ZCZC MIATCDAT4 ALL TTAA00 KNHC DDHHMM HURRICANE CRISTOBAL DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL AL042014 1100 AM EDT TUE AUG 26 2014 The center of Cristobal is partially exposed to the northwest of the deep convection. Analyses from UW-CIMSS and the SHIPS model show about 20 kt of west-northwesterly shear over Cristobal and dry air has wrapped into the southwestern quadrant of the circulation as the cyclone interacts with a mid/upper-level trough to its west. The initial intensity remains 65 kt based on data from the last NOAA Hurricane Hunter aircraft mission. Model guidance indicates that the upper-level winds will become less hostile during the next day or so as Cristobal moves underneath and then north of the aforementioned trough, which should allow for some intensification. The NHC forecast shows Cristobal peaking in 36-48 hours in agreement with the latest IVCN intensity consensus. After that time, Cristobal will be moving over cooler waters and into a higher shear environment, which should result in the system losing tropical characteristics in about 3 days. However, as this occurs the global models show Cristobal moving in a favorable position for baroclinic intensification ahead of a mid-latitude trough. This should result in Cristobal transitioning to a powerful extratropical cyclone over the north Atlantic late in the period. The initial motion estimate is 010/10, as Cristobal is currently being pulled slowly northward by the mid/upper-level trough situated east of Florida. During the next day or so Cristobal will begin moving north-northeastward around the western side of the Atlantic subtropical ridge. Then the cyclone should accelerate into the mid-latitude westerlies during the remainder of the forecast period. Overall, the track model guidance remains in good agreement on this scenario. The new NHC track has been shifted a little to the west, or left, of the previous one through 48 hours and lies along the eastern edge of the guidance envelope. After that time, the NHC forecast is largely an update of the previous one and is close to the multi-model consensus. FORECAST POSITIONS AND MAX WINDS INIT 26/1500Z 27.2N 71.7W 65 KT 75 MPH 12H 27/0000Z 29.4N 71.3W 70 KT 80 MPH 24H 27/1200Z 31.9N 70.7W 70 KT 80 MPH 36H 28/0000Z 33.9N 69.1W 75 KT 85 MPH 48H 28/1200Z 36.4N 65.1W 75 KT 85 MPH 72H 29/1200Z 43.0N 51.5W 65 KT 75 MPH...POST-TROPICAL 96H 30/1200Z 50.0N 37.0W 60 KT 70 MPH...POST-TROP/EXTRATROP 120H 31/1200Z 58.0N 26.0W 50 KT 60 MPH...POST-TROP/EXTRATROP $$ Forecaster Brennan NNNN