Tropical Cyclone Discussion
809 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