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Hurricane Season 2010: Danielle (Atlantic Ocean)
08.31.10
 
August 31, 2010

In this image are Hurricane Earl (lower left), Tropical Storm Fiona located to Earl's east, and Tropical Storm Danielle far in the Northern Atlantic. > View larger image
The GOES-13 satellite captured an image of the busy Atlantic Ocean at 1145 UTC (7:45 a.m. EDT) on August 31. In the visible image, was the large and powerful Hurricane Earl (lower left) passing Puerto Rico, Tropical Storm Fiona located to Earl's east, and Tropical Storm Danielle far in the Northern Atlantic.
Credit: NASA/GOES Project
GOES-13 Catches 3 Tropical Cyclones Thrashing Through the Atlantic

Powerful Hurricane Earl, growing Tropical Storm Fiona and fading Danielle were all captured in today's visible image from the GOES-13 satellite. The Geostationary Operational Environmental Satellite called GOES-13 captured an image of the busy Atlantic Ocean at 1145 UTC (7:45 a.m. EDT) on August 31. In the visible image, was the large and powerful Hurricane Earl passing Puerto Rico, Tropical Storm Fiona located to Earl's east, and Danielle far in the Northern Atlantic. Hurricane Earl's eye appear to be covered with high-clouds in the GOES-13 image, while Fiona appeared somewhat disorganized with no apparent center. Farther north in the North Atlantic Ocean, Danielle appeared more "U" shaped on the satellite imagery, although her maximum sustained winds were still near 70 mph at that time.

GOES satellites are operated by NOAA, and the NASA GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Md. provides images and animations of satellite data.


DANIELLE NOW A LOW IN THE NORTHERN ATLANTIC

Danielle has already transitioned into a cold-core low pressure area in the Northern Atlantic Ocean today. Tropical cyclones are warm-core systems, so when the core temperatures change, the dynamics of the system also changes. The final warning for Danielle was issued today (August 31) at 0300 UTC (Aug. 30 at 11 p.m. EDT). At that time, Danielle was about 475 miles southeast of Cape Race, Newfoundland, Canada near 41.3 North and 47.1 West and headed east-northeast at 15 mph. Her sustained winds were near 70 mph, but waning.

Danielle's effects are being felt along the shores of Newfoundland with heavy surf and waves up to 3 meters (10 feet).


EARL STILL A POWERFUL HURRICANE THREATENING THE U.S.

Hurricane Earl is a storm that's about 400 miles in diameter and the hurricane force winds are about 140 miles in diameter from side-to-side of the storm's eye. Earl is still a Category Four hurricane on the Saffir-Simpson scale, one category stronger that Hurricane Katrina was when she made landfall in Mississippi in 2005.

At 11 a.m. EDT on August 31, Hurricane Earl was located about 205 miles east of Grand Turk Island. That's about 1070 miles south-southeast of Cape Hatteras, North Carolina. Earl's center was located at 21.2 North and 67.9 West. Earl's maximum sustained winds were near 135 mph and he is moving west-northwest near 14 mph. Minimum central pressure is 939 millibars.

Earl's eye has become obscured in the latest imagery from the GOES-13 satellite, and the central pressure has increased. Forecasters believe that it's because Earl is undergoing "eyewall replacement." What that means is a new eye begins to develop around the old eye. The new eye gradually decreases in diameter and finally replaces the old eye.

Currently there is a warning and a watch in effect. A tropical storm warning is in effect for Turks and Caicos Islands and a tropical storm watch is in effect for the southeastern Bahamas. Meanwhile, residents from the Carolinas northward to New England should monitor the progress of Earl. A hurricane watch could be required for portions of the mid-Atlantic coast later today.


FIONA CAUSES WARNINGS AND WATCHES IN THE ISLANDS

Tropical Storm Fiona is battering the same areas that Hurricane Earl swept through days ago. A tropical storm warning is in effect for St. Martin and St. Barthelemy. A tropical storm watch is in effect for, Antigua, Barbuda, Montserrat, St. Kitts, Nevis, and Anguilla and St. Maarten, Saba, and St. Eustatius. The National Hurricane Center noted in its forecast this morning, August 31, Tropical storm conditions could spread over portions of the Northern Leeward Islands tonight or early Wednesday.

