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Tropical Depression 16W (Chan-hom), #26 FINAL

U.S. NAVY

By DAVE ORNAUER | STARS AND STRIPES Published: October 4, 2020

8 p.m. Monday, Oct. 12, Japan time: Joint Typhoon Warning Center has issued its final warning on Chan-hom, which has also been downgraded to a tropical depression.


UPDATED 8 p.m. Sunday, Oct. 11, Japan time: Joint Typhoon Warning Center indicated in its latest update on Tropical Storm Chan-hom that there is some potential for it to regenerate as it moves south toward warmer water in the coming days. Storm Tracker has the watch.


Noon Sunday, Oct. 11, Japan time: Closest point of approach by Tropical Storm Chan-hom to the Tokyo area has come and gone. Naval Air Facility Atsugi and Camp Zama reverted to Tropical Cyclone Condition of Readiness All Clear at mid-morning.

Chan-hom continues weakening, down to 46-mph sustained winds and 58-mph gusts, and continues heading east. Joint Typhoon Warning Center projects it to curve southeast and dissipate in the next day or so.

Yokosuka Naval Base
's weather forecast calls for continued rain with winds subsiding throughout Sunday. Conditions should improve but rain should continue throughout the week. Unless things change, this should be Storm Tracker's final report on Cham-hom.


11:30 p.m. Saturday, Oct. 10, Japan time: Japan Meteorological Agency has issued heavy rain emergency warnings for portions of the Izu Islands south of Tokyo due to Tropical Storm Chan-hom, according to NHK World.

But Chan-hom should largely spare U.S. bases in the Kanto Plain as it nears closest point of approach forecast for early Sunday morning, according to the Joint Typhoon Warning Center, though rain is forecast to continue through Sunday, with clearing on Monday.

At 9 p.m., Chan-hom was 250 miles south-southwest of Yokosuka Naval Base, moving east at 10 mph and holding steady at 58-mph sustsained winds and 75-mph gusts at center.

Naval Air Facility Atsugi
and Camp Zama remained in Tropical Cyclone Condition of Readiness Storm Watch through Saturday. The U.S. base closest to Chan-hom, Yokosuka, remained in seasonal TCCOR 5.

Chan-hom is forecast to pass 243 miles south of Yokosuka at 4 a.m. Sunday. Yokosuka's weather forecast calls for peak northerly winds of 26- to 32-mph sustained with 44-mph gusts through early Sunday morning, with showers, turning fair on Monday.


6:30 p.m. Saturday, Oct. 10, Japan time: Emergency warnings have been issued for the Izu Islands south of Tokyo as Tropical Storm Chan-hom approaches, according to NHK World. Heavy rain, flooding and landslides are affecting Japan's east coast near Tokyo.

At 3 p.m., Chan-hom was 276 miles southwest of Yokosuka Naval Base, moving east at 10 mph holding steady at 58-mph sustained winds and 75-mph gusts.

Fleet Activities Yokosuka has directed Tropical Cyclone Condition of Readiness All Clear, while Camp Zama and Naval Air Facility Atsugi remained in TCCOR Storm Watch as of 6 p.m.; expect the all clear to be issued soon.

If Chan-hom continues on present course, Joint Typhoon Warning Center projects it to weaken as it curves south and southeast of Tokyo-Kanto Plain. Rain and gusty winds are forecast for the holiday weekend.

Chan-hom is forecast to pass 227 miles south-southeast of Yokosuka at 4 a.m. Sunday. Yokosuka's weather forecast calls for rain through Sunday turning fair on Monday with northerly winds peaking at 18- to 23-mph sustained with 35-mph gusts early Sunday morning.

Model-track guidance
and forecast-ensemble best tracks have come into better alignment on a track southeast away from Japan in the long term. More around midnight.


12:15 p.m. Saturday, Oct. 10, Japan time: Expect a rainy, gusty Columbus Day weekend as Tropical Storm Chan-hom remains forecast to track well south of the Tokyo area, according to Joint Typhoon Warning Center.

At 9 a.m., Chan-hom was 323 miles southwest of Yokosuka Naval Base, wobbling northeast at 12 mph with 58-mph sustained winds and 75-mph gusts.

Yokosuka, Naval Air Facility Atsugi and Camp Zama remained in Tropical Cyclone Condition of Readiness Storm Watch at noon. Marine Corps Air Station Iwakuni reverted to seasonal TCCOR earlier Saturday.

If Chan-hom keeps on present heading, JTWC projects it to continue weakening as it curves southeast away from land in the coming days.

