September 1, 2009
NASA Infrared Imagery Sees Landfalling Jimena, Weak Kevin, and Pyrocumulus Clouds
Hurricane Season 2009: Tropical Storm Kevin (Eastern Pacific)
It's unusual to see towering clouds that are created from smoke and fires, but that's what showed up in the latest satellite imagery from NASA, when also capturing powerful Hurricane Jimena and Tropical Depression Kevin in the Eastern Pacific Ocean. Jimena's outer rainbands were already spreading over southern Baja California at 11 a.m. EDT.
"I have never before seen the signature of a pyrocumulus cloud in the infrared channel which I use for hurricane imagery," said Ed Olsen of the Atmospheric Infrared Sounder (AIRS) Team at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The pyrocumulus clouds are towering cumulus clouds that were created by the smoke and heat from the California wildfires that are currently burning around Los Angeles. In the AIRS infrared image, they stretch from Los Angeles, Calif. and sweep into Nevada, Arizona and New Mexico between latitude 32 and 36.
The AIRS instrument flies onboard NASA's Aqua satellite and provides valuable infrared data on cloud top temperatures. They're important because they tell forecasters how high thunderstorms are in a tropical cyclone. The higher the thunderstorm, the more powerful.
At the same time, an extremely dangerous Hurricane Jimena is approaching Baja California. This is a powerful storm with sustained winds that are a Category Four on the Saffir-Simpson Scale. AIRS revealed very high, cold, powerful thunderstorms in Jimena's center of circulation, so high that they're colder than minus 63 degrees Fahrenheit (F).
NASA's CloudSat also flew above Jimena and captured a side view of the storm earlier today. The CloudSat data indicated Jimena's highest clouds as high as 15 kilometers (9.3 miles), verifying the AIRS data and indicating strong convection and a powerful hurricane.
At 11:00 a.m. EDT (8 a.m. PDT) today, September 1, Jimena has maximum sustained winds near 145 mph, a 10-mile per hour drop from three hours before (Category five is 155 mph sustained winds are greater). Hurricane force winds extend 45 miles from her center, and tropical storm force winds go out up to 140 miles from her center. Her center was located near 20.6° North and 110.4° West, about 140 miles south-southwest of Cabo San Lucas, Mexico. She was moving north-northwest near 12 mph and had a minimum central pressure near 945 millibars, up from 931 millibars three hours ago. That rise in pressure indicates a weakening which was evidenced in her sustained winds dropping 10 mph over that same time.
Residents and interests in Baja California and northwestern mainland Mexico should have all their preparations and evacuations done.
Meanwhile, Tropical Depression Kevin appears dazed and confused on satellite imagery and is expected to fade to a remnant low pressure area later today. In fact, NASA's Tropical Rainfall Measuring Mission (TRMM) satellite showed this morning at 4:44 a.m. EDT that his center of circulation is so elongated that it looks like he has two possible centers of circulation.
Kevin is expected to slowly spin down, as more stable air enters into his circulation. Stable air means thunderstorm formation will slow to a stop and then Kevin will have faded. At 11 a.m. EDT today, September 1, Kevin had sustained winds of 35 mph, but that stable air moving in will weaken him. He's located in the Eastern Pacific Ocean about 835 miles west-southwest of the southern tip of Baja California, near 18.0 north and 121.7 west. He's moving north near 3 mph and is expected to slow to a stop where he'll fade to a remnant low tomorrow. His minimum central pressure was 1008 millibars.
Rob Gutro, NASA/Goddard Space Flight Center
August 31, 2009
NASA's QuikScat Satellite Sees Tropical Storm Kevin's Center Leaning
NASA's QuikScat satellite helped forecasters locate Kevin's center earlier today and QuikScat's wind data revealed that he's weakening. QuikScat uses microwave technology to "see through clouds" and also saw Kevin's mid-level circulation appears to be decoupling from his low-level center. Think of how when you push the top of "Slinky" wire toy to one side of it, and that's what's happening to Kevin's center. It means the storm's mid-level center is leaning away from the bottom center, and that's a sign of weakening.