At 11 a.m. EDT, Tropical Storm Fiona had maximum sustained winds near 40 mph and some strengthening is possible. It was located about 440 miles east of the Leeward Islands near 15.9 N and 55.3 W. Fiona is moving west-northwest near 24 mph and is expected to slow down.

Estimated minimum central pressure is 1006 millibars. Fiona's forecast track does not take her behind Earl, so she does not appear to be a threat to the U.S. mainland at this time.

Earl and Fiona are two storms keeping NASA satellites busy this week, and providing the scientists on NASA's Hurricane Genesis and Rapid Intensification Processes (GRIP) experiment with a lot of data. To see what's happening with GRIP, visit: www.nasa.gov/grip/.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, Md.



August 30, 2010

MODIS captured this visible image of hurricanes Danielle (top) and Earl (bottom)  in the Atlantic Ocean. > View larger image
At 14:20 UTC (10:20 a.m. EDT on August 29, 2010 the MODIS instrument on NASA's Terra satellite captured this visible image of hurricanes Danielle (top) and Earl (bottom) in the Atlantic Ocean.
Credit: NASA/MODIS Rapid Response Team
A very large area of powerful convection and strong, high thunderstorms that took up most of Hurricane Earl's center. > View larger image
NASA's AIRS instrument captured this infrared image on August 30 at 0535 UTC (1:35 a.m. EDT) that shows a very large area of powerful convection and strong, high thunderstorms (as cold as -63 Fahrenheit) that took up most of Hurricane Earl's center as it was moving through the Northern Leeward Islands and headed to Puerto Rico. Earl became a major hurricane later that morning.
Credit: NASA/JPL, Ed Olsen
This image from August 30 at 0523 UTC (1:23 a.m. EDT) shows cold areas (yellow-green) that indicate cold, high thunderstorms. > View larger image
Microwave images are created when data from NASA's Aqua satellite AIRS and AMSU instruments are combined. This image from August 30 at 0523 UTC (1:23 a.m. EDT) shows cold areas (yellow-green) that indicate where there is precipitation or ice in the cloud tops. The microwave image suggests cold, high thunderstorms.
Credit: NASA/JPL, Ed Olsen
Danielle and Earl Dueling in the Atlantic: Earl Threat to U.S. East Coast

Danielle and Earl are both spinning around in the Atlantic Ocean and NASA's Terra satellite captured one image of both storms at the same time, one in the Caribbean and the other approaching the North Atlantic Ocean. Both are expected to impact land.

Danielle is transitioning to an extra-tropical storm in the northern Atlantic and may impact southern Greenland. Before Earl reached hurricane status NASA's GRIP Hurricane Mission researchers flew out to analyze the storm. Earl is now threatening the U.S. east coast and earlier today, August 30, he became a major hurricane.

The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument that flies aboard NASA's Terra satellite captured a stunning image of the large Hurricane Danielle and the smaller, less organized Hurricane Earl, far to Danielle's south. In the image, Danielle's eye can be seen, despite some high clouds filling in most of it. An eye is not visible in Earl, however. The image shows the western edge of Earl affecting the Leeward Islands when this image was captured on August 29 at 10:20 a.m. EDT.

Danielle started causing problems for U.S. east coast residents this weekend with large waves and dangerous surf conditions. News reports indicated that more than 100 people were rescued from dangerous currents in beaches from Maryland to New Jersey over the weekend. Large waves and dangerous surf conditions are diminishing around Bermuda today, and will gradually subside along the U.S. east coast over the next couple of days. Waves near 10 feet however are expected to develop this afternoon along parts of Newfoundland, Canada as Danielle tracks northward.

