image: This TRMM rain map ending at 0600 UTC on Aug. 17 covers the three hour period of rainfall from Aug. 16 at 11 p.m. EDT to Aug. 17 at 2 a.m. EDT. The red area over southeastern and south central Louisiana indicates rainfall .3-.4 inches (6-8 millimeters) over that three hour period. view more
Credit: NASA TRMM, Hal Pierce
NASA's Aqua and TRMM satellites and the GOES-13 satellite have been keeping an eye on the meandering remnants of Tropical Depression 5 (TD5). More rainfall is something that southeastern Louisiana and coastal Mississippi does not need after TD5 tracked through the area this past weekend. However, NASA satellites see TD5 making a return appearance and bringing the heavy rains with it to the same areas today.
TD5 has been around the Gulf of Mexico for a week as of today, August 17. That's a long life for a tropical system. TD5 formed on August 10 and never made it to tropical storm status. After a day of being back over the warm waters of the Gulf of Mexico yesterday, TD5 is now back over land. That means that the TD5's remnant low pressure area is being cut off from the warm Gulf of Mexico waters that would re-strengthen it into a tropical depression.
On August 16 at 19:35 UTC (3:35 p.m. EDT) an infrared image of Tropical Depression 5's clouds from the Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aqua satellite showed a disorganized system. At that time, the strongest convection (and thunderstorms) appeared in several areas and had cloud-top temperatures as cold or colder than -63 Fahrenheit. Those areas appeared scattered in a half -moon shape from stretching from west to east and all south of Louisiana. The half-moon shape of storms stretched from southeastern Texas eastward to various areas south of Louisiana in the Gulf of Mexico.
Today, August 17, TD5's remnants moved inland over the western Mississippi Gulf Coast during the early morning hours (EDT), so the National Hurricane Center in Miami, Fla. noted that there is now a "near zero chance" that TD5's remnants will reform into a tropical depression. That doesn't mean that the Gulf coast will be devoid of effects, however.
The Tropical Rainfall Measuring Mission satellite (TRMM) has been measuring TD5's rainfall from space since it developed. "Rainmaps" showing how much rain has fallen over given areas in either in a three hour or seven day period are created at NASA's Goddard Space Flight Center in Greenbelt, Md. The three-hour rainfall accumulation map created today, August 17 for the three hour period of rainfall from Aug. 16 at 11 p.m. EDT to Aug. 17 at 2 a.m. EDT showed the heaviest rainfall over southeastern and south central Louisiana where rainfall between .3 and .4 inches (6-8 millimeters) fell early this morning.
Just as TD5 moved inland this weekend over Louisiana and Mississippi and brought heavy rainfall, its bringing them back for an encore performance. Locally heavy rainfall and occasional gusty winds associated with the low are still possible along portions of the north-central Gulf of Mexico coast today.
The Geostationary Operational Environmental Satellite, GOES-13 captured a visible image of TD5's remnants today at 1401 UTC (10:01 a.m. EDT). The image showed a disorganized and elongated system over Mississippi and southeastern Louisiana. The GOES series of satellites is operated by NOAA. NASA's GOES Project, located at NASA's Goddard Space Flight Center in Greenbelt, Md. provides satellite imagery and animations.
Despite the disorganization, the remnants of TD5 are still packed with abundant moisture, so the National Weather Service (NWS) office in New Orleans, La. has posted a Flash Flood Watch for portions of southeast Louisiana and southern Mississippi through Wednesday evening. Coastal flooding is also possible along the western Mississippi coast and portions of the east facing shores of southeast Louisiana so a coastal flood advisory is in effect through the first half of today.
TD5's remnant low pressure area is expected to move slowly west and northwest across southeast and east central Louisiana today and tonight. The NWS is expected another 3 to 5 inches of rainfall with isolated amounts up to 8 inches by Wednesday afternoon.To see live National Weather Service radar covering the region, go to: http://radar.weather.gov/radar.php?rid=LIX&product=NCR&overlay=11101111&loop=yes.
Any slower moving showers and thunderstorms with heavy rainfall could drop 2 to 4 inches in a short time, causing flash flooding.
NASA satellites will continue to provide forecasters with data as the remnants of Tropical Depression 5 continues on its second inland journey.