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Hurricane Iona Discussion Number  10
NWS Central Pacific Hurricane Center Honolulu HI   CP012025
Issued by NWS National Hurricane Center Miami FL
500 AM HST Tue Jul 29 2025

Iona is still rapidly intensifying. Satellite images indicate that
the eye of the hurricane is becoming more distinct, and it is
surrounded by a symmetric ring of cold cloud tops. A blend of the
latest intensity estimates from PHFO, JTWC, and UW-CIMSS supports
increasing the initial intensity to 110 kt, just below category 4
status. Iona has strengthened at a very rapid pace of about 50 kt
over the past 24 hours. Although Iona is very powerful, the wind
field is quite small. The hurricane- and tropical-storm-force
winds are estimated to only extend up to 20 n mi and 70 n mi
from the center, respectively.
 
The major hurricane could get a little stronger today, and the
official forecast is at the top end of the intensity guidance in
the short term.  However, as is the case in most major hurricanes,
internal dynamics like eyewall replacement cycles could occur that
cause fluctuations in the system's strength. Iona is expected to
move into less favorable conditions of drier air, stronger shear,
and slightly cooler SSTs by tonight, and that should end the
strengthening trend and induce weakening. This forecast is in best
agreement with the HCCA model.
 
Iona has been moving due westward at about 11 kt on the south side
of a narrow mid-level ridge situated across the Hawaiian Islands.
The hurricane should continue westward on the south side of the
ridge during the next few days, and then turn west-northwestward to
northwestward after that when it moves toward the southwestern
periphery of the high pressure system.  The models are a little
slower this cycle, and the new track forecast has been adjusted in
that direction. Iona is expected to cross the International Date
Line in a little more than 4 days.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  29/1500Z 10.8N 154.3W  110 KT 125 MPH
 12H  30/0000Z 10.8N 156.2W  120 KT 140 MPH
 24H  30/1200Z 10.9N 159.1W  105 KT 120 MPH
 36H  31/0000Z 11.2N 162.4W   95 KT 110 MPH
 48H  31/1200Z 11.6N 166.1W   85 KT 100 MPH
 60H  01/0000Z 12.2N 169.8W   75 KT  85 MPH
 72H  01/1200Z 13.0N 173.0W   70 KT  80 MPH
 96H  02/1200Z 15.0N 179.0W   55 KT  65 MPH
120H  03/1200Z 16.8N 176.0E   40 KT  45 MPH
 
$$
Forecaster Cangialosi
 
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