000 WTPZ42 KNHC 250237 TCDEP2 HURRICANE SANDRA DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP222015 800 PM MST TUE NOV 24 2015 Satellite imagery indicates that Sandra has continued to strengthen during the past several hours. The deep convection now wraps around the center, and there have been occasional attempts at eye formation. The initial intensity is increased to 65 kt based on a satellite intensity estimate from TAFB, a 65 kt estimate from the CIMSS ADT, and an earlier CIMSS AMSU estimate of 60 kt. The initial motion is 290/10. The hurricane is currently being steered by a mid-level ridge extending from southern Mexico westward over the Pacific. However, a strong deep-layer trough moving southeastward over the western United States should erode the ridge north of Sandra during the next couple of days. This evolution should cause the cyclone to turn northward in about 48 hours and recurve northeastward into the westerlies thereafter. There has been little change in the track guidance since the last advisory. Thus, the new track forecast is similar to the previous forecast in calling for Sandra to pass near the southern end of the Baja California Peninsula in about 72 hours, followed by landfall in northwestern Mexico between 72-96 hours. The new forecast lies near the center of the track guidance envelope. Sandra has rapidly intensified during the past 24 hours, and this trend is likely to continue as the hurricane remains in a light vertical shear environment and over warm sea surface temperatures. The Rapid Intensification Index of the SHIPS model shows better than a 60 percent chance of a 40 kt increase in strength during the next 24 hours and an almost 80 percent chance of a 25 kt increase. Based on this, the intensity forecast has been adjusted upward to show Sandra becoming a major hurricane in 36 hours, and this part of the forecast could be conservative. After 36 hours, the cyclone is expected to encounter strong southwesterly vertical shear, and all of the guidance forecasts rapid weakening before landfall over mainland Mexico. After landfall, Sandra should dissipate quickly over the mountains of northwestern Mexico. Overall, the new intensity forecast lies near the upper edge of the guidance envelope and is in best overall agreement with the Florida State Superensemble. It is too soon to know exactly how Sandra will affect portions of the southern Baja California peninsula or the west coast of mainland Mexico. However, a watch may be required on Wednesday, and interests in those areas should monitor the progress of Sandra. FORECAST POSITIONS AND MAX WINDS INIT 25/0300Z 12.0N 107.9W 65 KT 75 MPH 12H 25/1200Z 12.6N 109.3W 75 KT 85 MPH 24H 26/0000Z 14.0N 110.4W 90 KT 105 MPH 36H 26/1200Z 15.8N 110.9W 100 KT 115 MPH 48H 27/0000Z 17.7N 111.1W 90 KT 105 MPH 72H 28/0000Z 22.0N 109.0W 60 KT 70 MPH 96H 29/0000Z 26.0N 106.0W 20 KT 25 MPH...INLAND 120H 30/0000Z...DISSIPATED $$ Forecaster Beven