r/japanweather
▲ 28 r/japanweather
Yokohama noticeably cooler this June than last year,
It was a cool weather month in Yokohama.
June of this year was noticeably cooler than last year.
The daytime high breached 30C on 15th June last year and remained above 30C for the rest of the month.
The nighttime highs reached 25C on the 17th and hovered around 25C for the rest of the month.
This year excluding the 30C high of June 1st, the high temps have ranged in the mi 20s’
The nighttime highs, the high teens, and not once reaching 熱帯夜 (Tropical Night) levels.
u/MarsupialSalt4857 — 4 days ago
▲ 107 r/japanweather
By the way, if you looked out your window…
...And you live anywhere from Kanto on down, you’ve probably noticed that it is raining.
Nothing much to see, just a typical rainy season frontal pattern. Moving east-northeast, a thick band of rain is moving along the western and southern half of the country, stretching from Kyushu all the way to Kanto. Locally heavy rains pelted areas of Kyushu today, and intense precipitation down south will continue through the night. The bulk of the rain will travel along the country, bringing a sloppy Thursday morning commute from Kyushu and Shikoku on up through Kansai, Chubu, Kanto and on up to Sendai.
Rains associated with the front are expected to settle down by Friday, bringing partly-cloudy to cloudy conditions along much of the country.
Tohoku and Hokkaido, meanwhile, may see some scattered rains here and there, but will largely be free of the precipitation tomorrow.
Rain patterns over Japan, 1 Jul @ 21:00 JST
Development of Invest 95W from 30 Jun, 21:00 - 1 Jul 21:00 JST
Meanwhile, we have two developing typhoons in the tropical Pacific. One, developing just to the west of the Philippines, is expected to move into the Asian mainland soon after it forms. The other, named, for now, Invest 95W, which we covered yesterday, has plenty of room to grow. Compared to yesterday’s satellite images, the storm has a bit more development, and that patch of the Pacific is prime for cyclone growth right now, with sea temperatures of around 29-30c, giving the new storm lots of fuel.
Long term models are beginning to coalesce and the current consensus is that this storm, which should reach typhoon status as per the JMA within the next the evening of 2 July, can become one of 2026’s more serious events. Projected paths of this soon-to-be typhoon are currently forecasting it to run well south of Japan, with both the ECMWF and the GFS projecting runs toward Taiwan then on into the Chinese mainland around 10 Jul.
Of course, we are still 9-10 days out from that point, and a lot can happen in that time. Even though things right now look like this typhoon will not be a direct player in Japan’s weather (with the very real potential exception of Okinawa getting a day of very heavy storms), we do have to keep one eye open just in case something starts to steer the system up our way.
u/Neko_Dash — 5 days ago
▲ 88 r/japanweather
Our Next Typhoon. But...
Way, way out in the Western Pacific, near the remote atolls of eastern Micronesia, a small pocket of atmospheric instability has bubbled to life. Centered roughly 3,900 kilometers southeast of Tokyo near 9°N, 165°E, this broad disturbance is currently designated as Invest 95W. As things stand now, it is a loose, disorganized cluster of clouds and thunderstorms slowly rotating around a developing center, with sustained winds hovering around a modest 35 km/h.
However, the environment in this patch of the Pacific is extremely promising for cyclonic development. With exceptionally warm sea surface temperatures and low wind shear - the winds aloft that can tear a developing storm apart - surrounding conditions are highly favorable for growth. Over the next 24 to 36 hours, the system is expected to steadily consolidate. Forecasters anticipate it will climb the atmospheric ladder next week, graduating from a tropical depression to a tropical storm, and finally into a mature typhoon.
Despite this high confidence in its formation, trying to plot an exact path right now is a bit of a nonstarter. While major global weather models and the Pearl Harbor-based Joint Typhoon Warning Center acknowledge its potential, long-range tracking models show absolutely no consensus beyond 4 July.
To illustrate just how erratic early typhoon forecasting can be, the European (ECMWF) model projected a landfall near Nagoya on 11 July during Sunday's run, shifted its target to Korea on Monday, then today points toward Taiwan around 10 July. Meanwhile, the American (GFS) model initially hinted at a direct line toward the Kanto region, only to later shift its tracking data south toward Okinawa.
