634
WTPZ45 KNHC 031433
TCDEP5
TROPICAL STORM OCTAVE DISCUSSION NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL EP152025
800 AM PDT FRI OCT 03 2025
OCTAVE HAS CHANGED LITTLE DURING THE PAST SEVERAL HOURS. THE SYSTEM
STILL APPEARS TO BE SHEARED, AND SATELLITE INTENSITY ESTIMATES ARE
SIMILAR TO SIX HOURS AGO, SO THE INTENSITY IS HELD AT 45 KT FOR THIS
ADVISORY. THE OUTLOOK FOR OCTAVE IS RELATIVELY HIGH CONFIDENCE FOR
THE NEXT DAY OR SO. OCTAVE SHOULD CONTINUE MOVING WEST-NORTHWESTWARD
NEAR 7 KT, STEERED BY A SMALL MID-LEVEL RIDGE CENTERED BETWEEN
OCTAVE AND THE BAJA CALIFORNIA PENINSULA. DURING THAT TIME, IT
SHOULD ALSO REMAIN SOMEWHAT SHEARED WITH ITS INTENSITY ONLY
FLUCTUATING SLIGHTLY UP OR DOWN OVER THAT PERIOD. CONFIDENCE IN THE
NHC FORECAST IS HIGH THROUGH SATURDAY.
HOWEVER, BY SATURDAY EVENING, THE UNCERTAINTY IN THE FORECAST GROWS
SUBSTANTIALLY. FIRST, THE AFOREMENTIONED RIDGE IS EXPECTED TO
WEAKEN, RESULTING IN VERY WEAK STEERING FLOW FOR THE FOLLOWING
COUPLE OF DAYS. A TROUGH OVER THE FAR NORTHERN EAST PACIFIC WILL
PROBABLY CAUSE OCTAVE TO TURN AND DRIFT EASTWARD DURING THAT TIME.
AFTER THAT, ANOTHER LARGER DISTURBANCE TO OCTAVE'S EAST WILL LIKELY
ALSO INFLUENCE OCTAVE'S TRACK, POTENTIALLY CAUSING IT TO MOVE FASTER
TOWARD THE EAST BY THE MIDDLE OF NEXT WEEK. WITH STEERING CURRENTS
WEAK, ONLY SMALL CHANGES IN THE ENVIRONMENT COULD HAVE A LARGE
IMPACT ON OCTAVE'S TRACK. THE SPREAD IN THE TRACK GUIDANCE GROWS
SUBSTANTIALLY BEYOND 48 H, SO CONFIDENCE IN THE FORECAST IS MUCH
LOWER AT THAT POINT.
THE INTENSITY IS LIKEWISE UNCERTAIN BEYOND 24 TO 36 H. THE SHEAR
AFFECTING OCTAVE IS EXPECTED TO LESSEN, AND THE TROPICAL STORM
SHOULD BE IN AN ENVIRONMENT OTHERWISE CONDUCIVE FOR STRENGTHENING
FOR AT LEAST A DAY OR TWO. OCTAVE'S RELATIVELY SMALL SIZE COULD MAKE
IT SUSCEPTIBLE TO RELATIVELY QUICK CHANGES IN INTENSITY, UP OR
DOWN. ALL OF THE TRADITIONAL DYNAMICAL INTENSITY MODELS FORECAST
THAT OCTAVE WILL CHANGE LITTLE IN STRENGTH DURING THAT PERIOD. ON
THE OTHER HAND, GOOGLE DEEPMIND (GDM) ENSEMBLE SHOWS A VERY
DIFFERENT STORY WITH AN UNUSUALLY LARGE RANGE OF POSSIBILITIES
BETWEEN TROPICAL DEPRESSION AND MAJOR HURRICANE STRENGTH. THE NHC
FORECAST HAS NOT BEEN CHANGED, AND IS ON THE HIGH END OF THE
TRADITIONAL GUIDANCE, BUT BELOW THE GDM ENSEMBLE MEAN. BECAUSE OF
THIS DISCREPANCY, CONFIDENCE IN THE INTENSITY FORECAST IS LOW,
DESPITE THE FACT THAT NO CHANGES WERE MADE TO THE NHC FORECAST WITH
THIS ADVISORY.
FORECAST POSITIONS AND MAX WINDS
INIT 03/1500Z 13.4N 121.0W 45 KT 50 MPH
12H 04/0000Z 13.8N 122.0W 45 KT 50 MPH
24H 04/1200Z 14.4N 123.2W 45 KT 50 MPH
36H 05/0000Z 15.0N 123.9W 50 KT 60 MPH
48H 05/1200Z 15.4N 124.1W 55 KT 65 MPH
60H 06/0000Z 15.6N 123.7W 55 KT 65 MPH
72H 06/1200Z 15.7N 123.0W 50 KT 60 MPH
96H 07/1200Z 15.4N 121.2W 40 KT 45 MPH
120H 08/1200Z 15.0N 119.0W 35 KT 40 MPH
FORECASTER D. ZELINSKY
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