BULLETIN
Hurricane Ian Advisory Number 19
NWS National Hurricane Center Miami FL AL092022
500 PM EDT Tue Sep 27 2022
...HURRICANE WARNING EXTENDED SOUTHWARD IN SOUTHWESTERN FLORIDA...
...LIFE-THREATENING STORM SURGE, CATASTROPHIC WINDS AND FLOODING
EXPECTED WITH IAN IN THE FLORIDA PENINSULA...
SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION
another SE adjustment
000
WTNT44 KNHC 272059
TCDAT4
Hurricane Ian Discussion Number 19
NWS National Hurricane Center Miami FL AL092022
500 PM EDT Tue Sep 27 2022
The pressure on the last Air Force Hurricane Hunter aircraft fix
fell to about 952 mb, indicating that Ian is restrengthening
over the southeastern Gulf of Mexico. The eye of Ian remains
well-defined on visible imagery, although radar data from Key West
suggest that an eyewall replacement could be in the initial stages.
The initial wind speed is set to 105 kt, matching a blend of
earlier SFMR and flight-level wind data. The plane data also
showed that the area of hurricane-force winds is growing on the
east side of the cyclone.
Ian is moving east-of-due-north, or 010/9-kt, with occasional
wobbles to the north-northeast. A track toward the north-northeast
is expected for the next couple of days while it moves between a
ridge over the Bahamas and a trough over the western Gulf of Mexico.
There has been some model convergence this afternoon showing Ian
remaining stronger and vertically deeper through landfall. This
solution results in a faster track, again adjusted to the southeast,
and the new forecast is moved in that direction. This new NHC track
is close to the corrected model consensus and between the quicker
ECMWF and slower GFS models. It should be emphasized that this
track remains uncertain, with a typical spread in the steering
features leading to big speed and track differences down the line,
not to mention the oblique angle of approach to Florida. In a few
days, more of the guidance is showing Ian interacting with a
shortwave trough over the southeastern United States, causing the
system to move back over the northwestern Atlantic in the longer
range, before turning northwestward back over land. The day 3-5
track forecast is also shifted eastward, although significant
re-strengthening is not expected at long range.
The outflow pattern of the hurricane is beginning to be impinged
upon in the southwestern quadrant, a sign that upper-level
southwesterly flow is starting to affect the outer circulation.
While the shear should increase up through landfall, it is just too
close-to-call whether it starts to weaken Ian or not, or whether the
larger system is able to resist the shear. Additionally, an eyewall
replacement cycle could be in its initial phases, although
predicting these structural changes is extremely difficult. The new
forecast is near the last one, a little higher than the consensus.
I should note that whether Ian comes ashore as category 4 hurricane
or a large category 3 after an eyewall cycle, avoiding a large and
destructive hurricane for Florida seems very unlikely, and residents
should heed the advice of local emergency management officials.