Chan-hom is forecast to pass 205 miles south of Yokosuka at 6 a.m. Sunday. Extended weather forecast calls for rain throughout the weekend and northerly winds peaking at 35- to 40-mph sustained and 58-mph gusts at mid-evening Saturday into Sunday.

Model-track guidance and forecast-ensemble best tracks depict Chan-hom curving southeast later this weekend; just a matter of the timing of that curve. JTWC reports a spread of 192 miles among model solutions. More this evening.


12:15 a.m. Saturday, Oct. 10, Japan time: Chan-hom has been downgraded to a tropical storm by Joint Typhoon Warning Center, and its latest forecast track carries it even further south of the Tokyo area than Storm Tracker last reported.

At 9 p.m. Friday, Chan-hom was 439 miles southwest of Yokosuka Naval Base, trekking east-northeast at 7 mph and had weakened to 63-mph sustained winds and 81-mph gusts at center.

Yokosuka, Naval Air Facility Atsugi, Camp Zama and Marine Corps Air Station Iwakuni each remained in Tropical Cyclone Condition of Readiness Storm Watch at midnight.

If Chan-hom remains on present heading, JTWC projects it to keep weakening as it heads toward cooler seas, higher vertical wind shear and just an icky, cold environment near the Tokyo-Kanto Plain area.

Forecast closest point of approach to Iwakuni has come and gone. Chan-hom is due to pass 200 miles south of Yokosuka a bit later than last forecast, 6 a.m. Sunday, packing just 46-mph sustained winds and 58-mph gusts at center.

Disparity remains in model-track guidance, while forecast ensembles continue to struggle to resolve Chan-hom, with some solutions showing Chan-hom curving south and west in the late term. JTWC reports a cross-track spread of 112 miles 36 hours out and 226 two days out.

Still a chance for some changes. More at mid-day Saturday.


7:20 p.m. Friday, Oct. 9, Japan time: Those who are fans of heavy rain during a holiday weekend in the Tokyo area will most likely get their wish. As far as destructive winds, not likely to happen if Typhoon Chan-hom stays on its current Joint Typhoon Warning Center forecast track.

At 3 p.m., Chan-hom was 475 miles southwest of Yokosuka Naval Base, rolling north-northeast a 8 mph packing 81-mph sustained winds and 98-mph gusts.

Marine Corps Air Station Iwakuni
, Yokosuka, Naval Air Facility Atsugi and Camp Zama were each in Tropical Cyclone Condition of Readiness Storm Watch. Sasebo Naval Base has directed TCCOR All Clear.

Destructive winds are no longer forecast
to occur at Yokosuka, but between 4 to 6 inches of rain is forecast for the Tokyo area.

If Chan-hom remains on present heading, JTWC projects it to weaken to tropical-storm status early Saturday morning and steadily lose its punch as it moves south of the Kanto Plain.

Chan-hom is forecast to pass 171 miles south of Yokosuka, 187 south of Zama and Atsugi and 201 miles south of Yokota Air Base between 3 and 4 a.m. Sunday, packing 58-mph sustained winds and 75-mph gusts, but at storm's center.

Even with the storm now in its fifth day, there remains a spread among model solutions, 184 miles 36 hours out and 673 miles three days out, JTWC reports. Model-track guidance and forecast-ensemble best tracks also show similar disparity. More at around midnight.


12:30 p.m. Friday, Oct. 9, Japan time: Typhoon Chan-hom's latest  Joint Typhoon Warning Center track has deviated much further south of the Tokyo area than previously reported. If the current forecast track holds, the Kanto Plain could be spared Chan-hom's full fury.

At 9 a.m., Chan-hom was 521 miles southwest of Yokosuka Naval Base, crawling north at 4 mph and had weakened slightly, to 86-mph sustained winds and 104-mph gusts at center.

Yokosuka remained in Tropical Cyclone Condition of Readiness 3 at mid-day, while Camp Zama and Naval Air Facility Atsugi set TCCOR Storm Watch. Sasebo Naval Base and Marine Corps Air Station Iwakuni also remain in TCCOR Storm Watch.

If Chan-hom stays on present course, JTWC projects it to resume a northeast path, steadily weakening into a tropical storm as it encounters cooler waters and stronger wind shear.

Chan-hom is forecast to pass 289 miles southeast of Sasebo and 231 miles south-southeast of Iwakuni between 4 p.m. Friday and 1 p.m. Saturday.

JTWC then projects Chan-hom to curve due east, passing 169 miles south-southeast of Yokosuka and 186 south-southeast of Zama and Atsugi, packing 52-mph sustained winds and 63-mph gusts at center.

Yokosuka's weather forecast calls for showers throughout the weekend with winds peaking at 52- to 58-mph sustained and 69-mph gusts at 8 p.m. Saturday into Sunday morning.

