CPAC: IONA - Tropical Storm - Discussion

[Hurricane2022]

CDO is much more circular than it was a few hours ago and a new VHT is firing in the E eyewall
https://i.imgur.com/IpZYe9Z.jpeg

Likely a C2 right now.

[Hurricane2022]

[MarioProtVI]

BT lagging heavily with only 70 kt at 00z…this is definitely at least 20-25 kt stronger. Also nice it didn’t take long for the next CPac name after Hone (after taking 5 years to do so), then Keli forming immediately the day after

[StormWeather]

BT lagging heavily with only 70 kt at 00z…this is definitely at least 20-25 kt stronger. Also nice it didn’t take long for the next CPac name after Hone (after taking 5 years to do so), then Keli forming immediately the day after

Hey, what’s to say that if 98E can get its act together and move into the CPAC that we won’t get Lala as well soon?

[aspen]

Dang this got its act together quick. I looked away for 6 hours and it went from a solid looking Cat 1 to a likely pinhole major.

CPHC gonna CPHC so I expect some truly awful intensity estimates going forward. I’m guessing its true intensity may reach 130+ kt with how rapidly its structure has improved in the last few hours.

[Kingarabian]

Pinhole eye on IR. Closing in on MH status.

[Hurricane2022]

Dang this got its act together quick. I looked away for 6 hours and it went from a solid looking Cat 1 to a likely pinhole major.

CPHC gonna CPHC so I expect some truly awful intensity estimates going forward. I’m guessing its true intensity may reach 130+ kt with how rapidly its structure has improved in the last few hours.

It's the NHC that is issuing advisories on Iona and Keli. So I'd expect wind estimates being more reasonable from now on.

[sasha_B]

T5.5 fix from the JTWC:

F. T5.5/5.5/D3.0/24HRS STT: D1.0/03HRS

G. IR/EIR/VIS/MSI

H. REMARKS: 03A/PBO EYE/ANMTN. DG EYE SURROUNDED BY LG YIELDS AN
E# OF 5.0. ADDED 0.5 EYE ADJUSTMENT FOR W, TO YIELD A DT OF 5.5.
MET YIELDS 4.0. PT YIELDS 4.5. DBO DT. BROKE CONSTRAINTS DUE TO
RAPID INTENSIFICATION.

[StormWeather]

Dang this got its act together quick. I looked away for 6 hours and it went from a solid looking Cat 1 to a likely pinhole major.

CPHC gonna CPHC so I expect some truly awful intensity estimates going forward. I’m guessing its true intensity may reach 130+ kt with how rapidly its structure has improved in the last few hours.

It's the NHC that is issuing advisories on Ione and Keli. So I'd expect wind estimates being more reasonable from now on.

Is the NHC absorbing the CPHC like they did the EPHC in the 1980s?

[StormWeather]

T5.5 fix from the JTWC:

F. T5.5/5.5/D3.0/24HRS STT: D1.0/03HRS

G. IR/EIR/VIS/MSI

H. REMARKS: 03A/PBO EYE/ANMTN. DG EYE SURROUNDED BY LG YIELDS AN
E# OF 5.0. ADDED 0.5 EYE ADJUSTMENT FOR W, TO YIELD A DT OF 5.5.
MET YIELDS 4.0. PT YIELDS 4.5. DBO DT. BROKE CONSTRAINTS DUE TO
RAPID INTENSIFICATION.

Can I be bold and say this thing might have a shot at the ol’ Cat 4 or even dare I say Cat 5?

[Hurricane2022]

Dang this got its act together quick. I looked away for 6 hours and it went from a solid looking Cat 1 to a likely pinhole major.

CPHC gonna CPHC so I expect some truly awful intensity estimates going forward. I’m guessing its true intensity may reach 130+ kt with how rapidly its structure has improved in the last few hours.

It's the NHC that is issuing advisories on Ione and Keli. So I'd expect wind estimates being more reasonable from now on.

Is the NHC absorbing the CPHC like they did the EPHC in the 1980s?

I'm not sure about that, since we didn't get any notice from the US Gov nor the NWS (as far I know). We only saw the TWOs from EPAC and CPAC being merged in the NHC homepage.

[StormWeather]

2:35Z satellite view of Iona on TropicalTidbits shows a single pixel of clear in the eye.

[Kingarabian]

T5.5 fix from the JTWC:

F. T5.5/5.5/D3.0/24HRS STT: D1.0/03HRS

G. IR/EIR/VIS/MSI

H. REMARKS: 03A/PBO EYE/ANMTN. DG EYE SURROUNDED BY LG YIELDS AN
E# OF 5.0. ADDED 0.5 EYE ADJUSTMENT FOR W, TO YIELD A DT OF 5.5.
MET YIELDS 4.0. PT YIELDS 4.5. DBO DT. BROKE CONSTRAINTS DUE TO
RAPID INTENSIFICATION.

