Soaking rain from Usagi has begun to pelt parts of northern Philippines even though the center of the storm will pass well north of the country.
Western and northern Luzon will be most prone to flooding through Monday as Usagi tracks toward southern Taiwan and Southeast China. Rainfall amounts have been generally 1 to 3 inches across northern Luzon through Friday, however the heaviest rainfall is yet to come.
At the same time, the brunt of the powerful storm's severe winds should, in the Philippines, strike only some small far-northern islands and perhaps the northern tip of mainland Luzon.
Rainfall could be heavy enough to trigger flooding in the capital region of the Philippines, which was inundated by literally feet of rainfall at the middle of August.
At that time, extreme rainfall and widespread major flooding was sparked indirectly by Tropical Storm Trami (known as Maring in the Philippines), the center of which actually stayed hundreds of miles north of the Philippines.
Usagi, like Trami before it, will unleash heavy rain as it activates and strengthens the southwesterly monsoon wind flow over the South China Sea and the Philippines. Whenever this happens, these wet tropical winds typically get wrung out between the west coast and the mountain spine that runs the length of Luzon. Manila is well placed to get a soaking under such circumstances.
The vast metropolitan area of Manila, low-lying and crossed by many waterways, is prone to flooding during the heavy rains of the summer monsoon.
As for the fate of Usagi, the powerful storm will pose a serious threat of destructive wind and flooding rain to both Taiwan and South China along and near its direct path on Saturday through Monday.
Meteorologist Eric Leister contributed to this story.
A tropical wave is likely to become the Atlantic Basin's next tropical storm as it approaches or crosses the Caribbean Sea later this week.
Bouts of wet weather will soak the northeastern United States during the last full week of September.
Typhoon Megi will threaten lives and property across Taiwan and eastern China into the middle of the week.
Gusty winds will accompany a push of chilly air across the Great Lakes through Tuesday.
The final day of September will bring a rare lunar event that hasn’t occurred since March of 2014, a Black Moon.
Following some rain and gusty winds on Tuesday, a strong storm will target the United Kingdom on Thursday.
Washington, D.C. (1975)
Last of nine straight days with some rain. Total rainfall of 9.86 inches; total for September 1975 was was 12.36 inches.
Cape Hatteras, NC (1989)
Rained every day from the 12th to the 25th for a total of 15.51 inches. Normal for all of September is 5.78 inches.
Portland, ME (1991)
Record combined August-September rainfall of 19.65 inches up to Sept. 25. Old record was 14.65 inches in August-September 1954.