The MODIS instrument that flies aboard NASA's Aqua and Terra satellites provide some of the most clear and stunning imagery of tropical cyclones, and captured a visible image of Category 2 hurricane Miriam off the western coast of Mexico.
MODIS stands for the Moderate Resolution Imaging Spectroradiometer. Terra's MODIS and Aqua's MODIS view the entire Earth's surface every 1 to 2 days, acquiring data in 36 spectral bands, or groups of wavelengths. NASA's Aqua satellite flew over Hurricane Miriam on Sept. 24 at 21:00 UTC and the MODIS instrument captured a visible image of Hurricane Miriam off Mexico's west coast. The MODIS image showed that Miriam's eye was covered by high clouds, yet the eye is still about 30 nautical miles wide. Cloud top temperatures around the eye have cooled in infrared imagery, which indicates thunderstorms around the eye still have strong uplift and are shooting high into the troposphere.
On Sept. 25 at 5 a.m. EDT Hurricane Miriam's maximum sustained winds were near 105 mph (165 kmh), making it a category 2 hurricane on the Saffir-Simpson hurricane scale. Miriam 's hurricane-force winds extend only 30 miles (45 km) from the center. Slow weakening is forecast during the next 48 hours, according to the National Hurricane Center.
Miriam's center was located near latitude 18.7 north and longitude 114.3 west. Miriam is moving in a northwesterly direction near 6 mph (9 kmh) and is expected to turn to the north-northwest later on Sept. 25, followed by a turn to the north. Miriam's estimated minimum central pressure is 968 millibars.
Although Miriam is off-shore, the hurricane is producing very rough seas along the south and western coasts of the central Baja Peninsula, and those conditions will continue for the next several days.
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