at 9 kt. Estimated minimum
central pressure is 967 mb. Maximum sustained wind speed is 100 kt
with gusts to 120 kt. Fiona is the first major hurricane of the
2022 Atlantic hurricane season. Maximum wave heights are
currently 29 ft, but are forecast to build quite significantly to
around 45 ft over the next 48 hours as Fiona moves to a position
near 27N71W by 22/0600 UTC. Satellite imagery depicts a small
eye feature with Fiona. Numerous moderate to strong convection is
noted within 210 nm of the center in the NE quadrant, 120 nm in
the SE quadrant, 60 nm in the SW quadrant and within 90 nm of the
center in the NW quadrant. Outer bands consisting of scattered
moderate to isolated strong convection are seen 17N to 23N between
65W-69W and from 24N to 26N between 67W-71W. Scattered moderate
convection is within 60 nm of 24N73W. Fiona is forecast to
continue on its present motion through today, followed by a turn
toward the north tonight or Wed. On the forecast track, the center
of Fiona will pass near Grand Turk and the other eastern Turks
and Caicos during the next few hours. Strengthening is expected
during the next couple of days. On the forecast track, the center
of Fiona will pass near Grand Turk and the other eastern Turks and
Caicos during the next few hours. Swells generated by Fiona are
affecting the Virgin Islands, Puerto Rico, the northern coast of
Hispaniola, the Turks and Caicos Islands, and the southeastern
Bahamas. These swells will continue to spread westward across the
southwestern Atlantic toward the central and northwestern Bahamas
and the east coast of the United States through Wed night. The
swells 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 NHC
Forecast/Advisory and Public Advisory at www.hurricanes.gov for
more details.

Scattered moderate to isolated strong convection continues to
increase in association with a 1014 mb low pressure system located
over the central subtropical Atlantic near 31N46W. This convection
is observed within 180 nm north of the low between 44W-48W.
Scattered showers and isolated thunderstorms are seen from
29N to 31N between 43W-47W. Overnight ASCAT data depicted
fresh to strong winds associated with this low pressure, mainly
within 120 nm in the E semicircle of the low. Environmental
conditions appear marginally favorable for additional development,
and a tropical depression is likely to form over the next couple
of days before upper-level winds become less conducive later this
week. The system should generally move toward north or northeast.
This system has a medium chance of tropical cyclone development
within the next 48 hours.

...TROPICAL WAVES...

A central Atlantic tropical wave has its axis along 51W from
04N to 15N, moving westward at 15 kt. Satellite imagery shows
increasing clusters of numerous moderate to strong convection
ahead of the wave from 08N to 11N between the wave and 59W. An
overnight ASCAT data pass revealed fresh to strong southeast to
south winds 180 nm east of the wave from 07N to 11N. Gradual
development of this system is forecast during the next several
days as the system approaches the Windward Islands, and a tropical
depression could form toward the latter part of this week or
weekend as the system moves into the eastern and central Caribbean
sea. The chance of tropical cyclone formation during the next 48
hours is low, but medium within the next 5 days.

Another central Atlantic tropical wave has its axis along 60W
from 08N to 20N. It is moving westward about 15 kt. A surface
trough extends north-northeast of the wave from 20N60W to 26N56W.
Isolated showers and thunderstorms are along and within 60-90 nm
either side of the wave south of 15N. These showers and thunderstorms
will affect the Windward Islands this morning during the next
several hours. Scattered showers and isolated thunderstorms are
east of the trough from 22N-29N between 49-56W.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through coastal Senegal near 14N17W and
continues southwestward to low pressure of 1010 mb near 09N29W
and to 09N36W, where the ITCZ begins and continues to 10N44W and
to 11N50W. It resumes west of a tropical wave from 10N52W to
11N59W. Scattered moderate to isolated strong convection is within
240 nm northwest of the 1010 mb low. Scattered moderate
convection is within 120 nm south of the trough between the coast
of Africa and 18N.