So, the bottom line? We are looking at a system that has all the ingredients to become a formidable typhoon, but we simply cannot know where it is going yet. By 5-6 July, as the storm establishes a well-defined center, the steering currents will become clearer. For now, it’s just an active watch-and-wait situation.
By the way, a word about tracking models: When a storm like Invest 95W starts brewing, it’s only a matter of time before multi-model tracking charts, aka “spaghetti models”, start flooding your social media feeds. If you’ve ever seen these charts, which look like someone threw a handful of multicolored noodles onto a map of the Pacific and decided to call it a day, it’s easy to think these tracks are a study in randomness. But, there is some science here.
Here is how you should actually read them:
- Treat early lines as possibilities, not promises: A multi-model isn't showing you ten different guaranteed paths; it's showing you a range of mathematical guesses based on slightly different initial data. When a storm is this young and far away, the computers are working with a lot of missing pieces.
- Look for the bundle, ignore the outliers: Don't freak out over the one wild line that darts away from the rest toward your city. Pay attention to where the majority of the lines cluster together. That bundle of lines tells us where the highest probability lies.
- The farther out, the wider the spread: A forecast model is incredibly accurate for the next 48 hours. By day five, it's a bit blurry. By day ten? It’s mostly educated guesswork. If the lines look like a tangled, wide-open mess next week, it means the atmosphere hasn't made up its mind yet—and neither should you.
The Golden Rule: When a potential typhoon is more than a week away, use that time for awareness, not anxiety. Keep an eye on the official agencies like the Japan Meteorological Agency (JMA) or the Joint Typhoon Warning Center, and let the models sort themselves out over the next few days. We'll be tracking every data run right here.
u/Neko_Dash — 6 days ago
▲ 72 r/japanweather
So, What's Next?
The remains of T7 are out at sea, carried by the Jet Stream, and T8 lies tattered and strewn across the Pacific Ocean, like all the hopes and dreams of my youth.
It has been an eventful few days on the weather front here in Japan, along with a seismic jolt or two to spice things up. So, what happens now?
Well, we settle into a gentler rhythm of systems moving across the nation. The rainy season fronts are offshore now (remember this…I’m going to refer to it a little later), and a high pressure system floating about in the Sea of Japan will largely dominate our weather for the next couple of days. Through Wednesday evening, the country as a whole can expect partly-cloudy to cloudy skies and variable conditions with highs between 20-22 up north to 28-30 down south, with cooler highs in mountain areas. Hokkaido saw highs between the mid-teens to around 20 today but will get a warming trend through the week, with highs in Sapporo reaching 26 on Thursday.
Summer time humidity - the heavy, muggy summer air we all know and love here - came into Kanto today, with daytime percentages hovering around 80%. Most of the rest of the nation had drier daytimes today, but from Tuesday, Kyushu and Shikoku will begin to see midday humidities in the upper 80s as our next system begins to make its run across the country.
Our next weather player is expected to approach Kyushu from midday Wednesday, but the latest data suggests its track will stay south because of the positioning of the rainy season front (梅雨前線, Baiyu Zensen). The rainy season front is not expected to move much over the next few days and will act as a conveyor belt of sorts for the systems coming over from the mainland. High pressure domes both south and north of the front will also help channel the movement of the systems as they move across.
Rain is probable in most of Kyushu on Wednesday, then elevated possibilities exist in western Honshu, Kansai, Chubu (Nagoya) and Kanto through Thursday evening. There will not be much time to dry out as the next system coming over from the Asian mainland is set to land in Kyushu on Friday and take much the same path, giving western Honshu, Shikoku and Kansai the greatest chance for rain as we head into the weekend.
u/Neko_Dash — 7 days ago
▲ 121 r/japanweather
Earthquake Prep, Pt 1: Shelter In Place Kit
[Mod note: With the recent quakes we've had in Japan lately, I think it would be a good idea to assemble an Earthquake Prep Doc for the community. Some people here in Japan have no experience with quakes, so I hope this can be a good first stop to review what you need. This post is for shelter in place, which is the the most likely way of getting through post-quake life, but we will also cover what you need to do in case of evacuation and what happens if you are caught at work during a large quake. Also, this is a living document. It will be amended and updated as needed. - Neko Dash; June 28, 2026]
Shelter In Place Emergency Kit
Basic Scenario: A quake hits and knocks out utilities and some transport infrastructure. Your home is still livable and community evacuations are voluntary. You choose to shelter in place. You are in familiar surroundings. There may be some damage to your building, but it livable. There are no utilities, though. When it’s night, it’s completely dark. No electricity, no gas, no water. What do you do if you’re going to spend a week partying like it’s 1699?