At 11 a.m. EDT on August 30, Danielle's maximum sustained winds were near 75 mph, and it is expected to weaken in the next 48 hours and become extratropical. The center of Hurricane Danielle was located near latitude 40.9 north and longitude 50.7 west. Danielle is moving toward the northeast near 16 mph and is expected to speed up in this direction. The National Hurricane Center noted that Danielle will still remain a large and powerful cyclone over the far north Atlantic for the next two days. Tropical Storm force winds extend out from Danielle's center up to 310 miles, making this monster storm up to 620 miles in diameter!

As Danielle continues north and heads toward Greenland, Hurricane Earl has the residents of the U.S. East coast on watch. Earl reached hurricane strength as it approached the northern Leeward Islands on August 29 and NASA researchers were there collecting data.

NASA's Genesis and Rapid Intensification Processes (GRIP) experiment is a NASA Earth science field mission that's happening now out of Fort Lauderdale, Florida using three aircraft, 15 instruments and NASA satellites to better understand how tropical storms form and develop into major hurricanes.

NASA's DC-8 aircraft left Fort Lauderdale at 10:05 a.m. EDT on Saturday heading for St. Croix for a multi-day deployment that targeted (at that time) Tropical Storm Earl. Science missions to Earl were planned for Sunday and Monday in close support of operations being flown by NOAA aircraft. On Sunday, August 29, the DC-8 completed an 8.5-hour science flight over (then) Hurricane Earl west of St. Croix. The research aircraft flew at altitudes of 33,000 feet and 37,000 feet and descended to 7,000 feet northwest of the storm area to collect measurements of atmospheric aerosols. The flight originated in St. Croix but diverted to land in Fort Lauderdale, Fla., due to the degrading weather forecast for St. Croix associated with the approaching hurricane.

Early on August 30 at 0535 UTC (1:35 a.m. EDT), NASA's Atmospheric Infrared Sounder (AIRS) that flies on the Aqua satellite captured an infrared image that showed a very large area of powerful convection and strong, high thunderstorms (as cold as -63 Fahrenheit) that take up most of Hurricane Earl's center as it was moving through the Northern Leeward Islands and headed to Puerto Rico.

Later in the morning after NASA's Aqua satellite passed over Earl, it became a major hurricane (Category 3) with maximum sustained winds near 120 mph. Hurricane Earl was already impacting many islands and hurricane warnings are in effect. Earl's center was about 95 miles east-northeast of St. Thomas and 165 miles east of San Juan, Puerto Rico near 18.7 North and 63.6 West. It was moving west-northwest near 15 mph, and had a minimum central pressure of 960 millibars.

A hurricane warning is in effect for Anguilla, Saint Martin and Saint Barthelemy, St. Maarten, Saba, and St. Eustatius, the British Virgin Islands, the U.S. Virgin Islands and the Puerto Rican Islands of Culebra and Vieques. A Hurricane Watch is in effect for Puerto Rico. A tropical storm warning is in effect for Antigua, Barbuda, Montserrat, St. Kitts, and Nevis and Puerto Rico. A tropical storm watch is in effect for Turks and Caicos Islands.

The National Hurricane Center noted this morning, "Hurricane conditions will be spreading across the northern Virgin Islands during the next few hours. Tropical storm conditions will spread over portions of Puerto Rico this afternoon with Hurricane conditions possible this evening and tonight. Storm surge will raise water levels by as much as 3 to 5 feet above ground level primarily near the coast in areas of onshore wind within the hurricane warning area...and 1 to 3 feet in the tropical storm warning area. The surge will be accompanied by large and dangerous battering waves. Earl is expected to produce total rainfall accumulations of 4 to 8 inches over the Leeward Islands, The Virgin Islands and Puerto Rico with possible isolated maximum amounts of 12 inches especially over higher elevations."

Interests along the U.S. East coast should closely monitor the approach of Hurricane Earl. Beachgoers should be aware of dangerous surf and riptides developing as Earl approaches the U.S. coast later this week.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, Md.



