ZCZC MIATCDEP4 ALL TTAA00 KNHC DDHHMM HURRICANE NORBERT DISCUSSION NUMBER 14 NWS NATIONAL HURRICANE CENTER MIAMI FL EP142014 200 PM PDT FRI SEP 05 2014 Even though Norbert's cloud pattern remains fairly well organized in satellite imagery, cloud top temperatures in the central dense overcast have been slowly warming since this morning. Nevertheless, an Air Force Reserve Unit Hurricane Hunter aircraft reported maximum flight-level winds of 92 kt and peak SFMR winds of 76 kt in the northeastern quadrant, with a minimum pressure of 966 mb. These data support an initial intensity estimate of 80 kt for this advisory. While Norbert will be moving over above-normal SSTs of 27-29 deg C west of the southern Baja California peninsula during the next day or so, some northeasterly shear and an influx of drier and more stable air over the western part of circulation should contribute to a slow weakening. After that time, Norbert should reach substantially cooler waters and other thermodynamic variables should become much less favorable. These negative factors should result in a near-rapid weakening of the cyclone in 2-3 days, and remnant low status is forecast in 3 days. Encountering even cooler waters on day 4-5 and an increase in shear, Norbert should spin down further and dissipate just beyond the end of the forecast period. The NHC intensity forecast has not changed from the previous one and is near the multi-model consensus IVCN. Satellite and aircraft fixes indicate an initial motion toward the northwest or 325/7 kt. Some re-building of the mid-level ridge to the north of Norbert should cause a slight bend of the track toward the left during the next day or two. After that time, Norbert is expected to reach the western edge of the ridge and encounter a weakness caused by a mid-latitude trough advancing eastward from offshore of the California coast. This synoptic pattern should result in a gradual northward turn during with some decrease in forward speed. The mid-level center of the cyclone is likely to move rapidly northeastward into the southwestern United States on days 3-4, leaving the low-level center meandering offshore the west- central Baja California peninsula until dissipation. The NHC forecast track is little changed from the previous one, and lies on the far eastern side of the guidance envelope and east of the multi- model consensus TVCE. The hurricane-force wind radii have expanded in the northeastern quadrant based on SFMR data from the aircraft and now extend out 40 n mi from the center. Any deviation to the right of the forecast track would bring hurricane conditions onshore in the hurricane warning area. 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 05/2100Z 23.6N 112.2W 80 KT 90 MPH 12H 06/0600Z 24.3N 113.3W 75 KT 85 MPH 24H 06/1800Z 25.0N 114.4W 70 KT 80 MPH 36H 07/0600Z 25.8N 115.6W 60 KT 70 MPH 48H 07/1800Z 26.5N 116.6W 45 KT 50 MPH 72H 08/1800Z 28.4N 117.7W 30 KT 35 MPH...POST-TROP/REMNT LOW 96H 09/1800Z 29.2N 117.6W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 10/1800Z 29.5N 117.4W 15 KT 15 MPH...POST-TROP/REMNT LOW $$ Forecaster Kimberlain NNNN