Hurricane Simon, the latest in a long progression<\/a> of tropical cyclones in the Eastern Pacific this season, passed close to the Mexican coast as a category 4 storm on October 11, 2026. Sustained winds reached 250 kilometers (155 miles) per hour as it crept north-northwest.<\/p>\n Simon\u2019s eye was about 50 kilometers (30 miles) offshore, between Manzanillo and Puerto Vallarta, when the VIIRS<\/a>\u00a0(Visible Infrared Imaging Radiometer Suite) on the\u00a0Suomi NPP<\/a> satellite acquired this image around 2:30 p.m. local time (20:30 Universal Time) on October 11.<\/p>\n By that time, sustained winds were about 210 kilometers (130 miles) per hour, according to the National Hurricane Center<\/a> (NHC), and the storm\u2019s inner core was brushing up against the coast. The topography of the Sierra Madre mountains appeared to temper the storm\u2019s intensity somewhat and shrink the size of its wind field, the NHC noted. Still, the major hurricane delivered heavy rain and flooding to coastal areas, including the port city of Manzanillo, and raised the risk of mudslides in mountainous areas, according to news reports<\/a>.<\/p>\n In the early morning hours of October 11, satellites captured the storm\u2019s effects extending into the upper atmosphere<\/a>. This nighttime image (above), acquired with\u00a0VIIRS<\/a> on the\u00a0NOAA-21<\/a>\u00a0satellite, shows atmospheric gravity waves radiating from the hurricane. These ripples form when latent heat released near the tropical cyclone\u2019s eyewall drives strong convection, building tall cumulonimbus clouds<\/a> with updrafts that can send waves into the stratosphere and mesosphere.<\/p>\n But these waves are not always observable. Winds in the upper atmosphere can dissipate them before they reach the mesosphere, where they show up as ripples in airglow\u2014faint light emitted by gases at those high altitudes. The VIIRS\u00a0day-night band<\/a>\u00a0is sensitive to airglow but also detects reflected moonlight, which can wash it out. On the night this image was acquired, minimal illumination<\/a> from the Moon helped the airglow stand out.<\/p>\n On the morning of October 13, forecasts of Simon\u2019s intensity and path remained \u201cvery low confidence,\u201d as the storm\u2019s evolution continued to defy meteorologists\u2019 expectations<\/a>. The system may steer north<\/a> and enter the Gulf of California before making landfall. Large swells causing dangerous nearshore conditions were expected along portions of the southwestern and west-central coasts of Mexico in the coming days.<\/p>\n NASA Earth Observatory images by Michala Garrison,\u00a0using VIIRS data from NASA\u00a0EOSDIS LANCE<\/a>,\u00a0GIBS\/Worldview<\/a>, the Suomi National Polar-orbiting Partnership<\/a>, and the\u00a0Joint Polar Satellite System<\/a>\u00a0(JPSS). Story by Lindsey Doermann.<\/em><\/p>\n![\"The](\"https:\/\/assets.science.nasa.gov\/dynamicimage\/assets\/science\/esd\/eo\/images\/iotd\/2026\/hurricane-simon-lurks-off-the-mexican-coast\/hurricanesimon_vir_20261011_lrg.jpg?w=2160&h=1800&fit=clip&crop=faces%2Cfocalpoint\")
<\/figure>\n<\/div><\/div>\nOctober 11, 2026: Suomi NPP<\/h2>\n<\/p><\/div><\/div>\n
![\"Gravity](\"https:\/\/assets.science.nasa.gov\/dynamicimage\/assets\/science\/esd\/eo\/images\/iotd\/2026\/hurricane-simon-lurks-off-the-mexican-coast\/hurricanesimon_vir2_20261011_lrg.jpg?w=2160&h=1600&fit=clip&crop=faces%2Cfocalpoint\")
<\/figure>\n<\/div><\/div>\nOctober 11, 2026: NOAA-21<\/h2>\n<\/p><\/div><\/div><\/div><\/div>\n
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