823
WTPZ45 KNHC 140846
TCDEP5
HURRICANE SIMON DISCUSSION NUMBER 28
NWS NATIONAL HURRICANE CENTER MIAMI FL EP202026
200 AM MST WED OCT 14 2026
PROXY-VISIBLE AND INFRARED SATELLITE IMAGES OF SIMON SHOW THE TINY
EYE OF THE HURRICANE HAS FILLED DURING THE PAST FEW HOURS. THERE HAS
ALSO BEEN A WARMING OF THE INNER CORE CLOUD TOPS, AND THE CENTRAL
DENSE OVERCAST HAS BECOME LESS SYMMETRIC. THESE CHANGES COULD BE THE
RESULT OF SOME NORTHERLY SHEAR AFFECTING SIMON AS DIAGNOSED BY
UW-CIMSS. THERE IS NO RECENT PASSIVE MICROWAVE DATA AVAILABLE TO
ASSESS THE INTERNAL STRUCTURE OF SIMON, BUT RECENT SCATTEROMETER
DATA AND DISTANT RADAR DATA FROM LOS CABOS INDICATE THAT THE
HURRICANE REMAINS VERY SMALL. THE INITIAL INTENSITY IS LOWERED
SLIGHTLY TO 90 KT, IN BEST AGREEMENT WITH THE LATEST DVORAK CI
NUMBER (5.0) FROM TAFB AND AN EARLIER 88-KT D-MINT ESTIMATE.
THE HURRICANE IS MOVING SLOWLY SOUTHWESTWARD (230/3 KT). IN THE NEAR
TERM, SIMON IS EXPECTED TO REMAIN WITHIN VERY WEAK STEERING
CURRENTS. THUS, IT IS LIKELY TO MEANDER WELL OFFSHORE OF
WEST-CENTRAL MEXICO DURING THE NEXT COUPLE OF DAYS, WITH THE MODEL
CONSENSUS GENERALLY FAVORING A SLOW SOUTHWESTWARD OR SOUTHWARD
MOTION THROUGH THURSDAY. FROM THERE, THE FUTURE TRACK WILL DEPEND ON
THE VERTICAL DEPTH OF SIMON AND ITS INTERACTION WITH AN UPPER-LEVEL
TROUGH OVER THE WESTERN UNITED STATES. THIS FEATURE SHOULD CAUSE
SIMON TO TURN NORTHWARD AT SOME POINT, BUT THERE IS LARGE SPREAD
AMONG THE TRACK MODELS AS TO WHEN AND WHERE THIS TURN OCCURS. THERE
HAS BEEN A SUBSTANTIAL WESTWARD SHIFT IN THE LONG-RANGE TRACK
GUIDANCE, WITH ALMOST ALL MODELS NOW BRINGING SIMON NEAR OR WEST OF
THE BAJA CALIFORNIA PENINSULA AT 72-120 H. THE NHC FORECAST HAS BEEN
ADJUSTED IN THE DIRECTION OF THE LATEST MULTI-MODEL CONSENSUS TO
REFLECT THIS TREND, BUT FUTURE ADJUSTMENTS WILL LIKELY BE REQUIRED.
SIMON'S SMALL SIZE MAKES IT SUSCEPTIBLE TO INTENSITY FLUCTUATIONS
BASED ON THE STATE OF ITS COMPACT INNER CORE AND SMALL CHANGES IN
THE ENVIRONMENTAL CONDITIONS. THE HURRICANE IS FORECAST TO DRIFT
OVER VERY WARM WATERS IN A FAIRLY WEAK SHEAR ENVIRONMENT DURING THE
NEXT DAY OR TWO. HOWEVER, THE MID-LEVEL ENVIRONMENTAL HUMIDITY IS
ONLY AROUND 50 PERCENT, AND EVEN SLIGHTLY STRONGER SHEAR THAN
FORECAST COULD DISRUPT THE CORE AND INDUCE SOME WEAKENING. THE
OFFICIAL NHC FORECAST SHOWS LITTLE NET CHANGE IN THE NEXT 24-36 H,
RECOGNIZING THAT SOME OF THE HURRICANE REGIONAL MODELS SHOW ANOTHER
ROUND OF STRENGTHENING COULD OCCUR DURING THIS PERIOD. THERE IS
HIGHER CONFIDENCE THAT THE AFOREMENTIONED TROUGH WILL IMPART
STRONGER VERTICAL WIND SHEAR OVER SIMON BY FRIDAY, WHICH SHOULD
INDUCE A STEADY WEAKENING TREND THROUGH THE WEEKEND.
SIMON CONTINUES TO BE A CHALLENGING STORM TO FORECAST, AND
CONFIDENCE REMAINS LOWER THAN NORMAL GIVEN THE WEAK STEERING,
PROXIMITY TO LAND, VERY SMALL SIZE, AND SIGNIFICANT MODEL SPREAD.
KEY MESSAGES:
1. SIMON COULD BE NEAR LAS ISLAS MARIAS ON THURSDAY, WHERE A
HURRICANE WATCH REMAINS IN EFFECT. INTERESTS IN WEST-CENTRAL MEXICO
AND BAJA CALIFORNIA SUR SHOULD CONTINUE TO CLOSELY MONITOR THE
LATEST UPDATES. ADDITIONAL WATCHES OR WARNINGS COULD BE REQUIRED
OVER THE NEXT DAY OR TWO.
2. LARGE SWELLS WILL LIKELY AFFECT PORTIONS OF THE COAST OF
WEST-CENTRAL MEXICO AND BAJA CALIFORNIA SUR OVER THE NEXT SEVERAL
DAYS. THESE SWELLS COULD CAUSE LIFE-THREATENING SURF AND RIP CURRENT
CONDITIONS.
FORECAST POSITIONS AND MAX WINDS
INIT 14/0900Z 19.8N 107.9W 90 KT 105 MPH
12H 14/1800Z 19.6N 108.0W 95 KT 110 MPH
24H 15/0600Z 19.4N 108.1W 90 KT 105 MPH
36H 15/1800Z 19.2N 108.3W 90 KT 105 MPH
48H 16/0600Z 19.6N 108.5W 80 KT 90 MPH
60H 16/1800Z 20.9N 109.1W 65 KT 75 MPH
72H 17/0600Z 22.4N 109.8W 50 KT 60 MPH
96H 18/0600Z 24.6N 111.1W 35 KT 40 MPH...POST-TROP/INLAND
120H 19/0600Z 27.1N 113.0W 25 KT 30 MPH...POST-TROP/INLAND
FORECASTER REINHART
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