Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 12:52 PM GMT on September 28, 2009
The Philippine Islands continue to count the dead in the wake of the catastrophe left by Tropical Storm Ketsana on Saturday. Hard-hit was the capital of Manila, where the 16.7 inches of rain that fell in just 12 hours set a record for the heaviest 1-day rainfall ever recorded in the city (previous record: 13.2 inches in 24 hours, set in June 1967). In the six hours between 8am and 2pm local time on the 25th, Manila recorded 13.4 inches of rain--over 2.2 inches per hour. There rainfall rates were observable via satellite observations from NASA's TRMM satellite, well in advance of when the storm made landfall in the Philippines (Figure 2). The TRMM satellite showed a small core of heavy rain in excess of 1.6 inches per hours near the center of Ketsana, and this core moved directly over the city of Manila.
Figure 1. Cars being swept away by Ketsana's flood waters in a still frame from a dramatic YouTube video captured by medical students at the East Ramon Magsaysay Memorial Medical Center.
The flooding from Ketsana's rains was the worst in at least 42 years in Manila, and President Gloria Arroyo called Ketsana "a once-in-a-lifetime typhoon". At least 140 people are dead, 32 missing, and up to 450,000 homeless from the flooding in the Philippines.
Ketsana is not finished yet. The typhoon has begun a period of rapid intensification, and is now on the verge of attaining Category 2 typhoon status as it approaches a Tuesday landfall in Vietnam. Ketsana's heavy rains and high winds could exact a high toll in Vietnam.
Figure 2. Rainfall from Tropical Storm Ketsana as estimated by NASA's TRMM satellite, a few hours before the heavy rainfall began in Manila. Note the small core of heavy rain with rainfall rates off-scale (greater than 1.6 inches/hour) to the east of Manila. This region of heavy rain passed directly over the city between 8am and 2pm local time on 9/25/09. Image credit: Navy Research Lab, Monterey..
Quiet in the Atlantic
None of the computer models are forecasting tropical storm formation in the Atlantic over the next seven days. Wind shear is predicted to be high in the Gulf of Mexico and Caribbean this week, limiting the potential for anything to develop close to land.
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