Immediately after the quake, grocery stores and conbinis are going to be swarmed, and there will be a wave of panic buying. I have seen this twice - once after the Hanshin quake in January 1995 and again after the Tohoku quake of March 2011.
Avoid the rush and assemble a kit in advance. The kit should be stored in either in plastic bins or a large duffel bag - or both - at your home. Links are below.
There are starter emergency gear bags at Amazon and Rakuten, and you can build on these. A few links are below, but the links are not the end-all of these items. They are just a launchpad. Look through and find what gear suits your needs.
Gotta Have Gear:
- A solar charger w/ hand cranks option for phones, flashlights with rechargeable batteries, radios or other small electronics.
- Flashlight
- Spare batteries for electronics. Take an inventory of battery-powered items in your household and get the required batteries.
- Radio with hand crank power capacity.
- First Aid Kit
- Glow Sticks (7x). These things aren't just for anime raves. They are a good source of ambient light at night.
- Facial masks
Sanitary/Medical
- Hand sanitizer
- Disinfecting wipes / disposable oshibori
- Prescription medication
- OTC meds: Headache medicine, antacid medicine, pain relievers
- Feminine sanitary products [whatever your preferred format/brand]
- Spare eyeglasses or contact lenses
- Spare bottle of contact solution
- Emergency toilets
- Diapers, if you have toddlers/babies
- Paper towels
- Pet sheets
- Pet poop bags
Food, Food Prep: [Note - food and water should be rotated at least 2x a year]
- Paper plates, one week’s worth per person
- Gas cassette burner + 6 spare gas cassettes
- A small pot or pan
- Ready to eat pre-packaged fruits/vegetables
- Canned fish/meat not requiring refrigeration
- Instant Noodles
- Peanut Butter
- Energy drinks
- Protein Bars/Calorie Mate
- 2 liters of water per person for 7 days
- Other bottled drinks
- Infant formula
- Pet Food
- So here's some advice from one of the community's regulars: Most recs I used to see were for three days. You'll want nine fruits & veg choices, six hearty protein choices, three lesser protein choices and at least nine servings of carbs.
- Lighter choices: protein bars, box of crackers, dried fruit and nuts.
- Fun choices: fancy sardines, quail eggs, teeny tiny jars of jam, single serving tubes of honey, Walkers shortbreads or other fancy cookies.
- Extras: wet wipes, wooden ice cream spoons, a plate and a box of plastic wrap to cover the plate so you don't have to wash it. Paper cups.
- Food is medicine kit: in Altoids tins, three mint tea bags. Three chamomile tea bags. Three green tea bags. Single serving honey tubes. A bottle of coca cola (you'll drink this flat for stomach upset). Honey lemon and maybe ginger candies.
- Luxuries you'll want: anything you're addicted to, like coffee, tea, chocolate, sugar (single servings or candies).
- Switch it out to your regular pantry every six months and stock with fresh.
ETC
- Books, toys, games
FOR TOURISTS
- Copies of your passports/ID docs
- Hard copies of your travel itinerary, flight or transport schedules
- Phone numbers/websites of travel providers, lodging locations (hotels, hostels, etc)
Links (Neither r/japanweather nor Neko Dash are affiliated with the links below. They are solely for your convenience and to give you an idea of what’s out there. You may find other items which are better suited for your needs.)
Tokyo Metropolitan Government Disaster Preparation: https://www.bousai.metro.tokyo.lg.jp/book/pdf/en/02_Lets_Get_Prepared.pdf
Evacuation Parks: https://www.tokyo-park.or.jp/special/bousai/english/index.html
Disaster Prep Kit (ready made): https://amzn.asia/d/02NdXPvO
Solar Charger: https://amzn.asia/d/0eZ0RJyp
Hand Crank Radio: https://amzn.asia/d/0bJXnRsE
First Aid Kit: https://amzn.asia/d/02gVErV4
Emergency Toilet: https://amzn.asia/d/0bLegtaP
Eiyoukan (Calorie dense food): https://item.rakuten.co.jp/rakuten24/4901006111669/?iasid=07rpp_10095___31-mqxf8wgs-2n-9cf1423b-ede0-4734-968b-352d0dac32ab
Local Government Sites
Thank you to everyone for your contributions and suggestions.
u/Neko_Dash — 9 days ago
▲ 51 r/japanweather
The non-summer of '93
Anyone here remember the devastating events of 1993. I'm feeling a bit of dejavu with this year's weather.
