ZCZC MIATCDEP4 ALL TTAA00 KNHC DDHHMM HURRICANE NORBERT DISCUSSION NUMBER 17 NWS NATIONAL HURRICANE CENTER MIAMI FL EP142014 800 AM PDT SAT SEP 06 2014 First visible images reveal a pinhole eye surrounded by very deep convection. Nevertheless, after a rapid intensification observed on satellite last night, objective and subjective Dvorak T-numbers are decreasing, and only support an initial intensity of 100 kt. A portion of the circulation is already reaching cooler waters and moving into a more stable environment. This should result in a gradual weakening during the next 24 hours, with a faster rate of weakening thereafter. Norbert is expected to become a remnant low over the cold waters just west of the northern Baja California peninsula in 3 days or so. The best estimate of the initial motion is toward the northwest or 310 degrees at 7 knots. Norbert is forecast to be steered by the flow around the southwestern periphery of a mid-level ridge centered over the southwestern United States. In a 48 hours, the cyclone will reach the base of the mid-latitude westerlies and will begin to move northward and then northeastward. By then, Norbert is forecast to be a shallow cyclone, moving little in a weak low-level flow. There is high confidence in the short- term track forecast since there is a good guidance agreement. Beyond 3 days, global models either forecast Norbert to dissipate in situ near the west coast of the northern Baja California peninsula or continue to move the system eastward as a weak low or a trough. The NHC prefers the former global model solution. 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 06/1500Z 25.0N 114.1W 100 KT 115 MPH 12H 07/0000Z 25.6N 115.1W 80 KT 90 MPH 24H 07/1200Z 26.5N 116.4W 65 KT 75 MPH 36H 08/0000Z 27.3N 117.3W 50 KT 60 MPH 48H 08/1200Z 28.2N 117.8W 40 KT 45 MPH 72H 09/1200Z 29.5N 117.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 10/1200Z 30.0N 116.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 11/1200Z 30.0N 116.0W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Avila NNNN