The official start of the 2007 Atlantic hurricane season on June 1st was marked by the formation of Tropical Storm Barry in the Gulf of Mexico, the second named storm of the season. But, the news was good as Barry remained a weak tropical storm while delivering some much needed rain to Florida and parts of the Southeast, which are suffering from severe drought conditions and numerous wild fires.

Barry originated from a broad area of low pressure over the southeastern Gulf of Mexico. Following persistent showers and thunderstorms, the system was upgraded to a tropical storm at 21:00 UTC (5:00 pm EDT) on the 1st of June about 235 miles west of Key West, Florida. After a brief period of strengthening, Barry almost immediately began to suffer the effects of strong southwesterly wind shear brought on by an upper-level trough of low pressure extending down into the central Gulf of Mexico. As result, Barry quickly became disorganized as it was steered off to the northeast. The Tropical Rainfall Measuring Mission satellite (known as TRMM) was placed into service in November of 1997. From its low-earth orbit, TRMM has been providing valuable images and information on tropical cyclones around the Tropics using a combination of passive microwave and active radar sensors, including the first precipitation radar in space. The image on the right was taken by TRMM at 07:55 UTC (3:55 am EDT) 2 June 2007 as Barry was moving northeast in the southeastern Gulf of Mexico. The background 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). A tropical storm symbol marks the center of Barry. TRMM confirms that Barry was poorly organized. The low-level center of circulation (denoted by the tropical storm symbol) is displaced well to the southwest of the rain areas (green and blue areas). In fact, there is almost no rain in the immediate vicinity of the low-level center. This highly asymmetric structure is a result of the wind shear. Overlaid on this image is a 3D view of the rain shield courtesy of the TRMM PR. In general, storm tops are not especially deep, although some slightly higher tops (enhanced in red) are evident near the stronger echoes shown in dark red in the cross section. At the time of this image, Barry was a weak tropical storm with maximum sustained winds reported at 45 knots (52 mph) by the National Hurricane Center. Barry continued to move to the northeast and made landfall near Tampa Bay about 7 hours after the image was taken (11:00 am EDT). The system weakened as it moved diagonally across the state towards Jacksonville.

The TRMM-based, near-real time Multi-satellite Precipitation Analysis (MPA) at the NASA Goddard Space Flight Center monitors rainfall over the global Tropics. MPA rainfall totals are shown here for the period 31 May to 4 June 2007 for Florida and the surrounding region. The track for Barry is also shown for reference. The highest rainfall totals for the period (shown in red) are on the order of 4 to 6 inches over south-central Florida and east- central Georgia. Lesser amounts on the order of 2 to 3 inches (green to yellow areas) cover most of peninsular Florida and extend through the eastern half of Georgia and into the Carolinas. Despite the beneficial rains, most of the area remains in a drought.

Click to see a Quicktime animation (2.3MB) of Tropical Storm Barry rainfall.

TRMM is a joint mission between NASA and the Japanese space agency JAXA. Images produced by Hal Pierce (SSAI/NASA GSFC) and caption by Steve Lang (SSAI/NASA GSFC).