A weak high-pressure system led to a prolonged rainy season (tsuyu) and unusually cool temperatures across Japan. The poor weather severely damaged the domestic rice harvest. This forced Japan to import rice from the United States and Thailand.
The summer also saw several destructive typhoons.
u/MarsupialSalt4857 — 8 days ago
▲ 294 r/japanweather
Strong shake in west Kanto
Just what we need - a strong quake in the middle of a typhoon approach.
When it rains, it freaking pours. Literally.
Hope everyone is safe. Pretty strong (low 6) quake just struck around the Mt. Fuji area. Along with this afternoons’s mag 5 shaker centered in Chiba, it’s kind of concerning.
But, I’ll tell you, the alarm scared the bejeezus out of me.
u/Neko_Dash — 10 days ago
▲ 32 r/japanweather
Pop up rainstorms in Tokachi
My cats want in and out and back in again. I swear, I've toweled off dogs and cats five times a day the past few days.
On the bright side, blue sky! On the wet side, there was a cat fight (maybe just an argument) in the tall grass, and my boy Cessna came in more drenched than I'd ever seen him.
u/RedYamOnthego — 7 days ago
▲ 129 r/japanweather
Some thoughts on yesterday's quake near Mt. Fuji
Anyone who lives in central Japan certainly felt the quake last night at around 22:30. A light 6 on the Japanese scale and a M 5.7 from the USGS, it set off quake alarms over Kanagawa, Tokyo, Shizuoka among other locations as it fired off at a depth of 50.9km. Ultimately, no significant damage came from the quake.
On late in the afternoon of August 8, 2024, about one month after r/japanweather was created, the Hyuganada quake struck off the coast of Miyazaki Prefecture down in Kyushu. That shaker came in at a light 6, too, with a USGS magnitude of 7.1, and set off at a depth of 25km.
In the aftermath of the 2024 quake, the JMA issues a “Nankai Trough Earthquake Extra Information” advisory, which is the somewhat tortured, direct translation of the 南海トラフ地震臨時情報 notice issued by the Disaster Management Division of the Government’s Cabinet Office. The Nankai Trough, just for review, is a 900 km long submarine trench located off the southwestern Pacific coast of Japan. It marks a highly active tectonic subduction zone where the Philippine Sea Plate is sliding beneath the Eurasian Plate. Mt. Fuji, at the easternmost side of the fault which created the Nankai Trough, was created by the geological forces coming from a collision of plates in the area.
The advisory noted that the August quake could cause instability along the Nankai trough, and, following historical precedent, a 7+ megathrust quake could potentially hit along the trough, which, in turn, could trigger a potential severe tsunami along the Pacific coast of the country.
The thing that concerns me here is the August quake was near western terminus of the Nankai Trough. Yesterday’s quake was near the eastern terminus.
If we could predict earthquakes, people much smarter than me would be making very direct statements about what to expect. The problem is we do not know what will be next. Nobody in the government so far has issued any statements connecting the two, nor has the JMA, the MLIT (Ministry of Land, Infrastructure, Transport and Tourism, 国土交通省) or the Cabinet Office announced any further warnings of quakes or other seismic activity. There is a tidbit of historical activity about quakes along the Nankai Trough, and recent movements would suggest we are overdue for another one, but whether or not it will happen if very far from certain.
I really want to be 100% crystal clear here. I am in no way trying to gin up alarm or fear. That’s one of the rules I set for the sub back in 2024 - no panic posts. But, the locations and timelines of the two events should raise awareness that a large seismic event will eventually happen along the Nankai Trough at some point. We simply do not know when the next quake will hit or how strong it will be. Will it happen? If so, when? How large will it be? Will it generate a tsunami? Nobody knows.
Just be aware, keep alert and stay safe. That's the best we can do.
