450
WTPZ43 KNHC 280849
TCDEP3
TROPICAL STORM SONIA DISCUSSION NUMBER 15
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182025
200 AM PDT TUE OCT 28 2025
THE SATELLITE PRESENTATION OF SONIA HAS CHANGED LITTLE SINCE THE
PREVIOUS ADVISORY, WITH A SMALL AREA OF DEEP CONVECTION PERSISTING
OVER OR NEAR THE CYCLONE’S LOW-LEVEL CENTER. THE LATEST SUBJECTIVE
DVORAK CURRENT INTENSITY ESTIMATES FROM TAFB AND SAB ARE 2.0/30 KT
AND 1.5/25 KT, RESPECTIVELY, WHILE OBJECTIVE ESTIMATES FROM UW-CIMSS
RANGE FROM 33 TO 38 KT. A TIMELY 0507 UTC METOP-C ASCAT PASS
REVEALED A SWATH OF 35-KT WINDS, WITH A PEAK VECTOR OF 36 KT. TAKING
INTO ACCOUNT POSSIBLE UNDERSAMPLING IN THE SATELLITE-DERIVED WINDS
AND THE PERSISTENCE OF CONVECTION OVER OR NEAR THE CENTER FOR
ROUGHLY 12 HOURS, THE INITIAL INTENSITY IS RAISED TO 40 KT FOR THIS
ADVISORY.
SONIA IS MOVING WEST-NORTHWEST, OR 300 DEGREES, AT 7 KT. A TURN
TOWARD THE WEST IS EXPECTED LATER TODAY AS SONIA’S CIRCULATION
BECOMES SHALLOWER AND IS STEERED BY THE LOW-LEVEL FLOW. THE NHC
FORECAST HAS BEEN NUDGED SLIGHTLY NORTH OF THE PREVIOUS TRACK,
REFLECTING THE CONTINUED WEST-NORTHWEST MOTION OBSERVED SINCE THE
LAST ADVISORY. THE FORECAST TRACK LIES CLOSEST TO A BLEND OF THE
HFIP CORRECTED CONSENSUS AND GOOGLE DEEPMIND ENSEMBLE MEAN GUIDANCE.
SONIA’S DAYS APPEAR TO BE NUMBERED AS THE CYCLONE CONTINUES TO BE
AFFECTED BY MODERATE TO STRONG SOUTHERLY WIND SHEAR, ANALYZED NEAR
22 KT BY UW-CIMSS. THE SHEAR IS EXPECTED TO INCREASE SLIGHTLY
WITHIN ABOUT 12 HOURS, WHILE SONIA MOVES OVER GRADUALLY COOLING
WATERS AND INTO A DRIER MID-LEVEL ENVIRONMENT. SIMULATED SATELLITE
IMAGERY FROM THE GFS AND ECMWF INDICATES THAT DEEP CONVECTION SHOULD
COLLAPSE IN ABOUT 12 HOURS UNDER THESE INCREASINGLY HOSTILE
CONDITIONS. THIS IS EXPECTED TO RESULT IN GRADUAL WEAKENING, WITH
SONIA FORECAST TO BECOME A POST-TROPICAL REMNANT LOW TONIGHT AND
DISSIPATE ON THURSDAY. THE INTENSITY FORECAST IS UNCHANGED FROM THE
PREVIOUS ADVISORY AND REMAINS CLOSE TO A BLEND OF THE LATEST
CONSENSUS AND SHIPS GUIDANCE.
FORECAST POSITIONS AND MAX WINDS
INIT 28/0900Z 14.8N 122.8W 40 KT 45 MPH
12H 28/1800Z 15.0N 123.9W 35 KT 40 MPH
24H 29/0600Z 15.1N 125.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
36H 29/1800Z 15.0N 127.7W 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 30/0600Z 14.6N 129.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 30/1800Z...DISSIPATED
FORECASTER JELSEMA (CPHC)
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