Iona has continued to become better organized overnight with a
couple of recent microwave images depicting a well-defined low- to
mid-level eye feature. Recent geostationary satellite imagery has
shown what appears to be a banded-type eye becoming apparent. The
latest subjective satellite intensity estimates were T4.0/65 kt from
SAB, T3.5/55 kt from PHFO, and T3.0/45 kt from JTWC. Given the
recent improvement in structure as seen in the microwave images, the
initial intensity is increased to 65 kt, making Iona the first
hurricane in the Central Pacific basin of the 2025 hurricane season.
Iona remains in an environment favorable for strengthening. The
cyclone is over SSTs of around 28C, and the shear is forecast to
remain 10 kt or less during the next 24 to 36 hours. The only
inhibiting factor appears to be some drier mid-level air in the
surrounding environment. Given these conditions, steady to
possibly rapid strengthening is anticipated during the next 24 to
36 hours, and the official intensity forecast again shows a
higher peak than the previous advisory. After 36 hours, slightly
lower SSTs and an increase in vertical wind shear are likely to
result in gradual weakening throughout much of the remainder of the
forecast period. The updated intensity forecast is in good
agreement with the FSSE, HCCA, and IVCN consensus aids, and is
close to the peak shown by most of the regional hurricane models.
The storm is moving westward or 270 degrees at around 10 kt. There
has been no change in the track forecast reasoning. Iona should
continue to move westward along the southern side of a mid-level
ridge during the next couple of days. After that time, a faster
west-northwestward motion is expected as Iona reaches the
southwestern portion of the ridge. The updated track forecast is
very similar to the previous advisory and is a blend of the various
track consensus aids. Confidence remains high that Iona will stay
well south of the Hawaiian Islands.