But there's still a vast disparity in model-track guidance, though forecast-ensemble best tracks depict Chan-hom moving further south of the Tokyo area than previously reported. More change definitely possible. More coming Friday evening and again at midnight.


11:45 p.m. Thursday, Oct. 8, Japan time: Joint Typhoon Warning Center forecast tracks continue edging Typhoon Chan-hom further away from the Tokyo area than Storm Tracker reported Wednesday.

At 9 p.m., Chan-hom was 546 miles southwest of Yokosuka Naval Base, moving north-northeast at 9 mph and holding steady at 92-mph sustained winds and 115-mph gusts.

Yokosuka remained in Tropical Cyclone Condition of Readiness 3 at midnight, while Sasebo Naval Base and Marine Corps Air Station Iwakuni remained in TCCOR Storm Watch. Sasebo and Iwakuni are also further out of harm's way than previously reported.

If Chan-hom stays on its present heading, JTWC forecasts it to weaken gradually as it picks up forward speed northeast, passing south of the Tokyo area as a tropical storm late Saturday.

Chan-hom is forecast to pass 69 miles south-southeast of Yokosuka, 87 south-southeast of Camp Zama and Naval Air Facility Atsugi and 103 south-southeast of Yokota Air Base between 11 p.m. and midnight Saturday packing 58-mph sustained winds and 75-mph gusts. Between 4 to 6 inches of rain are forecast for the Kanto Plain.

Model-track guidance remains split, though forecast-ensemble best tracks are gradually coming into better agreement. But JTWC reports a cross-track spread of 301 miles two days out, increasing to 881 three days out. Things can still change. More to come at mid-day Friday.


6:10 p.m. Thursday, Oct. 8, Japan time: On the Typhoon Chan-hom TCCOR scoreboard, U.S. bases on Okinawa have reverted to seasonal Tropical Cyclone Condition of Readiness 4. Yokosuka Naval Base remains in TCCOR 3 and Sasebo Naval Base in TCCOR Storm Watch. Marine Corps Air Station Iwakuni has also set TCCOR Storm Watch, at mid-morning Thursday.

At 3 p.m., Chan-hom was 603 miles southwest of Yokosuka, moving due north at 10 mph and had reached forecast peak intensity, 92-mph sustained winds and 115-mph gusts at center.

If Chan-hom stays on current heading, JTWC projects it to miss Kyushu and Shikoku islands to their southeast, passing 255 miles away from Sasebo and 187 miles away from Iwakuni between 3 p.m. and midnight Friday.

For Tokyo and the Kanto Plain, the news got slightly better with the latest update. Chan-hom is forecast to remain a strong tropical storm as it passes 51 miles south-southeast of Yokosuka at 1 a.m. Sunday.

Model-track guidance remains divided, as do the GFS and ECMWF forecast ensembles. Still some room and time for change. Stay tuned. More at midnight.


1:30 p.m. Thursday, Oct. 8, Japan time: Closer, ever closer, Typhoon Chan-hom's forecast track is edging toward the Tokyo-Kanto Plain area. If the current forecast holds, it could pass just south of Yokosuka Naval Base around midnight Saturday.

At 9 a.m., Chan-hom was 322 miles east-northeast of Kadena Air Base, Okinawa, moving north-northwest at 8 mph and holding steady at 81-mph sustained winds and 98-mph gusts.

U.S. bases on Okinawa and Sasebo Naval Base in southwestern Kyushu remain in Tropical Cyclone Condition of Readiness Storm Watch. Fleet Activities Yokosuka set TCCOR 3 at noon Thursday.

JTWC reports that the window for Chan-hom to continue strengthening is closing; current projection is at 86-mph sustained winds and 104-mph gusts at mid-evening Thursday as it starts curving northeast toward the Tokyo area.

If Chan-hom's track holds, JTWC projects it to pass 256 miles south-southeast of Sasebo at 7 p.m. Friday, then 182 miles south of Marine Corps Air Station Iwakuni at 2 a.m. Saturday.

It's what happens after that with Chan-hom that could be of concern to the Kanto Plain.

If the current JTWC track holds, Chan-hom is due to pass 22 miles south-southeast of Yokosuka, 41 south-southeast of Camp Zama and Naval Air Facility Atsugi and 57 south-southeast of Yokota Air Base between midnight Saturday and 1 a.m. Sunday, still packing 69-mph sustained winds and 86-mph gusts at center.

Yokosuka's extended weather forecast
calls for rain to persist through the weekend with winds peaking north-northeasterly at 40- to 46-mph sustsained and 58-mph gusts at 1 a.m. Sunday.