At 5 a.m. EDT on Monday, August 31, Tropical Storm Kevin had sustained winds near 40 mph, and was 895 miles west-southwest of the southernmost tip of Baja California, near 16.3 north and 121.7 west. Kevin was moving north-northeast near 6 mph, with a minimum central pressure of 1005 millibars. Late last night , Sunday, August 30, NASA's QuikScat satellite flew over Kevin and confirmed that 40 mph winds "were confined to the deep convection over the northwestern quadrant of the storm."
NASA's Aqua satellite also flew over Kevin, and the Atmospheric Infrared Sounder (AIRS) captured an infrared image of Kevin earlier today. The image, which reveals cloud temperatures, showed that Kevin's clouds were not as cold as they were over the last few days, revealing a weakening storm. Colder cloud temperatures mean higher clouds, and more powerful thunderstorms. The AIRS image showed that Kevin is losing his punch.
The National Hurricane Center expects Kevin to weaken further and drop to tropical depression status later today.
Rob Gutro, NASA/Goddard Space Flight Center
August 30, 2009
Danny's Remnants Exit Newfoundland, Jimena and Kevin Active in Pacific
While Danny's remnants exit Newfoundland, Canada this morning, Jimena has become a powerful Category Three hurricane in the Eastern Pacific, and Tropical Storm Kevin developed to her west.
The Geostationary Operational Environmental Satellite, or GOES-12, operated by NOAA, caught remnants from Danny exiting Newfoundland and Hurricane Jimena on the Mexican west coast, and Tropical Storm Kevin farther west this morning at 7:45 a.m. EDT. NASA's GOES Project created imagery from the GOES-12 satellite that clearly shows Danny's clouds stretched from the Mid-Atlantic north to New England. The image also shows a powerful Hurricane Jimena with a clear eye, and a less intense Tropical Storm Kevin.
Danny merged with a low pressure area yesterday and brought rains to Long Island, eastern Massachusetts, coastal New Hampshire and Maine, before moving into Nova Scotia, and Newfoundland, Canada. On Sunday morning, August 30, the rains associated with what was Danny are exiting Newfoundland. Live Environment Canada radar reveals the rains: http://www.weatheroffice.gc.ca/radar/index_e.html?id=ERN
At 9 a.m. EDT this morning, Jimena's center was located about 305 miles south of Cabo Corrientes, Mexico near 16.0 north and 105.7 west. She had maximum sustained winds near 115 mph. She was moving northwest near 12 mph. Minimum central pressure is near 965 millibars, a drop of 25 millibars in 24 hours indicating rapid intensification. The National Hurricane Center noted "interests in western Mexico and the southern Baja California Peninsula should monitor the progress of Jimena."
Farther to her west, the second area of low pressure forecasters were watching on Friday has developed into Tropical Storm Kevin. He had sustained winds near 50 mph, and is forecast to strengthen. He's located about 995 miles southwest of the southern tip of Baja California, near 14.1 north and 121.9 west. Kevin was north at 7 mph and had a minimum central pressure of 1000 millibars.
Now that Danny is history. there is one new area in the Atlantic that forecasters are watching for likely development, located 950 miles east of the Windward Islands. This area has a greater than 50 percent chance of development, according to the National Hurricane Center.
Rob Gutro, NASA/Goddard Space Flight Center
August 29, 2009
NASA Sees Dying Danny Drenching Eastern New England, Jimena Exploding in Pacific
Weekends and tropical cyclones have gone together this hurricane season, and this weekend, Danny is dying in the Atlantic, while Jimena has exploded in fast development in the eastern Pacific Ocean.
Danny is in the process of being absorbed by an extra-tropical low pressure area over North Carolina, and has lost his punch in terms of sustained winds. Danny has been downgraded to a tropical depression this morning, Saturday, August 29. However, he's still packing a lot of heavy rain, and bringing dangerous surf along the U.S. east coast from the Mid-Atlantic to the Northeast into Canada.
