Advisories

000
WTPA42 PHFO 250850
TCDCP2
 
Hurricane Nolo Discussion Number  19
NWS Central Pacific Hurricane Center Honolulu HI   EP152026
Issued by NWS National Hurricane Center Miami FL
1100 PM HST Thu Sep 24 2026
 
An Air Force Reserve reconnaissance mission has provided some 
conflicting data regarding Nolo's current intensity. On one hand, 
the plane measured a peak flight-level wind of 81 kt in the 
southeastern eyewall, which reduces to an intensity of 70-75 kt. On 
the other hand, the central pressure has not fallen since the 
previous mission, with the latest dropsonde data suggesting around 
985 mb, and the 700-mb height has risen a bit. For now, the initial 
intensity is raised conservatively to 70 kt. Deep convection is 
becoming more symmetric around the eye, which is a bit ragged and 
elliptical.

The initial motion remains north-northeastward, or 030/4 kt, with 
Nolo being steered by a deep-layer trough located west of the 
Hawaiian Islands. This trough is expected to weaken and drift 
westward during the next 24-36 hours, with strong mid-level ridging 
taking its place over and north of Hawaii. As a result, Nolo is 
expected to come to a crawl by Friday night and early Saturday and 
then begin to move south of due west through Sunday. The track 
guidance has again shifted southward, responding to the 
strengthening ridge, and the NHC forecast lies near the northern 
edge of the envelope, closest to the Google DeepMind ensemble mean 
(GDMI). With nearly every other major model lying south of the 
official forecast, additional southward shifts in future 
advisories are possible, but not yet a guarantee.  The previously 
mentioned deep-layer trough is expected to re-amplify later in the 
forecast period, which is expected to cause Nolo to turn 
northwestward and then north-northwestward by Monday and Tuesday.

Various shear analyses suggest that Nolo is experiencing moderate 
deep-layer shear out of the south-southeast, which may be 
contributing to the broken eyewall on the east side. However, the 
shear is expected to abate during the next 24-36 hours, and along 
with warm sea surface temperatures, should support continued 
strengthening. There is a bit of model disagreement on exactly how 
much strengthening will occur, but it is noteworthy that the 
typically skillful HCCA model, as well as HAFS-A, shows Nolo 
reaching high-end category 4 strength in 3-4 days. As a result, the 
NHC intensity forecast has been increased slightly at that forecast 
time. Weakening is anticipated by days 4 and 5 due to a marked 
increase in southwesterly shear east of the trough.

 
Key Messages:
 
1. Nolo is expected 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 Friday night 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 on Friday. 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  25/0900Z 15.5N 155.6W   70 KT  80 MPH
 12H  25/1800Z 16.0N 155.4W   85 KT 100 MPH
 24H  26/0600Z 16.6N 155.2W   90 KT 105 MPH
 36H  26/1800Z 16.7N 155.6W   95 KT 110 MPH
 48H  27/0600Z 16.5N 156.7W  100 KT 115 MPH
 60H  27/1800Z 16.2N 158.5W  110 KT 125 MPH
 72H  28/0600Z 16.4N 160.5W  120 KT 140 MPH
 96H  29/0600Z 18.5N 163.5W  110 KT 125 MPH
120H  30/0600Z 21.3N 164.5W   85 KT 100 MPH
 
$$
Forecaster Berg