669
WTPZ45 KNHC 092046
TCDEP5
HURRICANE SIMON DISCUSSION NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL EP202026
300 PM CST FRI OCT 09 2026
AN INTERMITTENT WARM SPOT IN THE CDO OF SIMON HAS BEEN PRESENT SINCE
THIS MORNING, CO-LOCATED WITH A SMALL PINHOLE-LIKE EYE NOTED IN
VISIBLE IMAGERY. THE INITIAL INTENSITY OF 90 KT IS BASED PRIMARILY
ON THE LATEST TAFB DVORAK FIX, THOUGH THIS IS VERY UNCERTAIN DUE TO
THE VERY SMALL SIZE OF SIMON AND INTENSITY ESTIMATES RANGE FROM
AROUND 65 KT (DMINT) TO 97 KT (RCM-1 SAR). THE SAR DATA THIS MORNING
INDICATED THE SYSTEM HAS AN RMW NEAR 5 N MI, HIGHLIGHTING HOW SMALL
IT IS.
SIMON HAS CONTINUED TO STRENGTHEN TODAY, ALTHOUGH AT A SLIGHTLY
SLOWER RATE SINCE THIS MORNING. FURTHER RAPID INTENSIFICATION IS
STILL ANTICIPATED BUT THE EXACT TIMING OF WHEN THE RATE MIGHT PICK
UP AGAIN IS HIGHLY UNCERTAIN. SMALL HURRICANES LIKE SIMON ARE
PARTICULARLY SUSCEPTIBLE TO LARGE AND RAPID FLUCTUATIONS IN
INTENSITY. IN THE SHORT TERM, NO CHANGES OF NOTE WERE MADE TO THE
NHC INTENSITY FORECAST, WHICH REMAINS AT THE HIGH END OF THE
GUIDANCE ENVELOPE.
THE MAIN CHALLENGE WITH THIS FORECAST IS HOW SENSITIVE IT IS TO THE
EXACT TRACK SIMON TAKES OVER THE NEXT 2 DAYS AND WHETHER OR NOT IT
MOVES INLAND OVER THE MEXICAN STATES OF COLIMA AND JALISCO. A TRACK
SLIGHTLY EAST OF THE NHC OFFICIAL FORECAST TRACK WILL CAUSE SIMON TO
QUICKLY DISSIPATE AND MINIMIZE THE THREAT OF WIND IMPACTS FARTHER
NORTH IN MEXICO. HOWEVER, A TRACK JUST TO THE WEST WOULD LIKELY
ALLOW SIMON TO MOVE MUCH FARTHER NORTH AS A HURRICANE. AT THIS TIME,
THE DIFFERENCE BETWEEN THESE TRACK SCENARIOS IS LESS THAN THE
AVERAGE ERROR OF NHC FORECASTS. MOST OF THE DETERMINISTIC GLOBAL
MODELS SHIFTED SLIGHTLY EAST THIS CYCLE, BUT ENSEMBLE GUIDANCE
INDICATES BOTH SCENARIOS ARE STILL PLAUSIBLE. THE NHC TRACK AND
INTENSITY FORECAST THEREFORE IS LARGELY UNCHANGED AND CONTINUES TO
SHOW SIMON TRACKING FARTHER NORTH THAN IT MIGHT REALISTICALLY MAKE
IT TO EMPHASIZE THAT RISK.
KEY MESSAGES:
1. CATASTROPHIC WIND AND LIFE-THREATENING STORM SURGE IMPACTS ARE
LIKELY ALONG A PORTION OF THE WEST-CENTRAL COAST OF MEXICO, AND A
HURRICANE WARNING IS IN EFFECT FROM PUNTA SAN TELMO TO PUNTA MITA.
PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE COMPLETED BY
LATE TODAY.
2. HEAVY RAINFALL ASSOCIATED WITH SIMON WILL IMPACT PORTIONS OF
SOUTHWESTERN MEXICO THROUGH THIS WEEKEND. THIS RAINFALL WILL PRODUCE
LIFE-THREATENING FLOODING AND MUDSLIDES, ESPECIALLY IN AREAS OF
STEEP TERRAIN.
3. SWELLS WILL AFFECT PORTIONS OF THE SOUTHWESTERN AND WEST-CENTRAL
COAST OF MEXICO THROUGH THE WEEKEND. THESE SWELLS ARE LIKELY TO
CAUSE LIFE-THREATENING SURF AND RIP CURRENT CONDITIONS. PLEASE
CONSULT PRODUCTS FROM YOUR LOCAL WEATHER OFFICE.
FORECAST POSITIONS AND MAX WINDS
INIT 09/2100Z 16.2N 104.7W 90 KT 105 MPH
12H 10/0600Z 16.6N 104.9W 110 KT 125 MPH
24H 10/1800Z 17.5N 105.0W 125 KT 145 MPH
36H 11/0600Z 18.6N 105.1W 115 KT 130 MPH
48H 11/1800Z 20.0N 105.3W 95 KT 110 MPH...INLAND
60H 12/0600Z 21.4N 105.5W 75 KT 85 MPH...OVER WATER
72H 12/1800Z 22.8N 105.8W 60 KT 70 MPH...INLAND
96H 13/1800Z 24.6N 106.4W 30 KT 35 MPH...POST-TROP/INLAND
120H 14/1800Z...DISSIPATED
FORECASTER D. ZELINSKY
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