Model-track guidance shows a split in solutions, as do the forecast-ensemble best tracks. Will Chan-hom stay off shore or will it strike close to the Kanto Plain? That picture remains cloudy. Stay tuned. More this evening and again around midnight.


7:20 a.m. Thursday, Oct. 8, Japan time: U.S. bases on Okinawa  entered Tropical Cyclone Condition of Readiness Storm Watch at 6:30 a.m., joining Sasebo Naval Base, which entered Storm Watch on Wednesday.

Destructive winds are not forecast, but Typhoon Chan-hom remains close enough that a heightened state of alert is warranted, should Chan-hom strengthen and/or move closer to those locales.

Long term, Joint Typhoon Warning Center's latest forecast track indicates that Chan-hom could be significant wind event for the Kanto Plain early Sunday.

At 3 a.m., Chan-hom was 323 miles east of Kadena Air Base, moving northwest at 11 mph, holding steady at 81-mph sustained winds and 98-mph gusts at center.

If Chan-hom stays on present heading, JTWC projects it to peak at 92-mph sustained winds and 115-mph gusts early Friday morning, then curve northeast, well away from Japan's main islands in the short term.

Cham-hom is forecast to pass 317 miles east-northeast of Kadena at noon Thursday. Though out of range of Chan-hom's fiercest fury, the system's wind field is wide enough that gale-force winds could be felt on island, and elsewhere in Japan as it moves north, JTWC reports.

JTWC forecasts Chan-hom to pass 240 miles south-southeast of Sasebo at 5 p.m. Friday, then 176 south-southeast of Marine Corps Air Station Iwakuni at 1 a.m. Saturday.

From there, it's a question of how close Chan-hom tracks toward the Kanto Plain. Currently, JTWC forecasts Chan-hom to pass 41 miles south-southeast of Yokosuka Naval Base, still packing 69-mph sustained winds and 86-mph gusts at center.

Yokosuka's extended weather forecast calls for rain this weekend with winds peaking north-northeasterly at 40- to 46-mph sustained with 58-mph gusts early Sunday morning.

Model-track guidance
is somewhat divided, though forecast-ensemble best tracks keep Chan-hom just offshore from the Tokyo area. For the moment, Yokosuka and other Kanto bases remain in seasonal TCCOR, though that could be upgraded in the next day or so. Stay tuned.


11:45 p.m. Wednesday, Oct. 7, Japan time: Typhoon Chan-hom has intensified slightly, but with every passing update, the Joint Typhoon Warning Center's forecast track keeps edging Chan-hom further away from Okinawa, and closer to the Kanto Plain.

At 9 p.m., Chan-hom was 370 miles east of Kadena Air Base, 526 south-southeast of Marine Corps Air Station Iwakuni and 522 south-southeast of Sasebo Naval Base, moving northwest at 12 mph packing 81-mph sustained winds and 98-mph gusts at center.

U.S. bases on Okinawa remained in Tropical Cyclone Condition of Readiness 3 through Wednesday's end and Sasebo in TCCOR Storm Watch. All other U.S. bases in Japan remained in seasonal TCCORs.

If Chan-hom stays on present course, JTWC projects it to peak at 92-mph sustained winds and 115-mph gusts, Category 1-equivalent intensity, at mid-evening Thursday, then curve sharply northeast, skimming south of Japan's main islands and weakening as it goes.

Chan-hom is forecast to pass 299 miles northeast of Kadena at 7 p.m. Thursday, 233 miles south-southeast of Sasebo at midnight Friday and 183 south-southeast of Iwakuni at 8 a.m. Saturday.

Long-term, JTWC forecasts Chan-hom to weaken, but remain a strong tropical storm, passing 49 miles south-southeast of Yokosuka Naval Base at 6 a.m. Sunday, still packing 63-mph sustained winds and 81-mph gusts at center.

There remains a spread of about 115 miles in model solutions 36 hours out, according to JTWC. Model-track guidance is split, with GFS keeping the system over water and NAVGEM over land. Forecast-ensemble best tracks also show disparity. Changes could still happen. Stay tuned.


8 p.m. Wednesday, Oct. 7, Japan time: Here is the latest wind-forecast timeline for Okinawa for Tropical Storm Chan-hom, provided by Kadena Air Base's 18th Wing Weather Flight. U.S. bases on Okinawa remain in Tropical Cyclone Condition of Readiness 3:

-- Peak 35-mph sustained winds and 46-mph gusts for northeast Okinawa, 29-mph sustained and 40-mph gusts for Kadena: 9 a.m. Thursday.

Sustained 40-mph winds or greater are no longer forecast to occur at this time.

Weather Flight also forecasts 1/2 inch of rain associated with Chan-hom.


