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Posted at 11:22 AM ET, 09/28/2012

Typhoon Jelawat closing in on Okinawa, Japan; Nadine becomes hurricane (again)

Satellite image of Jelawat on Thursday morning when it was heading toward Taiwan with 155mph sustained winds. (JMA/NOAA)
Typhoon Jelawat remains a formidable storm as it passes dangerously close to Taiwan on path towards Okinawa and then mainland Japan.

On Sunday, Jelawat became the second super typhoon to pass over the region in two weeks: Sanba was just there on September 13-14. While the western Pacific is no stranger to frequent typhoons, it is quite rare to have two consecutive super typhoons (a “super typhoon” is a tropical cyclone with maximum sustained winds of 150 mph or greater).

After its meager beginnings as a tropical depression back on September 20, Jelawat reached a peak intensity of 160 mph on the 25th just east of the Philippines, but has weakened somewhat to its current intensity of 127 mph. Those wind speeds correspond to a Category 5 and high-end Category 3 hurricane on the Saffir-Simpson wind scale, respectively (a typhoon and a hurricane are just different regional names for the same thing).

Fortunately for Taiwan, the storm recurved prior to reaching the island (the center passed within 200 miles of the coast), and the brunt of the rain and wind remained over the open ocean. But, now it’s heading northeast toward the Ryukyu Islands and then the main Japanese islands by the end of the weekend. Along the way, another direct hit on island of Okinawa appears likely.

The Joint Typhoon Warning Center expects Jelawat to pass over Okinawa as formidable typhoon with maximum winds of 100 to 115 mph Saturday.

Radar image of the Jelawat approaching Okinawa around 11 a.m. EDT. (JMA - get latest image)
A recent radar image from Okinawa shows the storm’s outer rainbands already affecting the Ryukyu island chain, and the eyewall coming into view on the lower left corner of the image. I have a very long radar loop available that allows you to track the whole progress of the typhoon as it approaches and passes the area.

Aside from ground-based radar, the space-based equivalent is images taken of a storm at microwave wavelengths (very similar to conventional radars).

Like their ground-based counterparts, they can “see” through the clouds and capture just the precipitation structure. These instruments are currently only on polar-orbiting satellites, and rely on occasional fortuitous overpasses as the satellite zips around the globe.

Microwave image of Jelawat taken at 3 a.m. EDT this morning. Yellows and reds indicate stronger thunderstorm activity. Also, note the concentric eyewalls! (NRL-Monterey)
Sometimes the satellite passes directly over a storm and catches great images, and other times the swath completely misses or just catches the edge of a storm. Earlier this morning, the DMSP F15 satellite had a great overpass, giving a valuable big-picture snapshot of the storm’s structure.

Jelawat is forecast to reach mainland Japan as a low-end (category 1) typhoon Saturday night into Sunday. It is expected to make landfall on Honshu south of Tokyo.

Hurricane Nadine

Since September 11, we’ve been watching Nadine in the far eastern Atlantic. It was a hurricane for a couple days, then a humble tropical/subtropical/remnant storm for 12 days, and is now once again a hurricane.

It has been meandering, drifting, and looping near the Azores, and is expected to keep doing the same thing for at least another five days, perhaps much longer if some global models verify.

As of now, it’s not anywhere near breaking longevity records, but if it’s still around in a couple weeks, then we’ll be in record territory (in 1899, the longevity record-holder was a tropical storm or hurricane for 28 days)!

Observed (solid line) and forecast (dotted line) track of Nadine
At 11 a.m. today, in the National Hurricane Center’s 64th advisory on the storm, Nadine is packing 75 mph sustained winds and is forecast to hold approximately steady for another couple days before weakening slightly. It’s located about 730 miles southwest of the Azores and moving northwest at 8 mph.

* Brian McNoldy is a senior researcher at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science.

By Brian McNoldy  |  11:22 AM ET, 09/28/2012

Categories:  Latest, Tropical Weather

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