Tropical Storm Nolo

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WTPA42 PHFO 241450
TCDCP2
 
Tropical Storm Nolo Discussion Number  16
NWS Central Pacific Hurricane Center Honolulu HI   EP152026
Issued by NWS National Hurricane Center Miami FL
500 AM HST Thu Sep 24 2026

Satellite images indicate that Nolo is gradually becoming better
organized, with very deep convection in a curved band on the
southern and western side of the circulation.  Additionally, a GPM
pass from overnight indicated that an inner core is forming,
although the eastern side is fragmented.  Intensity estimates are
rising, and the current wind speed is set to 50 kt as a blend of
the lower subjective and higher objective values.
 
Nolo has not moved much during the last several hours but should
begin to move northward and north-northeastward later today due to
a mid-latitude trough dropping over the northwestern Hawaiian
Islands.  The trough is forecast to move westward by Saturday with
a building ridge north of the main Hawaiian Islands, causing a
sharp westward turn this weekend.  The big question is how close
does Nolo get before making that turn, with notable run-to-run
inconsistencies in much of the guidance.  Similar to the last
cycle, the bulk of the models have shifted slightly northward, and
the new NHC forecast is moved in that direction.  This remains a 
more uncertain forecast than normal given the large unresolved
north-south spread, with other possible complicating terrain 
influences of the Big Island (like we saw with Hurricane Lala last 
month).  Therefore, the long-range portion of the forecast is 
essentially unchanged.
 
With the formation of an inner core, conditions appear to be coming
together for rapid intensification given the other conducive
environmental factors of warm SSTs, low shear and high mid-level
moisture.  Nolo is likely to become a hurricane by tonight and 
reach major hurricane strength as it nears the Big Island on 
Saturday.  The new forecast is raised from the previous one, just 
below the HCCA aid, which has done well this year in these 
strengthening episodes.  Note that a track closer to the Big Island 
could substantially increase the threat of damaging winds, 
particularly over higher terrain, along exposed ridges, and in areas 
downwind of the ridges.
 
Key Messages:

1. Nolo is expected to strengthen into a hurricane today as it 
moves northward to north-northeastward, potentially making its 
closest approach to the Big Island of Hawaii as a major hurricane on 
Saturday. A Hurricane Watch remains in effect for the Big Island, 
and residents there should follow advice given by local officials, 
including evacuating if told to do so. A Hurricane Warning will 
likely be required for the Big Island later today.

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 and 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 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 portions of the 
Big Island's coastline into the weekend.

4. Interests elsewhere in Hawaii should closely monitor the 
latest forecast updates and ensure that they have their preparedness 
plans in place. Tropical Storm Watches may be required for other 
islands later today or on Friday.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/1500Z 14.9N 156.2W   50 KT  60 MPH
 12H  25/0000Z 15.2N 156.2W   65 KT  75 MPH
 24H  25/1200Z 16.1N 155.8W   80 KT  90 MPH
 36H  26/0000Z 17.1N 155.4W   95 KT 110 MPH
 48H  26/1200Z 17.8N 155.4W  100 KT 115 MPH
 60H  27/0000Z 18.0N 156.4W  105 KT 120 MPH
 72H  27/1200Z 18.1N 158.2W  105 KT 120 MPH
 96H  28/1200Z 19.0N 162.0W  105 KT 120 MPH
120H  29/1200Z 21.6N 164.4W   90 KT 105 MPH
 
$$
Forecaster Blake