Issued at 500 AM HST Sat Sep 12 2026
000 WTPZ44 KNHC 121434 TCDEP4 Tropical Storm Norbert Discussion Number 12 NWS National Hurricane Center Miami FL EP142026 500 AM HST Sat Sep 12 2026 This morning's conventional satellite presentation consists of an amorphous blob of deep convection near the surface center that has been bursting intermittently during the past several hours. A 1132 UTC AMSR3 color composite microwave image indicated that the surface center remains near the southern edge of the convective mass. The objective and subjective intensity estimates are unchanged from 6 hours ago, and the initial intensity is set at 50 kt. Norbert's initial motion is estimated to be west-northwestward, or 285/9 kt, and this general motion should continue through the weekend. Afterward, a subtropical ridge to the north of the cyclone should steer Norbert in a westward heading through most of next week. There has been a shift toward the north of the majority of the skilled models from the previous advisory, which has in turn placed the forecast track in increasingly unfavorable environmental conditions. Consequently, the official track forecast has been shifted to the right of the previous one and lies close to the GDMI ensemble mean and HCCA consensus aid. Although Norbert has been moving over warm oceanic surface temperatures, marginal moisture content in the low- to mid-levels and southerly vertical shear have been suppressing the tropical cyclone's opportunity to strengthen significantly. In fact, only the HFIP HCCA and the Google DeepMind WeatherNext 2 (GDMI) show some strengthening during the short term. Through the remaining forecast period, because of the significant northward adjustment of the models, gradual weakening is expected beginning early next week, and Norbert should become a post-tropical remnant low early Thursday (day 4). The NHC intensity forecast follows suit and has been adjusted downward from the previous forecast beyond the 24 hours. Norbert's 34-kt wind radii have been expanded in the north semicircle based on a 0842 UTC OSCAT-3 scatterometer overpass. FORECAST POSITIONS AND MAX WINDS INIT 12/1500Z 17.3N 128.3W 50 KT 60 MPH 12H 13/0000Z 17.7N 129.7W 55 KT 65 MPH 24H 13/1200Z 18.1N 131.6W 55 KT 65 MPH 36H 14/0000Z 18.4N 133.7W 50 KT 60 MPH 48H 14/1200Z 18.6N 136.0W 45 KT 50 MPH 60H 15/0000Z 18.7N 138.5W 40 KT 45 MPH 72H 15/1200Z 18.6N 141.1W 35 KT 40 MPH 96H 16/1200Z 17.7N 146.3W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 17/1200Z 15.9N 151.7W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Roberts
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