388
WTPZ43 KNHC 251451
TCDEP3
TROPICAL STORM SONIA DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL EP182025
800 AM PDT SAT OCT 25 2025
SONIA APPEARS TO BE STRENGTHENING THIS MORNING. WHILE IT HAS BEEN
DIFFICULT TO PINPOINT SONIA'S CENTER, IT APPEARS TO BE WELL
EMBEDDED WITHIN THE CENTRAL DENSE OVERCAST. SUBJECTIVE DVORAK
ESTIMATES FROM TAFB AND SAB HAVE INCREASED TO 45 KT, AND VARIOUS
OBJECTIVE INTENSITY TECHNIQUES FROM UW-CIMSS HAVE ALSO INCREASED
WITH A MEAN VALUE NEAR 45 KT, SO THAT IS INITIAL INTENSITY FOR THIS
ADVISORY.
GIVEN THE HIGHER INITIAL INTENSITY, THE INTENSITY FORECAST FOR
SONIA HAS ALSO INCREASED A LITTLE, AND NOW SHOWS THE CYCLONE COULD
APPROACH HURRICANE STRENGTH TOMORROW. SEVERAL MODELS NOW SHOW SONIA
BECOMING A HURRICANE LATE THIS WEEKEND. THE NEW NHC INTENSITY
FORECAST IS JUST BELOW THE MODEL CONSENSUS, SO AN ADDITIONAL UPWARD
ADJUSTMENT COULD BE NECESSARY IN THE NEXT ADVISORY. BEYOND 2 DAYS,
SONIA IS STILL EXPECTED TO GRADUALLY WEAKEN AS A RESULT OF
INCREASING SHEAR AND DRIER MID-LEVEL AIR WRAPPING INTO ITS
CIRCULATION. MODELS STILL INDICATE THAT SONIA WILL LOSE ITS DEEP
CONVECTION BY DAY 4, AND IT WILL LIKELY DEGENERATE INTO A TROUGH BY
THE END OF THE FORECAST PERIOD.
SONIA HAS CONTINUED MOVING GENERALLY WEST. NO SUBSTANTIAL CHANGES TO
THE OFFICIAL TRACK FORECAST WERE MADE ASIDE FROM A SLIGHT NORTHWARD
TWEAK TO ACCOUNT FOR THE LATEST INITIAL POSITION OF THE TROPICAL
STORM. IN GENERAL, THE TROPICAL STORM SHOULD KEEP ON ITS CURRENT
HEADING TODAY, THEN SLOW AND TURN NORTHWESTWARD ON SUNDAY. BY THE
MIDDLE OF NEXT WEEK, SONIA SHOULD TURN BACK WESTWARD AS IT WEAKENS
AND BECOMES STEERED BY LOW-LEVEL FLOW. THE SPREAD IN THE MODEL
GUIDANCE IS UNUSUALLY HIGH, SO UNCERTAINTY IN THE TRACK IS SLIGHTLY
HIGHER THAN NORMAL, BUT THE NHC FORECAST IS STILL BASED ON A BLEND
OF HCCA AND GDM.
FORECAST POSITIONS AND MAX WINDS
INIT 25/1500Z 13.5N 118.1W 45 KT 50 MPH
12H 26/0000Z 13.6N 118.9W 50 KT 60 MPH
24H 26/1200Z 13.7N 119.7W 55 KT 65 MPH
36H 27/0000Z 13.9N 120.3W 60 KT 70 MPH
48H 27/1200Z 14.4N 121.0W 60 KT 70 MPH
60H 28/0000Z 14.9N 122.1W 55 KT 65 MPH
72H 28/1200Z 15.2N 123.3W 45 KT 50 MPH
96H 29/1200Z 15.0N 126.5W 30 KT 35 MPH...POST-TROPICAL
120H 30/1200Z...DISSIPATED
FORECASTER D. ZELINSKY
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