Aug. 5, 2015

GPM Views Fading Rare Southern Hemisphere Tropical Cyclone

It is a little unusual to see a tropical cyclone forming in the southern Pacific Ocean this time of the year but tropical cyclone 01P formed northeast of Vanuatu recently. The Global Precipitation Measurement or GPM core observatory satellite saw Tropical Cyclone 01P on Monday August 3, 2015 at 2106Z (5:06 p.m. EDT/9:06 a.m. local time).
GPM's Microwave Imager (GMI) found rain falling at a rate of over 30 mm (1.2 inches) per hour in a small area of showers near the center of the tropical cyclone. A 3-D view constructed from GPM's Dual-Frequency Precipitation Radar (DPR) instrument (Ku band) showed that some showers located between the tropical cyclone's center and Vanuatu were shallow and reached heights of only about 6.5 km (4 miles). The highest storm tops of 12.4 km (7.7 miles) located northwest of the tropical cyclone were not associated with the TC01P.
Tropical Cyclone 01P ran into wind shear that weakened it to a remnant low pressure area on August 4. At 1500 UTC (11 a.m. EDT), former Tropical Cyclone 01P was located near 10.4 south latitude and 170.6 east longitude, about 458 nautical miles north-northeast of Port Vila, Vanuatu.
The Joint Typhoon Warning Center is watching 01P for the possibility of regeneration. Currently, it has a medium chance to regain tropical depression status in the next day.
It is unusual for a tropical cyclone to develop in the Southern Pacific in August, but Tropical Cyclone 1P formed as NASA-NOAA's Suomi NPP satellite passed overhead on August 3, 2015

The South Pacific cyclone season has an interesting time frame. It normally runs from November to April. This past season ran from November 1, 2014 to April 30, 2015, although a tropical cyclone could form at any time between July 1, 2014 and June 30, 2015, and that would count toward the season total. However, since Tropical Cyclone 01P formed in August, it will be part of the 2015-2016 season.
At 0900 UTC (5 a.m. EDT) on August 3, 2015, Tropical Cyclone 01P was located near 10.9 South latitude and 172.6 East longitude, about 548 nautical miles northwest of Suva, Fiji. Maximum sustained winds were near 35 knots (40 mph/62 kph) and it was moving to the east at 2 knots (2 mph/3.7 kph).
The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA's Suomi satellite captured an infrared image of 01P on August 3 at 13:14 UTC (9:14 a.m. EDT) that showed some thunderstorms within the tropical storm with very cold cloud top temperatures (near -63F/-53C). An SSMI image showed that the elongated low-level center was defined and had shallow bands of thunderstorms wrapping into it. The storm was being battered by moderate vertical wind shear.
Over the next couple of days, the tropical storm is forecast to move between Vanuatu to the west and the island of Fiji to the east.
01P is expected to move to the southwest and intensify to 45 knots (51.7 mph/83.3 kph) before vertical wind shear kicks in and weakens the storm. By August 5, it is expected to turn to the southeast and adverse conditions are expected to lead to its demise.

Image:
(Left) The Global Precipitation Measurement mission's Core Observatory saw showers located between the tropical cyclone's center and Vanuatu that were shallow and reached heights of only about 6.5 km (4 miles).
(Right) On August 3, 2015 the VIIRS instrument aboard NASA-NOAA's Suomi satellite captured an infrared picture Tropical Cyclone 1P. Yellow and red indicate coldest cloud tops and strongest thunderstorms.