6:50 p.m. Wednesday, Oct. 7, Japan time: Chan-hom has been upgraded to a Category 1-equivalent typhoon by the Joint Typhoon Warning Center. Its latest forecast track continues to take it well northeast of Okinawa and skim south of Japan's main islands.

At 3 p.m., Chan-hom was 435 miles east of Kadena Air Base, had picked up forward speed, moving northwest at 13 mph packing 75-mph sustained winds and 92-mph gusts at center.

U.S. bases on Okinawa remain in Tropical Cyclone Condition of Readiness 3. Sasebo Naval Base in southwestern Kyushu has set TCCOR Storm Watch. All other U.S. bases in Japan remain in seasonal TCCOR.

If Chan-hom stays on present heading, JTWC projects it to peak at 92-mph sustained winds and 115-mph gusts at mid-afternoon Thursday, then curve northeast, pick up forward speed and gradually weaken as it passes south of Kyushu, Shikoku and Honshu over the weekend.

Chan-hom is forecast to pass 283 miles northeast of Kadena at 4 p.m. Thursday, 215 miles south-southeast of Sasebo at 3 a.m. Saturday and 164 miles south-southeast of Marine Corps Air Station Iwakuni at 1 p.m. Saturday.

Long term, JTWC forecasts Chan-hom pass just southeast of Tokyo and the Kanto Plain, 62 miles away from Yokosuka Naval Base at mid-day Sunday, still packing 63-mph sustained winds and 81-mph gusts at center, possibly as a post-tropical system.

JTWC still projects a spread of 150 miles among solutions two days out. Model-track guidance and forecast-ensemble best tracks agree on a northwest to northeast track over the next two to three days. Stay tuned.


1:40 p.m. Wednesday, Oct. 7, Japan time: Here is the latest wind-forecast timeline for Okinawa for Tropical Storm Chan-hom, provided by Kadena Air Base's 18th Wing Weather Flight. U.S. bases on Okinawa remain in Tropical Cyclone Condition of Readiness 3:

-- Onset of 40-mph sustained winds: 3 a.m. Thursday.
-- Onset of 58-mph destructive sustained winds: Not forecast to occur at this time.
-- Peak 40-mph sustained winds and 52-mph gusts for northeast Okinawa, 35-mph sustained and 46-mph gusts for Kadena: 9 a.m. Thursday.
-- Winds subsiding below 40-mph sustained: 3 p.m. Thursday.

Weather Flight reports that winds are stronger in Chan-hom's northwest quadrant than the southwest; thus, Okinawa is forecast to get stronger winds earlier than projected closest point of approach, which remains 276 miles northeast at 1 a.m. Friday.

A reminder that 40-mph sustained winds meet the criteria for upgrade to TCCOR 1-C (caution) and 58-mph sustained winds and/or 69-mph gusts to TCCOR 1-E (emergency).

Weather Flight also forecasts 1 inch of rain associated with Chan-hom.


12:40 p.m. Wednesday, Oct. 7, Japan time: Chan-hom has intensified to just below typhoon strength, as its latest Joint Typhoon Warning Center forecast track continues to keep it off shore and away from U.S. bases in Japan.

At 9 a.m., Tropical Storm Chan-hom was 525 miles east of Kadena Air Base, Okinawa, moving west-northwest at 8 mph, packing 69-mph sustained winds and 86-mph gusts at center.

U.S. bases on Okinawa remain in Tropical Cyclone Condition of Readiness 3, while other U.S. bases in Japan remain in seasonal TCCORs.

If Chan-hom remains on its present course, JTWC projects it to reach typhoon strength at mid-evening Wednesday, then peak at Category 1-equivalent intensity, 92-mph sustained winds and 115-mph gusts at mid-evening Thursday as it passes Okinawa.

Kadena's weather forecast
calls for winds to pick up Wednesday, peaking northerly at 34-mph sustained with 48- to 50-mph gusts Thursday afternoon with a 50-percent chance of showers and thunderstorms into Friday morning.

Chan-hom is forecast to pass 276 miles northeast of Kadena at 1 a.m. Friday, then curve sharply northeast, maintaining typhoon strength as it passes 228 miles south-southeast of Sasebo Naval Base and 191 miles south-southeast of Marine Corps Air Station Iwakuni between 8 a.m. and 6 p.m. Saturday.

Sasebo's weather forecast calls for northeasterly winds between 21 and 26 mph sustained with 40-mph gusts from Friday morning into Saturday.

JTWC then forecasts Chan-hom to pick up forward speed and remain a strong tropical storm as it passes 92 miles south-southeast of Yokosuka Naval Base at 7 p.m. Sunday.

