Typhoon Bopha, A category 4 (131 – 155 MPH) late-season cyclone that formed unusually close to the equator in the Western Pacific Ocean, is bearing down on the nation of Palau this weekend.

Palau is a small nation of approximately 21,000 inhabitants located to the east of the southern edge of the Philippines. Bopha may also make landfall over Mindanao, an island which was devastated by Washi in December, 2011.

Bopha’s maximum sustained winds are currently at 130 mph and may increase slightly before the core of the system impacts the islands. Typhoons do not typically impact Palau due to its low latitude outside of more common West Pacific storm tracks.

NASA’s TRMM Satellite noticed several “hot towers” in Bopha. When a cumulonimbus cloud reaches the top of the troposphere, it is called a hot tower. The troposphere is the lowest layer of the atmosphere. In the part of the tropics where Bopha is located, the troposphere extends nine miles high into the sky. Bopha’s hot towers were over 9.3 miles high. Latent heating allows these cumulonimbus towers to reach so high into the atmosphere. As water vapor condenses into liquid, it releases latent heat. NASA has done research showing that when a tropical cyclone has hot towers in its eyewall, it is twice as likely to intensify within the followers six or more hours, than a comparative cyclone without these hot towers. After NASA’s TRMM satellite spotted the hot towers of Bopha, the storm soon intensified into a typhoon.

The last Typhoon to impact the island of Koror was way back in 1976, and was a much weaker storm, bringing winds of about 85 mph to the island.

The National Weather Service official forecast track takes Bopha south of Ngulu and very close to the islands of Koror and Kayangel in the Republic of Palau.

National Weather Service updates on Bopha can be found here: http://www.prh.noaa.gov/koror/kororCyclone.php