Typhoon Soulik's large eye wide open on NASA satellite imagery

When NASA's Terra satellite passed over Typhoon Soulik in the Northwestern Pacific Ocean on Aug. 20 water vapor imagery revealed a large, clear eye.

NASA's Terra satellite passed over Soulik on Aug. 20 at 8:45 a.m. EDT (1245 UTC) and the Moderate Resolution Imaging Spectroradiometer or MODIS instrument gathered water vapor content and temperature information.

Water vapor analysis of tropical cyclones tells forecasters how much potential a storm has to develop. Water vapor releases latent heat as it condenses into liquid. That liquid becomes clouds and thunderstorms that make up a tropical cyclone. Temperature is important when trying to understand how strong storms can be. The higher the cloud tops, the colder and the stronger they are.

MODIS saw coldest cloud top temperatures around the 40 nautical mile wide eye. Those cloud top temperatures were as cold as minus 70 degrees Fahrenheit (minus 56.6 degrees Celsius). Storms with cloud top temperatures that cold have the capability to produce heavy rainfall.

The Joint Typhoon Warning Center or JTWC noted, "The cyclone appears annular with fairly uniform convection surrounding the eye."

On Aug. 20 at 11 a.m. EDT 1500 UTC), Soulik's maximum sustained winds were near 115 mph (100 knots/185 kph). Soulik was centered near 26.7 degrees north latitude and 134.0 degrees east longitude, about 360 nautical miles east of Kadena Air Base, Okinawa Island, Japan. Soulik was moving to the west-northwestward at11.5 mph (10 knots/18.5 kph).

JTWC said Soulik will maintain current strength for two days, before turning northward and weakening rapidly over the Korean peninsula.