436
WTPZ45 KNHC 150232
TCDEP5
TROPICAL STORM SIMON DISCUSSION NUMBER 31
NWS NATIONAL HURRICANE CENTER MIAMI FL EP202026
800 PM MST WED OCT 14 2026
SIMON REMAINS A TINY STORM. THE EARLIER AIR FORCE HURRICANE HUNTER
DATA ALONG WITH AN ASCAT-C PASS INDICATE THAT THE TROPICAL-
STORM-FORCE WIND FIELD IS VERY SMALL, ONLY EXTENDING UP TO 30 N MI
FROM THE CENTER. THE LAST PASS OF THE AIRCRAFT THROUGH THE CENTER
SUGGESTED THAT SIMON HAS FALLEN BELOW HURRICANE STRENGTH, AND THE
PRESSURE HAS RISEN TO ABOUT 991 MB. THE INITIAL INTENSITY IS
ESTIMATED TO BE AROUND 55 KT BASED ON A COMBINATION OF THE AIRCRAFT
DATA AND VARIOUS SATELLITE FIXES. SATELLITE IMAGES SHOW THAT SIMON
IS PRODUCING A CONCENTRATED AREA OF DEEP CONVECTION OVER THE CENTER
THAT HAS BEEN INCREASING IN COVERAGE OVER THE PAST FEW HOURS.
THE COMPACT STORM IS MOVING SOUTHWESTWARD AT ABOUT 4 KT. THE MODELS
SUGGEST THAT SIMON WILL MOVE EVEN SLOWER OR POSSIBLY STALL OVER THE
NEXT DAY OR SO AS IT REMAINS CAUGHT IN WEAK STEERING CURRENTS.
HOWEVER, A TURN TO THE NORTHWEST SEEMS LIKELY ON FRIDAY WHEN THE
SYSTEM MOVES ON THE EAST SIDE OF A DEEP-LAYER CUT OFF LOW. THE NHC
TRACK FORECAST HAS BEEN NUDGED TO THE LEFT OF THE PREVIOUS ONE,
TOWARD THE LATEST HCCA AND GDMI GUIDANCE.
SIMON HAS WEAKENED AT A RAPID RATE OF ABOUT 40 KT OVER THE PAST 24
HOURS. THIS HIGHLIGHTS HOW CHALLENGING IT IS TO PREDICT INTENSITY
CHANGES IN VERY COMPACT SYSTEMS LIKE THIS ONE. THE ENVIRONMENTAL
CONDITIONS APPEAR GENERALLY FAVORABLE FOR THE NEXT 12 TO 24 HOURS,
SO LITTLE CHANGE IN STRENGTH IS PREDICTED IN THE SHORT TERM.
HOWEVER, AFTER THAT TIME, A NOTABLE INCREASE IN SOUTHWESTERLY
VERTICAL WIND SHEAR AND INTRUSION OF DRY AIR SHOULD CAUSE THE SYSTEM
TO DECAY. THIS FORECAST IS QUITE A BIT LOWER THAN THE PREVIOUS ONE
GIVEN THE LOWER INITIAL INTENSITY AND TRENDING TOWARD THE MIDDLE OF
THE GUIDANCE ENVELOPE. IN FACT, IT WOULD NOT BE SURPRISING IF SIMON
WEAKENS FASTER THAN SHOWN HERE.
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 FEW DAYS.
THESE SWELLS COULD CAUSE LIFE-THREATENING SURF AND RIP CURRENT
CONDITIONS.
FORECAST POSITIONS AND MAX WINDS
INIT 15/0300Z 19.1N 108.6W 55 KT 65 MPH
12H 15/1200Z 19.0N 108.5W 55 KT 65 MPH
24H 16/0000Z 19.1N 108.6W 50 KT 60 MPH
36H 16/1200Z 19.7N 109.1W 45 KT 50 MPH
48H 17/0000Z 20.8N 110.3W 40 KT 45 MPH
60H 17/1200Z 21.7N 111.2W 35 KT 40 MPH
72H 18/0000Z 22.8N 112.3W 30 KT 35 MPH
96H 19/0000Z 24.6N 113.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 20/0000Z 26.6N 114.8W 20 KT 25 MPH...POST-TROP/REMNT LOW
FORECASTER CANGIALOSI
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