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Tropical Storm Oscar (Atlantic Ocean)
10.05.12
 
MODIS image of Oscar› Larger image
NASA's Aqua satellite passed over Tropical Storm Oscar on Oct. 4 at 1335 UTC (9:35 a.m. EDT) and captured this true-color image of the storm in the central Atlantic Ocean. The bulk of Oscar's clouds and showers were southeast of the center of circulation as a result of northwesterly wind shear. Credit: NASA JPL, Ed Olsen
NASA Satellites Indicate Wind Shear Taking Toll on Oscar

Satellite data is showing that northwesterly wind shear is taking a toll on Tropical Storm Oscar in the central Atlantic and it is expected to dissipate the storm late on Oct. 5, 2012.

NASA's Aqua satellite passed over Tropical Storm Oscar on Oct. 4 at 1335 UTC (9:35 a.m. EDT) and the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument captured a true-color image of the storm. The imagery showed bulk of Oscar's clouds and showers were southeast of the center of circulation as a result of wind shear.

On Oct. 5 at 5 a.m. EDT, Oscar's maximum sustained winds were near 50 mph (85 kph), and wind shear is expected to batter Oscar into oblivion over the next day. Oscar was 1,085 miles (1,745 km) west-northwest of the Cape Verde Islands, near latitude 23.0 north and longitude 38.9 west. Oscar is moving toward the northeast near 15 mph (24 kph) and is expected to continue with an increase in forward speed today. The estimated minimum central pressure is 997 millibars.

Oscar's low-level center continued to be exposed on Oct. 5 and is northwest of the bulk of showers and thunderstorms. The National Hurricane Center (NHC) expects Oscar will be absorbed by an approaching cold front later on Oct. 5. NHC noted "strong southerly gale-force winds are expected to continue ahead of the cold front after Oscar dissipates."

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



Oct. 4, 2012

near-infrared (left) and infrared images of Oscar and Nadine

NASA's Aqua satellite passed over both Tropical Storm Nadine and Tropical Storm Oscar on Oct. 3 at 1553 UTC (11:53 a.m. EDT) and captured a near infrared (almost visible) (left) and infrared image (right) of both storms. A cold front (top left) is expected to merge with Nadine. (Credit: NASA JPL, Ed Olsen)
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NASA Gets 2 Infrared Views of Tropical Storms Nadine, Oscar

NASA's Aqua satellite provided two different infrared views of the two tropical storms swirling in the Atlantic Ocean. Oscar is battling wind shear that appears destined to tear it apart, while Nadine is merging with a cold front.

NASA's Aqua satellite passed over both Tropical Storm Nadine and Tropical Depression 15 (TD15) on Oct. 3 at 1553 UTC (11:53 a.m. EDT), before TD15 became Tropical Storm Oscar. While overhead, the Atmospheric Infrared Sounder (AIRS) instrument aboard Aqua captured two different images of both storms. One image was near infrared and almost visible light, while the other was infrared.

The near infrared image on Oct. 3 provided a look at the cloud cover and the cloud top temperatures as well as the sea surface temperatures. Most of the strongest thunderstorms were identified in infrared imagery by the coldest cloud top temperatures (meaning that they are higher in the atmosphere where temperatures are colder). Strongest storms in Oscar were located east of the center of circulation. That's because wind shear was pushing them away from the center, and that wind shear would continue to batter the storm again on Oct. 4.

Nadine wasn't even showing any high, powerful thunderstorms. Although the circulation of Nadine could be seen on the near-infrared, almost visible image, there were no strong storms around the circulation center.

Tropical Storm Oscar Stretching Out

Tropical Depression 15 strengthened into Tropical Storm Oscar at 11 p.m. EDT on Oct. 3, 2012. On Oct. 4, Oscar's maximum sustained winds were near 40 mph (65 kph). The National Hurricane Center doesn't expect much change in Oscar in the near term, before things get worse for the storm. Oscar's center was 1,245 miles 2,005 km west-northwest of the Cape Verde Islands, near latitude 20.0 North and longitude 42.5 West. Oscar is moving toward the north-northwest near 9 mph (kph) and is expected to turn north, followed by a turn to the northeast on Oct. 5.

Infrared imagery showed that although strong convection and thunderstorms have increased in intensity and coverage during the morning on Oct. 4, the bulk of them are east of the center because of westerly wind shear between 15 and 20 knots. The storm was not symmetric as a result of the wind shear. A storm needs to be symmetric to strengthen, and the wind shear is preventing that from occurring. As a result, the National Hurricane Center expects Oscar to become an open trough (elongated area) of low pressure by late Friday, Oct. 5.

Tropical Storm Nadine Being Chased by a Cold Front

Tropical Storm Nadine is becoming associated with a nearby cold front that appeared on near-infrared and infrared imagery as a strong wedge of clouds with cold cloud top temperatures. That front was moving toward Nadine from the northwest.

In the meantime, a Tropical Storm Warning for the Azores was still in effect. At 8 a.m. EDT on Oct. 4, Tropical Storm Nadine had maximum sustained winds near 45 mph (75 kph). Nadine was located near latitude 39.0 North and longitude 27.2 West, just 20 miles (30 km) north-northwest of Lajes in the Azores. Nadine is moving to the northeast at 23 mph (37kph) and is losing tropical characteristics. The National Hurricane Center expects Nadine to become post-tropical later in the day, on Oct. 4, Thursday.

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



Oct. 3, 2012

satellite image of TD 15

NASA's Terra satellite passed over newborn Tropical Depression 15 on Oct. 3 at 8:52 a.m. EDT in the central Atlantic Ocean. (Credit: NASA/NRL)
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NASA Sees 15th Atlantic Tropical Depression Born

The fifteenth tropical depression of the Atlantic Ocean hurricane season was born on Oct. 3; an NASA's Terra satellite captured an image of it as it came to be.

NASA's Terra satellite passed over newborn Tropical Depression 15 on Oct. 3 at 8:52 a.m. EDT in the central Atlantic Ocean and the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument captured an image of the storm. Shortly after the image was created, forecasters at the National Hurricane Center looking at the MODIS and other satellite data determined that the low pressure area had become a depression.

On Oct. 3 at 11 a.m. EDT, the center of tropical depression fifteen (TD15) was located near latitude 17.3 north and longitude 41.5 west, about 1,160 miles (1,870 km) west of the Cape Verde Islands. The depression is moving toward the northwest near 15 mph (24 kmh) and is expected to turn north and slow down by Oct. 4 before turning to the northeast. TD15's maximum sustained winds were near 35 mph (55 kph). TD15's estimated minimum central pressure was 1008 millibars.

The depression is expected to strengthen into Tropical Storm Oscar later on Oct. 3 or by Oct. 4 and move to the north and northeast. The National Hurricane Center does not expect Oscar to last very long because it is forecast to move into hostile atmospheric territory.

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