864
WTPZ45 KNHC 090321 CCA
TCDEP5
HURRICANE SIMON DISCUSSION NUMBER 7...CORRECTED
NWS NATIONAL HURRICANE CENTER MIAMI FL EP202026
900 PM CST THU OCT 08 2026
CORRECTED MALFORMED NON-UNICODE CHARACTER IN THIRD PARAGRAPH.
SIMON HAS BECOME A HURRICANE THIS EVENING. THE SATELLITE
PRESENTATION CONSISTS OF A DEVELOPING SMALL, INTENSE, CENTRAL DENSE
OVERCAST WITH -82C COLD CLOUD TOPS, AND A PRIMARY CURVED BAND
WRAPPING INTO THE CENTER FROM THE NORTHWEST PART OF THE CYCLONE. THE
TAFB DVORAK SATELLITE INTENSITY ESTIMATE IS 65 KT, AS WELL AS THE
INITIAL INTENSITY FOR THIS ADVISORY.
SIMON'S WIND RADII WERE ADJUSTED BASED ON A 1920 UTC OSCAT-3
OVERPASS.
ALL CONDUCIVE OCEAN HEAT CONTENT, DYNAMIC, AND THERMODYNAMIC
ENVIRONMENTAL CONTRIBUTIONS INDICATE THAT SIMON SHOULD QUICKLY
INTENSIFY DURING THE NEXT 24-36 HRS. SUBSEQUENTLY, THE SHIPS RI
INDEX SHOWS A NEAR 70 PERCENT THAT THE CYCLONE INTENSITY WILL
INCREASE BY 30 KT IN 24 HRS. THIS SEEMS QUITE REASONABLE GIVEN THAT
SIMON'S INNER CORE IS RATHER SMALL, INDICATIVE OF A RECENT AMSR3 MI
PASS. ACCORDINGLY, THE OFFICIAL INTENSITY FORECAST WILL CONTINUE TO
PREDICT AN RI EVENT ON FRIDAY, WITH SIMON BECOMING A CATEGORY 4
HURRICANE WHILE HEADING TOWARD THE COAST OF WEST-CENTRAL MEXICO.
THE NHC INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ONE, IS CLOSE
TO THE HFIP-HCCA, AND NOW SHOWS A PEAK INTENSITY OF 120 KT ON
SATURDAY MORNING.
SIMON'S INITIAL MOTION IS ESTIMATED TO BE WEST-NORTHWESTWARD, OR
295/5 KT. A TURN TO THE NORTHWEST IS EXPECTED BY EARLY FRIDAY. 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 THAT HAVE BEEN TO THE LEFT OF THE FORECAST TRACK
OUTLIERS HAVE TRENDED EASTWARD DURING THE PAST 24 HOURS, AND NOW
ALIGN MORE WITH THE SKILLED HCCA AND GDMI AIDS. THEREFORE,
CONFIDENCE IN THE FORECAST TRACK IS INCREASING. THE OFFICIAL
FORECAST IS SLIGHTLY TO THE LEFT OF THE PREVIOUS ADVISORY AND A
LITTLE SLOWER TO CONFORM TO THE HCCA MODEL, WHICH INCLUDES THE
GOOGLE DEEPMIND TC ENSEMBLE MEAN.
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 09/0300Z 15.6N 104.6W 65 KT 75 MPH
12H 09/1200Z 16.1N 105.0W 85 KT 100 MPH
24H 10/0000Z 16.9N 105.2W 100 KT 115 MPH
36H 10/1200Z 17.8N 105.3W 120 KT 140 MPH
48H 11/0000Z 19.0N 105.3W 110 KT 125 MPH
60H 11/1200Z 20.4N 105.3W 75 KT 85 MPH...INLAND
72H 12/0000Z 21.6N 105.3W 35 KT 40 MPH...INLAND
96H 13/0000Z 23.3N 105.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 14/0000Z...DISSIPATED
FORECASTER ROBERTS
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