TRMM captured this image of Danielle as it was beginning to move away from Bermuda. > View larger image CAPTION
Credit:
HURRICANE DANIELLE WEAKENS AS IT MOVES AWAY FROM BERMUDA

Hurricane Danielle, the first major hurricane of the 2010 Atlantic season back, intensified into a Category 4 storm back on the 27th of August with sustained winds estimated at 115 knots (~132 mph) by the National Hurricane Center as it was moving northwest towards Bermuda. However, a large mid- to upper-level trough of low pressure moving off of the US East Coast steered Danielle to the north and then northeast causing the storm to recurve before it was able to reach Bermuda. The ensuing wind shear also helped to weaken Danielle as it moved away from Bermuda to the northeast. TRMM captured this image of Danielle as it was beginning to move away from Bermuda. The image was taken at 09:48 UTC (5:48 am EDT) on August 29th, 2010. By this time, Danielle's sustained winds had diminished to 80 knots (~92 mph). Danielle no longer has a well-defined eye. Instead the storm's center has been eroded away by southwesterly wind shear from the trough with most of the rain, including nearly all of the moderate to heavy rain (shown in green and red, respectively), occurring north of the center.

Danielle is expected to remain a fairly strong storm for a while as it transitions to an extratropical storm over the northern Central Atlantic.

TRMM is a joint mission between NASA and the Japanese space agency JAXA.

Text credit: Steve Lang and Hal Pierce, SSAI/NASA Goddard Space Flight Center

August 27, 2010

Powerful thunderstorms in Danielle's eye wall are dropping extreme amounts of rain, especially in the northwest quadrant. > View larger image
This TRMM image of Hurricane Danielle's rainfall was captured on August 27 06:46 UTC (2:46 a.m. EDT) and showed that Danielle now has a well-formed eye surrounded by sharply curved rainbands--all signs of mature storm with an intense circulation. There are very powerful thunderstorms in Danielle's eye wall dropping extreme amounts of rain, especially in the northwest quadrant (dark red areas).
Credit: NASA/SSAI, Hal Pierce
A 3D view of Danielle shows an area of deep convective towers (red) are prominently visible in the center of the storm. > View larger image
A 3D view of Danielle shows an area of deep convective towers (red) are prominently visible in the center of the storm. These tall towers are the key to Danielle's intensification. They are associated with the strong thunderstorms responsible for the areas of intense rain.
Credit: NASA/SSAI, Hal Pierce
NASA Peers Into The Eye Of Powerful Hurricane Danielle

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 and NASA's Tropical Rainfall Measuring Mission satellite known as TRMM provided an "eagle eye" view of the rainfall and clouds in powerful Danielle.

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.

TRMM revealed that Danielle now has a well-formed eye surrounded by sharply curved rainbands--all signs of mature storm with an intense circulation. TRMM also reveals that there are very powerful thunderstorms in Danielle's eye wall dropping extreme amounts of rain, especially in the northwest quadrant, falling as much as 2 inches per hour.

TRMM data is also used to create 3D images of tropical cyclones (the generic name for tropical depressions, tropical storms, hurricanes or typhoons). A 3D view of Danielle was created at NASA Goddard using data from the TRMM PR. An area of deep convective towers were prominently visible in Danielle's center in the 3D image from August 27 at 2:46 a.m. EDT. These tall towers are the key to Danielle's intensification. They are associated with the strong thunderstorms responsible for the areas of intense rain. These storms within a storm are releasing vast amounts of heat into the core of Danielle. This heating, known as latent heating, is what is driving the storm's circulation and intensification.

Danielle was still a powerful Category 4 hurricane on the Saffir-Simpson scale on Friday, August 27 at 11 a.m. EDT. She had maximum sustained winds near 135 mph, and was moving northwest near 12 mph. Danielle's center was about 480 miles southeast of Bermuda near 26.9 North and 59.8 West. Her minimum central pressure is 946 millibars.

Although Danielle is not expected to be directly affected by the hurricane, Danielle will create large and dangerous surf conditions in Bermuda over the weekend. Those large ocean swells will also begin affecting the U.S. east coast beginning this weekend into next week. Beachgoers along the U.S. eastern seaboard should be aware of dangerous rip currents as a result of Danielle's passage.

Danielle is expected to remain a major hurricane until it recurves east of Bermuda and then weaken as it moves northeastward over cooler waters in the central Atlantic.

