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WTPZ45 KNHC 090846
TCDEP5
HURRICANE SIMON DISCUSSION NUMBER 8
NWS NATIONAL HURRICANE CENTER MIAMI FL EP202026
300 AM CST FRI OCT 09 2026
SIMON HAS QUICKLY STRENGTHENED THIS MORNING. A EUMETSAT METOP-B
MICROWAVE HUMIDITY SOUNDER (MHS) IMAGE REVEALED A SMALL BANDING EYE
FEATURE, AND THE IR-BD CURVE ENHANCEMENT INDICATES -83C COLD CLOUD
TOPS ASSOCIATED WITH A SMALL CENTRAL DENSE OVERCAST OVER THE
SURFACE CENTER. WATER VAPOR IMAGERY AND SATELLITE WIND DATA
INDICATE DEVELOPING CYCLONIC OUTFLOW ABOVE 200 MB. BASED ON THE
MUCH IMPROVED CLOUD PATTERN AND THE TAFB SUBJECTIVE INTENSITY
ESTIMATE OF T4.5 (77 KT), THE INITIAL INTENSITY IS INCREASED TO 80
KT.
SIMON'S SMALL, INTENSE INNER CORE, FAVORABLE ENVIRONMENTAL
CONDITIONS, LOW SHEAR, VERY WARM OCEANIC TEMPERATURES, AND HIGH
MID-LEVEL MOISTURE CONTENT ALL SUPPORT A RAPID INTENSIFICATION
EVENT, WHICH APPEARS TO BE WELL UNDERWAY. FURTHER SIGNIFICANT
STRENGTHENING IS EXPECTED, AND THE CYCLONE IS FORECAST TO BE A VERY
DANGEROUS MAJOR HURRICANE WHEN IT APPROACHES THE COAST OF MEXICO.
THE GUIDANCE ALSO SHOWS COMPACT SIMON QUICKLY WEAKENING AND OVER THE
HIGH MOUNTAINOUS TERRAIN BY EARLY NEXT WEEK. THE NHC FORECAST IS
ONCE AGAIN HEDGED TOWARD THE HIGH END OF THE GUIDANCE, IN BEST
AGREEMENT WITH THE HFIP-HCCA MODEL.
SIMON'S INITIAL MOTION IS ESTIMATED TO BE NORTHWESTWARD, OR
315/4 KT. A NORTHWARD MOTION IS FORECAST BY EARLY SATURDAY WHILE
HIGH PRESSURE OVER CENTRAL MEXICO WEAKENS AND SHIFTS EASTWARD, IN
RESPONSE TO AN AMPLIFYING MID-TROPOSPHERIC TROUGH APPROACHING BAJA
CALIFORNIA. THE HIRES GLOBAL MODELS (ECM/GFS/CMC/UKM), HAFS
HURRICANE MODELS AND THE NOAA GEFS AI ENSEMBLE MEAN CONTINUE TO
AGREE MORE WITH SIMON APPROACHING THE WEST-CENTRAL COAST OF MEXICO
ON SUNDAY. THE HCCA AND THE GOOGLE DEEPMIND ENSEMBLE MEAN HAVE
BEEN SOMEWHAT INCONSISTENT DURING THE PAST 2 CYCLES,
WINDSHIELD-WIPERING WITH A TRACK EITHER INLAND OR JUST OFFSHORE
BEYOND THE 48-HOUR PERIOD. ADDITIONALLY, THE ALONG-TRACK FORWARD
SPEEDS HAVE ALSO BECOME INCONSISTENT, WHICH HAS SLIGHTLY AFFECTED
THE WIND IMPACT TIMING. TO MINIMIZE THESE TRACK FORECAST
INCONSISTENCIES, THE NHC FORECAST BLENDS THE VARIOUS CONSENSUS AIDS
AND IS NUDGED TO THE RIGHT OF THE HCCA AND GDM ENSEMBLE MEAN
SOLUTIONS.
KEY MESSAGES:
1. SIMON IS EXPECTED TO APPROACH THE WEST-CENTRAL COAST OF MEXICO
AS A MAJOR HURRICANE ON SATURDAY.
2. LIFE-THREATENING WIND AND STORM SURGE IMPACTS ARE EXPECTED 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 FRIDAY.
3. HEAVY RAINFALL ASSOCIATED WITH SIMON WILL IMPACT PORTIONS OF
SOUTHWESTERN MEXICO THROUGH THIS WEEKEND. THIS RAINFALL MAY PRODUCE
LIFE-THREATENING FLOODING AND MUDSLIDES, ESPECIALLY IN AREAS OF
STEEP TERRAIN.
4. 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 09/0900Z 15.8N 104.5W 80 KT 90 MPH
12H 09/1800Z 16.1N 104.7W 100 KT 115 MPH
24H 10/0600Z 16.7N 104.9W 120 KT 140 MPH
36H 10/1800Z 17.6N 105.0W 125 KT 145 MPH
48H 11/0600Z 18.6N 105.1W 120 KT 140 MPH
60H 11/1800Z 19.9N 105.3W 110 KT 125 MPH...INLAND
72H 12/0600Z 21.4N 105.4W 80 KT 90 MPH...OVER WATER
96H 13/0600Z 23.7N 106.0W 60 KT 70 MPH...INLAND
120H 14/0600Z 24.9N 106.3W 35 KT 40 MPH...INLAND
FORECASTER ROBERTS
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