JTWC
reports a spread of some 220 miles in model solutions, so this could still change. Model-track guidance and forecast-ensemble best tracks are in general agreement on a track northwest followed by a northeast curve. More this evening and again at midnight.


1:30 a.m. Wednesday, Oct. 7, Japan time: Here is the latest wind-forecast timeline for Okinawa for Tropical Storm Chan-hom, provided by Kadena Air Base's 18th Wing Weather Flight. U.S. bases on Okinawa remain in Tropical Cyclone Condition of Readiness 3:

-- Onset of 40-mph sustained winds: Noon Thursday.
-- Onset of 58-mph destructive sustained winds: Not forecast to occur at this time.
-- Peak 40-mph sustained winds and 58-mph gusts for northeast Okinawa, 35-mph sustained and 46-mph gusts for Kadena: 4 a.m. Friday.
-- Winds subsiding below 40-mph sustained: 9 a.m. Friday.

A reminder that 40-mph sustained winds meet the criteria for upgrade to TCCOR 1-C (caution) and 58-mph sustained winds and/or 69-mph gusts to TCCOR 1-E (emergency).

Weather Flight also forecasts between 1 to 2 inches of rain associated with Chan-hom.


11:45 p.m. Tuesday, Oct. 6, Japan time: Tropical Storm Chan-hom continues strengthening, but Joint Typhoon Warning Center's latest forecast track keeps it well northeast of Okinawa early Friday and skimming south of Japan's main island this weekend.

At 9 p.m., Chan-hom was 635 miles east-southeast of Kadena Air Base, 745 miles south-southeast of Marine Corps Air Station Iwakuni and 783 miles southeast of Sasebo Naval Base, crawling west at 6 mph and had strengthened to 63-mph sustained winds and 81-mph gusts at center.

U.S. bases on Okinawa remained in Tropical Cyclone Condition of Readiness 3 late Tuesday. Other bases in Japan remain in seasonal TCCOR for now; Sasebo and Iwakuni could upgrade soon.

If Chan-hom stays on present heading, JTWC projects it to reach typhoon strength Wednesday evening and peak at Category 1-equivalent intensity, 92-mph sustained winds and 115-mph gusts at mid-evening Thursday.

Chan-hom is forecast to pass 222 miles northeast of Kadena at 5 a.m. Friday, then curve sharply northeast, maintaining typhoon-strength as it passes 206 miles south-southeast of Sasebo and 179 miles south-southeast of Iwakuni between 10 a.m. and 8 p.m. Saturday.

Long term, Chan-hom is forecast to remain a significant tropical storm as it arcs south of Tokyo, passing 133 miles south of Yokosuka Naval Base at mid-evening Sunday.

JTWC still reports a spread of 230 miles among model solutions three days out, the big question being when that curve northeast begins.

Model-track guidance is in better alignment and forecast ensemble best tracks (thick black lines) look to be in better agreement, though many outliers remain among solutions. Stay tuned.


8 p.m. Tuesday, Oct. 6, Japan time: Here is the initial wind-forecast timeline for Okinawa for Tropical Storm Chan-hom, provided by Kadena Air Base's 18th Wing Weather Flight. U.S. bases on Okinawa remain in Tropical Cyclone Condition of Readiness 3:

-- Onset of 40-mph sustained winds: Noon Thursday.
-- Onset of 58-mph destructive sustained winds: Not forecast to occur at this time.
-- Peak 40-mph sustained winds and 58-mph gusts for northeast Okinawa, 35-mph sustained and 46-mph gusts for Kadena: 4 a.m. Friday.
-- Winds subsiding below 40-mph sustained: 6 p.m. Friday.

A reminder that 40-mph sustained winds meet the criteria for upgrade to TCCOR 1-C (caution) and 58-mph sustained winds and/or 69-mph gusts to TCCOR 1-E (emergency).

Weather Flight also forecasts between 1 to 2 inches of rain associated with Chan-hom.


6 p.m. Tuesday, Oct. 6, Japan time: While U.S. bases have entered an elevated state of readiness, Joint Typhoon Warning Center's latest forecast track shows Tropical Storm Chan-hom passing more than 200 miles northeast of Okinawa early Friday morning.

At 3 p.m., Chan-hom was 674 miles east of Kadena Air Base, 806 miles southeast of Sasebo Naval Base and 771 miles south-southeast of Marine Corps Air Station Iwakuni, moving northwest at 5 mph and holding steady at 52-mph sustained winds and 63-mph gusts.

U.S. bases on Okinawa entered Tropical Cyclone Condition of Readiness 3 at 5 p.m. Destructive winds of 58 mph or greater are possible within 48 hours. All other U.S. bases in Japan remain in seasonal TCCOR.

