Issued at 200 AM PDT Fri Oct 03 2025
000 WTPZ45 KNHC 030841 TCDEP5 Tropical Storm Octave Discussion Number 13 NWS National Hurricane Center Miami FL EP152025 200 AM PDT Fri Oct 03 2025 Octave remains a sheared tropical cyclone, with the low-level center mostly exposed and displaced east of a recent burst of deep convection. The latest subjective Dvorak current intensity estimates from TAFB and SAB are 3.5/55 kt and 3.0/45 kt, respectively, while the UW-CIMSS objective estimates have ranged between 35 and 44 kt during the past several hours. A recent 03/0435Z Metop-B ASCAT pass was helpful in determining the tropical-storm-force wind radii and the center location, and it also indicated peak winds of 38 kt. Based on a blend of these data, and accounting for some undersampling in the scatterometer data, the initial intensity is set at 45 kt for this advisory. Octave is estimated to be moving west-northwestward, or 290 degrees at 7 kt. This general motion is expected to continue through tonight as the cyclone is steered along the southern periphery of a weak subtropical ridge located to its north. Octave is forecast to slow considerably and turn northward by late Saturday, followed by a sharp eastward turn by late Sunday as a mid-level trough approaches from the northwest and the subtropical ridge to its east weakens due to the influence of a larger tropical cyclone developing offshore of the southwestern or west-central coast of Mexico. The new NHC track forecast is similar to the previous prediction and lies near a blend of the multi-model consensus aids. Octave will remain over warm waters and within a moist environment for the next few days. East-southeasterly vertical wind shear is expected to continue impacting the cyclone for the next 12 to 24 hours, which should inhibit strengthening. Beyond 24 hours, the shear is forecast to decrease to light levels, while the cyclone remains over waters near 27C and within a sufficiently moist environment. These conditions should allow for some modest strengthening over the weekend. By days 4 and 5, Octave is forecast to encounter increasing southeasterly shear and a drier mid-level environment, which should result in steady weakening. The official intensity forecast has been lowered slightly to account for a notable decrease among the various intensity aids. The forecast now lies above most of the intensity guidance throughout the period, and future forecasts may need to adjust the intensity downward further if the weakening trends in the guidance persist. FORECAST POSITIONS AND MAX WINDS INIT 03/0900Z 13.1N 120.4W 45 KT 50 MPH 12H 03/1800Z 13.6N 121.3W 45 KT 50 MPH 24H 04/0600Z 14.1N 122.6W 45 KT 50 MPH 36H 04/1800Z 14.6N 123.6W 50 KT 60 MPH 48H 05/0600Z 15.1N 124.0W 55 KT 65 MPH 60H 05/1800Z 15.5N 123.9W 55 KT 65 MPH 72H 06/0600Z 15.5N 123.3W 50 KT 60 MPH 96H 07/0600Z 15.4N 121.8W 40 KT 45 MPH 120H 08/0600Z 15.1N 119.4W 35 KT 40 MPH $$ Forecaster Jelsema (CPHC)
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