Text credit: Steve Lang/NASA SSAI and Rob Gutro/NASA's Goddard Space Flight Center, Greenbelt, Md.



NASA's Aqua satellite captured an image of Hurricane Danielle on August 26 that clearly showed the eye of the hurricane. > View larger image
The AIRS instrument that flies aboard NASA's Aqua satellite captured an image of Hurricane Danielle on August 26 at 16:53 UTC (12:53 p.m. EDT) that clearly showed the eye of the hurricane. The coldest, highest clouds appear in purple and indicate strong convection and powerful thunderstorms. Those cloud tops are as cold as or colder than -63 degrees Fahrenheit.
Credit: NASA/JPL, Ed Olsen
A Hurricane Danielle NASA Image Collection

Instruments on NASA's Aqua and Terra satellites have been gathering data on Hurricane Danielle. The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument that flies aboard both the Aqua and Terra satellites captured visible imagery of Danielle as it exploded into a major hurricane between August 26 and 27.

The MODIS instrument on NASA's Terra satellite captured an image of Hurricane Danielle at 14:25 UTC 10:25 a.m. EDT) on August 27, 2010. To see the image, go to: http://rapidfire.sci.gsfc.nasa.gov/gallery/?2010239-0827/Danielle.A2010239.1425/. It was created by the MODIS Rapid Response Team at NASA's Goddard Space Flight Center in Greenbelt, Md.

The previous day, the MODIS instrument on NASA's Aqua satellite captured a visible image of Hurricane Danielle at 16:55 UTC (12:55 p.m. EDT) on August 26. To see the image, go to: http://rapidfire.sci.gsfc.nasa.gov/gallery/?2010238-0826/Danielle.A2010238.1655/.

Another instrument on the Aqua satellite captured an infrared image of Hurricane Danielle on August 26 at 16:53 UTC (12:53 p.m. EDT) that clearly showed the eye of the hurricane. The Atmospheric Infrared Sounder (AIRS) instrument captures infrared images and provides data to scientists on cloud top temperatures and sea surface temperatures, two important factors in tropical cyclones. The coldest, highest clouds indicated strong convection and powerful thunderstorms and those cloud tops are as cold as or colder than -63 degrees Fahrenheit. AIRS images are created by the AIRS team at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Danielle was still a powerful Category 4 hurricane on the Saffir-Simpson scale on Friday, August 27 at 11 a.m. EDT. She had maximum sustained winds near 135 mph, and was moving northwest near 12 mph. Danielle's center was about 480 miles southeast of Bermuda near 26.9 North and 59.8 West. Her minimum central pressure is 946 millibars.

Text credit: Rob Gutro/NASA's Goddard Space Flight Center, Greenbelt, Md.



August 26, 2010

Satellite image of storms Danielle and Earl › Larger image
This visible image from the GOES-13 satellite shows Hurricane Danielle (left) approaching Bermuda and Tropical Storm Earl (right) trailing to its east. Danielle is a well-developed hurricane, while the circulation in Earl appears a lot less developed. Credit: NASA/GOES Project
GOES-13 Captures Danielle and Earl Racing Through the Atlantic Ocean

Two tropical cyclones are racing through the warm waters of the Atlantic Ocean today, and the GOES-13 satellite captured a visible image of them. Danielle is a well-developed hurricane and over 700 miles south of Bermuda, while Earl is a strengthening tropical storm and lies far to Danielle's east.

The Geostationary Operational Environmental Satellite, GOES-13 is operated by NOAA, and NASA's GOES Project at the NASA Goddard Space Flight Center in Greenbelt, Md. creates images and animations from GOES data. The GOES-13 image created at NASA on August 26 at 13:45 UTC (10:45 a.m. EDT) showed that Danielle's clouds have the "signature" comma shape of a hurricane, while Tropical Storm Earl appeared as a more elongated north-to-south circulation.

The GOES-13 image of Danielle does not show a clear eye, as high clouds fill its center of circulation. However, the eye is now apparent to satellites such as Aqua that utilize infrared imagery (from the Atmospheric Infrared Sounder instrument) after showing earlier in the day today, August 26, then becoming obscured.