If Chan-hom stays on present course, JTWC projects it to reach typhoon strength early Thursday morning and peak at Category 1-equivalent intensity, 92-mph sustained winds and 115-mph gusts at mid-afternoon Friday, still well away from any land masses.

Chan-hom is forecast to pass 217 miles northeast of Kadena at 4 a.m. Friday, just before reaching forecast peak intensity.

At this point, destructive winds of 58 mph or greater are not forecast to occur on Okinawa, though 40-mph sustained winds are forecast to begin at noon Thursday, according to Kadena's official Facebook page.

From there, JTWC forecasts Chan-hom to hook sharply northeast, passing 194 miles south-southeast of Sasebo and 167 miles south-southeast of Iwakuni between 11 a.m. and 10 p.m. Saturday, still packing 75-mph sustained winds and 92-mph gusts at storm's center.

Model-track guidance remains inconclusive, though it and forecast ensembles generally agree on an initial northwest track followed by a curve northeast. Just a question of timing and location when it makes the turn northeast. Stay tuned. More around midnight.


5 p.m. Tuesday, Oct. 6, Japan time: U.S. bases on Okinawa have entered Tropical Cyclone Condition of Readiness 3. Destructive winds of 58 mph or greater are possible with 48 hours.


2 p.m. Tuesday, Oct. 6, Japan time: Tropical Storm Chan-hom has picked up forward speed and its latest Joint Typhoon Warning Center forecast track takes it closer to Kyushu by week's end, still well away from Okinawa.

At 9 a.m., Chan-hom was 690 miles east-southeast of Kadena Air Base, 833 miles southeast of Sasebo Naval Base and 796 miles south of Yokosuka Naval Base, moving west-northwest at 9 mph with 52-mph sustained winds and 63-mph gusts at center.

U.S. bases throughout Japan remain in seasonal tropical cyclone conditions of readiness.

If Chan-hom stays on its present heading, JTWC projects it to peak at Category 1-equivalent intensity, 92-mph sustained winds and 115-mph gusts, at mid-morning Friday, still well away from land masses and weakening as it heads toward Kyushu's southern tip.

Chan-hom is forecast to pass 222 miles east-northeast of Kadena at 3 a.m. Friday as it reaches peak strength.

Kadena's extended weather forecast calls for northerly winds picking up Wednesday evening, peaking at 36-mph sustained and 53-mph gusts Thursday afternoon and evening with a 50-percent chance of showers and thunderstorms on Friday.

JTWC projects Chan-hom to then curve sharply northeast, spinning just south of Kyushu, passing 178 miles south-southeast of Sasebo and 161 south of Marine Corps Air Station Iwakuni between 6 p.m. Saturday and 5 a.m. Sunday.

Sasebo's extended forecast calls for northeasterly winds between 18 and 23 mph sustained and 40-mph gusts Friday evening into Saturday morning.

JTWC reports a spread among solutions of 243 miles three days out. Model-track guidance has come into better alignment, but the forecast ensembles remain all over the lot. More later, this evening and around midnight.


11:30 p.m. Monday, Oct. 5, Japan time: Though a vast spread remains among model solutions and Tropical Storm Chan-hom's future remains cloudy at best, Joint Typhoon Warning Center's latest forecast track still keeps it well away from Japan land masses.

At 9 p.m., Chanhom was 849 miles south of Yokosuka Naval Base, 903 miles southeast of Sasebo Naval Base and 753 miles east-southeast of Kadena Air Base, Okinawa, crawling north at 4 mph and holding steady at 40-mph sustained winds and 52-mph gusts.

U.S. bases throughout Japan remain in seasonal tropical cyclone conditions of readiness.

If Chan-hom remains on present heading, JTWC forecasts it to turn northwest Tuesday morning, reach typhoon intensity at mid-morning Wednesday and peak at Category 2-equivalent strength, 98-mph sustained winds and 121-mph gusts late Thursday.

Chan-hom is forecast to pass 276 miles east of Kadena at 2 a.m. Friday, make a sharp turn northeast late Friday and pass 224 miles south-southeast of Sasebo and 200 miles south-southeast of Marine Corps Air Station Iwakuni between 1 and 9 p.m. Saturday.

But model solutions are vastly spread out. JTWC reports a spread of 311 miles three days out and -- get this -- 805 miles five days out. Model-track guidance and forecast ensembles show much the same.

Keep in mind, Chan-hom is a day old, still putting itself together and much can change over the next few days. Stay tuned. This will be updated at mid-day Tuesday.


