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Hurricane Season 2007: Karen (Atlantic)
Tropical Storm Karen Still in the Central Atlantic, Away from Land

Satellite image of Tropical Storm Karen
Click image for enlargement.

Tropical Storm Karen is in the central Atlantic Ocean and remains no threat to land over the weekend of Sept. 28-30.

The National Hurricane Center reported at 11:00 a.m. EDT on Thursday, Sept. 27 that Tropical Storm Karen was maintaining tropical storm strength, despite being disorganized.

At 1100 a.m. EDT Karen's center was located near latitude 13.7 north and longitude 47.3 west or about 920 miles east of the Windward Islands. Karen was moving west-northwest near 12 mph and the motion is expected to continue for the next day. Extended forecasts take Karen on a track turning her further to the north-northwest and away from the Windward Islands Sunday and Monday, Sept. 30 and Oct. 1.

Maximum sustained winds are near 65 mph with higher gusts. Karen is currently in an area of unfavorable upper-level winds...and some further weakening is forecast during the next 24 hours. Her minimum central pressure was 1004 millibars.

This image from NASA's QuikSCAT satellite was taken at 4:52 p.m. EDT (20:52 UTC) on Sept. 26. It depicts Karen's wind speed in color and wind direction with small barbs. White barbs point to areas of heavy rain. The highest wind speeds, are shown in purple, which indicate winds over 40 knots (46 mph).

Rob Gutro
Goddard Space Flight Center
Image credit: NASA/JPL

Tropical Storm Karen in Central Atlantic, No Threat to Land

Satellite image of Tropical Storm Karen
Click image for enlargement.

Late at night, around 11 p.m. EDT on Monday, Sept. 24, a large area of low pressure in the eastern Atlantic Ocean became organized enough to be classified as a tropical depression. Hours later, this twelfth tropical depression of the Atlantic Ocean hurricane season strengthened into a tropical storm, and was named Karen.

At 5:00 a.m. EDT on Tuesday, Sept. 25, Tropical Storm Karen was located near latitude 10.4 degrees north, and longitude 38.0 degrees west, or about 1,565 miles east of the Windward Islands.

Maximum sustained winds are near 40 mph with higher gusts. Some additional strengthening is forecast during the next 24 hours. Minimum central pressure was 1005 millibars.

Karen was moving toward the west-northwest near 16 mph and is expected to continue moving in that direction for the next day. Thereafter, Karen is forecast to turn toward the west-northwest and pass far to the east of the Windward Islands.

This image from the National Oceanic and Atmospheric Administration's Geostationary Operational Environmental Satellite-12 (GOES-12) shows Tropical Storm Karen far to the east of the Windward Islands in the lower right corner. This image was taken on Wednesday, Sept. 25 at 8:41 a.m. EDT. The image was created by NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md.

Rob Gutro
Goddard Space Flight Center
Image credit: NASA/GOES

Tropical Storm Karen Forms in the Atlantic

Karen recently became the eleventh named storm of the 2007 Atlantic hurricane season. There are about 10 named storms in an average year with 6 typically becoming hurricanes. Although the peak of the Atlantic season, which is around mid-September, is now past, October can still be a fairly active month. The season officially runs through November.

The 12th tropical depression (TD #12) of the season originated from an area of low pressure in the central Atlantic during the night of 24 September 2007 (local time). Systems that form this far east are known as Cape Verde storms. They are more common in the middle of hurricane season as warmer waters expand farther east towards Africa. On the morning of the 25th, TD #12 was upgraded to Tropical Storm Karen. With plenty of warm water available, Karen started to show signs of strengthening on the morning of the 26th; however, later that day the system began to encounter strong southwesterly wind shear and stopped intensifying.

TRMM image of Tropical Storm Karen taken on September 24, 2007.

This image was taken by the Tropical Rainfall Measuring Mission satellite (known as TRMM) at 01:19 UTC 27 September (9:19 pm EDT 26 September) 2007 and shows Tropical Storm Karen as it was moving west-northwest through the central Atlantic about 1100 miles east of the Windward Islands. The image shows the horizontal pattern of rain intensities estimated from TRMM satellite data. Rain rates in the center swath are based on the TRMM Precipitation Radar (PR), and those in the outer swath on the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). The effects of the southwesterly shear are readily apparent. Nearly all of the rain, including several areas of heavy rain (shown by the darker reds), is displaced northeast of the center of circulation (denoted by the tropical storm symbol). This disruption to the storm's structure greatly inhibits its ability to strengthen as the heat released by the active convection (associated with the moderate to heavy rain) is blown downstream away from the center of circulation. At the time of this image, Karen's maximum sustained winds were reported at 60 knots (69 mph) by the National Hurricane Center. The system is expected to slowly weaken as a result of the ongoing wind shear and turn more northward away from the Caribbean. TRMM is a joint mission between NASA and the Japanese space agency JAXA. Credits: Images produced by Hal Pierce (SSAI/NASA GSFC) and caption by Steve Lang (SSAI/NASA GSFC).