[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 281704
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Wed Sep 28 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 1200 UTC surface analysis and satellite imagery through
1650 UTC.

...SPECIAL FEATURES...

Hurricane Ian is centered near 26.4N 82.4W at 28/1700 UTC or 30 nm
WSW of Ft. Myers, FL. Ian is moving NNE at 8 kt. Minimum central
pressure is 937 mb. Maximum sustained wind speed is 135 kt with
gusts to 165 kt. Ian is a strong category 4 hurricane. Hurricane
force winds extend out 40 nm from the center. Tropical storm force
winds extend out 120 nm NE quadrant, 140 nm SE quadrant, 100 nm
SW quadrant and 150 nm NW quadrant. Seas of 12 ft or greater
extend outward 45 nm in the NE quadrant, 120 nm SE quadrant, 300
nm SW quadrant and 240 nm NW quadrant. Peak seas are 30 ft.
Numerous strong convection extends outward 90 nm from the center
in the N semicircle and 120 nm S semicircle. Scattered moderate to
strong convection is noted elsewhere within 390 nm NE quadrant,
330 nm SE quadrant and 150 nm W semicircle. The well-defined eye
is 25 nm in diameter on NWS Doppler radar, and 30 nm in diameter
on GOES-16 infrared satellite imagery. Ian is expected to cause a
catastrophic storm surge, winds and flooding over portions of the
Florida Peninsula this afternoon. The eyewall is moving onshore
now in the area of Sanibel Island, Captiva, Cape Coral, and Boca
Grande. 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.

Tropical Depression Eleven has formed near 16.1N 34.4W at 28/1500
UTC, or 600 nm W of the Cabo Verde Islands, moving N at 8 kt.
Minimum central pressure is 1008 mb. Maximum sustained wind speed
is 30 kt with gusts to 40 kt. Peak seas are near 10 ft. Scattered
moderate isolated strong convection is occurring within 180 nm of
the center in the NE semicircle. A north to north-northwest
motion is forecast over the next several days until the system
dissipates. Some slight strengthening is possible today, and the
depression could become a short-lived tropical storm. However,
weakening is expected by the end of this week, with the system
dissipating by Saturday. Please see the latest NHC
Forecast/Advisory and Public Advisory at www.hurricanes.gov for
more details.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave axis extends from 21N24W through
the Cabo Verde Islands to 09N25W, moving W at around 10 kt.
Scattered moderate convection is noted within 120 nm either side
of the wave axis from 11N to 16N.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through northern Mauritania from 16N17W
to 09N25W to 08N30W. The monsoon trough continues from 11N40W
10N47W. The ITCZ extends from 10N47W to 12N60W. Scattered moderate
convection is noted from 04N-10N between 10W-19W, from 01N-07N
between 19W-40W, and from 09N-14N between 53.5W-61W.

GULF OF MEXICO...

Although the winds and squalls directly related to Hurricane Ian
are confined to areas east of about 85.5W longitude, strong to
near gale force N to NE winds extend across the northern Gulf as
far west as 94W due to a strong pressure gradient between Ian and
an area of high pressure over east Texas. Significant wave heights
as far west as NOAA buoy 42501 near 26.0N 89.6W are 11 ft as of
28/1600 UTC. Seas of 11 to 16 ft cover most of the Gulf between
86W and 90W. Seas of 8 ft or greater cover the Gulf of Mexico east
of 94.5W and north of 22N. Over the southwestern Gulf, fresh N
winds prevail along with seas of 5-8 ft. Isolated showers and
tstorms are noted in the Bay of Campeche.

Major Hurricane Ian will move inland over southwest Florida to
27.3N 82.1W this evening, then weaken to a tropical storm near
28.3N 81.4W Thu morning. Ian will move off northeast Florida into
the Atlantic Thu evening to near 29.3N 80.8W then continue to move
north of the area into the Carolinas. Winds and seas will
gradually diminish across the northeast Gulf Thu night through Fri
night, with light breezes and slight seas persisting across the
basin thereafter. Looking ahead, a weak cold front may enter the
northeast Gulf late Sat or Sun, then stall and dissipate.

CARIBBEAN SEA...

Large seas are still occurring across the Yucatan Channel due to
large northerly swell from Major Hurricane Ian, which is about to
make landfall along the west coast of Florida. Recent ASCAT data
indicates fresh to strong N winds are still occurring in the
Yucatan Channel. Scattered moderate convection associated with
Ian is still occurring over western and central Cuba, but has
ended for the Caribbean Sea.

An upper-level low centered northeast of the basin near 22N62W
extends an upper-level trough southwestward to the northeastern
Caribbean. As a result, upper-level divergence over the
southeastern Caribbean is enhancing scattered moderate to strong
convection from 10N-15N between 61W-71W. Similar convection is
noted in the SW Caribbean in association with the east Pacific
monsoon trough, mainly south of 15N and west of 75.5W. Recent
ASCAT data shows gentle to moderate E winds over the eastern and
central Caribbean. Gentle W winds are in the NW Caribbean,
becoming fresh northerly in the Yucatan Channel. South of 20N and
east of 80W, seas are 2-4 ft across the basin. Seas are 3-6 ft in
the NW Caribbean, except 7-11 ft in the Yucatan Channel.

Major Hurricane Ian is north of the area, making landfall on the
west coast of Florida now. Large N swell associated with Ian will
persist in the Yucatan Channel through Fri night. Elsewhere
gentle to moderate winds and slight to moderate seas will persist
across the basin.

ATLANTIC OCEAN...

A stationary front extends from 31N78.5W to St. Augustine, FL.
Near-gale force NE winds are located north of the stationary
front, along the coast of Georgia and Jacksonville, FL. Major
Hurricane Ian is making landfall now on the west coast of Florida.
The combination of the front and outer squalls from Ian is
producing scattered moderate to strong convection, extending from
Florida eastward to a line extending from 31N72W to 24N76W. Winds
of 20 to 33 kt associated with the circulation of Ian are now
starting to emerge over the Atlantic to the east of Florida, and
seas are building.

An upper-level low centered near 22N62W is producing scattered
moderate convection from 19N-25N between 57W-65W. Another upper-
level low centered near 31N37W is inducing scattered moderate
convection north of 25.5N between 31.5W and 43W. Fresh NE to E
winds cover much of the area north of 25N and east of 40W. Seas
are 6 to 10 ft in this area. Elsewhere across the basin, mostly
moderate winds and 5-6 ft seas prevail.

Major Hurricane Ian will move onshore over southwest Florida this
afternoon, reach inland to 27.3N 82.1W this evening, then weaken
to a tropical storm over central Florida near 28.3N 81.4W Thu
morning. Ian will then enter the Atlantic off northeast Florida,
reaching 29.3N 80.8W Thu evening, and 30.8N 80.6W Fri morning. Ian
will continue to move north of the area into the Carolinas
through Fri night. Elsewhere moderate to fresh E to SE winds will
persist. Looking ahead, winds and seas will diminish across the
region Sat into Sun.

$$
Hagen
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