Links to government sources regarding Nankai Trough Warnings and Preparation
https://www.bousai.go.jp/jishin/nankai/rinji/index3.html
https://www.bousai.go.jp/jishin/nankai/pdf/multileaflet01.pdf
https://www.jma.go.jp/jma/kishou/know/jishin/nteq/index.html
u/Neko_Dash — 9 days ago
▲ 62 r/japanweather
What’s with all the earthquakes today?
Just felt I think the third one for today in Chiba. This one was a long one, too. Anyone else feel it, or any of the other ones earlier?
u/miseenen — 10 days ago
▲ 0 r/japanweather
Trying to get a sense of the weather rn - would ya’ll say comparable to florida?
Hi ya’ll - planning a super last min flight to Tokyo/Osaka/Kyoto.
Seeing all sorts of mixed things online about the typhoon and how hot it is etc. it seems like people are focused on heat but im def more concerned with rain. Im currently in florida and from the weather app it seems like humidity and heat are comparable (loving the florida heat) but trying to get a sense of if the downpours are short and temporary like florida too or if the weather app is correct and its downpours all day.
If its similar to Florida in July seems like my ideal weather. If its full on rainy all day/sad clouds/no outdoor activities because of rain, its prob not for me. Anyone have a sense??
u/redfoxxy23 — 8 days ago
▲ 35 r/japanweather
Slingshot action?
Just checked up on where we are with these twin typhoons, and I was surprised to find No.8 well ahead of its predicted position, currently sitting off the coast of Miyagi Prefecture.
Given their anti-clockwise spin, did the stronger No.7 essentially 'slingshot' it off to the east?
u/TakaIka83 — 9 days ago
▲ 59 r/japanweather
The clouds after the storm
How was it in your location?
Photos Location: West Tokyo near Ome
u/DetailGullible5148 — 9 days ago
▲ 125 r/japanweather
Fast, Loose and Poorly Organized
Although it sounds like an uncannily specific description of my ex-spouse, we are talking about the tracks of Typhoon 7 and 8 here, so stop snickering and pay attention. Especially you troublemakers in the back.
Now, then.
Typhoon 7 (data as of 18:00 JST):
Position: 24.8N 126.0E, 260km southwest of Kadena AFB, Okinawa
Movement: 345 degrees at 18kph
Max Sustained Winds: 82kph Gusts: 144kph over open water
Central atmospheric pressure: 985hPa
Synopsis: T7 has lost a lot of its integrity in the past 24 hours. 24-36 hours ago, the eye was very visible from Himawari satellite images. Now, not so much. The storm’s strength peaked earlier today, and will encounter less favorable conditions from here on out. It will complete its northeastward pivot at it makes its closest approach to Okinawa around 6am tomorrow morning. After it pivots, it will pick up speed, pushed on by strong westerly winds aloft. About 24-36 hours from now (26 June, 21:00~27 June, 03:00), it will encounter a double strike of drier air and more severe vertical wind shear (VWS...more on VWS a little bit below), as well as cooler sea surface temperatures as it moves out of the tropics.
Where is it going? After completing its pivot overnight, T7 will set a course for the Pacific coast of Japan’s main islands. The path was tweaked a little eastward since last night, and the new path will put the Pac coast right in line for some very heavy rain. Winds are forecast to run about 40-60kph along the southern Pacific coast, but maintain about 80kph over water. Winds should taper down to about 30-45kph over land by the time the system reaches Shikoku onwards, and maintain about 72kph winds over water.
Trying to forecast the rain profile has been tough, partially due to the weakening and loosening of the system. It is also expected to merge with an existing rainy season front over Kyushu, Shikoku and the Kii Peninsula, which further muddies the waters, but is largely expected to extend the rain profile out toward Nagoya. Suffice it to say Kyushu, Shikoku, western Honshu up to Kansai will be under rain. Further up, Chubu (Nagoya) and Kanto will get significant rainfall through Saturday, locally heavy in some parts, while Hokuriku (the vicinity of Kanazawa, and up the Sea of Japan coast) will get some scattered bands of rain.
