Want to see what a major hurricane looks like chewing through a nation of 29 islands, 661 cays, and 2,387 islets? NASA’s TRMM satellite has the goods, displaying Hurricane Irene—white tendrils of tropical fury stretching hundreds of miles north and south of the island chain—as it whips over Crooked Island in the Bahamas.
TRMM, which stands for Tropical Rainfall Measuring Mission, also has its eye on Irene’s moisture output. According to NASA, the satellite’s been able to track rainfall rates, cloud heights and “hot towering clouds that act as hurricane heat engines.”
Irene, now a formidable Category 3 hurricane with wind speeds of 115 mph, pummeled the Bahamas early this morning as it continues to swing to the north on its way toward the U.S. East Coast. It’s expected to intensify to an even more frightening Category 4 (wind speeds of 131 to 155 mph) as it speeds over warm Atlantic water east and south of Florida.
NASA says its TRRM satellite passed directly over Irene on Tuesday, snapping several jaw-dropping pics and highlighting a few curious details. For instance, Irene didn’t have a visible “eye”—the circular area in a tropical storm of relatively light winds and clear skies, surrounded by the “eyewall,” an area of towering, often deadly thunderstorms. But TRRM was able to discern one anyway, “deep down under the cloud tops.”
It’s able to do so by capturing multiple data types and overlaying each, like precipitation radar, which quantifies rain rates, and microwave imaging, which measures energy emissions to gauge everything from air and sea surface temperatures to how much water vapor there is between the satellite’s measuring instrument and the earth’s surface.
How much rain are we talking? TRRM found that in one corner of Irene’s eyewall, the rain was pouring at a rate of 2 inches an hour. And that’s while it was still a Category 1.
When TRRM came around for a second pass yesterday at 11:42 a.m. EDT, it noticed that Irene’s eye was now visible, that the storm had intensified causing rainfall to be more evenly distributed around the center and that pressure at the storm’s center was still falling—a clear indication Irene’s continuing to pick up speed (winds were 120 mph at TRRM’s last check) meaning it could well become a Category 4 hurricane as it moves to menace the U.S. Eastern Seaboard.
Although Irene’s still over 200 miles south of Florida, it’s making its presence known—according to The Boston Globe, you can already see its (pretty darned ominous looking) cloud bands over Miami’s Biscayne Bay, today.