Tropical Cyclone Discussion
Issued by NWS
Issued by NWS
909 WTPZ44 KNHC 131435 TCDEP4 Tropical Storm Norbert Discussion Number 16 NWS National Hurricane Center Miami FL EP142026 500 AM HST Sun Sep 13 2026 Norberts overnight burst of convection has faded since the previous advisory, however proxy-visible satellite imagery shows that a new convective burst appears to be developing. Water vapor imagery shows that there is still plenty of dry air surrounding the system. The latest TAFB Dvorak fix came in with an intensity of 45 kt, and the UW-CIMSS objective intensity estimates are in the range of 37-43 kt. Therefore the initial intensity remains at 45 kt for this advisory. The initial motion is estimated to be 285/10 kt. The storm is expected to move west-northwestward to westward as it moves to the south of a low- to mid-level subtropical ridge. The track guidance continue to show good agreement on this general heading of the cyclone. The current NHC track forecast has been nudged a little right of the previous forecast track and remains close to the multi-model consensus (HCCA) and the Google DeepMind (GDMI) ensemble mean. Some fluctuations in intensity are possible in the short term as Norbert remains in a marginal environment. The cyclone is contending with mid-level dry air intrusions and light west-southwesterly vertical wind shear. After 12 h, the wind shear is expected to increase, which should result in a generally weakening trend. Around 60 h, the simulated GFS and ECMWF satellite imagery shows that the cyclone should lose organized deep convection and it is therefore expected to become a post-tropical remnant low and then dissipated around 72 h. The current NHC intensity forecast is in line with the latest guidance including the HCCA and GDMI. FORECAST POSITIONS AND MAX WINDS INIT 13/1500Z 18.2N 132.7W 45 KT 50 MPH 12H 14/0000Z 18.6N 134.4W 45 KT 50 MPH 24H 14/1200Z 19.0N 137.0W 40 KT 45 MPH 36H 15/0000Z 19.4N 139.7W 35 KT 40 MPH 48H 15/1200Z 19.7N 142.4W 35 KT 40 MPH 60H 16/0000Z 19.8N 145.1W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 16/1200Z...DISSIPATED $$ Forecaster Katz/Brown