Tropical Storm Darby has been increasing in intensity since yesterday and is expected to become a hurricane. NASA provided a visible look at the structure of the storm and peered through it to determine surface wind speed.
On July 12 at 21:45 UTC (5:45 p.m. EDT) the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA-DOD's Suomi NPP satellite captured a visible light image of Hurricane Celia and Tropical Storm Darby in the Eastern Pacific Ocean. Celia is located to the northwest of Darby. As of today, July 13, Celia has weakened to a tropical storm.
VIIRS collects visible and infrared imagery and global observations of land, atmosphere, cryosphere and oceans.
On July 12, RapidScat saw Darby's strongest winds (red) southwest of the center at 27 meters per second (60.4 mph/97.2 kph). Since that time, the National Hurricane Center noticed that Darby had been rapidly intensifying with a 30 knot wind increase over 24 hours. RapidScat is a scatterometer instrument that flies aboard the International Space Station. It measures surface wind speeds and direction over open waters of oceans.
On July 13 at t 5 a.m. EDT (0900 UTC), the center of Tropical Storm Darby was located near latitude 15.3 North, longitude 111.5 West. That's about 540 miles (870 km) west-southwest of Manzanillo, Mexico. Darby was moving toward the west near 12 mph (19 kph) and the National Hurricane Center (NHC) said this general motion is expected for the next couple of days.
Maximum sustained winds have increased to near 70 mph (110 kph) with higher gusts. RapidScat imagery shows tropical-storm-force winds extend outward up to 70 miles (110 km) from the center. The estimated minimum central pressure is 998 millibars.
The NHC expects Darby to become a hurricane later today.