[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 281212
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Wed Sep 28 2022...Updated

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
1000 UTC.

Updated at 1210 UTC For Hurricane Ian Special Feature

...SPECIAL FEATURES...

Hurricane Ian is centered near 26.0N 82.7W at 28/1200 UTC or 50
nm W of Naples Florida, moving NNE at 9 kt. Minimum central
pressure is 937 mb. Maximum sustained wind speed has increased to
135 kt with gusts to 165 kt. Ian is a strong category 4 hurricane.
Hurricane force winds extend out 35 nm from the center. Tropical
storm force winds extend out 120 nm NE quadrant, 130 nm SE
quadrant, 100 nm SW quadrant and 150 nm NW quadrant. To the north
and west of the main area of tropical storm force winds, strong
NE winds near the coast from the Florida Panhandle to SE Louisiana
have prompted Gale Warnings where frequent gusts to gale force
are occurring and expected to continue. Seas of 12 ft or greater
extend out 120 nm E semicircle, 270 nm SW quadrant and 210 nm NW
quadrant. Peak seas are 29 ft. Numerous strong convection extends
from 23N to 28N between 80W and 85W. Numerous moderate to isolated
strong convection in banding extends from 23N to 31N between
75.5W and 80W. Ian is expected to cause a catastrophic storm
surge, winds and flooding over portions of the Florida Peninsula
later today. 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.

Showers and thunderstorms associated with a 1010 mb low pressure
center near 15N35W continue to show signs of organization several
hundred miles W of the Cabo Verde Islands. Numerous moderate to
isolated strong convection extends from 14N to 18N between 31W and
37W. Although environmental conditions are expected to be
marginally conducive for development, only a slight increase in
organization would result in the formation of a short-lived
tropical depression today. Further development will become less
likely by the end of the week due to increasing upper-level winds.
This low is forecast to meander for the next day, then turn NNW
Thu. The chance of formation into a tropical cyclone during the
next 48 hours is high. Please, read the Tropical Weather Outlook,
at the following website,
https://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=2, for more
details.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 23W, from 20N, moving W
at around 10 kt. Scattered moderate convection is noted from 07N
to 20N between 15W and 25W.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal border of
Mauritania and Senegal to 11N22W to 09N30W and from 12N38W to
11N47W. The ITCZ extends from 11N47W to 12N58W. Convection in the
vicinity of these features is primarily associated with the
tropical wave and low pressure, described in the section above.

GULF OF MEXICO...

Please see the Special Features above for details on Major
Hurricane Ian moving through the eastern Gulf of Mexico.

A stationary front over the northern Gulf of Mexico has dissipated
early this morning and away from Ian, high pressure is building
into the region. The rest is dry conditions with NE winds. Strong
NE winds are occurring in the northern and central Gulf, with
moderate NE winds in the SW. Seas across the basin are on the rise
from Hurricane Ian, with seas generally over 12 ft E of 89W, and
over 8 ft E of 92W. The remainder of the western and southwestern
Gulf has seas of 4 to 7 ft.

Major Hurricane Ian is near 25.6N 82.9W with 953 mb
at 5 AM EDT moving NNE at 9 kt. Maximum sustained winds are 120
kt with gusts to 145 kt. Ian will move to 26.7N 82.4W this
afternoon, inland to 27.7N 81.8W Thu morning, then weaken to a
tropical storm inland near 28.7N 81.1W Thu afternoon. Tropical
Storm Ian will move offshore to 29.8N 80.7W Fri morning and reach
31.6N 80.8W Fri afternoon. Ian will then move inland and weaken to
a tropical depression near 33.6N 81.4W Sat morning. Tropical
Depression Ian will be over North Carolina early Sun. Winds and
seas will gradually diminish across the Gulf starting Thu night as
Ian continues to move northeast of the region.

CARIBBEAN SEA...

In the wake of Major Hurricane Ian, that is now well N of the area
in the eastern Gulf of Mexico, a modest pressure gradient exists
over the basin, with significant moisture in place. The result is
isolated trade wind showers and thunderstorms over much of the
basin, with clusters of moderate convection south of Hispaniola,
along the Colombian coast, and in the east-central Caribbean,
north of Bonaire.

Winds in the central and eastern Caribbean are mainly moderate,
with light to gentle winds in the SW basin. Winds in the NW basin
are generally moderate and SW, but near western Cuba, fresh to
locally strong winds persist in the outermost influence of
Hurricane Ian. Seas are 3 to 4 ft, except 4 to 6 ft in the NW
Caribbean. In the Yucatan Channel, northerly swell being produced
by Ian is leading to seas of 8 to 10 ft.

Strong winds and rough seas will diminish over the northwest
Caribbean this morning as Ian continues to move north and away
from the region, although large N swell will persist in the
Yucatan Channel through Fri. Elsewhere gentle to moderate winds
and slight to moderate seas will persist across the basin.

ATLANTIC OCEAN...

Please read the Special Features section above for details on
Major Hurricane Ian and on a low pressure W of the Cabo Verde
Islands that is likely to develop into a tropical depression
today.

Elsewhere, a pair of surface troughs disrupted overall high
pressure across the basin. These troughs extend from N of 31N47W
to 19N43W, and from 31N27W to 17N33W, respectively. Neither trough
is producing much in the way of sensible weather, and dry
conditions dominate the basin. W of 50W, moderate E winds prevail.
To the E, N of 25N, a band of mainly fresh E winds dominate, with
gentle E winds to the S. Seas are 4 to 7 ft, with a zone of 8 to
10 ft seas N of 25N between 20W and 40W.

Major Hurricane Ian will move to 26.7N 82.4W this afternoon,
inland to 27.7N 81.8W Thu morning, then weaken to a tropical storm
inland near 28.7N 81.1W Thu afternoon. Tropical Storm Ian will
move offshore to 29.8N 80.7W Fri morning and reach 31.6N 80.8W Fri
afternoon. Ian will then move inland and weaken to a tropical
depression near 33.6N 81.4W Sat morning. Tropical Depression Ian
will be over North Carolina early Sun. Expect deteriorating marine
conditions off northeast Florida today, with tropical storm or
hurricane conditions possible through Fri. Elsewhere moderate to
fresh E to SE winds will persist.

$$
Hagen/Konarik
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