Tropical Storm Simon forms off Mexico with major-hurricane forecast and extreme rainfall risk
Event summary
The U.S. National Hurricane Center upgraded Tropical Depression Twenty-E to Tropical Storm Simon at 21:00 UTC October 7, with 40 mph winds and a forecast of potentially major-hurricane intensity near southwestern Mexico by Saturday.
CHRONOS Wire · October 8 · Alert 6
Publication details
- Published
- Updated
- Revision
- r497616
- Source
- National Hurricane Center
Cliff Notes
- The U.S. National Hurricane Center upgraded Tropical Depression Twenty-E to Tropical Storm Simon at 21:00 UTC October 7, with 40 mph winds and a forecast of potentially major-hurricane intensity near southwestern Mexico by Saturday.
The U.S. National Hurricane Center upgraded Tropical Depression Twenty-E to Tropical Storm Simon at 21:00 UTC October 7, with 40 mph winds and a forecast of potentially major-hurricane intensity near southwestern Mexico by Saturday. NHC Advisory 2 locates Simon near 15.5N 101.6W, about 175 miles south-southeast of Lázaro Cárdenas, and forecasts 8-12 inches of rainfall with localized 15-25 inches in Colima and Michoacán through Sunday. A major hurricane is a forecast possibility, not current observed intensity. No coastal watches were in force in Advisory 2. Important limitations: No coastal watch or warning in Advisory 2; no verified landfall or storm-caused fatalities at publication.
ELI5: Plain-English Explanation
A new tropical storm is near Mexico. Forecasters say it could grow much stronger and bring dangerous flooding even before its center reaches land.
Why Urgent Level 3
The forecast includes life-threatening flooding and mudslides and possible major-hurricane intensity near populated coasts.
What Changed
NHC upgraded the system from tropical depression to named tropical storm at 21:00 UTC October 7.
What Is Genuinely New
Official storm classification and updated rainfall/intensity projections.
CHRONOS Bottom Line
Confirmed tropical storm with significant forecast hazard, not yet a major hurricane.
Direct Effects
- Potential extreme rainfall, flooding and landslides
- Possible coastal wind, surf and surge impacts
Indirect / Second-Order Effects
- Disruption to roads, ports, tourism and regional logistics
- Agricultural and local infrastructure damage if forecasts verify
Market Reality Gap
Forecast Category 3 intensity is not current observed strength; the track cone and intensity can change.
Negative Evidence / Invalidation
No coastal watch or warning in Advisory 2; no verified landfall or storm-caused fatalities at publication.
Confirmation Signals
Subsequent NHC advisories, Mexico SMN watches, satellite and aircraft observations.
Invalidation Signals
Sustained weakening, an offshore track and rainfall forecasts materially lowered.
What Would Prove CHRONOS Wrong
Sustained weakening, an offshore track and rainfall forecasts materially lowered.
What Would Raise This to Level 4
Hurricane upgrade, coastal warnings, confirmed dangerous flooding or damage.
What Would Lower This Alert
Storm tracks away and rainfall threats decline.
Watch Windows
- Next NHC advisory at 03:00 UTC October 8
- October 9-12: forecast strengthening and possible land impacts
Uncertainties / Known Unknowns
Track, intensity, landfall timing, rainfall distribution and local terrain effects.
Detailed Analysis
NHC Advisory 2 locates Simon near 15.5N 101.6W, about 175 miles south-southeast of Lázaro Cárdenas, and forecasts 8-12 inches of rainfall with localized 15-25 inches in Colima and Michoacán through Sunday. A major hurricane is a forecast possibility, not current observed intensity. No coastal watches were in force in Advisory 2.
Affected Countries
- Mexico
Affected Industries
- Tourism
- Transport
- Agriculture
Affected Assets
- Mexico Pacific coast
- Colima
- Michoacán
Sources / Evidence
- 01Tropical Storm Simon Public Advisory 2National Hurricane Center
- 02Tropical Storm Simon Forecast Advisory 2National Hurricane Center