Danny's heavy rainfall is mostly located to the north and northeast of the storm, as evidenced in NASA satellite data. As he continues merging with the extra-tropical low pressure system today, his center will stay off-shore and keep moving north. Ahead of his center, heavy rains will pour over eastern Long Island, eastern Massachusetts, coastal New Hampshire and Maine, before moving into Nova Scotia, Canada.
When the Tropical Rainfall Measuring Mission satellite (managed by NASA and JAXA) flew over tropical storm Danny yesterday, August 28, it revealed that only moderately heavy rain was occurring then in an area northeast of Danny's center of circulation. That also holds true today, August 29 as Danny is now raining on the northeastern U.S. On the radar, Danny's rainfall looks like a large "V" shape entering New England.
For live radar from Boston, Massachusetts, go to: http://radar.weather.gov/radar.php?rid=BOX&product=NCR&overlay=11101111&loop=yes
Dangerous surf is the other issue Danny is causing. Beachgoers should not venture into the ocean, as Tropical Depression Danny is stirring up surf 3-5 feet high in the mid-Atlantic. Surf is much higher, as much as 6-10 feet, near Long Island, N.Y., and coastal Rhode Island, Connecticut, and south and east-facing Cape Cod, Massachusetts.
At 5 a.m. EDT today, Saturday, August 29, the National Hurricane Center in Miami, Fla. issued its last advisory on Tropical Depression Danny. At that time, Danny's remnants had sustained winds near 35 mph, and he was moving north-northeast near the same speed! Danny's center was located 540 miles south-southwest of Nantucket, Mass.; or 80 miles southeast of Cape Hatteras, North Carolina. He had an estimated minimum central pressure near 1007 millibars.
The Geostationary Operational Environmental Satellite, or GOES-12, operated by NOAA, caught a dying Danny on the U.S. east coast and an explosive Tropical Storm Jimena on the Mexican west coast this morning at 7:45 a.m. EDT. NASA's GOES Project created imagery from the GOES-12 satellite that clearly shows Danny's clouds stretched from the Mid-Atlantic north to New England. The image also shows a powerful Tropical Storm Jimena that developed early this morning.
Tropical Storm Jimena developed from one of the two areas that forecasters were watching yesterday. It developed and intensified quickly and by 8:18 a.m. this morning, Saturday, August 29, she had maximum sustained winds near 70 mph. Light upper level winds and warm sea surface temperatures are fueling her intensification.
At 9 a.m. EDT this morning, Jimena's center was located about 270 miles southwest of Acapulco, Mexico near 14.2 north and 102.8 west. She was moving west near 10 mph and will turn north-northwest in the next day or so. Minimum central pressure is near 990 millibars. Jimena is expected to become a hurricane later today.
Rob Gutro, NASA/Goddard Space Flight Center
August 28, 2009
NASA Infrared Satellite Eyes 2 Potential Pacific Tropical Cyclones
Two areas of showers and thunderstorms located south of Tropical Storm Ignacio's remnants are being closely watched for development. Forecasters use infrared satellite imagery to determine cloud temperatures, and get an idea about the height and strength of thunderstorms.
The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite flies over the Eastern Pacific Ocean daily, and captured the two areas on August 27at 5:23 p.m. EDT. Although both didn't have signature shapes of tropical cyclones yet, the National Hurricane Center reported on Friday, August 28 that the potential for development is at least 50%. So, over the weekend, there's a potential for them to develop into tropical storms. If they do, they'd be named Jimena and Kevin.
Infrared imagery measures temperatures and not only can it see cold, high cloud tops in tropical cyclones, but also the warm ocean waters that fuel them. The colder the clouds are, the higher they are, and the more powerful the thunderstorms are that make up the cyclone.
The first area of disorganized showers and thunderstorms are located a couple of hundred miles south of Acapulco, Mexico, and are associated with a low pressure area. Because conditions are favorable for development, there's a medium chance (30-50 percent) of the system becoming a tropical depression this weekend.
The second area of showers and thunderstorms are further west, about 950 miles south-southwest of the southern tip of Baja California. Conditions there are also favorable for development: warm waters over 80 degrees Fahrenheit and light surrounding winds. This system has the same chance to develop over the weekend.
Rob Gutro, NASA's Goddard Space Flight Center