920 
 WTPZ45 KNHC 070234
 TCDEP5
  
 TROPICAL STORM OLIVIA DISCUSSION NUMBER   3
 NWS NATIONAL HURRICANE CENTER MIAMI FL       EP152012
 800 PM PDT SAT OCT 06 2012
 
 OLIVIA IS STRENGTHENING THIS EVENING.  THE CLOUD PATTERN SHOWS A LOT
 OF CURVATURE WITH MANY BANDING FEATURES AND PERHAPS A DEVELOPING
 CENTRAL DENSE OVERCAST.  SUBJECTIVE DVORAK ESTIMATES FROM TAFB AND
 SAB ARE BOTH 45 KT...SO THAT VALUE WILL BE THE INITIAL WIND SPEED. 
 THERE DOES NOT SEEM TO BE MUCH IN THE LARGE-SCALE ENVIRONMENT
 TO PREVENT FURTHER INTENSIFICATION OF OLIVIA FOR THE NEXT DAY OR
 TWO WITH LIGHT SHEAR AND WARM WATER PRESENT.  AFTER THAT TIME...AN
 INCREASE IN SOUTHWESTERLY SHEAR SHOULD CAUSE THE CYCLONE TO START A
 WEAKENING TREND...WHICH COULD BE AIDED BY PLENTIFUL DRY AIR ALOFT. 
 THE OFFICIAL FORECAST IS CONSERVATIVELY RAISED FROM THE PREVIOUS ONE
 IN THE FIRST 48 H AND NOW SHOWS OLIVIA BECOMING A HURRICANE...NOT
 TOO FAR FROM THE LATEST INTENSITY CONSENSUS AND LGEM MODELS.  IT
 WOULD NOT BE TOO SURPRISING...GIVEN THE CONDUCIVE ENVIRONMENT...IF
 THE HIGHER PEAK INTENSITIES OF THE FSU SUPERENSEMBLE AND HWRF
 MODELS ENDED UP CLOSER TO REALITY. 
 
 THE TROPICAL STORM IS MOVING SLIGHTLY NORTH OF WEST AT ABOUT 9 KT
 BENEATH A LARGE FLAT RIDGE OVER THE EASTERN PACIFIC.  THE RIDGE
 SHOULD WEAKEN AND SLIDE EASTWARD OVER THE NEXT DAY OR SO DUE TO A
 STRONG LOW DIVING DOWN THE WEST COAST OF THE UNITED STATES.  THIS
 PATTERN CHANGE WILL LIKELY STEER OLIVIA MORE TO THE WEST-NORTHWEST
 AND NORTHWEST AT A SLOWER FORWARD SPEED DURING THE NEXT COUPLE OF
 DAYS.  BY TUESDAY...THE CYCLONE IS EXPECTED TO DECOUPLE FROM THE
 MID-LEVEL STEERING AND BECOME SHALLOWER...WHICH WOULD CAUSE OLIVIA
 TO TURN TO THE WEST OR WEST-SOUTHWEST IN THE LONGER RANGE.  THE
 FORECAST MODELS ARE IN REASONABLE AGREEMENT ON THIS SCENARIO...WITH
 THE BIGGEST DISCREPANCY BEING HOW LONG THE NORTHWESTWARD TRACK
 CONTINUES.  SINCE OLIVIA IS EXPECTED TO BE A LITTLE STRONGER THAN
 LAST TIME...THE NEW NHC FORECAST SHOWS THE CYCLONE GAINING A BIT
 MORE LATITUDE IN A COUPLE OF DAYS...BUT STILL ENDS UP ALONG THE
 PREVIOUS FORECAST TRACK BY DAYS 4 AND 5.
  
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  07/0300Z 14.0N 120.5W   45 KT  50 MPH
  12H  07/1200Z 14.6N 121.6W   55 KT  65 MPH
  24H  08/0000Z 15.4N 122.4W   60 KT  70 MPH
  36H  08/1200Z 16.0N 122.7W   65 KT  75 MPH
  48H  09/0000Z 16.3N 122.9W   60 KT  70 MPH
  72H  10/0000Z 16.0N 124.0W   45 KT  50 MPH
  96H  11/0000Z 15.5N 125.5W   35 KT  40 MPH
 120H  12/0000Z 15.0N 127.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
  
 $$
 FORECASTER BLAKE