When the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired this image at 10:40 a.m. local time (17:40 Universal Time) on June 12, 2014, Tropical Cyclone Cristina was churning over the eastern Pacific Ocean off the coast of Mexico. The storm had maximum sustained winds near 240 kilometers (150 miles) per hour, making it the equivalent of a category 4 hurricane. The storm was moving west-northwest at a speed of 13 kilometers (8 miles) per hour. Read more

NASA image courtesy of the LANCE/EOSDIS MODIS Rapid Response Team at NASA GSFC. Caption by Adam Voiland.

From time to time, in the wake of winter rain, dense fog fills the wide valley between California’s Sierra Nevada and Coastal Range. Called Tule fog, the phenomenon is as much a part of winter in the Central Valley as snow is in the mountain. In recent years, however, the fog has come less often. In fact, since 1981 the number of fog days between November and February has decreased by 46 percent, according to a recent study. The decrease is bad news for California’s fruit and nut farmers.

This image, acquired on January 17, 2011, by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite, shows one of the more recent valley fog events. (Drought has limited the number of fog events since 2012.) University of California–Berkeley researchers Dennis Baldocchi and Eric Waller used images from MODIS and from NOAA’s advanced very high resolution radiometer (AVHRR) to count the number of fog days since 1981. They found a downward trend. Read more

NASA Earth Observatory image by Jesse Allen with data from the Land Atmosphere Near real-time Capability for EOS (LANCE). Caption by Holli Riebeek.

On Sunday, March 30, 2014, the outlook appeared grim for cities in northwestern Madagascar. Tropical cyclone Hellen spun offshore, gaining strength with surprising rapidity and with a track destined to bring it ashore. The day started with the storm being the equivalent of a Category 2 storm with winds of 170 kilometers per hour (100 miles per hour or 90 knots). Twelve hours later, winds reached 240 kilometers per hour (150 miles per hour or 130 knots), making it a strong Category 4 storm.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired this image of Cyclone Hellen at 7:20 UTC on March 30 in the middle of the storm’s rapid intensification. The storm had a distinct open eye and a classic tight circular shape. Its outer bands were already over northwestern Madagascar. Read more

NASA image courtesy Jeff Schmaltz, LANCE/EOSDIS MODIS Rapid Response Team at NASA GSFC. Caption by Holli Riebeek.

Rarely do weather patterns and satellite overpass schedules align to provide cloud-free views of Western Europe in the spring. However, a high-pressure pattern kept skies spectacularly clear over the Iberian Peninsula and east into France and Germany as the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite passed over on March 8, 2014. The cloud-free area began to emerge on March 5 and persisted through March 11. Explore Worldview—a near-real time browser from the MODIS Rapid Response Team—to see a wider view and how the cloud-free area changed over time. Read more

NASA image courtesy Jeff Schmaltz, LANCE/EOSDIS MODIS Rapid Response Team at NASA GSFC. Caption by Adam Voiland.