Can I be bold and say this thing might have a shot at the ol’ Cat 4 or even dare I say Cat 5?

It'll reach a point where the upper level westerlies will provide great ventilation before it gets decapitated.

[StormWeather]

It's the NHC that is issuing advisories on Ione and Keli. So I'd expect wind estimates being more reasonable from now on.

Is the NHC absorbing the CPHC like they did the EPHC in the 1980s?

I'm not sure about that, since we didn't get any notice from the US Gov nor the NWS (as far I know). We only saw the TWOs from EPAC and CPAC being merged in the NHC homepage.

If the whole Pacific East of the dateline is showing on the EPAC area of the TWO, what’s the point of the CPAC graphic now then?

[StormWeather]

Iona is unprecedented, right? We haven’t had a homebrew CPAC storm become a hurricane in July before right?

[StormWeather]

What? WHAT? 75 kts! What?

The NHC went 75 kts!

[StormWeather]

WTPA41 PHFO 290255
TCDCP1

Hurricane Iona Discussion Number 8
NWS Central Pacific Hurricane Center Honolulu HI CP012025
Issued by NWS National Hurricane Center Miami FL
500 PM HST Mon Jul 28 2025

The satellite presentation of Iona has improved since earlier today,
with very cold cloud tops ranging from -70°C to -80°C surrounding a
developing eye that is becoming increasingly well-defined.
Subjective Dvorak current intensity estimates came in at 4.0/65
knots from PHFO, 4.0/65 knots from SAB, and 4.5/77 knots from JTWC.
Objective estimates from ADT, AiDT, and SATCON have ranged between
65 and 82 knots over the past several hours. Based on a blend of
these data, the initial intensity for this advisory has been
increased to 75 knots.

Hurricane Iona is moving due west, or 270 degrees at 11 knots. This
general motion, along with a gradual increase in forward speed, is
expected to continue over the next several days as the cyclone moves
along the southern periphery of a subtropical ridge to the north. A
turn toward the west-northwest is anticipated by late in the week as
the system is influenced by a weakness in the mid-level ridge,
created by a developing upper-level low west of the International
Date Line. The official track forecast remains near the center of
the guidance envelope and is nearly identical to the previous
advisory. Confidence remains high that Iona will stay well south of
the Hawaiian Islands.

Environmental conditions appear primed for further intensification
during the next 24 hours. Iona will remain over warm sea surface
temperatures near 28C, with sufficient mid-level moisture and
minimal vertical wind shear. The latest ECMWF SHIPS guidance
indicates a greater than a 40 percent probability of a 30-knot
intensity increase within 24 hours. Given the improving structure
and conducive environment, the intensity forecast explicitly calls
for rapid intensification during the next 24 hours, with Iona
expected to become a major hurricane on Tuesday. Steady weakening
is forecast to begin Tuesday night or Wednesday as the system moves
over slightly cooler waters, encounters increasing westerly vertical
wind shear, and begins to entrain drier mid-level air. Iona is
expected to weaken to tropical depression status by day 5, and it is
possible the system could become a post-tropical remnant low by that
time. The intensity forecast has been adjusted slightly upward from
the previous advisory, reflecting the latest trends in the intensity
guidance. This aligns well with regional hurricane models through
day 2 and then closely follows the HCCA consensus guidance
thereafter.


FORECAST POSITIONS AND MAX WINDS

INIT 29/0300Z 10.9N 152.2W 75 KT 85 MPH
12H 29/1200Z 10.9N 153.8W 95 KT 110 MPH
24H 30/0000Z 10.9N 156.3W 105 KT 120 MPH
36H 30/1200Z 10.9N 159.3W 95 KT 110 MPH
48H 31/0000Z 11.2N 162.9W 75 KT 85 MPH
60H 31/1200Z 11.5N 166.7W 60 KT 70 MPH
72H 01/0000Z 12.1N 170.4W 50 KT 60 MPH
96H 02/0000Z 13.7N 178.0W 40 KT 45 MPH
120H 03/0000Z 15.9N 176.5E 35 KT 40 MPH

$$
Forecaster Jelsema (CPHC)

[sasha_B]

75 kts per NHC despite the (arguable) pinhole eye and subjective Dvorak fix of 5.5. Iona is now officially forecast to become a major in 24 hours, though. One of the more remarkably good-looking Category 1 hurricanes in recent memory.

[Hurricane2022]

Dang this got its act together quick. I looked away for 6 hours and it went from a solid looking Cat 1 to a likely pinhole major.

CPHC gonna CPHC so I expect some truly awful intensity estimates going forward. I’m guessing its true intensity may reach 130+ kt with how rapidly its structure has improved in the last few hours.

Soooo...We just saw a CPHC forecaster going with a 75 kt "estimate" for Iona now. Great job, Aspen!

[Kingarabian]

Would've went 90kts with that pinhole eye.