Potential Tropical Cyclone One-C

514 
WTPA42 PHFO 130251
TCDCP2
 
Potential Tropical Cyclone One-C Discussion Number   3
NWS Central Pacific Hurricane Center Honolulu HI   CP012026
Issued by NWS National Hurricane Center Miami FL
500 PM HST Wed Aug 12 2026
 
The disturbance remains poorly organized, with at least two
mesovortices rotating around the larger circulation.   A recent
OSCAT pass also shows a very elongated circulation, with gale-force
winds confined to the northeastern quadrant. There has been some
suggestion in recent imagery that the southern side of the
circulation is becoming more dominant, but the overall system
is still too ill-defined to be considered a tropical cyclone.  The
initial wind speed remains 35 kt per earlier scatterometer data.
 
The overall circulation envelope appears to be moving westward at
about 8 kt.  A large high pressure system north of the Hawaiian
Islands should cause a west to west-northwestward track of the
disturbance for the next several days.  At this point, the track
forecast is highly dependent on where a true center forms, with the
most northward model formations generally gaining the most
latitude, and the southward model solutions usually staying just 
south of the Hawaiian Islands.  The overall model trend is slightly 
south of the previous forecast, and the new forecast is adjusted in 
that direction.  This should not be considered a high-confidence
prediction given the uncertainties on where a center will form.
 
The environment should generally be conducive for intensification
during the next few days with warm sea-surface temperatures,
low-to-moderate vertical wind shear and ample low- to mid-level
humidities in the system's path.  Due to the sprawling structure,
only a gradual strengthening is anticipated. The intensity forecast
near the Hawaiian Islands is challenging because of land
interaction and an upper-low dropping near the cyclone.  Models
tonight generally show a more conducive trough interaction than a
high-shear one, and the system is expected to be near hurricane
strength by the time it nears the Hawaiian Islands.  The new
intensity forecast is slightly higher than the previous one, but is
leveled off near Hawaii.  This forecast could be conservative
beyond 3 days, especially if the system moves south of expected.
 
 
Key Messages:
 
1. The disturbance is expected to become a tropical storm on
Thursday and strengthen while it moves west-northwestward near or
over the Hawaiian Islands late this week and this weekend.  Although
it is too soon to specify the exact location and magnitude of
impacts, residents should closely monitor the latest forecast
updates and ensure that they have their preparedness plan in place.
 
2. Heavy rainfall associated with the system will begin to impact
the Big Island Friday, spreading westward into Maui Saturday, and
Lanai, Molokai, Oahu and Kauai on Sunday.  This rainfall may
produce life-threatening flooding and mudslides, especially in areas
of steep terrain.
 
3. There is an increasing risk of wind and wave impacts in the
Hawaiian Islands regardless of the exact track and intensity of the
system.  Hurricane or Tropical Storm Watches may be required for
portions of the Hawaiian Islands early Thursday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  13/0300Z 14.8N 143.5W   35 KT  40 MPH...POTENTIAL TROP CYCLONE
 12H  13/1200Z 15.2N 144.6W   40 KT  45 MPH...POTENTIAL TROP CYCLONE
 24H  14/0000Z 16.2N 146.6W   45 KT  50 MPH...TROPICAL CYCLONE
 36H  14/1200Z 17.3N 149.0W   50 KT  60 MPH
 48H  15/0000Z 18.1N 151.6W   55 KT  65 MPH
 60H  15/1200Z 18.8N 154.1W   60 KT  70 MPH
 72H  16/0000Z 19.6N 156.7W   60 KT  70 MPH
 96H  17/0000Z 21.4N 162.2W   55 KT  65 MPH
120H  18/0000Z 23.3N 167.6W   60 KT  70 MPH
 
$$
Forecaster Blake