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Hurricane Season 2009: Honduran Low (Atlantic/Caribbean Sea)
June 8, 2009

Infrared image of the Honduran Low from NASA's AIRS instrument. Purple indicates coldest clouds and strongest thunderstorms. Infrared image of the Honduran Low from NASA's AIRS instrument. Purple indicates coldest clouds and strongest thunderstorms. > Larger image
Image Credit: NASA JPL/Ed Olsen
Honduran Low Being Eyed for Tropical Development

There's a low pressure area producing showers and thunderstorms over the southwestern Caribbean Sea that forecasters are watching for possible development into a tropical depression.

The National Hurricane Center notes that there's a 30 percent chance of the low developing into a tropical depression. Although that may seem low, that was the chance the first tropical depression of the Atlantic Ocean season was given before it "went tropical."

Tropical depression one for the Atlantic season formed at sea on May 28, about 310 miles south of Providence, Rhode Island and stayed in the open ocean. It never strengthened into a tropical storm and didn't get a name.

The showers and thunderstorms associated with the Low pressure system, located to the east of Honduras, Central America, will produce heavy rains over portions of Central America and Jamaica during the next couple of days. The upper level winds in the region, however, are limiting the Low's ability to organize any further at this time. If it does become tropical, it would likely happen by Wednesday morning, June 10.

NASA's Aqua satellite flew over the "Honduran Low" on Monday, June 8 at 3:11 a.m. EDT (7:11 UTC) and captured this infrared image from its Atmospheric Infrared Sounder (AIRS). AIRS is used to identify the cloud temperatures in storms to help determine the height and temperature of the clouds. The colder the clouds, the higher they are, and the stronger the thunderstorms.

There's a large temperature difference between typhoon's cloudtops and the warmer ocean waters. The lowest temperatures (in purple) are associated with high, cold cloud tops in the storm. Those temperatures are as cold as or colder than 220 degrees Kelvin or minus 63 degrees Fahrenheit (F). The blue areas are around 240 degrees Kelvin, or minus 27F.

Because the AIRS infrared signal doesn't penetrate through clouds areas of clear skies show the infrared (heat) signal from the ocean and land surfaces, revealing warmer temperatures (colored in orange and red). The orange temperatures are 80F (300 degrees Kelvin) or greater (the darker the color, the warmer the temperature). Notice that the waters in the Gulf of Mexico are warm enough to support tropical cyclone formation. It's just that the upper level winds are lowering the chances for this storm to come together.

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