What meteorologists are calling a massive monsoon gyre has produced three named tropical storms in the Northwest Pacific Ocean on August 19, 2016, and all three of them are simultaneously threatening Japan. The Japan Meteorological Agency (JMA) named them Mindulle, Lionrock, and Kompasu.
According to the American Meteorological Society (AMS), a monsoon gyre is a convection of the summer monsoon circulation of the western North Pacific characterized by 1) a very large nearly circular low-level cyclonic vortex (not the result of the expanding wind field of a preexisting monsoon depression or tropical cyclone) that has an outermost closed isobar with a diameter on the order of 1 200 nautical miles (2 500 km / 1 380 miles); 2) a cloud band bordering the southern through eastern periphery of the vortex/surface low; and 3) a relatively long (two week) life span.
"Initially, a subsequent regime exists in its core and western and northwestern quadrants with light winds and scattered low cumulus clouds; later, the area within the outer closed isobar may fill with deep convective cloud and become an isobar or tropical cyclone. A series of midget tropical cyclones may emerge from the "head" or leading edge of the peripheral tropical cyclone of a monsoon gyre," the AMS explains.
Wind + rain model at 12:00 UTC on August 20, 2016. Credit: MeteoEarth
"In one of the more bizarre patterns you will ever see, 3 tropical cyclones are threatening Japan simultaneously," Meteorologist Anthony Sagliani said a couple of hours ago.
Here is the massive monsoon gyre north of Guam as southwesterlies prevail over tropical West Pacific. pic.twitter.com/4GLK3Vk39O— Anthony Sagliani (@anthonywx) August 18, 2016
Meanwhile in W-Pac, in one of the more bizarre patterns you will ever see, 3 TCs threatening Japan simultaneously. pic.twitter.com/x9Hw2p2G1z— Anthony Sagliani (@anthonywx) August 20, 2016
"The tropics right now, especially just south of Japan, are a 'hot mess' right now," Meteorologist Robert Speta said. "This monsoon gyre is one of the most extreme cases I have seen. The models are all over the place."
See his first analysis in the video below:
Video courtesy Robert Speta / WestPacWx
Tropical Storm "Mindulle"
According to the JMA, the center of Tropical Storm "Mindulle" was located about 1 392 km (865 miles) south of Tokyo at 09:00 UTC on August 20.
The system had a maximum wind speed of 74 km/h (46 mph), with gusts to 111 km/h (69 mph). Its minimum estimated central pressure at the time was 992 hPa. Gradual strengthening is expected.
Mindulle is moving northward at 30 km/h (18.6 mph) and, according to the current JMA model, is forecast to make landfall near Tokyo around 06:00 UTC on Monday, August 22, with maximum wind speed near the center of around 92.6 km/h (57.5 mph).
Tropical Storm "Mindulle" forecast track by JMA at 09:00 UTC on August 20, 2016. Copyright: JMA
Tropical Storm "Lionrock"
At 09:00 UTC on August 20, Tropical Storm "Lionrock" was located about 524 km (325 miles) SSW of Tokyo and was moving WSW at 25 km/h (15.5 mph). Maximum wind speed near the center was 64.8 km/h (40 mph) at the time, with gusts to 92.6 km/h (57.5 mph).
Lionrock's minimum estimated pressure was 994 hPa.
Tropical Storm "Lionrock" forecast track by JMA at 09:00 UTC on August 20, 2016. Copyright: JMA
Tropical Storm "Kompasu"
At 12:45 UTC on August 20, Kompasu was located about 460 km (286 miles) east of Tokyo and was moving NW at 45 km/h (28 mph).
Its maximum wind speed was 64.8 km/h (40 mph), gusts were reaching 92.6 km/h (57.5 mph). Kompasu's central pressure at the time was 994 hPa.
This system is not expected to strengthen over the next 72 hours but it poses an imminent threat to the country. This is a fast moving storm and JMA's current models take it very close to Miyako by 21:00 UTC on August 20. Landfall is expected near Horoizumi, Hokkaido around 09:00 UTC on August 21.
Tropical Storm "Kompasu" forecast track by JMA at 09:00 UTC on August 20, 2016. Copyright: JMA
Another low pressure area produced by the gyre has reached the Iwate prefecture at around 10:30 UTC today.
Continued precipitation throughout Japan over the coming days will cause a threat of flooding and landslides.
Featured image credit: EarthNullSchool