The coldest convective cloud tops (where the strongest thunderstorms are within the tropical cyclone) are around the eye/center of Danielle but have been fluctuating in coverage, according to the National Hurricane Center (NHC), Miami, Fla.

At 11 a.m. EDT, Hurricane Danielle had maximum sustained winds near 105 mph with higher gusts. The NHC said that some strengthening is forecast and Danielle could become a major (Category 3) hurricane by tonight or Friday. Minimum central pressure is 970 millibars in the storm today.

Danielle was located about 770 miles southeast of Bermuda, and 630 miles northeast of the Northern Leeward Islands, near 24.4 North latitude and 55.9 West longitude. Because Danielle is moving northwest near 16 mph, Danielle is not expected to be closest to Bermuda until the very early morning hours on Sunday, August 29.

A large mid/upper-level trough (an elongated area of low pressure) moving through the northeastern U.S. and the Canadian maritimes is expected to cause Danielle to turn toward the north and the northeast.

Currently, because wind shear is expected to be low for the next couple of days, the National Hurricane Center forecasts Danielle to be a major hurricane at that time, and it is forecast to past to Bermuda's east. Impacts are not yet known and no watches or warnings are posted for Bermuda yet, but residents should prepare.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, Md.



August 25, 2010

This infrared image of Danielle indicates some very strong thunderstorms. > View larger image
This infrared image of Danielle's cloud temperatures was captured on August 25 at 0511 UTC (1:11 a.m. EDT) and shows some strong convection (purple) and high clouds as cold as -80 degrees Fahrenheit, indicating some very strong thunderstorms.
Credit:NASA/JPL, Ed Olsen
The TRMM rainfall data showed most of the rainfall was moderate and falling between 20 and 40 millimeters per hour. > View larger
The TRMM rainfall data showed most of the rainfall was moderate (green and blue) and falling between 20 and 40 millimeters (.78 to 1.57 inches) per hour. The red area just north of the center of circulation is heavy rain, falling at about 2 inches per hour.
Credit:NASA/SSAI, Hal Pierce
NASA and Bermuda Paying Attention to Hurricane Danielle

Hurricane Danielle has strengthened back into a Category One hurricane on the Saffir-Simpson Scale today and NASA infrared imagery confirmed some strong convection and very cold, high cloud tops of strong thunderstorms within the storm. NASA imagery revealed that rainfall rates were moderate to heavy within Danielle yesterday.

The National Hurricane Center's latest forecast track takes Danielle to the east of Bermuda this weekend, so Bermuda residents are paying close attention.

NASA's latest infrared image of Danielle's cloud top temperatures and sea surface temperatures tell a story of a strengthening storm. The Atmospheric Infrared Sounder (AIRS) instrument that flies aboard NASA's Aqua satellite captured an infrared image of Danielle's cloud temperatures on August 25 at 0511 UTC (1:11 a.m. EDT) and showed some strong convection around the center of circulation and high clouds as cold as -80 degrees Fahrenheit (F), indicating some very strong thunderstorms. AIRS also indicated that sea surface temperatures in Danielle's path were warmer than the 80F threshold needed to maintain a tropical cyclone.

The National Hurricane Center (NHC) in Miami, that issues the official forecasts for Danielle noted this morning, "Recent microwave imagery shows that the convection is organized in bands (of showers and thunderstorms) east of the center with no evidence of an eyewall. Upper-level westerly winds associated with a trough to the northwest of the hurricane are causing 15-20 knots of westerly vertical shear...and this has likely affected the convective structure."

On August 24, the Tropical Rainfall Measuring Mission (TRMM) satellite passed over Danielle at 1431 UTC (10:31 a.m. EDT) providing rainfall data. The rainfall analysis derived from TRMM's Precipitation Radar (PR) and TRMM Microwave Imager instruments (TMI) overlaid on Visible and infrared images from TRMM's Visible and Infrared Scanner (VIRS). TRMM is a joint mission between NASA and the Japanese space agency JAXA.

