495
WTPZ45 KNHC 150839
TCDEP5
TROPICAL STORM SIMON DISCUSSION NUMBER 32
NWS NATIONAL HURRICANE CENTER MIAMI FL EP202026
200 AM MST THU OCT 15 2026
THE SATELLITE PRESENTATION OF SIMON HAS NOT CHANGED MUCH SINCE THE
PRIOR ADVISORY. THE CENTER OF THE TROPICAL STORM REMAINS EMBEDDED
UNDERNEATH A SMALL, COLD CENTRAL DENSE OVERCAST. NO RECENT PASSIVE
MICROWAVE DATA IS AVAILABLE TO ASSESS THE INTERNAL STRUCTURE OF
SIMON, BUT CONVENTIONAL SATELLITE IMAGES INDICATE IT IS STILL A
SMALL STORM. THE INITIAL INTENSITY IS LOWERED SLIGHTLY TO 50 KT.
THIS IS BASED ON A BLEND OF THE TAFB DVORAK ESTIMATE (T3.5/55 KT)
AND THE LATEST UW-CIMSS OBJECTIVE ESTIMATES (43-52 KT), WITH SOME
CONSIDERATION GIVEN TO THE EARLIER AIRCRAFT DATA AS WELL.
SIMON HAS BEEN NEARLY STATIONARY FOR THE PAST FEW HOURS, BUT ITS
LONGER-TERM MOTION HAS BEEN A SOUTHWESTWARD DRIFT. THE STORM IS
LIKELY TO MEANDER WITHIN VERY WEAK STEERING CURRENTS DURING THE NEXT
12-24 H. BY FRIDAY, THE TRACK MODELS GENERALLY AGREE THAT SIMON WILL
TURN NORTHWESTWARD ON THE EAST SIDE OF A CUTOFF LOW NEAR THE
SOUTHWESTERN UNITED STATES. THIS SHOULD BRING THE CENTER OF THE
COMPACT TROPICAL CYCLONE NEAR BUT TO THE WEST OF BAJA CALIFORNIA
OVER THE WEEKEND. BASED ON THE LATEST TRACK GUIDANCE, THE NHC
FORECAST HAS BEEN SHIFTED SLIGHTLY LEFT OF THE PREVIOUS PREDICTION,
IN THE DIRECTION OF HCCA AND CLOSER TO THE TVCN SIMPLE CONSENSUS.
LITTLE CHANGE IN STRENGTH IS EXPECTED TODAY WHILE SIMON MEANDERS
OVER WARM WATERS AND VERTICAL WIND SHEAR OVER THE STORM GRADUALLY
STRENGTHENS. MUCH STRONGER SOUTHWESTERLY SHEAR IS FORECAST ON FRIDAY
AND INTO THE WEEKEND, WHICH SHOULD DISRUPT THE VERTICAL STRUCTURE OF
THE STORM AND INTRODUCE DRIER AIR INTO ITS CIRCULATION. THE NHC
FORECAST HAS ONCE AGAIN TRENDED WEAKER, FOLLOWING THE LATEST
MULTI-MODEL CONSENSUS AIDS. SIMON IS PREDICTED TO LOSE ORGANIZED
CONVECTION AND BECOME POST-TROPICAL BY 72 H. IT WOULD NOT BE
SURPRISING IF THIS OCCURS EVEN SOONER, AS SOME MODELS LIKE THE ECMWF
AND GOOGLE DEEPMIND SHOW SIMON DISSIPATING LATE THIS WEEKEND. GIVEN
THE LATEST TRACK FORECAST TRENDS AND THE SMALL SIZE OF SIMON, WIND
WATCHES ARE NOT NEEDED FOR BAJA CALIFORNIA SUR AT THIS TIME.
KEY MESSAGES:
1. INTERESTS IN BAJA CALIFORNIA SUR SHOULD CONTINUE TO CLOSELY
MONITOR THE LATEST UPDATES AS SIMON IS EXPECTED TO PASS NEAR OR WEST
OF THAT AREA THIS WEEKEND.
2. LARGE SWELLS WILL LIKELY AFFECT PORTIONS OF THE COAST OF
WEST-CENTRAL MEXICO AND BAJA CALIFORNIA SUR OVER THE NEXT COUPLE OF
DAYS. THESE SWELLS COULD CAUSE LIFE-THREATENING SURF AND RIP CURRENT
CONDITIONS.
FORECAST POSITIONS AND MAX WINDS
INIT 15/0900Z 19.2N 108.5W 50 KT 60 MPH
12H 15/1800Z 19.1N 108.5W 50 KT 60 MPH
24H 16/0600Z 19.6N 108.9W 45 KT 50 MPH
36H 16/1800Z 20.5N 109.8W 40 KT 45 MPH
48H 17/0600Z 21.3N 110.9W 35 KT 40 MPH
60H 17/1800Z 22.2N 112.0W 30 KT 35 MPH
72H 18/0600Z 23.2N 113.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 19/0600Z 26.0N 114.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 20/0600Z...DISSIPATED
FORECASTER REINHART
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