781
WTPZ45 KNHC 080234
TCDEP5
TROPICAL STORM SIMON DISCUSSION NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL EP202026
900 PM CST WED OCT 07 2026
SIMON HAS CONTINUED TO BECOME BETTER ORGANIZED ON SATELLITE IMAGERY
OVER THE PAST 6 HOURS WITH A LARGE AREA OF DEEP CONVECTION AND
IMPROVED CURVED BANDING. A RECENT WSF-M MICROWAVE PASS ALSO SHOWS
IMPROVED CURVED BANDING STRUCTURE. THE LATEST SUBJECTIVE DVORAK
CLASSIFICATION FROM TAFB WAS 3.0/45 KT, AND THE INITIAL INTENSITY
HAS BEEN RAISED TO 45 KT ACCORDINGLY, AND THIS COULD BE
CONSERVATIVE.
ENVIRONMENTAL CONDITIONS ARE QUITE FAVORABLE FOR SIGNIFICANT
INTENSIFICATION. THE SHIPS RAPID INTENSITY INDEX INDICATES GREATER
THAN A 50 PERCENT CHANCE OF 55 KT OF STRENGTHENING OVER THE NEXT
48 H. MOST OF THE HURRICANE REGIONAL MODELS, AS WELL AS HCCA AND
GDMI SHOW SIGNIFICANT INTENSIFICATION OVER THE NEXT COUPLE OF DAYS,
AND THE NHC INTENSITY FORECAST HAS BEEN INCREASED ACCORDINGLY. THE
NHC FORECAST NOW INDICATES A 110 KT INTENSITY AT 60 AND 72 H, AND
THIS IS AT THE HIGH END OF THE MODEL SUITE, IN GOOD AGREEMENT WITH
THE HCCA MODEL.
THE INITIAL MOTION IS WEST-NORTHWESTWARD, OR 290 DEGREES AT 8 KT.
SIMON IS LIKELY TO CONTINUE THIS GENERAL WEST-NORTHWESTWARD MOTION
FOR THE NEXT DAY OR SO, TO THE SOUTH OF A WEAK MID-LEVEL RIDGE. BY
FRIDAY, THE SYSTEM SHOULD TURN NORTHWESTWARD AND THEN NORTHWARD
AHEAD OF A 500 MB TROUGH APPROACHING BAJA CALIFORNIA. IN 3-5 DAYS,
THE CYCLONE SHOULD MOVE GENERALLY NORTHWARD BETWEEN A MID-LEVEL
ANTICYCLONE AND THE TROUGH NEAR BAJA CALIFORNIA. THE OFFICIAL
FORECAST TRACK HAS BEEN SHIFTED A BIT TO THE LEFT FROM 12-60 HOURS,
BUT IS NEARLY ON TOP OF THE PREVIOUS TRACK FROM DAYS 3 TO 5, AND IS
QUITE SIMILAR TO THE LATEST HFIP CORRECTED CONSENSUS APPROACH
(HCCA). THE FORECAST TAKES SIMON TOWARD THE COAST OF WEST-CENTRAL
MEXICO AS A DANGEROUS MAJOR HURRICANE IN A FEW DAYS. THERE IS A
FAIR AMOUNT OF SPREAD IN THE GUIDANCE, AND THAT IS IMPORTANT TO NOTE
BECAUSE SIMON IS FORECAST TO BE MOVING NEARLY PARALLEL TO THE
COASTLINE IN ABOUT 72 HOURS WHEN IT NEARS WEST-CENTRAL MEXICO. A
TRACK FARTHER WEST WOULD KEEP SIMON OVER WATER LONGER, BUT A TRACK
FARTHER EAST WOULD MEAN A SOONER LANDFALL.
KEY MESSAGES:
1. SIMON IS EXPECTED TO STRENGTHEN INTO A HURRICANE BY THURSDAY
NIGHT AND APPROACH THE WEST-CENTRAL COAST OF MEXICO AS A MAJOR
HURRICANE ON SATURDAY. THERE IS A RISK OF DANGEROUS WIND AND STORM
SURGE IMPACTS ALONG PORTIONS OF THIS COAST OVER THE WEEKEND AND INTO
EARLY NEXT WEEK, AND WATCHES COULD BE REQUIRED OVERNIGHT INTO EARLY
THURSDAY.
2. HEAVY RAINFALL ASSOCIATED WITH SIMON WILL IMPACT PORTIONS OF
SOUTHWESTERN MEXICO LATER THIS WEEK AND INTO THE WEEKEND. THIS
RAINFALL MAY 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 08/0300Z 15.6N 102.5W 45 KT 50 MPH
12H 08/1200Z 15.8N 103.6W 60 KT 70 MPH
24H 09/0000Z 16.1N 104.6W 70 KT 80 MPH
36H 09/1200Z 16.4N 105.3W 85 KT 100 MPH
48H 10/0000Z 16.9N 105.5W 100 KT 115 MPH
60H 10/1200Z 17.8N 105.6W 110 KT 125 MPH
72H 11/0000Z 18.9N 105.5W 110 KT 125 MPH
96H 12/0000Z 21.6N 105.8W 90 KT 105 MPH
120H 13/0000Z 24.2N 106.8W 70 KT 80 MPH...INLAND
FORECASTER HAGEN
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