Oct. 24, 2008
TD 17-E in the Eastern Pacific Not Expected to Last Much Longer
Hurricane Season 2008: Tropical Depression 17 (Eastern Pacific)
The seventeenth tropical depression in the eastern Pacific Ocean was raining on parts of southwestern Mexico on Oct. 24, but is expected to fizzle at sea by the beginning of next week. Forecasters using computer models and NASA satellite data are getting in inside look at why the storm is weakening.
On Friday, Oct. 24 at 11:00 a.m. EDT (8:00 a.m. PDT) Tropical Depression 17-E (TD 17) was very poorly organized. What was identified as its center was about 240 miles southwest of Manzanillo, Mexico, near latitude 16.4 degrees north and longitude 106.7 west. It had sustained winds near 35 mph, and it is expected to weaken over Saturday and Sunday, Oct. 25 and 26. TD 17 is moving northwest near 8 mph and is expected to turn west-northwest and head out to sea on Sat. Oct. 25. Its minimum central pressure was 1008 millibars.
On Friday, October 24, the depression brought some heavy rain to parts of southwestern Mexico. The National Hurricane Center forecast between 3 and 5 inches of rain across the southwestern Mexican states of Jalisco, Colima and Michoachan. Some areas could see isolated amounts to 8 inches. Residents in those states have been warned that the rain may produce life-threatening flash floods and mudslides.
Computer Models and Satellite Data See Why TD 17 Is Weakening
Computer model and satellite data are helping forecasters understand why TD 17 is weakening. Forecasters at the Cooperative Institute for Meteorological Satellite Studies (CIMSS), located at the University of Wisconsin-Madison analyzed the upper level winds around southwestern Mexico using NASA QuikScat satellite data in computer models.
NASA's Quick Scatterometer satellite (QuikScat) can actually "see" winds by using microwaves to peer into the clouds. QuikScat can also determine the speed of the rotating winds. CIMSS forecasters determined the upper level winds are blowing at 30-50 knots (34-57 mph) meaning they're strong enough to create wind shear that is tearing the structure of the tropical depression apart.
The CIMSS forecasters shared that information with the National Hurricane Center, who noted that "The low-level center [of TD 17] has become elongated and difficult to identify making the initial motion estimate an uncertain [northwesterly direction near 8 mph].
The National Hurricane Center forecast calls for gradual weakening of TD 17. It is expected to become a remnant low pressure area by Sunday, Oct. 26 (12 p.m. EDT), and dissipate by Monday, Oct. 27.
GOES Catches TD 17's Clouds Over Southwestern Mexico
This satellite image was captured on October 24 at 14:45 UTC (10:45 a.m. EDT) from the Geostationary Operational Environmental Satellite (GOES-11). Tropical Depression 17-E is the circular area of clouds in the bottom left corner of the image.
GOES is operated by the National Oceanic and Atmospheric Administration. It was created by NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md. Text credit: Rob Gutro/Goddard Space Flight Center
Oct. 23, 2008
Seventeenth Tropical Depression Forms in Eastern Pacific
The Eastern Pacific Ocean hurricane season marches on, and the seventeenth tropical depression formed on Oct. 23, around 9:15 a.m. PDT (12:15 p.m. EDT).
Tropical Depression 17 (TD 17)formed about 410 miles south of Manzanillo, Mexico, near l3.1 degrees north latitude and 104.9 degrees east longitude. TD 17's maximum sustained winds were near 35 mph, but it had higher gusts, and is expected to strengthen into a tropical storm by Friday, Oct. 24. When it does, it will get the name "Polo."
TD 17 was moving north near 6 mph, but it's forecast to hook to the northwest then west over the weekend. The good news is that it is expected to move away from the mainland. TD 17's estimated minimum central pressure was 1008 millibars.
This visible image was created on Oct. 23 at 15:32 UTC or 1:32 p.m. EDT from the Geostationary Operational Environmental Satellites (GOES-11 and GOES-12). In the image, TD 17 is located in the bottom center, as a round swirl of clouds.
GOES-11 and 12 are operated by the National Oceanic and Atmospheric Administration. This image was created by NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md.
Rob Gutro, NASA's Goddard Space Flight Center