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Hurricane Polo rocketed from a tropical storm to a Category 5 hurricane in under 24 hours, reaching sustained winds near 180 mph (290 km/h). The National Hurricane Center says Polo weakened to Category 4 on Sept. 23 but had re‑intensified to Category 5 by the morning of Sept. 24.
How Polo strengthened so quickly
Meteorologists point to an unusually favorable combination of ocean and atmospheric conditions that allowed Polo to deepen remarkably fast. Warm sea surface temperatures provided abundant heat and moisture, while light wind shear and strong upper‑level outflow let thunderstorms organize and persist.
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Julian Heming, an environmental scientist at the U.K.’s Met Office, told Live Science that rapid intensification typically requires three elements: very warm water, low wind shear and upper‑air conditions that let air escape efficiently from the storm’s core. Polo also developed a compact, well‑defined inner core, focusing its energy into a relatively small area and accelerating intensification.
The El Niño link
Polo strengthened over waters warmed by the current strong El Niño event that has been present since June. El Niño forms when eastern tropical Pacific waters become warmer than average; the National Oceanic and Atmospheric Administration classifies El Niño conditions when those waters are at least 0.5°C (0.9°F) above normal.
Scientists sometimes call the present episode a “super” El Niño when sea surface anomalies exceed about 2°C, a label meant to convey its exceptional strength rather than a formal scientific category. The World Meteorological Organization has indicated this El Niño could be the most intense on record and may persist into early 2027, amplifying extreme weather patterns worldwide.
Risks for Mexico and the U.S. West Coast
As Polo moves northwest off Mexico’s southwest coast, forecasters expect heavy rain and dangerous surf even if the storm remains offshore. The NHC warned of up to 8 inches (20 centimeters) of rain in some areas and cautioned that flooding and mudslides could be life‑threatening.
- Flooding and landslides: Torrential downpours where terrain is steep and soils are saturated.
- Coastal hazards: Large swells, rip currents and very hazardous surf for beaches along the coast.
- Uncertain track: Models disagree on whether Polo will stay well offshore or turn northeast toward Mexico.
If the storm shifts northward, Southern California could see heavy rain, strong surf and heightened coastal hazards. For now, the NHC’s official forecast keeps the core offshore and moving northwest, but long‑range trajectory remains uncertain.
Where Polo ranks among Eastern Pacific storms
AccuWeather has described Polo as one of the strongest Eastern Pacific hurricanes on record, second only to Hurricane Patricia in 2015. Its rapid escalation highlights how powerful ocean‑atmosphere interactions can drive sudden changes in tropical cyclone intensity.
