Tropical Storm Oli Kicking Up Waves in South Pacific

NASA’s Atmospheric Infrared Sounder (AIRS) instrument captured an infrared image of Oli’s cloud temperatures on February 2 at 0041 UTC. High thunderstorm cloud tops surrounded Oli’s center as cold as minus 63F. There is a separate band of clouds associated with Oli to the north.

At 1500 UTC (10 a.m. ET) on February 2, Oli had maximum sustained winds near 52 mph (45 knots) with higher gusts. It was located about 480 nautical miles west of Bora Bora, near 14.8 South and 159.5 West. Oli has tracked eastward at 11 mph (10 knots).

Tropical Cyclone Bongani dissipated today, November 26, in the Mozambique Channel as a result of wind shear.

Wind shear is a difference in wind speed and direction over a relatively short distance in the atmosphere. Wind shear can be both vertical and horizontal. Horizontal wind shear is seen across front, while vertical wind shear can be near the Earth’s surface or higher levels in the atmosphere near upper level jet streams. Wind shear can tear storms apart.

If you think of a tropical cyclone as a haystack, and you direct giant fans blowing at different heights of the stack, going different ways, that’s similar to how wind shear affects a tropical cyclone. It pushes into its circulation, weakening it.

It seems like a common occurrence this season that there are two tropical cyclones spinning in the Western Pacific Ocean and this week, Lupit and newly formed 23W are proof. NASA’s Aqua satellite flew over the Western Pacific early today and captured both storms in one satellite image.

Tropical Storm Lupit is becoming extra-tropical and is expected to track parallel to Japan while remaining at sea, east of the island. Meanwhile, Tropical Storm 23W is approaching Saipan and Andersen Air Force Base and is moving west. The U.S. Navy’s Joint Typhoon Warning Center (JTWC) forecasts tropical cyclones in the Western Pacific Ocean. The JWTC issued their final warning for Extra-tropical Storm Lupit today, October 26 at 0300 UTC (12 a.m. local time Tokyo).

At that time, Lupit had maximum sustained winds near 52 mph and was stirring up rough surf and high waves along eastern Japan’s coastline. Extra-tropical storm Lupit was located approximately 580 nautical miles southwest of Tokyo, Japan, near 28.4 North and 134.8 East. It was moving northeast at 21 mph, and is expected to continue moving in that direction staying in open ocean. Lupit was completing transition to an extra-tropical storm and is also being adversely affected by wind shear (winds blowing at the storm in different levels of that atmosphere, that tear the storm apart). NASA’s Aqua satellite flew over both Lupit and TD23W on October 26 at 3:41 UTC (October 25 at 11:41 p.m. EDT).

The Atmospheric Infrared Sounder (AIRS) instrument on Aqua captured both a visible and infrared image of the storms. The infrared satellite image confirmed that all of Lupit’s deep convection (developing strong thunderstorms) has dissipated, and the most intense precipitation has shifted all to the northeast of the center of circulation, further exposing the center to wind shear. Meanwhile, the image also showed that 23W appeared to be getting well-organized.

Tropical Storm 23W had maximum sustained winds near 40 mph at 11 a.m. EDT on October 26. The storm’s center was about 200 nautical miles east of Guam, near 13.4 North and 147.7 East. It was moving west-northwest near 17 mph. NASA’s CloudSat satellite also flew over 23W earlier this morning.

CloudSat captured a side view of 23W’s clouds on Oct. 26 between 03:43 – 03:46 UTC. CloudSat revealed sustained winds of 27 mph and a minimum central pressure of 1002 millibars when it was centered near 122 North and 151.3 East. Sustained winds have since increased to 40 mph. CloudSat also showed some high, strong thunderstorm cloud tops over 14 kilometers (almost 9 miles) high. The forecast track from the JTWC takes Tropical Storm 23W between Andersen Air Force Base (island) and the island of Saipan, located north of Andersen. The storm is then forecast to intensify and move west toward the Philippines.

20W Grows into Tropical Storm Melor, Threatens Guam

Guam just got through Tropical Depression 18W and is still contending with heavy surf from the storm. Now, Tropical Depression 20W has strengthened into a tropical storm named “Melor” and that storm is headed toward Guam. It is expected to start affecting Guam in the next two days.

Tropical Storm Melor was packing sustained winds near 80 mph (70 knots) on September 30 at 1500 UTC (11 a.m. EDT) or October 1 at 3 a.m. local time in Guam. Its center was located about 495 miles east-southeast of Saipan near 12.9 north and 153.9 east. It was moving west-northwest near 9 mph.

Melor’s tropical storm-force winds extend up to 50 miles from the center, and its generating waves up to 17 feet high. Melor is still intensifying and is forecast to move west-northwest toward Guam. Melor is expected to reach typhoon strength.

The Aqua satellite flew over Tropical Storm Melor at 1 p.m. local (Guam) time, September 30 and the Atmospheric Infrared Sounder (AIRS) instrument provided valuable infrared data on its cloud top temperatures. They’re important because they tell forecasters how high thunderstorms are, and the higher the thunderstorm, the more powerful it is, and the data helped forecasters see Melor’s cloud tops were as cold as or colder than minus 63 degrees Fahrenheit (F). The infrared satellite imagery also showed Melor had two large areas of high, strong, thunderstorm cloud tops around its center, indicating it is likely developing an eye and strengthening.