120 
 WTPZ45 KNHC 132046
 TCDEP5
  
 TROPICAL STORM OCTAVE DISCUSSION NUMBER   4
 NWS NATIONAL HURRICANE CENTER MIAMI FL       EP152013
 200 PM PDT SUN OCT 13 2013
  
 DURING THE PAST 6 HOURS...OUTER BAND CONVECTION HAS DISSIPATED WHILE
 INNER CORE CONVECTION HAS MADE SOMEWHAT OF A COMEBACK.  THE INNER
 CORE CONVECTION NOW CONSISTS OF A SMALL RING OF CONVECTION ABOUT
 100 NMI IN DIAMETER WITH A 25 NMI DIAMETER EYE FEATURE EMBEDDED
 NEARLY IN THE CENTER OF THE CONVECTIVE RING.  HOWEVER...SEVERAL
 PASSIVE MICROWAVE IMAGES INDICATE THAT THE MID-/UPPER-LEVEL EYE
 FEATURE IS TILTED MORE THAN 20 NMI TO THE NORTH OF THE LOW-LEVEL
 CENTER. SATELLITE INTENSITY ESTIMATES HAVE JUMPED SHARPLY TO
 T4.0/65 KT FROM TAFB AND T3.5/55 KT FROM SAB SINCE THE PREVIOUS
 ADVISORY...BUT A 1639Z ASCAT-B OVERPASS ONLY REVEALED 35-40 KT
 WINDS WITHIN 20 NMI EAST OF THE CENTER...AND A 1725Z ASCAT-A
 OVERPASS ONLY INDICATED 45 KT IN THE EASTERN EYEWALL. THIS SUGGESTS
 THAT OCTAVE MIGHT NOT BE AS STRONG AS THE SATELLITE SIGNATURES
 INDICATE. THE INITIAL INTENSITY BLENDS THESE ESTIMATES AND IS
 GENEROUSLY SET TO 55 KT. UW-CIMSS SHEAR ANALYSES INDICATE THAT
 OCTAVE IS EXPERIENCING 15-20 KT OF SOUTHERLY MID-LEVEL SHEAR THAT
 IS UNDERCUTTING THE OTHERWISE FAVORABLE 6 KT OF 850-200 MB SHEAR...
 WHICH EXPLAINS THE NORTHWARD TILT OF THE EYE FEATURE. SOME
 ADDITIONAL STRENGTHENING IS POSSIBLE DURING THE NEXT 12 HOURS OR
 SO...BUT THE TILTED EYE FEATURE...ALONG WITH THE RATHER COMPACT
 SIZE OF THE CYCLONE...MEANS THE OCTAVE SHOULD QUICKLY WEAKEN ONCE
 IT MOVES OVER MUCH COOLER WATERS IN ABOUT 18-24 HOURS. AFTER
 THAT...STEADILY INCREASING SOUTHWESTERLY SHEAR SHOULD DECOUPLE THE
 LOW- AND UPPER-LEVEL CIRCULATIONS...RESULTING IN OCTAVE BECOMING A
 REMNANT LOW BY 96 HOURS...IF NOT SOONER.
  
 THE INITIAL MOTION ESTIMATE IS 335/11 KT. OCTAVE SHOULD CONTINUE TO
 MOVE AROUND THE WESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE
 THROUGHOUT THE FORECAST PERIOD. THE CYCLONE SHOULD GRADUALLY SLOW
 DOWN AND TURN NORTHWARD BY MONDAY AND TOWARD THE NORTH-NORTHEAST
 AND NORTHEAST ON TUESDAY. BY WEDNESDAY...A VERTICALLY SHALLOW AND
 WEAK OCTAVE COULD BECOME NEARLY STATIONARY AS IT APPROACHES THE
 SOUTHWESTERN COAST OF THE BAJA CALIFORNIA AND COMPLETELY DECOUPLES.
 THE MID-/UPPER-LEVEL CIRCULATIONS AND THE ASSOCIATED MOISTURE
 PLUME...HOWEVER...SHOULD CONTINUE TO MOVE NORTHEASTWARD AND SPREAD
 LOCALLY HEAVY RAINS ACROSS BAJA AND NORTHERN MEXICO AND INTO THE
 SOUTHWESTERN U.S.  THE NHC FORECAST TRACK IS SIMILAR TO THE
 PREVIOUS TRACK...AND IS CLOSE TO A BLEND OF THE TCVE AND FSSE
 MODELS.
  
 DESPITE THE RECENT STRENGTHENING OF OCTAVE...THE CURRENT TRACK
 AND INTENSITY FORECASTS...PLUS AVAILABLE INTENSITY GUIDANCE...DOES
 NOT WARRANT ANY TROPICAL STORM WATCHES OR WARNINGS FOR THE BAJA
 CALIFORNIA PENINSULA.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  13/2100Z 19.2N 112.7W   55 KT  65 MPH
  12H  14/0600Z 20.6N 113.5W   55 KT  65 MPH
  24H  14/1800Z 22.3N 113.7W   45 KT  50 MPH
  36H  15/0600Z 23.7N 113.6W   35 KT  40 MPH
  48H  15/1800Z 24.6N 113.2W   30 KT  35 MPH
  72H  16/1800Z 25.1N 113.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
  96H  17/1800Z 26.0N 112.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 120H  18/1800Z...DISSIPATED
  
 $$
 FORECASTER STEWART