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Hurricane Kiko Discussion Number  34
NWS Central Pacific Hurricane Center Honolulu HI   EP112025
Issued by NWS National Hurricane Center Miami FL
500 AM HST Mon Sep 08 2025
 
Before departing, the final Air Force Reserve Hurricane Hunter 
aircraft fix into Kiko showed that the hurricane's structure 
continues to degrade, with the dropsonde launched at 1104 UTC 
showing increasing tilt with height between the surface center and 
flight level center. Maximum flight level winds from earlier in the 
mission were still 94 kt at 700 mb, but the structure has degraded 
further since that time. In fact satellite-based intensity estimates 
are much lower, and only support an intensity of 55 to 75 kt. The 
initial intensity of Kiko this advisory is being lowered to 75 kt, 
on the higher end of the satellite estimates, in deference to the 
earlier recon data. 
 
Kiko continues to move west-northwestward, with its estimated motion 
at 300/13 kt. For the next 12-24 hours this motion should continue 
as Kiko remains vertically deep, and is steered along the 
southwestern periphery of a subtropical ridge. However, the 
hurricane is quickly approaching a large deep-layer trough, which is 
imparting significant southwesterly mid- to upper-level flow. At 
this juncture, this flow is expected to significantly shear the 
cyclone, making it more vertically shallow, and it will become 
increasingly steered by the mid- to low-level flow which still has 
an anticyclone to its north. Thus, the west-northwestward motion is 
expected to continue beyond 24 hours too, and may even turn slightly 
leftward in days 3-4. The track guidance remains is good agreement 
on this scenario, and the latest NHC track forecast is very close 
to the prior one, blending the reliable consensus aids HCCA and 
TVCE with the Google Deep-Mind ensemble mean (GDMI). On the 
forecast track, Kiko is expected to pass north of the Hawaiian 
islands later this week and at this time no tropical storm watches 
are necessary for the island chain. 
 
The hurricane now appears to be feeling the effects of southwesterly 
vertical wind shear, which is now above 25 kt and expected to 
increase further over the next 24 hours. In addition, very dry air 
as seen on GOES-18 water vapor imagery is located in that upshear 
direction, and will likely be imported into Kiko's small inner core. 
Thus, weakening is anticipated to continue, and Kiko will likely 
weaken below hurricane intensity even as the cyclone starts to move 
over warmer sea-surface temperatures in 24-48 hours. There is a 
brief period where the shear weakens in 2-3 days before it increases 
again out of the east. Given the latest guidance, it seems more 
likely Kiko's structure will not allow the cyclone to recover much, 
and slow weakening is still forecasted through the end of the 
forecast period. The latest NHC intensity forecast is close to the 
middle of the guidance envelope through the 5 day period.
 
 
Key Messages:
 
1. Kiko is forecast to pass north of the Hawaiian Islands on Tuesday 
and Wednesday.  While the risk of direct impacts on the islands 
continues to decrease, interests there should continue to monitor 
Kiko's progress and the latest forecast.
 
2. Swells generated by Kiko are expected to gradually build and are 
forecast to peak along east-facing exposures of the Hawaiian Islands 
late today through the middle of the week, potentially producing 
life-threatening surf and rip currents. Listen to the latest updates 
and potential High Surf Warnings issued from the National Weather 
Service in Honolulu, Hawaii.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  08/1500Z 20.3N 148.8W   75 KT  85 MPH
 12H  09/0000Z 21.2N 150.5W   65 KT  75 MPH
 24H  09/1200Z 22.4N 152.9W   55 KT  65 MPH
 36H  10/0000Z 23.4N 155.6W   50 KT  60 MPH
 48H  10/1200Z 24.3N 158.0W   45 KT  50 MPH
 60H  11/0000Z 25.0N 160.4W   40 KT  45 MPH
 72H  11/1200Z 25.9N 162.6W   40 KT  45 MPH
 96H  12/1200Z 27.3N 166.4W   35 KT  40 MPH
120H  13/1200Z 29.1N 168.7W   35 KT  40 MPH
 
$$
Forecaster Papin/Shieh
 
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