wunderground.com - Dr. Jeff Masters - 11 August 2013

Earth's most dangerous tropical cyclone so far in 2013 is Category 4 Typhoon Utor, which is closing in on the northern Philippine Island of Luzon. Landfall is expected at approximately 20 UTC (4 pm EDT) Sunday near Casigran. Satellite imagery shows a formidable storm with well-organized spiral bands, a prominent eye, and good (but not excellent) upper-level outflow. Ocean temperatures are very warm, about 30°C (86°F), which is approximately 0.5 - 1.0°C above average. These warm waters extend to tremendous depth, giving Utor a huge source of energy to tap into. Wind shear is low, 5 - 10 knots. Theoretically, the Maximum Potential Intensity (MPI) that Utor can achieve under these conditions is sustained winds of 185 mph. However, Utor will not have time to reach that strength before encountering Luzon. The official forecast from the Joint Typhoon Warning Center calls for intensification to 140 mph winds by 18 UTC Sunday, but it is possible that Utor will have time to intensify to a 150 mph super typhoon before landfall. Utor is a very wet storm, and will likely bring a large swath of 8+ inches of rain across Luzon. These rains will cause dangerous flash flooding and mudslides. Utor will likely weaken to a Category 1 storm as it passes over Luzon, but is expected to re-intensify to a Category 2 storm before hitting China a few hundred miles south of Hong Kong about 20 UTC on Tuesday.

Utor is a Marshallese word for squall line, and has been used for three tropical cyclones in the Western Pacific--in 2001, 2006, and 2013. Typhoon Utor is called Typhoon Labuyo in the Philippines. Utor's 135 mph winds make it the 2nd strongest tropical cyclone globally so far in 2013. Earth's most powerful tropical cyclone in 2013 was Typhoon Soulik, which reached Category 4 strength with 145 mph winds on July 10, before weakening to a Category 2 storm that hit Taiwan on July 12.


Figure 1. MODIS satellite image of Typhoon Utor taken at 04:30 UTC on Sunday, August 11. Image credit: NASA.
 

The eruption could be seen from the Maurole district of East Nusa Tenggara province

Six people have been killed in a volcanic eruption on a tiny island in Indonesia, officials have said.

Mount Rokatenda, on the island of Palue some 2,000km (1,250 miles) east of Jakarta, spewed ash and rocks 2km into the air.

Disaster officials said hot ash covered a nearby beach, leaving four adults and two children dead.

The volcano had been rumbling since late last year, forcing the evacuation of hundreds of people.

A 3km exclusion zone was set up after an eruption last October.

CHANCE OF STORMS: NOAA forecastesrs estimate a 65% chance of polar geomagnetic storms on August 10th when one and perhaps two CMEs are expected to hit Earth's magnetic field. The incoming clouds were propelled from the sun by a flurry of erupting magnetic filaments on Aug. 6-7. High-latitude sky watchers should be alert for auroras. Aurora alerts: text, voice.

SPACE CHASE: On August 3rd, Japan launched a robotic spacecraft, the HTV-4, to re-supply the International Space Station (ISS). Last night, Larry Sloss saw the HTV-4 in hot pursuit of the ISS in the twilight skies over Priest Lake, Idaho:

"The HTV-4 was trailing the ISS by just 3 seconds," says Sloss.

Many observers noted "HTV-4 flares" this week. Apparently sunlight is glinting off a flat surface of the spacecraft, briefly raising its luminosity to match that of the much larger ISS. Sloss saw one too: "In the image, a brief, bright flare from the HTV-4 is slightly offset from the ISS trail."