WTPA44 PHFO 052039 TCDCP4 HURRICANE JIMENA DISCUSSION NUMBER 41 NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP132015 1100 AM HST SAT SEP 05 2015 JIMENA HAS ALL THE SIGNS OF A SHEARED WEAKENING TROPICAL CYCLONE IN THE SATELLITE IMAGERY THIS MORNING. LOW LEVEL CLOUD LINES IN THE VISIBLE IMAGERY INDICATE THAT THE LOW LEVEL CIRCULATION CENTER IS SOUTHWEST OF THE REMAINING DEEP CONVECTION AND THE UPPER LEVEL OUTFLOW IS LIMITED TO JUST THE NORTHEASTERN SEMICIRCLE. THE LOW LEVEL CENTER POSITION IS SUPPORTED BY 37 GHZ DATA IN THE SSMI PASSES FROM 1431...1611 AND 1616 UTC. THE DETERIORATING CONDITION OF JIMENA IS NOT SURPRISING CONSIDERING 27 KT OF VERTICAL SHEAR FROM THE WEST-SOUTHWEST BASED ON THE CIMSS 1800 UTC ANALYSIS. DVORAK INTENSITY ESTIMATES CHECKED IN AT 4.5/77 KT FROM PHFO AND JTWC...AND 3.5/55 KT FROM SAB. THE UW/CIMSS 1800 UTC ADT ESTIMATE WAS 59 KT. BASED ON AN AVERAGE OF THESE ESTIMATES...THE CURRENT INTENSITY FOR THIS ADVISORY IS 65 KT WHICH IS BARELY A HURRICANE...AND THIS MAY BE GENEROUS. SATELLITE ALTIMETER DATA FROM ABOUT 1530 UTC WERE USED TO EXPAND THE 12 FT SEAS RADII IN THE NORTHERN SEMICIRCLE. THE INITIAL MOTION FOR THIS ADVISORY IS 325/7 KT AS JIMENA MOVES BETWEEN A LARGE MID- AND UPPER-LEVEL TROUGH TO THE WEST AND A RIDGE TO THE NORTH AND EAST. THE GLOBAL MODELS STRENGTHEN THE RIDGE TO THE NORTH...THEN DEVELOP AN ANTICYLONE TO THE NORTHWEST OF JIMENA AFTER 72 HOURS. THIS WILL RESULT IN A WESTWARD TURN FOLLOWED BY A SLIGHTLY SOUTH OF WEST TRACK IN THE 96 TO 120 HOUR TIME FRAME. THE MAIN DYNAMICAL MODELS ARE IN GENERAL AGREEMENT WITH THIS SCENARIO THROUGH 48 HOURS WITH INCREASING SPREAD IN THE SOLUTIONS AFTERWARD. THE CURRENT FORECAST IS CLOSE TO THE PREVIOUS FORECAST WITH SMALL NUDGES TOWARD THE GFS AND ECMWF CONSENSUS...GFEX...THROUGHOUT THE FORECAST PERIOD. THE LARGE MID- AND UPPER LEVEL TROUGH WEST OF THE MAIN HAWAIIAN ISLANDS IS RESULTING IN WEST-SOUTHWESTERLY VERTICAL WIND SHEAR ACROSS JIMENA. THE WEST-SOUTHWESTERLY SHEAR IS EXPECTED TO CONTINUE...THEN GRADUALLY SHIFT TO THE WEST-NORTHWEST. THE FORECAST TRACK ALSO KEEPS THE TROPICAL CYCLONE OVER SEA SURFACE TEMPERATURES JUST ABOVE 26.5C. THE COMBINED PERSISTENCE OF THE VERTICAL WIND SHEAR AND THE BARELY ADEQUATE SEA SURFACE TEMPERATURES SHOULD CONTINUE TO RESULT IN A WEAKENING OF JIMENA THROUGH THE FORECAST PERIOD. THE MAIN QUESTION AT THIS TIME IS HOW FAST THE WEAKENING WILL OCCUR. SHIPS IS THE MOST AGGRESSIVE AND CALLS FOR DISSIPATION BY 72 HOURS. HWRF AND GFDL ALSO SHOW WEAKENING BUT ARE MORE CONSERVATIVE THAN SHIPS. THE FORECAST WEAKENS JIMENA STEADILY AND IS CLOSE TO THE PREVIOUS FORECAST AND THE INTENSITY CONSENSUS. FORECAST POSITIONS AND MAX WINDS INIT 05/2100Z 21.8N 146.7W 65 KT 75 MPH 12H 06/0600Z 22.7N 147.3W 60 KT 70 MPH 24H 06/1800Z 23.9N 148.2W 55 KT 65 MPH 36H 07/0600Z 24.8N 149.3W 50 KT 60 MPH 48H 07/1800Z 25.2N 150.3W 45 KT 50 MPH 72H 08/1800Z 25.1N 153.0W 35 KT 40 MPH 96H 09/1800Z 24.5N 156.5W 35 KT 40 MPH 120H 10/1800Z 24.5N 160.0W 30 KT 35 MPH $$ FORECASTER KODAMA