GULF OF MEXICO...

High pressure over the southeastern United States extends weak
surface ridging southwestward into the north-central and NW Gulf
of Mexico, supporting moderate NE to E winds across the eastern
and central Gulf. A surface trough is over the far eastern Gulf,
off southwest Florida. Recent buoy observations and altimeter data
passes indicate wave heights of 2-4 ft across the Gulf, highest
in the central Gulf. 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 above for information on
Hurricane Fiona.

Scattered showers and thunderstorms trailing behind from Fiona
are north of 16N between 64W-71W. Similar activity is south of 15N
and west of 74W and south of 14N between 64W-67W. Isolated
showers and thunderstorms are elsewhere across the basin.

Fresh northeast winds are in the Windward Passage and in between
Jamaica and Haiti per latest ASCAT data. Wave heights with these
winds are 4-5 ft. Moderate SE winds are occurring east of 70W,
while moderate W winds are noted on the latest scatterometer data
between 70W-78W. Seas are still 5-7 ft over the east Caribbean in
large swell coming through the Mona Passage. Wave heights are
still 8 ft or higher in the Mona passage, but will be subsiding
later today. In the northwestern Caribbean, gentle to moderate
northeast to east winds continue,  where seas are 1-2 ft.

Major Hurricane Fiona north of the area located about 20 nm
southeast of Grand Turk Island will continue to move farther away
from the Caribbean through Wed while strengthening. Residual swell
over the eastern Caribbean from Fiona will subside through Tue. A
tropical wave, currently east of the area near 52W, is expected
to move across the Tropical N Atlantic from tonight through Wed,
across the eastern Caribbean Wed night through Thu and across the
central Caribbean Fri through Sat night. Gradual development of
this system is forecast during the next several days as the system
approaches the Windward Islands, and a tropical depression could
form toward the latter part of this week or weekend as the system
moves into the eastern and central Caribbean sea.

ATLANTIC OCEAN...

Refer to the Special Features section above for details on
Hurricane Fiona and the 1014 mb low pressure system near 31N46W.
Refer to the Tropical Waves section for details on the tropical
waves moving across the basin.

A surface trough extends from near 31N78W southwestward across
the central Florida Peninsula. Scattered showers and thunderstorms
remain across the western Atlantic waters mainly north of 28N and
west of 76W. Fresh trade winds are noted in the tropical Atlantic
from 11N-18N between 40W-56W. Wave heights are 5-6 ft in this
area. Elsewhere outside of the circulation of Fiona, winds are
moderate or weaker with wave heights of about 4-6 ft.

The area of 20 kt or greater winds associated with the circulation
of Fiona currently extend from the Greater Antilles to 25N
between 65W-73W. Seas of 8 ft or greater extend from 18N-26N
between 65W-73W

For the forecast west of 55W, major Hurricane Fiona is near 21.3N
70.9W 967 mb at 5 AM EDT moving NNW at 9 kt. Maximum sustained
winds 100 kt gusts 120 kt. Fiona will continue to strengthen as it
moves to near 22.3N 71.4W this afternoon, to near 23.6N 71.7W
late tonight with maximum sustained winds 115 kt gusts 140 kt, to
near 25.1N 71.5W Wed afternoon with maximum sustained winds 120 kt
gusts 145 kt, and maintain intensity as it moves to near 27.1N
70.7W late Wed night and to near 29.6N 69.4W Thu afternoon. Fiona
will begin to weaken as it tracks northeastward to north of the
area near 32.6N 66.8W late Thu night, and transition to a post-
tropical cyclone well north of the area by late Sat night. Swells
generated by Fiona will spread westward across the southwestern
Atlantic toward the central and northwestern Bahamas through Wed
night. A cold front will drop south over the northern and central
waters Fri through Sat night followed by fresh northeast winds and
building seas. High pressure will build in behind the cold front.

$$
Aguirre
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