Visible from NASA’s Aqua satellite revealed the effects of wind shear on Tropical Cyclone Riley in the Southern Indian Ocean.
On Jan. 29, 2019, the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA’s Aqua satellite captured a visible image of Tropical Cyclone Riley, located far to the west of Western Australia. Easterly wind shear pushed the bulk of clouds and storms west of the center.
At 4 a.m. EDT (0900 UTC) on Jan. 29, Riley was located near 19.4 degrees south latitude and 105.8 east longitude, approximately 475 nautical miles west-northwest of Learmonth, Australia. Rile was moving to the west-southwestward. Maximum sustained winds were near 35 knots (40 mph/65 kph).
Forecasters at the Joint Typhoon Warning Center expect Riley to maintain its west-southwestward track until it dissipates later in the day.
Jan. 28, 2019 – Satellite Sees Tropical Cyclone Riley Pushing Further from Australia
Tropical Cyclone Riley continued to move west in the Southern Indian Ocean, and move away from Western Australia. NASA-NOAA’s Suomi NPP satellite provided a visible image of the storm.
Suomi NPP passed over Riley on Jan. 28 and the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument provided a visible image of the storm. The VIIRS image showed a rounded area of storms in the northwestern quadrant of the storm. The Joint Typhoon Warning Center (JTWC) noted “A microwave image indicated the bulk of the deep convection is confined to the northwest quadrant with tightly-curved shallow banding wrapping into a defined low-level circulation center.”
On January 28, the Australian Bureau of Meteorology noted that “Tropical Cyclone Riley lies over open waters well to the northwest of the west Pilbara coast. Riley is forecast to move towards the west southwest over the coming days, continuing on its path away from the Western Australia mainland.” At 10 a.m. EDT (1500 UTC), Riley was near 18.4 degrees south longitude and 108.9 east latitude, about 375 nautical miles northwest of Learmonth, Western Australia. Maximum sustained winds were near 60 knots
Forecasters at the Joint Typhoon Warning Center noted that Riley will track west-southwest and will continue to weaken. Riley is expected to dissipate within 3 days.
System 94S developed about 240 miles west-northwest of Darwin, Australia on Jan. 22, 2019. The next day, it had strengthened into a tropical cyclone, and was named Riley. NASA-NOAA’s Suomi NPP satellite provided a look at Riley when it was closest to Australia.
When it developed on Jan. 22, the low pressure area known as System 94S had sustained winds near 35 kilometers per hour. The Australian Bureau of Meteorology (ABM) posted a Cyclone Watch for the northwest Kimberley coast on that day.
On January 23, the ABM said Tropical Cyclone Riley continues tracking west, away from Kimberley coast. But the Tropical Cyclone Watch continued for the Pilbara coast. There was also a Blue Alert in effect for people between Whim Creek and Onslow including the towns of Roebourne, Wickham, Point Samson, Karratha, Dampier and Onslow.
On Jan 23, Riley had maximum sustained winds near 85 kph. It was centered near 17.0 degrees South and 119.5 degrees East, approximately 310 kilometers west northwest of Broome and it was moving west.
ABM said at the time “Tropical Cyclone Riley is expected to continue moving west southwest over open water, parallel to the Pilbara coast, throughout Friday and during the weekend. The cyclone may intensify to Category 2 overnight, and possibly to Category 3 on Friday to the north of the Pilbara coast. If the system takes a more southerly track then gales may develop along the Pilbara coast from Saturday morning.”