6:30 p.m. Monday, Oct. 5, Japan time: Tropical Storm Chan-hom could spare Japan land masses and remain off shore, if the current Joint Typhoon Warning Center forecast track holds.

At 3 p.m., Chan-hom was 898 miles south of Yokosuka Naval Base, 940 miles southeast of Sasebo Naval Base and 764 miles east-southeast of Kadena Air Base, Okinawa.

It had remained quasi-stationary the last 12 hours, holding steady at 40-mph sustained winds and 52-mph gusts. JTWC projects Chan-hom to peak at 98-mph sustained winds and 121-mph gusts at mid-afternoon Thursday, then weakening as it moves northeast.

U.S. bases throughout Japan remain in seasonal Tropical Cyclone Conditions of Readiness.

If Chan-hom keeps its present heading, JTWC forecasts it to pass 255 miles east of Kadena at 2 a.m. Friday, 255 south-southeast of Sasebo at mid-morning Saturday and 240 south of Marine Corps Air Station Iwakuni at mid-afternoon Saturday.

But there remains much uncertainty regarding Chan-hom's forecast track. What meteorologists refer to as the "cone of error" runs between southwestern Ishigaki Island and Tokyo -- some 1,200 miles.

JTWC reports a spread of 282 miles among solutions three days out and nearly 700 miles five days out. Model-track guidance and the GFS, CMC and ECMWF forecast ensembles show similar disparity.

In short, way too early to tell. Much can change in the coming days. More to follow at midnight and again at mid-day Tuesday.


12:15 p.m. Monday, Oct. 5, Japan time: Chan-hom wasted little time spinning up into a tropical storm Monday, having spawned southeast of Japan overnight Sunday. Southwestern Japan appears a possible target, according to Joint Typhoon Warning Center.

At 9 a.m., Chan-hom was 753 miles east-southeast of Kadena Air Base, Okinawa, and 919 miles southeast of Sasebo Naval Base, crawling west-northwest at 3 mph packing 40-mph sustained winds and 52-mph gusts at center.

U.S. bases on Okinawa and in southwestern Japan remain in seasonal Tropical Cyclone Condtions of Readiness. Prepare for possible upgrades in the coming days.

Kadena's extended weather forecast calls for winds picking up Tuesday, peaking at 34-mph sustained with gusts between 49 and 52 mph on Thursday with a 20- to 30-percent chance of showers and thunderstorms. Not destructive winds, but strong nonetheless.

If Chan-hom stays on present course, JTWC forecasts it to peak at Category 2-equivalent intensity, 98-mph sustained winds and 121-mph gusts at about mid-morning Thursday, still well east of Okinawa and south-southeast of Kyushu, then weaken as it moves north.

Chan-hom is forecast to pass about 247 miles east of Kadena early Friday morning, then curve north toward the southern tip of Kyushu by Saturday afternoon.

JTWC reports a cross-track spread among solutions of about 250 miles three days out and 290 four days out. The GFS, CMC and ECMWF forecast ensembles show a similar disparity.

Much can change. Chan-hom isn't even a day old yet. Stand by for more early Monday evening and again around midnight.


Midnight Sunday, Oct. 4, Japan time: Disturbance 90W Invest remained well southeast of Japan and model solutions remained an exercise in guesswork overnight Sunday into Monday.

At midnight, 90W was 777 miles east-southeast of Kadena Air Base, Okinawa, and 910 miles south-southeast of Marine Corps Air Station Iwakuni, moving generally north.

The spread among model-track guidance and forecast ensembles remains vast, and provide a strong visual example of why TV weather forecasters in the States refer to them as "spaghetti models."

The main reason for the disparity: It's very early in the life of the disturbance. Much can change, and much has been changing as 90W continues developing.The only thing certain is uncertainty at this point.

By early morning to mid-day Monday, 90W could morph into a tropical cyclone; in any case, it's days away from any land mass, if it affects one at all. This post will be updated at mid-day Monday.


7 p.m. Sunday, Oct. 4, Japan time: A tropical cyclone formation alert was issued at 6 p.m. Japan time on disturbance 90W Invest by the Joint Typhoon Warning Center.

At 6 p.m., 90W was 794 miles east-southeast of Kadena Air Base, Okinawa, and 897 miles south-southeast of Marine Corps Air Station Iwakuni, Japan, moving due north at 8 mph. All U.S. bases in Japan remain in seasonal Tropical Cyclone Conditions of Readiness.

Model solutions are inconclusive at this point. Global Forecast System forecast ensemble depicts initial northwest movement, then a curve northeast in Tokyo’s general direction, while the Europe and UK ensembles favor a track more toward southwest Japan and Okinawa.

In short, too early to tell at this point what it might do.

This post will be updated at mid-day Monday.