NASA eyes Tropical Storm Nalgae negotiating wind shear
Infrared imagery from NASA looked at cloud top temperatures in Tropical Storm Nalgae and revealed that wind shear was still affecting the storm.
The Atmospheric Infrared Sounder or AIRS instrument aboard NASA's Aqua satellite looked at cloud top temperatures in Tropical Storm Nalgae using infrared light. The AIRS data were taken on Aug. 2 at 10:29 a.m. EDT (1429 UTC) and showed coldest cloud tops were still northeast and east of center indicating that the storm was dealing with wind shear. Cloud top temperatures of minus 63 degrees Fahrenheit (minus 53 degrees Celsius) in the eastern side of the storm indicated storms high in the troposphere.
Nalgae was also being affected by an upper atmospheric system which is inhibiting development of storms in the other quadrants of the storm.
Basically, the higher the cloud tops, the colder and stronger the storms than make up the tropical cyclone. So, infrared light as that gathered by the AIRS instrument can identify the strongest sides of a tropical cyclone. The infrared data was false-colored at NASA's Jet Propulsion Laboratory in Pasadena, California, where AIRS data is managed.
At 11 a.m. EDT (1500 UTC) on Aug 3 the center of Tropical Storm Nalgae was located near 27.7 degrees north latitude and 163.3 degrees east longitude. That's about 519 nautical miles northwest of Wake Island. Maximum sustained winds were near 46 mph (40 knots/74 kph).Nalgae was moving to the northwest at 8 mph (7 knots/13 kph).
Upper-level analysis indicates that the system is located under an upper low pressure area, which is hindering thunderstorm development.
The Joint Typhoon Warning Center said that Nalgae is expected to strengthen slightly before becoming extra-tropical in the next couple of days.