NASA, NOAA Satellites Show Wind Shear Affecting Tropical Storm Ida

On Sept. 22 at 12:17 p.m. EDT the Atmospheric Infrared Sounder, or AIRS, instrument aboard NASA's Aqua satellite provided an infrared look at Ida. AIRS data showed that southwesterly vertical wind shear was pushing clouds and strongest storms with coldest cloud tops to the east and northeast of the center. Cloud top temperatures were as cold as -63 degrees Fahrenheit/-53 degrees Celsius, indicative of strong storms with the potential for heavy rain. Fortunately, Ida remains over open ocean.

The next day a visible image of Tropical Storm Ida continued to show wind shear persisted. An image of Ida was taken from NOAA's GOES-East satellite on Sept. 23 at 7:45 a.m. EDT and showed clouds being blown to the east-northeast of the center from wind shear.

Forecaster Berg of NOAA's National Hurricane Center noted on Sept. 23, "Shortwave infrared satellite imagery and a microwave pass (a look at the storm using microwaves) suggest that multiple low-level swirls are revolving around Ida's center, which has been fixed to the west-northwest of an ongoing burst of deep convection (rising air that form the thunderstorms that make up a tropical cyclone). This pattern is the consequence of 30 knots of west-northwesterly [wind] shear."

At 5 a.m. EDT (0900 UTC), the center of Tropical Storm Ida was located near latitude 20.4 North, longitude 47.2 West. About 1,045 miles (1,685 km) east of the Northern Leeward Islands, Ida has been meandering toward the south near 2 mph (4 kph). A slow eastward motion is expected later today, followed by a turn toward the north on Thursday.


On Sept. 22 at 12:17 p.m. EDT the AIRS instrument aboard NASA's Aqua satellite provided this infrared look at Ida and saw wind shear pushing strongest storms with coldest cloud tops being pushed northeast of the center (in purple).
Credits: NASA JPL, Ed Olsen



This image of Tropical Storm Ida was taken from NOAA's GOES-East satellite on Sept. 23 at 7:45 a.m. EDT and showed clouds being blown to the east-northeast of the center from wind shear.
Credits: NASA/NOAA GOES Project

Maximum sustained winds are near 40 mph (65 kph) with higher gusts. Little change in strength is forecast through Thursday night. Tropical storm force winds extend outward up to 175 miles (280 km) mainly to the east of the center. The estimated minimum central pressure is 1005 millibars.

There are no coastal watches or warnings in effect as Ida is in the open central Atlantic Ocean.

In three days, the vertical wind shear is expected to ease enough to allow Ida to strengthen. Ida is expected to move to the east and then curve north later on Sept. 24.

Bron:http://www.nasa.gov/feature/goddard/ida-atlantic-ocean