Tropical Cyclone Discussion

410
WTPA42 PHFO 290851
TCDCP2
 
Hurricane Nolo Discussion Number  35
NWS Central Pacific Hurricane Center Honolulu HI   EP152026
Issued by NWS National Hurricane Center Miami FL
1100 PM HST Mon Sep 28 2026
 
Hurricane Nolo remains a 100 kt major hurricane for now, in
agreement with the objective and subjective satellite intensity
estimates. The cyclone continues to endure moderate to strong
vertical wind shear, a consequence of an approaching mid- to
upper-level trough located to its northwest. An RCM-3 Synthetic
Aperture Radar (SAR) overpass from around 0455 UTC informed the
present analysis of the wind radii and provided a helpful center
fix.
 
The cyclone is now moving to the north-northwest at 330/13 kt. A
more northward motion is expected through Tuesday in response to the
mid- to upper-level trough. By Wednesday, Nolo is forecast to slow
down dramatically as it interacts with and ultimately merges with
the trough. Significant along-track uncertainty remains beyond 36
hr. The differences in forward motion depend largely on how quick
Nolo completes the merger with the trough and the strength of a
mid-level ridge that will build to the northwest. By the latter part
of this week, the mid-level ridge should steer the system generally
westward and nearly parallel to the northwestern Hawaiian Islands
within the Papahanaumokuakea National Monument. The track forecast
blends the previous one toward the latest HCCA and GDM guidance, and
attempts to reconcile these many complicated steering features.
 
Vertical wind shear is expected to increase even further, and this 
should continue to ventilate Nolo with dry and stable air over the 
next couple of days. The new intensity forecast shows Nolo weakening 
to a tropical storm by 48 hr, though this could happen sooner. 
Beyond 60 hr, Nolo is forecast to re-intensify as the vertical wind 
shear subsides, but dry mid-level atmospheric conditions could limit 
the pace and magnitude of intensification. The intensity forecast is 
at the upper-end of the guidance envelope at 12 hr due to recent 
trends in infrared satellite imagery, and after that time lies 
within the middle of the guidance envelope.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  29/0900Z 20.0N 164.3W  100 KT 115 MPH
 12H  29/1800Z 21.3N 164.5W   90 KT 105 MPH
 24H  30/0600Z 22.5N 164.6W   70 KT  80 MPH
 36H  30/1800Z 22.7N 164.9W   65 KT  75 MPH
 48H  01/0600Z 22.6N 165.4W   55 KT  65 MPH
 60H  01/1800Z 22.7N 166.0W   55 KT  65 MPH
 72H  02/0600Z 23.1N 167.0W   60 KT  70 MPH
 96H  03/0600Z 23.4N 168.5W   70 KT  80 MPH
120H  04/0600Z 24.1N 174.0W   75 KT  85 MPH