Hurricane Danielle became the first major hurricane of the 2010 Atlantic hurricane season overnight as it continued to make its way through the central Atlantic.

Danielle, which had been a Category 2 storm the day before with sustained winds estimated at around 95 knots (~110 mph) by the National Hurricane Center, quickly intensified overnight and by morning was a power Category 4 hurricane on the Saffir-Simpson scale with sustained winds of 115 knots (132 mph).

“The TRMM satellite passed directly over Danielle during the night and captured remarkable images as the storm was in the process of intensifying,” said Steve Lang, research meteorologist on the TRMM team in the Mesoscale Atmospheric Processes Branch at NASA’s Goddard Space Flight Center in Greenbelt, Md.

Two images were taken from TRMM at 06:46 UTC (2:46 a.m. EDT) on August 27. The first image showed a top-down view of the horizontal pattern of rain intensity within the storm. Rain rates in the center of the swath are from the TRMM Precipitation Radar (PR), and those in the outer swath are from the TRMM Microwave Imager (TMI).The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS), and are created at NASA Goddard. TRMM is managed by both NASA and the Japanese Space Agency, JAXA.

A trough is an elongated area of low pressure and that’s what the remnants of the once major hurricane known as Darby are becoming today. On June 28 at 6:55 p.m. EDT NASA and the Japanese Space Agency’s Tropical Rainfall Measuring Mission (TRMM) satellite captured isolated areas of rainfall off the western Mexico coast from Darby’s remnants.

The center of Darby the remnant low pressure area is located near 15 North and 97.5 West. Those remnants are still showing some scattered moderate to strong convection (rapidly rising air that creates clouds and thunderstorms) southwest of its center. Isolated strong convection likely associated with a nearby tropical wave is also being seen over the Gulf of Tehauntepec and within 60 nautical miles of the Mexican coast between 98 West and 101 West.

Darby’s remnants still have southwest to westerly winds between 20 and 25 knots (23-28 mph). The National Hurricane Center noted that “Darby should weaken to an open trough later today then extend northwest to Caribbean Tropical Storm Alex. The trough will move northwest in tandem with Alex over the next few days.”

Celia has exploded into a monster hurricane in the Eastern Pacific, and is now a Category 5 storm over open waters. NASA’s Aqua satellite captured an infrared image (that shows temperature) of Celia’s clouds and clearly shows an eye in the storm. Celia’s eye appears well-defined and is between 15-20 nautical miles wide.

Warm sea surface temperatures are also critical for a tropical cyclone’s development, and AIRS infrared imagery is able to read those temperatures from space, too. AIRS imagery taken on Friday, July 25 at 9:05 UTC (5:05 a.m. EDT) showed that the sea surface temperatures around Celia were over the 80 degree Fahrenheit threshold needed to continue powering tropical cyclones. As Celia continues to move west-northwestward, however, those waters will become cooler and they are expected to weaken Celia.

At 5 a.m. EDT (2 a.m. PDT) on Friday, June 25, powerful Category Five Hurricane Celia was packing maximum sustained winds near 160 mph (260 km/hr). Hurricane force winds extend outward up to 50 miles (85 km) from the center…and tropical storm force winds extend outward up to 140 miles (220 km). Celia’s center was located about 805 nautical miles southwest of the southern tip of Baja California, near 13.4 North and 117.0 West. Celia’s minimum central pressure is 926 millibars, and she is moving west-northwest near 13 mph (20 km/hr).

The morning of June 24 revealed that Darby had strong convection that is an indicator of a strengthening storm. Tropical Storm Darby became the second hurricane of the Eastern Pacific Ocean season this morning.

When NASA’s Aqua satellite flew over Darby on June 24 at 08:23 UTC (4:23 a.m. EDT), the Atmospheric Infrared Sounder (AIRS) instrument onboard the satellite captured an infrared image of Darby’s clouds, hours before it achieved hurricane status. The infrared imagery showed very high, cold thunderstorm cloud tops in the southeast and northern quadrants of the storm indicating strong convection. Convection is rapidly rising air the condenses and forms clouds (and in a tropical cyclone, it forms the thunderstorms that power the cyclone).

At 11 a.m. EDT (8 a.m. PDT) on June 24, the National Hurricane Center announced that Darby achieved hurricane status, making it the second hurricane of the Eastern Pacific Ocean season, just after Celia, which is spinning at sea much farther west. Hurricane Darby has maximum sustained winds near 75 mph, making it a category one hurricane on the Saffir-Simpson scale. (Category one hurricanes begin at 74 mph). Darby is located about 235 miles (375 km) south-southwest of Puerto Escondido, Mexico, near 12.8 North and 98.7 West. Darby is moving west near 9 mph (15 km/hr) and has a minimum central pressure near 990 millibars.

The National Hurricane Center forecasters expect vertical wind shear (winds that can tear a tropical cyclone apart) to remain light, so there’s an opportunity for Darby to strengthen a little over the next couple of days before the winds increase.

Tropically speaking Celia is in the Major Leagues. She’s now a Category Three hurricane on the Saffir-Simpson hurricane scale and classified as the Eastern Pacific’s first major hurricane. That’s quite a “batting average” for also being that season’s first hurricane. The other storms that formed before her in the Eastern Pacific didn’t make it to hurricane status.

Both Geostationary Operational Environmental Satellites, GOES-11 (west) and GOES-13 (east) captured visible images of Hurricane Celia and Tropical Storm Darby in the Eastern Pacific on June 23, and Celia’s eye was visible in them.

At 8 a.m. PDT (11 a.m. EDT) on June 24, Hurricane Celia’s maximum sustained winds were near 115 mph (185 km/hr) with higher gusts. Hurricane force winds extend outward up to 30 miles (45 km) from the center and tropical storm force winds extend outward up to 115 miles (185 km).

She was located in the open waters of the Eastern Pacific Ocean near latitude 12.5 north and longitude 113.9 west. Minimum central pressure is 962 millibars. Celia is moving toward the west near 13 mph (20 km/hr) and a turn toward the west-northwest is expected over the next couple of days. Some additional strengthening is possible later today, followed by gradual weakening on Friday.

Celia’s eye has appeared to be “blinking” over the last couple of days because it has been visible in some satellite imagery, then not visible. This morning, June 24, satellite imagery sees the open eye again.