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Tropical Storm Henriette Discussion Number  17
NWS National Hurricane Center Miami FL       EP082025
1100 PM HST Thu Aug 07 2025
 
Henriette’s satellite presentation remains unimpressive this 
evening, having lost nearly all deep convection and with the 
low-level center fully exposed.  The latest subjective Dvorak 
current intensity estimate from TAFB was T2.5/35 kt, while 
objective estimates from UW-CIMSS have ranged from 26 to 34 kt over 
the past several hours. A timely 08/0534z Metop-B Ascat pass 
depicted quite a few 30 to 33 kt wind barbs and this was the basis 
for holding the initial intensity steady at 35 kt for this advisory.
 
Henriette is moving westward, or 280 degrees at 15 kt. A turn toward 
the west-northwest is expected soon, with this general motion 
expected to persist over the next couple of days as the cyclone 
tracks along the southwestern periphery of a subtropical ridge to 
its northeast. A turn toward the northwest is forecast this weekend 
and into early next week as Henriette becomes steered between an 
amplifying longwave trough northwest of Hawaii and the subtropical 
ridge to its northeast. The official track forecast remains in close 
agreement with the latest multi-model consensus aids and is very 
close to the previous advisory.  Confidence remains high that 
Henriette will remain far to the north of Hawaii.
 
Henriette will traverse sea surface temperatures near 24C with 
mid-level relative humidity below 50 percent during the next 24 
hours or so. Despite these unfavorable thermodynamic conditions, the 
cyclone’s well-defined circulation is expected to remain fairly 
resilient within the prevailing low-shear environment, allowing for 
occasional pulses of deep convection to continue.  As a result, 
little change in intensity is anticipated during the next day or so. 
If Henriette can withstand the next 24 hours over cooler waters, as 
continues to be indicated by the GFS and ECMWF models again with the 
00Z cycle, re-intensification will likely occur over the weekend and 
into early next week as sea surface temperatures steadily rise to 
levels conducive for strengthening.  The official forecast continues 
to reflect intensification, bringing Henriette to hurricane strength 
by 72 hours.  The cyclone will begin to experience increasing 
vertical wind shear as it moves toward the higher latitudes, which 
should result in rather rapid weakening beginning between 96 and 120 
hours.  The intensity forecast is on the higher end of the guidance 
envelope, and is most closely aligned with the CTCI and HMNI 
intensity aids, but below the peak depicted by the HAFS models.

Future information on Henriette can be found under Central Pacific 
basin headers beginning at 500 AM HST.  Future Tropical Cyclone 
Discussions will be issued under AWIPS header HFOTCDCP3 and WMO 
header WTPA43 PHFO.  Products will continue to be available on the 
web at hurricanes.gov.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  08/0900Z 19.2N 140.1W   35 KT  40 MPH
 12H  08/1800Z 19.7N 142.3W   35 KT  40 MPH
 24H  09/0600Z 20.7N 145.0W   35 KT  40 MPH
 36H  09/1800Z 21.9N 147.5W   40 KT  45 MPH
 48H  10/0600Z 23.3N 149.8W   45 KT  50 MPH
 60H  10/1800Z 24.9N 152.0W   55 KT  65 MPH
 72H  11/0600Z 26.9N 154.5W   65 KT  75 MPH
 96H  12/0600Z 31.1N 159.2W   70 KT  80 MPH
120H  13/0600Z 35.8N 163.8W   55 KT  65 MPH
 
$$
Forecaster Jelsema (CPHC)
 
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