816
WTPZ45 KNHC 072039
TCDEP5
TROPICAL STORM SIMON DISCUSSION NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL EP202026
300 PM CST WED OCT 07 2026
THE SYSTEM CONTINUES TO GRADUALLY BECOME BETTER ORGANIZED ON
SATELLITE IMAGERY WITH CONVECTIVE BANDING FEATURES BECOMING MORE
PROMINENT. THE LATEST SUBJECTIVE DVORAK CLASSIFICATION FROM TAFB
HAD A T-NUMBER OF 2.5, CORRESPONDING TO AN INTENSITY OF 35 KT. ON
THIS BASIS, THE CYCLONE IS BEING UPGRADED TO TROPICAL STORM SIMON
FOR THIS ADVISORY. THE STORM HAS DEVELOPED UPPER-LEVEL ANTICYCLONIC
OUTFLOW OVER ALL QUADRANTS OF THE CIRCULATION.
ASCAT-B SCATTEROMETER DATA SUGGESTED THAT THE CENTER OF THE CYCLONE
IS A LITTLE NORTH OF THE PREVIOUS TRACK, BUT THE OVERALL MOTION
STILL APPEARS TO BE TOWARD THE WEST-NORTHWEST, OR ABOUT 300/7 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 REMAINS ON THE RIGHT SIDE OF THE GUIDANCE ENVELOPE,
AND IS CLOSE TO THE GOOGLE DEEPMIND ENSEMBLE MEAN.
FOR THE NEXT FEW DAYS, SIMON IS EXPECTED TO REMAIN WITHIN AN
ENVIRONMENT OF LOW VERTICAL WIND SHEAR AND MOIST LOW- TO MID-LEVEL
AIR, WHILE MOVING OVER WATERS OF HIGH OCEANIC HEAT CONTENT. THESE
FACTORS SHOULD RESULT IN A SIGNIFICANT INCREASE IN INTENSITY THIS
WEEK, AND THE SYSTEM IS LIKELY TO STRENGTHEN INTO A HURRICANE,
AND THEN INTO A MAJOR HURRICANE LATER THIS WEEK. THE NHC INTENSITY
FORECAST IS A LITTLE ABOVE THE INTENSITY MODEL CONSENSUS, IVCN.
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.
2. THERE IS A RISK OF DANGEROUS WIND AND STORM SURGE IMPACTS ALONG
PORTIONS OF THE WEST-CENTRAL COAST OF MEXICO OVER THE WEEKEND AND
INTO EARLY NEXT WEEK, AND WATCHES COULD BE REQUIRED BY TONIGHT.
3. 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.
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 07/2100Z 15.5N 101.6W 35 KT 40 MPH
12H 08/0600Z 15.9N 102.7W 45 KT 50 MPH
24H 08/1800Z 16.3N 104.0W 55 KT 65 MPH
36H 09/0600Z 16.6N 104.8W 65 KT 75 MPH
48H 09/1800Z 17.0N 105.1W 75 KT 85 MPH
60H 10/0600Z 17.8N 105.2W 90 KT 105 MPH
72H 10/1800Z 18.9N 105.3W 100 KT 115 MPH
96H 11/1800Z 21.2N 105.6W 80 KT 90 MPH
120H 12/1800Z 23.6N 106.7W 80 KT 90 MPH...INLAND
FORECASTER PASCH
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