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Hurricane Iona Discussion Number  14
NWS Central Pacific Hurricane Center Honolulu HI   CP012025
Issued by NWS National Hurricane Center Miami FL
500 AM HST Wed Jul 30 2025
 
Iona has continued to rapidly weaken since the last advisory. A GPM 
microwave overpass showed an exposed low-level center located well 
to the northwest of the mid-level center apparent in geostationary 
imagery, with little or no organized convection near the low-level 
center. Subjective and objective satellite intensity estimates have 
decreased significantly and currently are in the 45-75 kt range.  
Based on a blend of these estimates, the initial intensity is 
reduced to a likely generous 65 kt.

The initial motion is now 280/17 kt. This general motion is 
expected to continue during the next day or two as the cyclone 
moves along the southern periphery of a low- to mid-level 
subtropical ridge to the north.  A turn toward the west-northwest 
and a gradual decrease in forward speed are expected late in the 
week and over the weekend, as the system is steered into a weakness 
in the ridge. The official forecast is nudged just a little north 
of the previous track  and lies near the center of the track 
guidance envelope. Iona has stayed well south of the Hawaiian 
Islands, and the cyclone is forecast to move farther away from the 
islands during the next couple of days.
 
Rapid weakening is expected to continue for the next 12-24 h due to 
increasing westerly vertical shear and a track over cooler sea 
surface temperatures.  After that, the intensity forecast shows a 
period of little change in strength as sea surface temperatures 
begin to warm along the forecast track and the atmospheric 
conditions become a little more favorable.  By the end of the 
forecast period, Iona should again weaken as it encounters mid-level 
dry air and another bout of vertical shear.  The intensity forecast 
was lowered below the previous forecast mainly in response to the 
current intensity trends.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  30/1500Z 11.5N 160.2W   65 KT  75 MPH
 12H  31/0000Z 11.8N 162.8W   55 KT  65 MPH
 24H  31/1200Z 12.2N 166.4W   45 KT  50 MPH
 36H  01/0000Z 12.8N 169.8W   45 KT  50 MPH
 48H  01/1200Z 13.5N 173.2W   45 KT  50 MPH
 60H  02/0000Z 14.5N 176.3W   45 KT  50 MPH
 72H  02/1200Z 15.4N 179.2W   45 KT  50 MPH
 96H  03/1200Z 17.3N 176.0E   40 KT  45 MPH
120H  04/1200Z 19.2N 171.1E   35 KT  40 MPH
 
$$
Forecaster Beven
 
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