Typhoon 8 (data as of 18:00 JST):
Position: 19.7N 135.5E, 1,350km south-southwest of Kagoshima
Movement: 315 degrees at 35kph
Max Sustained Winds: 82kph Gusts: 126kph over open water
Central atmospheric pressure: 998hPa
Synopsis: The looser, faster one of the two, T8 is also weaker. It is a scattered, weak storm on satellite images, with no discernible eye or even structure. T8 is being pushed northwest along a band of high pressure out over open ocean. Already pretty fast moving at 35kph, it will pivot along the endpoint of that high pressure band in about 12 hours (around 9am, 26 June) and then accelerate as it heads toward Japan. In about 24-36 hours from now, (26 June, 21:00~27 June, 03:00), T8 will wander into the bad part of town, at least for tropical storms, and will get slammed by a very aggressive environment of strong VWS (vertical wind shear…remember…I talked about a bit up in the T7 passage), forceful winds aloft, surrounding dry air and cooler sea surface temperatures. The result will take some of the edge off of T8’s strength, but the high winds aloft will assist in keeping T8 alive by maintaining storm outflow.
Where is it going? There is a lot of disagreement on the path of T8. The JTWC says will move on a curved heading northeast and will make landfall around Shizuka, while WeatherNews is betting that T8 grazes Chiba around Saturday morning on its way out to sea, without any landfall. Right now, it’s really up in the air for the 24-36 hours. Anything can happen.
Except the Fujiw(h)ara Effect. Ain’t no way in this universe that’s gonna happen. Period.
There is also a chance that T8 may completely unravel by Saturday, depending on its vulnerability to the surrounding environmental factors outlined above. If that happens, it will just be a line of thunderstorms instead of a coherent system. Even so, it will still pack rain and winds.
https://reddit.com/link/1ufajat/video/o0ew0dvznf9h1/player
Now, VWS. Vertical Wind Shear. What is that Y50,000 term?
Typhoons for all their majestic, awesome power, are really fragile structures on a global scale. Typhoons need very specific conditions to grow and thrive and system-scale challenges to that environment can bring a strong typhoon down to a tropical storm in a matter of hours. The most common threat to typhoons is vertical wind shear. In ideal environment for a typhoon is one where there is very little surrounding wind movement. This allows the vertical cyclonic movement of a new typhoon to form and solidify. Now, throw in some strong, sustained winds from anywhere from 2,000 meters on up at different speeds and directions, and that starts to mess around with a typhoon’s structure. The central core (the eye) and its surrounding walls will start to degrade with persistent VWS exposure. Down in the tropics, wind shear at that level doesn’t really exist much. But, bring it up to around 25 degrees latitude on up, and vertical wind shear is more common.
u/Neko_Dash — 11 days ago
▲ 29 r/japanweather
Anyone else getting blasted in Kanagawa?
We've got thunderstorms and crazy downpours right now (1:00 PM)! It's very cozy but a LOT, windy, rainy, really dark.
u/miettethefootball — 10 days ago
▲ 291 r/japanweather
Two Typhoons To Go and a Very Cool June, Please
But first, the weather. The regular weather.
There is a lot going on and Japan’s atmosphere right now is as wacky as a sack of cats. There’s a lot to get through.
It’s been a very cool summer so far, something that has been noted in other subs. As much as this is cause for jubilation and dancing in the streets, especially after the brutal, brutal summer we had last year, our little cool wave is temporary. It is the product of several factors, chiefly a proper rainy season setup, and placement of local high and low pressure systems bringing down northerly air.
Pressure and wind profiles of T7 and T8 as of 09:00 JST this morning.
Himawari Sat Movie for the 24 hours from 23 June, 09:00 - 24 June, 09:00.
 Looking at long-term data, I’m seeing a gradual weakening of this pattern in the July 1-4 timeframe, being replaced my more seasonal (i.e, hot) temperatures, probably with the standard humidity that goes with it. Nationally, we will go from highs in the low 20s to the low 30s by 4 July. Bottom line: Enjoy the cool summer now, while we have it. By mid-July, we will have this memory and powerful AC to keep us cool.
The 5-Day Forecast: The rainy season setups are still strong over the country, and they are being enhanced by the approach of couple of typhoons, which I will get to in a moment.
WEST JAPAN (Kansai on down to Kyushu, Shikoku inclusive): For the next three days, through the evening of 26 June, western Japan will be under rainy skies much of the time, with some of the rainfall, particularly in Kyushu and Shikoku, very heavy. Much of this rain is generated from rainy season fronts, but the approach of Typhoon 7 on Friday will give the rain just a bit more strength. Things will begin to settle out with the rain moving on by midday Saturday, and some areas may get some sun poking through the clouds on Sunday.
