Tropical Storm 13W (Lupit), # 6; TCFA issued on 97W Invest

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13W upgraded to tropical storm, named Lupit; Standby Signal 1 raised for Hong Kong; forecast to pass 244 miles northwest of Kadena late Sunday. (Joint Typhoon Warning Center)

11:20 a.m. Wednesday, Aug. 4, Japan time: A tropical cyclone formation alert has been issued for tropical disturbance 97W Invest by the Joint Typhoon Warning Center. At 9 a.m., it was 161 miles south-southwest of Kadena Air Base, Okinawa, according to JTWC.

Current model track guidance and the GFS forecast ensemble indicate that it could reach the Tokyo area by the weekend as a potential tropical storm, and perhaps impact Saturday’s and Sunday’s events at the 32nd Summer Olympic Games in Tokyo.

Yokosuka Naval Base’s long-range forecast calls rain and thunderstorms into the weekend with southeasterly 29- to 40-mph sustained winds and 52-mph gusts early Sunday morning, shifting southeasterly later Sunday morning and diminishing as the day wears on.

More immediately, local forecasts for Okinawa call for high winds picking up Wednesday afternoon and continuing into Thursday.

Kadena’s 18th Wing Weather Flight forecast continues to call for rain, showers, scattered thunderstorms and easterly winds, shifting to southerly as high as 23-mph sustained and 34-mph gusts into Thursday, increasing as the weekend approaches with Tropical Storm Lupit forecast to be close by.

U.S. bases on Okinawa remain in seasonal Tropical Cyclone Condition of Readiness 4 for the moment. More to come, particularly if 97W develops into a tropical cyclone and we get an official forecast track from JTWC.

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6:30 a.m. Wednesday, Aug. 4, Japan time: Checking out the tropical scoreboard, 13W has been upgraded to a tropical storm, 97W Invest remains just southwest of Okinawa, and Kadena Air Base’s 18th Wing Weather Flight and Japanese weather forecasts continue to call for blustery conditions and rain, heavy at times, over the next few days.

At 3 a.m., 13W was 98 miles south-southeast of Hong Kong, moving east at 6 mph with 40-mph sustained winds and 52-mph gusts, according to Joint Typhoon Warning Center. Hong Kong Observatory issued Standby Signal 1 at 4:20 a.m. Hong Kong Time, with 13W moving out of the area.

U.S. bases on Okinawa remain in seasonal Tropical Cyclone Condition of Readiness 4. The weather flight’s extended forecast continues to call for a 50- to 70-percent chance of showers and thunderstorms through the rest of the week, with southerly winds peaking at 31-mph sustained and 44- to 47-mph gusts on Saturday, shifting southwesterly into Sunday and diminishing.

Japanese weather forecast calls for high winds, gale-force at times, picking up out of the southeast and shifting southwest through Wednesday into Thursday, with rain, heavy at times. Japan Meteorological Agency has posted a thunderstorm and high-wave advisory; check here for the latest as the day wears on.

If 13W remains on present heading, it faces an uphill struggle, as the forecast track shows it skimming China’s southeast coast, heading inland for a bit, then resuming its march over water as a tropical depression, passing 244 miles west-northwest of Kadena at 11 p.m. Sunday.

Long-term, whether 13W or 97W or both have an impact on Japan’s main islands remains to be seen. More to come this evening.

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9 p.m. Tuesday, Aug. 3, Japan time: Tropical Depression 13W remains far from Okinawa, 1,081 miles west-southwest as of 3 p.m., moving east-northeast at 5 mph, with 35-mph sustained winds and 46-mph gusts at center.

Strong Wind Signal 3 has been raised by the Hong Kong Observatory, and should remain in effect until morning.

Extended forecast from Kadena Air Base’s 18th Wing Weather Flight remains the same as earlier, peak 35-mph sustained winds and 48-mph gusts forecast for Wednesday, with 40- to 60-percent chance of rain and thunderstorms continuing through the week.

U.S. bases on Okinawa remain in seasonal TCCOR 4.

If 13W stays on forecast track, it’s due to skim China’s southeast coast and pass 340 miles west-northwest of Kadena at 9 a.m. Sunday as a tropical depression.

97W Invest does remain west-northwest of Okinawa and could impact the weather as well.

Joint Typhoon Warning Center has issued its final warning on Tropical Depression 12W, which remains well away from any major land mass.

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8 a.m. Tuesday, Aug. 3, Japan time: Not just one, but two tropical depressions are out there now, 12W and 13W. Joint Typhoon Warning Center’s forecast tracks indicate neither to be an imminent threat to any U.S. facilities in Japan, though Okinawa can expect some blustery, rainy weather as this week wears on.

At 3 a.m., JTWC 12W was 1,064 miles southeast of Yokosuka Naval Base, moving north-northwest at 21 mph with 35-mph sustained winds and 46-mph gusts. 13W was 113 miles southwest of Hong Kong, moving east at 14 mph with 29-mph sustained winds and 40-mph gusts; Standby Signal 1 is in effect for Hong Kong.

12W remains forecast to die out early Friday morning about 330 miles north-northeast of Iwo Jima. 13W is forecast to peak at 52-mph sustained winds and 63-mph gusts as it skims China’s southeast coast, splits the difference between China and Taiwan and passes 371 miles west of Kadena Air Base early Sunday morning.

But with 12W and 97W Invest in the vicinity, the weather picture for Okinawa is fairly rough, according to Kadena’s 18th Wing Weather Flight. U.S. bases on Okinawa remain in seasonal Tropical Cyclone Condition of Readiness 4.

Kadena’s extended weather forecast calls for a 40- to 60-percent chance of rain and scattered thunderstorms the rest of the week, with southerly 32-mph sustained winds and gusts between 45 and 48 mph on Wednesday afternoon, continuing as the week wears on.

A weather picture that bears considerable watching. Storm Tracker has the watch.

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11:30 p.m. Monday, Aug. 2, Japan time: Not only is Tropical Depression 12W out there well southeast of Japan, but several other disturbances are lurking, two of which, 97W Invest and 90W Invest, could impact southwestern Japan in the coming days.

Joint Typhoon Warning Center issued a tropical cyclone formation alert on 90W, which has crossed the Leizhou Peninsula in southeastern China and is heading east-northeast through the South China Sea. 97W is labeled a “medium” area for development in the next 24 hours by JTWC; it sits about 170 miles west-northwest of Kadena Air Base, Okinawa, and is sitting quasi-stationary as it develops.

At lot to keep eyes on. More just after sunrise.

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6:30 p.m. Monday, Aug. 2, Japan time: Tropical Depression 12W spawned Monday afternoon well southeast of Japan. According to the Joint Typhoon Warning Center’s initial forecast track, it appears as though it should remain a tropical depression and die out within a couple of days well away from land.

At 3 p.m., 12W was 1,219 miles southeast of Yokosuka Naval Base, tracking north-northwest at 18 mph with 29-mph sustained winds and 40-mph gusts. If it remains on present heading, JTWC projects it to curve northwest, then west, weakening the whole while before dissipating about 420 miles northeast of Iwo Jima at mid-afternoon Wednesday.

Dave Ornauer