Tropical Cyclone Discussion
245 WTPA42 PHFO 040837 TCDCP2 Hurricane Nolo Discussion Number 55 NWS Central Pacific Hurricane Center Honolulu HI EP152026 Issued by NWS National Hurricane Center Miami FL 1100 PM HST Sat Oct 03 2026 Nolo's inner-core continues to evolve this evening as its eyewall replacement cycle (ERC) progresses. On geostationary satellite, the small eye that was observed earlier today has largely decayed, with the coldest cloud tops now organizing in a broader ring as a larger ragged eye begins to clear out. Earlier, an AMSR3 microwave pass over Nolo at 0043 UTC showed an inner eyewall fragment remained on the 37 GHz channel, but a more recent 0549 UTC WSF-M pass showed the outer eyewall solidifying with the inner eyewall no longer observed. This evolution suggests the ERC will likely complete in the near future. For now, the subjective and objective intensity estimates have lowered some during Nolo's inner-core fluctuations, and the initial intensity is set at 95 kt this advisory. The hurricane continues to move quickly westward at an estimated motion of 275 degrees at 16 kt. A large subtropical ridge is draped to the north of Nolo and should continue to steer the tropical cyclone quickly westward for the next 3-4 days. On the forecast track, Nolo should cross the International Dateline during the day on Sunday. At the end of the forecast period, Nolo will likely reach the westward edge of the large-scale ridging, and some slowdown in its forward motion is anticipated. However, by this point in the forecast, Nolo's vertical depth could be more shallow. Substantial across-track uncertainty in the guidance exists, related to if the cyclone will begin to recurve northward or continue to maintain a slower westward motion. The latest NHC track forecast is very similar to the prior one, but just a little slower and further northward in the 96-120 h period, following the trends in the reliable HFIP Corrected Consensus Approach (HCCA), Google DeepMind ensemble mean (GDMI), and its newer version (WN3I). Assuming the current ERC completes cleanly over the next 6-12 h, Nolo is expected to start intensifying again while the tropical cyclone remains over 28-29 C sea-surface temperatures, and very low shear, currently diagnosed at 5 kt by UW-CIMSS. The NHC intensity forecast continues to show a 115 kt peak, which is still below the peak intensity reached in the raw output in both the 00 UTC HAFS-B and HMON runs. After 48 h, a very amplified upper-level flow pattern induced by recurving Typhoon Choi-Wan will lead to an abrupt increase in northeasterly shear over Nolo. This ramp-up in shear will likely advect very dry mid-level air into the cyclone's core. Thus, the NHC intensity forecast shows significant weakening occurring between 48-72 h, when the brunt of the shear will affect Nolo. By the latter half of the forecast period, this shear could lessen somewhat, but it is possible Nolo will continue to struggle as it remains embedded in a very dry mid-level air environment. The NHC intensity forecast remains on the high side of the guidance over the first 36-48 h, but falls back to the mean of the intensity aids thereafter. FORECAST POSITIONS AND MAX WINDS INIT 04/0900Z 23.6N 176.7W 95 KT 110 MPH 12H 04/1800Z 24.0N 179.2W 105 KT 120 MPH 24H 05/0600Z 24.8N 177.6E 110 KT 125 MPH 36H 05/1800Z 25.3N 174.5E 115 KT 130 MPH 48H 06/0600Z 25.4N 171.0E 110 KT 125 MPH 60H 06/1800Z 25.5N 166.7E 90 KT 105 MPH 72H 07/0600Z 26.1N 162.5E 65 KT 75 MPH 96H 08/0600Z 28.0N 155.5E 55 KT 65 MPH 120H 09/0600Z 30.0N 152.5E 50 KT 60 MPH