000
WTPA42 PHFO 252056
TCDCP2
 
Hurricane Nolo Discussion Number  21
NWS Central Pacific Hurricane Center Honolulu HI   EP152026
Issued by NWS National Hurricane Center Miami FL
1100 AM HST Fri Sep 25 2026

The eye of Nolo is becoming better defined on South Point Hawaii 
radar as well as on the latest satellite imagery, though is still a 
bit ragged.  The Air Force Reserve Hurricane Hunters have found 
peak 700-mb flight-level winds of 106 kt, which generally 
correspond to surface winds of about 95 kt using standard reduction 
factors.  However, the radius-of-maximum winds is pretty large, 
some dropsonde data suggests it isn't quite mixing down at a normal 
rate, and the central pressure is fairly high around 978 mb.  These 
factors point to a somewhat lower current wind speed, so the 
initial intensity is set to 90 kt.  

Nolo is gradually bending leftward, with the current motion 
estimated at 015/4 kt.  Nolo should slow down by late tonight and 
start to drift westward on Saturday as the steering flow changes 
from an upper-level trough over the far northwestern Hawaiian 
Islands to a building ridge north of the main Hawaiian Islands.  
This ridge is forecast to push Nolo faster to the west by Sunday 
before eventually the cyclone is likely to turn more to the 
north-northwest early next week due to another encounter with that 
upper trough.  The new model guidance is fairly close to the last 
cycle, and no significant changes were made to the last NHC 
forecast.  

Some increase in shear, along with nearby dry air, could briefly 
arrest Nolo's strengthening trend for the next day or so.  After 
that time, most of the guidance is showing Nolo becoming a very 
strong hurricane with decreasing shear and increasing ocean heat 
content.  The new forecast is leveled off tonight, but then is 
raised from the last one early next week, and I wouldn't be 
surprised if Nolo ended up stronger in 2-3 days given the upper- 
level wind pattern.  Weakening is still expected by days 4 and 5 due 
to forecast strong southwesterly shear east of the trough.
 
Key Messages:
 
1. Nolo is expected to remain south of the Big Island of Hawaii
through Saturday before turning westward and moving away from the
island. Tropical storm conditions are expected to begin on the Big
Island tonight with hurricane conditions possible on Saturday,
particularly in areas of steep terrain. Residents should follow
advice given by local officials, including evacuating if told to do
so.
 
2. The time to finish preparations for significant heavy rain and
flooding impacts on the Big Island is now as heavy rain increases in
both coverage and intensity late today. Periods of heavy rain are
expected to continue across the Big Island and Maui through the
weekend. Life-threatening, catastrophic flooding and mudslides are
possible, especially in areas of steep terrain across the eastern
and southern portions of the Big Island and Maui. Across the
remainder of Hawaii, lesser rainfall totals are expected, with
isolated flooding possible.
 
3. Large and damaging waves are likely along portions of the
Big Island's coastline into the weekend.
 
4. A Tropical Storm Watch is in effect for Maui County where
tropical storm conditions are possible beginning on Saturday.
Interests elsewhere in Hawaii should closely monitor the latest
forecast updates and ensure that they have their preparedness plans
in place.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  25/2100Z 16.5N 155.4W   90 KT 105 MPH
 12H  26/0600Z 16.9N 155.3W   95 KT 110 MPH
 24H  26/1800Z 17.1N 155.7W   95 KT 110 MPH
 36H  27/0600Z 17.0N 157.0W  100 KT 115 MPH
 48H  27/1800Z 16.8N 158.8W  110 KT 125 MPH
 60H  28/0600Z 17.2N 160.8W  125 KT 145 MPH
 72H  28/1800Z 18.4N 162.6W  120 KT 140 MPH
 96H  29/1800Z 21.5N 164.4W   95 KT 110 MPH
120H  30/1800Z 23.5N 165.0W   70 KT  80 MPH
 
$$
Forecaster Blake