OKINAWA: Okinawa will see their sunny weather turn to heavy rain with the approach of Typhoon 7 from Thursday evening (more about that later).
CENTRAL JAPAN (Chubu/Hokuriku/Kanto): Rainy season frontal system-derived showers will fall over much of the central part of the country on Thursday. Rain bands from Typhoon 8 and, later, Typhoon 7, will begin to be a player in central Japan’s weather from Friday as it moves northeast over Honshu. The central part of Honshu and Hokuriku (Sea of Japan) side of the country are expected to get the most intense and sustained rainfall from the at-that-point rapidly weakening T7.
TOHOKU/HOKKAIDO: Tohoku and Hokkaido both will see fair to cloudy skies today, with increased chances of rain on Friday as the remains of T7 push through the area. Cloudy to partly cloudy skies remain in the area after the storm.
TYPHOON 7 and TYPHOON 8
We have something of a traffic jam this week, as both Typhoon 7 (aka, “Mekkhala”) and Typhoon 8 (aka, “Higos”) churn their way through the Pacific Ocean on their way to Japan. There’s a lot to unpack here as these storms have very different characteristics.
First things first: Models, although in general agreement about both T7 and T8 over the next 36-48 hours, then start to go all over the place regarding the path and intensity of each typhoon. What follows is my interpretation of what each typhoon will do, based on data from the JTWC, WeatherNews, the JMA and the ECMWF.
Typhoon 7: T7 is the stronger of the two storms in the Pacific right now. The latest data runs on T7’s 5-day forecast position the storm further westward than before. Its strength has already peaked, a day or two before its expected encounter with Okinawa and it will begin a. Slow decline. Located as of 9:00 JST at 21.0N 124.6E, about 530km south-southeast of Taipei, T7 has a central pressure of 983 hPa and sustained maximum winds of 140kph with gusts of up to 170kph over open water. T7 is executing its pivot now, presently tracking at 354 degrees, just a little west of true north at a lumbering 15kph. It will move northeast toward Okinawa later today, and set a course over the main Japanese islands.
Once the recurvature is complete (that is, once it completes its pivot), it will pick up speed as it runs into stronger winds aloft coming from the west.
In the next 24 hours, T7 will begin to run into some hostile areas, with stronger wind shear which will tear at the integrity of the system. About 36 hours from now, movement into cooler waters will further sap T7’s strength, although the outward flow aloft will continue saucking air upward and helping the storm maintain its fierce intensity through Tau72 despite the cold water.
T7 will bring large bands of rain and some storm-level winds to Japan’s main islands through Thursday evening into Friday, finally moving away from Japan around Saturday afternoon.
Typhoon 8 was classified as a typhoon-level storm by the JMA this morning, but it is just barely in that classification. As of 09:00 JST, the storm had 72kph sustained winds with gusts of 108koh over open water and a central barometric pressure reading of 1000 hPa. It is not powerful, as typhoons go, and it is not expected to develop much stronger than it is now. T8 is not expected to make landfall, although current models suggest it will graze the Pacific coast of Chiba while staying about 100-150km offshore.
Now, a note about these typhoons, and this is directed mostly to travelers. First, typhoons, by the time they get up to the latitudes of Osaka or so, lose a lot of their power. They are still formidable storms bringing a lot of wind and rain, don’t get me wrong, but they are not the super destructive beasts they were earlier when thrashing the tropics. Typhoons up beyond Kyushu/Shikoku may mess with travel infrastructure, but they are rarely lethal forces of nature. We have a list of transportation services pinned to the top of the sub. If you are unsure whether your flight/train/trolley/go-kart/donkey ride will be affected, please consult your travel provider, which may be in this list. For those taking ferries or other marine transport, no sensible operator is going to see 15 foot waves and think, “Yeah, I can make it to Okinawa today.”
Edit: Why in the name of all that's crazy do the pictures and movies flake out? They just disappear. WTH, Reddit?
u/Neko_Dash — 12 days ago
▲ 94 r/japanweather
The Fujiw(h)ara Effect And Why It Won't Happen This Time
Good morning everyone. This is going to be a busy day on the sub, with the movement of Typhoons 7 and 8, and a steady rainy season front. Lots to get through, but I want to go through the fun stuff first.
