ZCZC MIATCDEP4 ALL TTAA00 KNHC DDHHMM HURRICANE NORBERT DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL EP142014 200 AM PDT FRI SEP 05 2014 Norbert has changed little in organization during the past several hours. The hurricane continues to have a large central dense overcast with cloud tops colder than -80C. However, microwave data shows that the convection under the overcast is asymmetric and occurring mainly south of the center. Subjective and objective Dvorak estimates are unchanged and the initial intensity remains 80 kt. The initial motion is a somewhat uncertain 330/7. The cyclone is expected to move generally northwestward around the southwestern portion of a mid-level ridge over northern Mexico during the next 3 days or so. The track guidance for this part of the forecast has changed little since the last advisory, with all of the models and the official forecast keeping the center offshore of the Baja California peninsula. However, as mentioned in the previous package, only a slight deviation to the right of the track would bring hurricane-force winds to the coast. After 3 days, there continues to be a large spread in the guidance, with the GFS and NAVGEM calling for Norbert to recurve toward the northeast, while the ECMWF, UKMET, and Canadian models forecasting it to stall west of the northern Baja California peninsula. This part of the forecast again compromises between these extremes by showing a slow northward motion. Norbert should weaken during the forecast period as it moves over gradually decreasing sea surface temperatures and interacts with land. The new intensity forecast is similar to the previous forecast in showing Norbert weakening to a tropical storm in about 48 hours and degenerating to a remnant low by 96-120 hours. The intensity forecast generally lies between the SHIPS model and the intensity consensus. Moisture from the remnants of Dolly and the Pacific ITCZ is being advected northward by the outer circulation of Norbert across northern Mexico and into the southwestern United States. This could result in heavy rains and life-threatening flash flooding in these areas during the next few days. Please see information from your local weather office for more details. FORECAST POSITIONS AND MAX WINDS INIT 05/0900Z 22.5N 111.4W 80 KT 90 MPH 12H 05/1800Z 23.4N 112.2W 75 KT 85 MPH 24H 06/0600Z 24.4N 113.3W 70 KT 80 MPH 36H 06/1800Z 25.3N 114.6W 65 KT 75 MPH 48H 07/0600Z 26.1N 115.8W 55 KT 65 MPH 72H 08/0600Z 27.5N 117.5W 35 KT 40 MPH 96H 09/0600Z 28.5N 118.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 10/0600Z 29.0N 118.0W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Beven NNNN