The TRMM rainfall data showed most of the rainfall in Danielle was moderate and falling at a rate between 20 and 40 millimeters (.78 to 1.57 inches) per hour. There was an isolated area of heavy rain north of the center of circulation where rain was falling at a rate of about 2 inches per hour.

The image also revealed that bands of rainfall around the center were broken and Danielle's low level center of circulation was exposed. Since that time, Danielle's center of circulation has become more organized.

At 11 a.m. EDT on August 25, Danielle's maximum sustained winds were 85 mph with higher gusts. The NHC said today that some slow strengthening is possible over the next 48 hours. The center of Hurricane Danielle was located near latitude 19.6 North and longitude 52.3 West. Estimated minimum central pressure is 982 millibars.

Danielle is moving toward the west-northwest near 17 mph and is expected to turn toward the northwest and slow down in the next couple of days.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, Md.



August 24, 2010

This infrared image of Danielle's clouds from NASA's Aqua satellite shows a tightly compact cyclone. > View larger image
This infrared image of Danielle's clouds from NASA's Aqua satellite was captured on August 23 at 16:17 UTC (12:17 p.m. EDT) and shows a tightly compact cyclone. The strongest convection (and thunderstorms) are colored in purple and appear as a large circle in the inside of the storm. The purple coloration indicates highest cloud tops as cold as or colder than -63 Fahrenheit.
Credit:NASA/JPL, Ed Olsen
This image MODIS shows a compact, rounded tropical storm Danielle. > View larger image
This high-resolution image from the MODIS instrument that flies about NASA's Terra satellite was taken shortly after the AIRS image from the Aqua satellite on Aug. 23, and also shows a compact, rounded tropical storm Danielle. Danielle became a hurricane just over three hours later.
Credit:NASA Goddard/MODIS Rapid Response Team
TRMM noticed a large area of moderate to heavy rainfall of over 50 mm/hr (~2 inches) in Danielle (in red). > View larger image
On Monday, August 23 at 1:38 a.m. EDT TRMM flew directly over Danielle and measured its rainfall. TRMM noticed a large area of moderate to heavy rainfall of over 50 mm/hr (~2 inches) in Danielle (in red).
Credit:NASA/TRMM, Hal Pierce
Danielle Now a Cat 2 Hurricane, NASA Satellites Working in High Gear

NASA's Aqua, Terra and TRMM satellites are providing data on Hurricane Danielle daily, and forecasters are using that data to help determine Danielle's behavior and movement. At 5 p.m. EDT yesterday, August 23, when Danielle became a hurricane, these NASA satellites fed forecasters data on cloud extent and formation, cloud top temperatures, pressure, sea surface temperatures, rainfall rates within the storm and more factors.

By 5 a.m. EDT today, August 24, Danielle had reached Category 2 status on the Saffir-Simpson Scale. That means that it has maximum sustained winds between 96-110 mph (83-95 knots), and has "Extremely dangerous winds will cause extensive damage" if it impacts land areas. For more information about the Saffir-Simpson Hurricane scale, go to: http://www.nhc.noaa.gov/aboutsshws.shtml.

The Tropical Rainfall Measuring Mission satellite (TRMM) has been measuring Danielle's rainfall from space since it developed. On Monday, August 23 at 05:38 UTC (1:38 a.m. EDT) TRMM flew directly over Danielle and measured its rainfall with the TRMM Microwave Imager (TMI) instrument. At that time, there was a large area of moderate to heavy rainfall of over 50 mm/hr (~2 inches) in Danielle around it's center. The rainfall images are at NASA's Goddard Space Flight Center in Greenbelt, Md.

On August 23 at 16:17 UTC (12:17 p.m. EDT) an infrared image of Hurricane Danielle's clouds from the Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aqua satellite showed a tightly compact cyclone. The strongest convection and thunderstorms appeared as a large circle in the inside of the storm. The thunderstorms were so high, and powerful that the infrared data measured their temperatures as cold as or colder than -63 Fahrenheit. NASA's Jet Propulsion Laboratory in Pasadena, Calif. creates the images from the AIRS instrument.

