625 
WTPA44 PHFO 311458
TCDCP4
 
Tropical Storm Lowell Discussion Number  16
NWS Central Pacific Hurricane Center Honolulu HI   EP122026
Issued by NWS National Hurricane Center Miami FL
500 AM HST Mon Aug 31 2026

Lowell consists of a large central dense overcast with very cold 
cloud tops.  A 31/1047 UTC AMSR2 pass indicates the low-level center 
is rapidly becoming better organized underneath the convective 
canopy.  The latest subjective Dvorak estimates from PHFO and JTWC 
range from 45-55 kt, and objective estimates are a bit lower than 
the subjective estimates.  The initial intensity is raised to 55 kt 
based on the improved structure noted on the AMSR2 pass.
 
The initial motion is just south of due west, or 260 degrees at 12 
kt.  A mid-level ridge north of Lowell will be the primary steering 
mechanism for the next few days.  Lowell should move generally 
westward to west-northwestward during that time.  Thereafter, model 
spread increases as Lowell slows.  A west-northwestward motion is 
forecast after day 4 as Lowell feels some pull from a mid- to 
upper-level trough located well to its north.  The HCCA and Google 
DeepMind ensemble (GDMI) are the fastest and farthest south models. 
The latest NHC forecast track is slightly to the left of the 
previous track, but not quite as far south as the GDMI.
 
The moderate easterly shear that has been affecting Lowell appears 
to be diminishing.  Lowell seems poised to take advantage of warm 
waters to rapidly intensify, as shown by the HAFS-A and HAF-B 
models, which forecast Lowell becoming a major hurricane within the 
next 36 h.  SHIPS is forecasting weak vertical wind shear magnitudes 
over the next 5 days.  Given that the cyclone has developed a closed 
ring on 37 GHz microwave imagery, it is probably just a matter of 
time before we see Lowell strengthen significantly. The new NHC 
intensity forecast explicitly forecasts rapid intensification over 
the next 36 h, and then holds Lowell at category 3 strength through 
the day 5 period, since SSTs are forecast to still be between 28-29C 
and the shear is still forecast to be light at day 5.  The new 
intensity forecast is between the middle and higher end of the 
intensity guidance envelope.  This forecast is slightly above the 
intensity consensus, but not nearly as strong as the HCCA.

 
Key Messages:
 
1. Lowell is forecast to move generally westward and could be in the
vicinity of the Hawaiian Islands late this week. Interests in Hawaii
should monitor the progress of this storm.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  31/1500Z 12.8N 145.7W   55 KT  65 MPH
 12H  01/0000Z 12.9N 147.1W   65 KT  75 MPH
 24H  01/1200Z 13.1N 149.0W   80 KT  90 MPH
 36H  02/0000Z 13.4N 150.9W   95 KT 110 MPH
 48H  02/1200Z 13.6N 152.7W  100 KT 115 MPH
 60H  03/0000Z 14.0N 154.7W  105 KT 120 MPH
 72H  03/1200Z 14.4N 156.5W  105 KT 120 MPH
 96H  04/1200Z 14.9N 159.4W  105 KT 120 MPH
120H  05/1200Z 15.4N 161.7W  105 KT 120 MPH
 
$$
Forecaster Hagen