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ZCZC MIATCDEP2 ALL TTAA00 KNHC DDHHMM HURRICANE SANDRA DISCUSSION NUMBER 8 NWS NATIONAL HURRICANE CENTER MIAMI FL EP222015 800 AM MST WED NOV 25 2015 Sandra's convective pattern continues to become better organized, and a pinhole eye was observed in a 1201 UTC SSMIS microwave pass. An eye has also been apparent in the latest infrared satellite images. The intensity is increased to 85 kt based on Dvorak estimates of T5.0/90 kt from TAFB and T4.8/85 kt from the UW-CIMSS ADT. This intensity makes Sandra the strongest hurricane in the eastern North Pacific Ocean for this late in the year (the previous record was Hurricane Winnie of 1983, which reached an intensity of 80 kt on December 6). Low shear and warm sea surface temperatures should allow additional strengthening, and the SHIPS Rapid Intensification Index is still showing a 3 in 4 chance of a 30-kt increase during the next 24 hours. Therefore, the NHC official forecast continues to show Sandra reaching major hurricane strength during the next 12-24 hours, in best agreement with the SHIPS and LGEM models. Southwesterly shear is expected to increase to about 30 kt by 48 hours, and even higher thereafter, which should induce a fast weakening trend as Sandra approaches the Baja California peninsula and west coast of Mexico. The official intensity forecast after 24 hours is generally an update of the previous forecast and very close to the IVCN intensity consensus. The hurricane appeared to take a short-term jog to the west during the past 6-12 hours, but the longer-term average motion is still 295/9 kt. A subtropical ridge continues to extend from southern Mexico westward to near 20N110W, but the ridge is expected to be shunted eastward during the next 24 hours by an amplifying mid- to upper-level trough near the west coast of North America. This should cause Sandra to turn northwestward and northward during the next 36 hours and then northeastward by 96 hours. The track guidance is tightly clustered for the first 36 hours, but the spread increases after that time. The models which maintain a deeper circulation (i.e., the GFS and HWRF) show a sharper and faster recurvature, while the models which depict a weakening, shallower system (i.e., the ECMWF and UKMET) show a slower and more gradual recurvature. Since fast weakening is expected after 48 hours, the updated NHC track forecast is slowed down and shifted a bit westward during that period to be closer to the models that show a faster weakening trend. Although Sandra is forecast to weaken, 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. A watch may be required later today or tonight for portions of Mexico, and interests in those areas should monitor the progress of Sandra. FORECAST POSITIONS AND MAX WINDS INIT 25/1500Z 12.6N 109.5W 85 KT 100 MPH 12H 26/0000Z 13.5N 110.3W 95 KT 110 MPH 24H 26/1200Z 15.1N 110.9W 105 KT 120 MPH 36H 27/0000Z 16.9N 111.1W 95 KT 110 MPH 48H 27/1200Z 18.7N 110.9W 80 KT 90 MPH 72H 28/1200Z 22.5N 109.7W 40 KT 45 MPH 96H 29/1200Z 26.0N 106.5W 20 KT 25 MPH...POST-TROP/INLAND 120H 30/1200Z...DISSIPATED $$ Forecaster Berg NNNN