Another instrument on NASA's Aqua satellite helped find the center of Danielle early this morning. At 04:34 UTC (12:34 a.m. EDT), Danielle's eye (that developed yesterday) was no longer evident, indicating that it was obscured by clouds. Using the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) instrument that flies on Aqua, microwave imagery helped locate the center and confirmed that Danielle's center was just left of the previous estimate.

One hour and fifteen minutes after Aqua's AIRS instrument captured an infrared image, the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA's Terra satellite captured a high-resolution visible image of Danielle. MODIS images are created by the MODIS Rapid Response Team at NASA Goddard. The data that was captured on August 23 at 1:50 p.m. EDT also showed a compact, rounded, tropical storm Danielle. Danielle became a hurricane just over three hours later.

At 5 a.m. EDT on August 24, Danielle became a category 2 hurricane with maximum sustained winds of 100 mph. Hurricane-force winds currently extend 30 miles out from the center, while tropical storm-force winds extend 115 miles from the center.

Danielle is moving west at 20 mph, and was still far away from land areas. Danielle's center was located about 1,110 miles east of the Lesser Antilles near 15.9 North and 44.6 West. A turn toward the west-northwest and then northwest is expected by early Wednesday, according to the National Hurricane Center, Miami, Fla. Danielle's estimated minimum central pressure is 973 millibars.

Global computer models show Danielle remaining in an environment with low vertical wind shear for the next 24 hours over warm water temperatures between 28 and 29 Celsius (82 and 84 FahreLow wind shear and warm waters help power a tropical cyclone (the general name for tropical depressions, tropical storms and hurricanes). Those factors are expected to help Danielle continue to intensify over the next 24 hours, so Danielle could become a major hurricane (Category 3) by Wednesday, August 25.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, Md.



August 23, 2010

satellite image of Danielle > View larger image
NASA's Aqua satellite's AIRS instrument captured this infrared image of Tropical Storm Danielle on August 22 at 11:35 a.m. EDT and revealed strong convection (purple) and high, thunderstorm clouds around Danielle's center. The purple areas are as cold as -63 Fahrenheit. Higher, colder clouds indicate stronger storms.
Credit: NASA/JPL Ed Olsen
NASA Satellite Sees Tropical Storm Danielle Develop in the Eastern Atlantic

NASA's Aqua satellite passes over the eastern Atlantic twice a day, and over the weekend, it captured infrared images of Tropical Depression 6 that formed on August 22 at 5 a.m. EDT. By 5 p.m. EDT that same day, the depression had already strengthened into Tropical Storm Danielle and it is now headed west toward the central Atlantic Ocean.

The Atmospheric Infrared Sounder instrument, known as AIRS, flies aboard NASA's Aqua satellite and captures infrared imagery of the Earth. The infrared imagery is indicative of temperatures, and can see such things as frigid thunderstorm cloud tops that extend into the tropopause and warm sea surface temperatures that power tropical cyclones. When Aqua flew over Danielle on August 22 at 11:35 a.m. EDT, AIRS data revealed strong convection around Danielle's center. That indicates strong uplift (and creation of thunderstorms that power the tropical cyclone) and strong thunderstorms. That strong convection indicated cloud tops so high in the atmosphere that they were colder than -63 degrees Fahrenheit and signaled that the storm was strengthening.

By 5 a.m. EDT on August 23, Tropical Storm Danielle had maximum sustained winds near 60 mph. Danielle is now expected to strengthen into a hurricane by Tuesday, August 24. Danielle's center was located about 850 miles west of the southernmost Cape Verde islands near 14.8 North and 37.1 West. It was moving west-northwest near 14 mph and is expected to speed up in forward motion. Danielle's estimated minimum central pressure is 997 millibars.

East of Danielle is another area that forecasters are watching for development. It is an area of disturbed weather located near the west coast of Africa, associated with a tropical wave. Some slow development of that system is possible over the next couple of days as it moves westward. However, there's only a 10 percent chance it will develop into a tropical cyclone in the next 48 hours.

Text credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, Md.