On a couple of other Japan-related subs, there are some folks going on talking about T7 and T8 merging to create a super typhoon that will blow us all into Pyongyang along with our little dog Azuki.
So, tell you what - let the other subs have their fun (and some of the creativity is a hoot to read), but here’s what really happens when the so-called “Fujiwhara Effect” takes place, why it is so difficult to see, and why it won’t happen in this case.
The Fujiw(h)ara Effect is named after Japanese meteorologist Sakuhei Fujiwhara, who first described the phenomenon in the 1920s. At that time, romanization of Japanese names hadn’t been standardized, so the extra “h” stuck in there, but like Stewie and his “h” pronunciation of “Cool Whip” on “Family Guy”. But I digress. Double Neko Points to anyone resident in Japan with the guts to say “Fujiwhara”, with the distinct “h” pronunciation, in every day life. [Images re-uploaded at the bottom of the post.]
Today's WeatherNews chart showing positions of Typhoons 7 and 8.
Course of 2019's T5. It ate T6 out over in the open ocean around 155 degrees E.
FUJIW(H)ARA EFFECT RUNDOWN
Typhoons are massive low-pressure systems which rotate counter-clockwise in the Northern Hemisphere. The Fujiwhara Effect posits that two typhoons within a certain distance of each other begin to influence each other and their low pressure centers begin to move to combine to create one storm. This happens in one of two ways: 1) Stronger storm “eats” the weaker storm: This is basic physics. The more powerful storm will consume the smaller member. Or, 2) A Merger of Equals. This is much more difficult to pull off, but two equals willl begin to orbit around each other until they merge.
In either event, the resulting storm generally does not become more powerful on its own. If a storm is at 950hPa and has a radius of 500km before merging with a companion storm, the strength will probably not change. The storm may become a bit larger, but generally not stronger. I’ll address a couple of real-life observations in a moment.
WHY THE FUJIW(H)ARA EFFECT IS SO RARE
Conditions must be absolutely perfect for storms to combine. Being in general proximity alone is not enough. Both storms have to be free of other disruptions, such as wind shear from other systems, high winds aloft (Minor Jets or Jet Stream), insertion of drier air from surrounding systems, landmasses, cooler water temps, etc. The Fujiw(h)ara Effect truly needs a pristine canvas to create this particular painting.
HISTORICAL PRECEDENT
So, I went back through the Neko_Dash Weather Library (known also as “The Internet”), and found that there was one recent instance of the Fujiw(h)ara Effect in the western Pacific. in 2017, tropical storm Kulap (T2017/06) and typhoon Nori (T2017/05) merged, with the more powerful Nori eating Kulap for lunch, getting much stronger due to a southward dip into warmer, calmer seas, and then made a run for Japan coming up from Kyushu and over Honshu as a very pedestrian, not-very-noteworthy typhoon. There merger took place out in open water, about 25 degrees N / 155 degrees E, far from any other systems which could have disturbed the merger.
In 2009, there was a brief interaction between T2009/17 and T2009/18 (“Parma” and “Melor”) in the Philippines Sea, but it didn’t lead to a full merger. T2009/17 went on to hassle the Philippines before smashing into Vietnam, while T209/18 hooked up north and did some time on Japan’s central Pacific coast.
WHY IT WON’T HAPPEN WITH T7 and T8
The current T7 and T8 won’t combine and the biggest reason is because there is definitely not a pristine canvas to work on. T7 is already weakening, wandering into a more challenging environment of hostile wind shear, drier air coming from the north and cooling sea surface temperatures. T8 was never a strong storm to begin with and has remained disorganized. Within 36 hours (that is, before 18:00 on 26 June), T8 will start to be picked up by Jet Stream-associated winds aloft and, that will be, for all intents and purposes, the end of the line for T8.
Any questions?
[Edit: For whatever reason, the images I uploaded are not coming through. Here they are again.
u/Neko_Dash — 11 days ago
▲ 370 r/japanweather
Best Tsuyu ever
The cool air rolling through on a breeze. The mild days with less lung-boiling humidity. The consistent rain making the veggie garden so luscious. The more gradual transition into needing aircon to survive the heat.
This year has been quite literally the most refreshing tsuyu and early summer that I’ve experienced in almost a decade of living here. Compared to stressing about wet-bulb-esque conditions for three or four months, this has been incredible.
u/My-goats — 13 days ago