000 WTPZ42 KNHC 232042 TCDEP2 TROPICAL STORM BUD DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL EP022012 200 PM PDT WED MAY 23 2012 THE CONVECTION ASSOCIATED WITH BUD HAS DEVELOPED INTO AN ELONGATED SPIRAL BAND WRAPPING AROUND THE CENTER OF CIRCULATION. DVORAK ESTIMATES ARE UNCHANGED FROM THIS MORNING...SO THE INITIAL INTENSITY REMAINS 55 KT. TWO SEPARATE CIRA AMSU ESTIMATES OF WIND RADII FROM THIS MORNING ARE IN GOOD AGREEMENT THAT THE WIND FIELD IS LARGER THAN PREVIOUSLY ESTIMATED...AND THE WIND RADII HAVE BEEN ADJUSTED ACCORDINGLY. BUD HAS AN INITIAL MOTION OF 325/6 KT AND CONTINUES TO MOVE INTO A WEAKNESS IN THE SUBTROPICAL RIDGE OVER NORTHWESTERN MEXICO. THE CYCLONE WILL TURN NORTH AND NORTH-NORTHEASTWARD DURING THE NEXT 48 HOURS AS A LONGWAVE TROUGH DEEPENS OVER THE WESTERN UNITED STATES. A BUILDING MID-LEVEL HIGH OVER THE GULF OF MEXICO WILL THEN CAUSE BUD TO STALL JUST OFFSHORE THE MEXICAN COAST ON DAY 3. THERE HAS NOT BEEN ANY APPRECIABLE CHANGE IN THE TRACK GUIDANCE...AND THE UPDATED NHC TRACK FORECAST LIES VERY CLOSE TO THE PREVIOUS ONE. THE ECMWF CONTINUES TO BE THE MODEL THAT MOST CLOSELY APPROACHES THE MEXICAN COAST...AND THE OFFICIAL FORECAST THEREFORE LEANS ON THE EASTERN SIDE OF THE GUIDANCE ENVELOPE. ON DAYS 4 AND 5...A SLOW SOUTHWESTWARD MOTION SHOWN BY THE GFS AND ECMWF IS FAVORED OVER THE NORTHWARD MOTION TOWARDS THE GULF OF CALIFORNIA SHOWN BY THE GFDL AND HWRF. BUD SHOULD CONTINUE TO BE IN A LOW-SHEAR ENVIRONMENT FOR ANOTHER 48 HOURS OR SO...SO GRADUAL STRENGTHENING IS EXPECTED WHILE THE CYCLONE REMAINS OVER WATERS WARMER THAN 26.5C. AFTER 48 HOURS...A COMBINATION OF INCREASING SHEAR...ENVIRONMENTAL DRY AIR...WARM 200/250 MB TEMPERATURES...AND COOLER SSTS IS EXPECTED TO INDUCE WEAKENING. IN FACT...ALL THE GLOBAL MODELS SHOW THE VORTEX ASSOCIATED WITH THE CYCLONE DISSIPATING DURING THE FORECAST PERIOD. THE NHC INTENSITY FORECAST IS NEAR THE INTENSITY CONSENSUS DURING THE FIRST 48 HOURS AND THEN FOLLOWS THE WEAKENING INDICATED BY THE LGEM MODEL. INTERESTS ALONG THE SOUTHWESTERN COAST OF MEXICO SHOULD CONTINUE TO MONITOR THE PROGRESS OF BUD. BUD IS GROWING IN SIZE...AND EVEN IF THE CENTER DOES NOT REACH THE COAST...TROPICAL-STORM-FORCE WINDS AND HEAVY RAINFALL COULD STILL AFFECT PORTIONS OF THE JALISCO... COLIMA...AND MICHOACAN COASTS ON SATURDAY. FORECAST POSITIONS AND MAX WINDS INIT 23/2100Z 13.9N 107.8W 55 KT 65 MPH 12H 24/0600Z 14.5N 108.0W 65 KT 75 MPH 24H 24/1800Z 15.5N 107.5W 70 KT 80 MPH 36H 25/0600Z 16.7N 106.8W 65 KT 75 MPH 48H 25/1800Z 17.8N 106.3W 60 KT 70 MPH 72H 26/1800Z 18.5N 106.0W 45 KT 50 MPH 96H 27/1800Z 18.0N 106.5W 35 KT 40 MPH 120H 28/1800Z 17.5N 108.0W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ FORECASTER BERG