Advisories

000
WTPA42 PHFO 232056
TCDCP2
 
Tropical Storm Nolo Discussion Number  13
NWS Central Pacific Hurricane Center Honolulu HI   EP152026
Issued by NWS National Hurricane Center Miami FL
1100 AM HST Wed Sep 23 2026
 
The system has continued to become better organized this morning, 
with tighter curved banding features noted on satellite imagery.  
The low-level circulation remains on the southeastern side of most 
of the deep convection.  Satellite estimates are rising, and the 
bulk of the values now show this at or above 35 kt.  The initial 
intensity is set to 35 kt, marking the formation of a tropical 
storm. 

Nolo is moving west-northwestward at about 5 kt.  There is no 
change to the synoptic reasoning with a ridge located to the 
northeast of Hawaii forecast to weaken and push eastward as a mid-
latitude trough deepens over the northwestern Hawaiian islands.
This pattern is likely to the cause Nolo to slow down tonight and 
then turn north-northeastward by tomorrow with some increase in 
forward speed.  The trough is forecast to move westward this weekend 
as the ridge rebuilds north of Hawaii, which should force a sharp 
leftward turn while the cyclone is close to the Big Island.  It 
really depends on how far northeast Nolo gets before the ridge 
rebuilds, with the solutions that gain the most latitude in the 
next few days generally getting closest to Hawaii.  Although there 
has been a small southward shift in the overall guidance on this 
cycle, there is still a large spread approaching 250 n mi from 
north-to-south by the weekend.  The new forecast is nudged south on 
this advisory, but it should be considered low confidence.

The current disorganized structure would seem to promote only slow 
strengthening during the next day or so under otherwise favorable 
environmental conditions.  However, the system is likely to 
develop an inner core on Thursday, which could support rapid 
intensification given very warm waters, low shear and high 
mid-level moisture values.  Intensity guidance is a little higher 
than the last cycle, and the NHC forecast is raised slightly from 
day 3 and beyond, showing a major hurricane near and west of Hawaii.
 
Key Messages:
 
1. Tropical Storm Nolo is expected to strengthen into a hurricane 
on Thursday as it moves northward, potentially making its closest 
approach to the Big Island of Hawaii on Saturday. A Hurricane Watch 
is now in effect for the Big Island, and residents there should 
follow advice given by local officials, including evacuating if told 
to do so.

2. The time to prepare for significant heavy rain and flooding 
impacts on the Big Island is now, as heavy rain becomes more likely 
by Thursday and Friday. Periods of heavy rain are likely 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 Big Island and Maui. 
Across the remainder of Hawaii, lesser rainfall totals are expected, 
with isolated flooding possible.

3. Large and damaging waves are possible along the coast of the Big 
Island into the weekend.

4. Interests elsewhere in Hawaii should closely monitor the latest 
forecast updates and ensure that they have their preparedness plan 
in place. 
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  23/2100Z 14.5N 155.3W   35 KT  40 MPH
 12H  24/0600Z 14.7N 155.6W   40 KT  45 MPH
 24H  24/1800Z 15.1N 155.6W   50 KT  60 MPH
 36H  25/0600Z 15.8N 155.2W   65 KT  75 MPH
 48H  25/1800Z 16.7N 154.8W   80 KT  90 MPH
 60H  26/0600Z 17.5N 154.8W   90 KT 105 MPH
 72H  26/1800Z 17.8N 155.6W  100 KT 115 MPH
 96H  27/1800Z 17.6N 158.5W  105 KT 120 MPH
120H  28/1800Z 18.8N 161.8W  100 KT 115 MPH
 
$$
Forecaster Blake