Rapid scan of increasingly angry core of #Koppu / #LandoPH as it bears down on #Philippines (Img: NOAA/RAMMB/CIRA) - @Stu Ostro
Disastrous Rains Possible in Philippines from Typhoon Koppu
By: Jeff Masters and Bob Henson, Weather Underground
Heavy rains have begun on the Philippines' main island of Luzon as intensifying Typhoon Koppuheads west-northwest at 11 mph towards the Philippines. At 8 am EDT Friday, Koppu was a Category 2 storm with 105 mph winds, and satellite loops showed that Koppu had an impressive ring of eyewall clouds with very cold cloud tops that extended high into the atmosphere.
The combination of low wind shear, warm ocean waters that extend to great depth and the presence of two impressive upper level outflow channels make it likely that Koppu will rapidly intensify to Category 4 status before landfall occurs near 18 UTC (2 pm EDT) Saturday on Luzon. Unfortunately for the Philippines, Koppu will then slow and turn to the north as the storm begins to feel the steering influence of a trough of low pressure passing to its north, and the center of the storm is likely to spend 2 - 2.5 days over Luzon before finally emerging to the north of Luzon on Monday or Tuesday.
This will subject the island to an extended period of torrential rains, and some truly prodigious amounts of rainfall are being predicted. The 06Z (2 am EDT) Friday runs of the both the HWRF andGFDL models predicted that Koppu would intensify to Category 4 strength before making landfall, and showed large areas of 24+ inches of rain for Luzon over the next five days.
The capital of Manila (population 12 million) was near the southern boundary of the predicted 12-inch rainfall totals. While rainfall forecasts from these two models are often overdone by 50%, it appears likely that a historic rainfall event is likely for the Philippines. Expect widespread damaging flooding capable of causing a top-five most expensive disaster in Philippine history.
Best historical analogue for Koppu's rains: the historic rains of August, 2013?
The best historical analogue for the rains expected from Koppu may be an extreme monsoon rainfall event on August 18 - 21, 2013, which was enhanced by moisture from Tropical Storm Trami.
The best historical analogue for the rains expected from Koppu may be an extreme monsoon rainfall event on August 18 - 21, 2013, which was enhanced by moisture from Tropical Storm Trami.
Up to 600 millimeters (23.5 inches) of rain fell during one 24-hour stretch, and about 60% of metro Manila was under water at one point. At least 27 people died, and damage was estimated at $2.2 billion, making it the Philippines' second most expensive disaster in their history.
The top five most expensive disasters in Philippines history, according to EM-DAT (dollar values unadjusted for inflation):
1) Super Typhoon Haiyan, 11/8/2013, $10 billion
2) Monsoon rains increased by Tropical Storm Trami, 8/20/2013, $2.19 billion
3) Super Typhoon Bopha, 12/4/2012, $898 million
4) Super Typhoon Rammasun, 7/15/2014, $821 million
5) Tropical Storm Nina, 9/4/1995, $700 million
The top five most expensive disasters in Philippines history, according to EM-DAT (dollar values unadjusted for inflation):
1) Super Typhoon Haiyan, 11/8/2013, $10 billion
2) Monsoon rains increased by Tropical Storm Trami, 8/20/2013, $2.19 billion
3) Super Typhoon Bopha, 12/4/2012, $898 million
4) Super Typhoon Rammasun, 7/15/2014, $821 million
5) Tropical Storm Nina, 9/4/1995, $700 million
 |
| Figure 1. Typhoon Koppu (left) and Typhoon Champi (right) as seen by Japan's Himawari satellite on Friday, October 16, 2015. Image credit: Japan Meteorological Agency. |
