ZCZC MIATCDEP4 ALL TTAA00 KNHC DDHHMM HURRICANE NORBERT DISCUSSION NUMBER 16 NWS NATIONAL HURRICANE CENTER MIAMI FL EP142014 200 AM PDT SAT SEP 06 2014 Norbert continued to rapidly intensify through about 06Z. Since then, the hurricane appears to have peaked in intensity, with the eye becoming less distinct and the cold cloud tops in the eyewall becoming asymmetric. Satellite intensity estimates at 06Z were 115 kt from TAFB and 102 kt from SAB, while the CIMMS ADT estimates peaked at 110 kt. Based on these data, the initial intensity is increased to 105 kt as a compromise between these estimates and the decay of the cloud pattern since 06Z. The initial motion is now 315/7. The track forecast reasoning remains unchanged, as Norbert will be steered around the western periphery of a mid-level ridge centered over the southern United States through 48 hours. After that time, the ridge weakens as a mid-latitude trough moves into the U.S. West Coast, which should result in a weakening of the steering currents. The track guidance has come into better agreement that Norbert should move northeastward or eastward after 72 hours, with several of the models showing the remnants making landfall over the northern portion of the Baja California peninsula. The new forecast track reflects this change in the guidance by showing an northeastward and eastward drift after 72 hours. The new forecast track is a little to the right of the center of the guidance envelope through 48 hours, and after that it is slower than the consensus model TVCE. The forecast track takes Norbert over steadily decreasing sea surface temperatures. The cyclone should thus weaken through the forecast period. Despite the higher initial intensity compared to 6 hours ago, the guidance is in good agreement that Norbert should decay into a remnant low in about 3 days. The new intensity forecast is increased from that of the previous forecast through 36 hours, and then is similar to the previous forecast. The new forecast is in best agreement with the LGEM model. 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 06/0900Z 24.6N 113.4W 105 KT 120 MPH 12H 06/1800Z 25.2N 114.4W 100 KT 115 MPH 24H 07/0600Z 26.0N 115.6W 85 KT 100 MPH 36H 07/1800Z 26.9N 116.6W 65 KT 75 MPH 48H 08/0600Z 27.8N 117.2W 50 KT 60 MPH 72H 09/0600Z 29.5N 117.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 10/0600Z 30.0N 116.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 11/0600Z 30.0N 116.0W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Beven NNNN