Advisories

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WTPA42 PHFO 251453
TCDCP2
 
Hurricane Nolo Discussion Number  20
NWS Central Pacific Hurricane Center Honolulu HI   EP152026
Issued by NWS National Hurricane Center Miami FL
500 AM HST Fri Sep 25 2026

Nolo continues on a gradual strengthening trend this morning.  On 
the last pass through the hurricane, Air Force Hurricane Hunters 
reported that the pressure had dropped to about 980 mb, and  
satellite imagery shows deepening convection in the ragged eyewall. 
On this basis, the initial intensity is set to 75 kt, which is also 
at the top end of the various satellite estimates.

The hurricane is moving north-northeastward at 4 kt, as it is being 
steered by a deep-layer trough located west of the Hawaiian Islands. 
This trough should begin to move away from Nolo on Saturday, 
causing the hurricane to drift westward while it is located south of 
Hawaii.  A westward motion with increasing forward speed is then 
expected by early Sunday due to a ridge re-building.  Model 
guidance has, unfortunately, not been very consistent on exactly 
when this westward turn occurs, as there has been a shift to the 
north on this cycle.  This new forecast is moved in that direction 
through the weekend, though still a fair distance south of Hawaii.  
At long range, Nolo should again encounter the aforementioned 
upper-level trough, now re-invigorated, which should cause a 
north-northwestward turn early next week.  No significant changes 
were made to the long-range NHC forecast. 

Nolo should further intensify today, though rapid intensification is 
not expected due to its large radius-of-maximum wind, moderate 
shear and some dry mid-level air in the northern semicircle.  The 
shear is forecast to weaken in about 36 hours, which should allow 
the hurricane to significantly intensify.  Additionally, Nolo could 
be moving over a patch of high ocean heat content, and model 
guidance is in better agreement on this system becoming rather 
strong by early next week.  The new forecast is similar to the 
previous one but raised just a bit through day 3 to come into 
better agreement with the typically skillful HCCA model. Weakening 
is 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 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  25/1500Z 16.0N 155.5W   75 KT  85 MPH
 12H  26/0000Z 16.7N 155.3W   90 KT 105 MPH
 24H  26/1200Z 17.1N 155.5W   95 KT 110 MPH
 36H  27/0000Z 17.1N 156.3W  100 KT 115 MPH
 48H  27/1200Z 16.9N 157.8W  110 KT 125 MPH
 60H  28/0000Z 16.9N 159.8W  120 KT 140 MPH
 72H  28/1200Z 17.4N 161.6W  120 KT 140 MPH
 96H  29/1200Z 20.2N 164.3W  100 KT 115 MPH
120H  30/1200Z 22.7N 164.8W   70 KT  80 MPH
 
$$
Forecaster Blake