952
WTPZ45 KNHC 050833
TCDEP5
TROPICAL STORM OCTAVE DISCUSSION NUMBER 21
NWS NATIONAL HURRICANE CENTER MIAMI FL EP152025
200 AM PDT SUN OCT 05 2025
SATELLITE IMAGERY INDICATES THAT OCTAVE REMAINS A COMPACT TROPICAL
CYCLONE, WITH THE DIAMETER OF ITS CENTRAL DENSE OVERCAST (CDO) NEAR
150 MILES. INTERMITTENT BURSTS OF DEEP CONVECTION CONTINUE NEAR THE
EMBEDDED CENTER, WITH CLOUD-TOP TEMPERATURES OCCASIONALLY EXCEEDING
−80 DEGREES C. SUBJECTIVE DVORAK CURRENT INTENSITY ESTIMATES ARE
4.0/65 KT FROM TAFB AND 3.5/55 KT FROM SAB, WHILE OBJECTIVE
ESTIMATES ARE AS HIGH AS 60 KT. AN ASCAT-B PASS AT 0534 UTC
DEPICTED THE SMALL AND COMPACT SYSTEM, WITH PEAK SURFACE WINDS JUST
OVER 50 KT AND TROPICAL-STORM-FORCE WINDS EXTENDING ONLY ABOUT 60 N
MI FROM THE CENTER. A BLEND OF THESE DATA SUPPORTS AN INITIAL
INTENSITY OF 60 KT FOR THIS ADVISORY.
OCTAVE IS NOW MOVING SLOWLY NORTH-NORTHEASTWARD AT ABOUT 3 KT, AND
THIS MOTION IS EXPECTED TO CONTINUE TODAY WHILE THE STORM GRADUALLY
TURNS NORTHEASTWARD WITHIN A WEAK STEERING PATTERN BETWEEN AN
UPPER-LEVEL TROUGH ALONG THE U.S. WEST COAST AND TROPICAL CYCLONE
PRISCILLA, WHICH IS DRIFTING NORTHWESTWARD WELL TO THE EAST OFF THE
SOUTHWESTERN COAST OF MEXICO. BEGINNING MONDAY, OCTAVE SHOULD TURN
EASTWARD AND GRADUALLY ACCELERATE. BY MIDWEEK, FORECAST UNCERTAINTY
INCREASES SIGNIFICANTLY AS OCTAVE BECOMES INCREASINGLY INFLUENCED BY
PRISCILLA’S EVOLUTION AND TRACK. THE NEW NHC FORECAST TRACK IS VERY
SIMILAR TO THE PREVIOUS ADVISORY AND CLOSELY FOLLOWS THE CONSENSUS
AIDS, WITH OCTAVE EXPECTED TO DISSIPATE BY DAY 5 (THURSDAY NIGHT) AS
IT BECOMES ABSORBED BY THE LARGER TROPICAL CYCLONE PRISCILLA.
OCTAVE HAS INTENSIFIED SLIGHTLY SINCE THE PREVIOUS ADVISORY, AND
WITH THE ENVIRONMENT REMAINING MARGINALLY CONDUCIVE FOR THE NEXT 12
TO 18 HOURS, SOME ADDITIONAL STRENGTHENING CANNOT BE RULED OUT.
GUIDANCE, HOWEVER, GENERALLY SUPPORTS THE INTENSITY HOLDING STEADY
DURING THIS PERIOD, WHICH IS REFLECTED IN THIS FORECAST THROUGH THE
DAY TODAY. THEREAFTER, INCREASING VERTICAL WIND SHEAR, COMBINED WITH
THE INTERACTION WITH PRISCILLA, SHOULD INDUCE A GRADUAL WEAKENING
TREND. OCTAVE IS FORECAST TO OPEN UP INTO A TROUGH AND BE ABSORBED
BY PRISCILLA BY THE END OF THE FORECAST PERIOD. THE INTENSITY
FORECAST REMAINS CLOSE TO THE PREVIOUS NHC ADVISORY AND NEAR THE
MIDDLE TO UPPER PORTION OF THE GUIDANCE ENVELOPE.
FORECAST POSITIONS AND MAX WINDS
INIT 05/0900Z 15.6N 124.1W 60 KT 70 MPH
12H 05/1800Z 15.9N 123.8W 60 KT 70 MPH
24H 06/0600Z 16.1N 122.9W 55 KT 65 MPH
36H 06/1800Z 16.1N 121.9W 50 KT 60 MPH
48H 07/0600Z 15.9N 120.7W 45 KT 50 MPH
60H 07/1800Z 15.5N 119.6W 40 KT 45 MPH
72H 08/0600Z 15.3N 118.4W 35 KT 40 MPH
96H 09/0600Z 16.3N 115.4W 30 KT 35 MPH
120H 10/0600Z...DISSIPATED
FORECASTER GIBBS (CPHC)
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