411 
 WTNT44 KNHC 261442
 TCDAT4
 
 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