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The story
A linear rain band formed in Ishikawa and Toyama prefectures in the early hours of the 27th, triggering an emergency heavy rain warning — but the Japan Meteorological Agency (JMA) failed to predict it in advance. Following the miss during the August 13 Chiba downpour, this second “missed forecast” sparked a mix of reactions on 5ch: some defended the agency, arguing preparation should simply assume forecasts will fail; others voiced broader distrust of weather forecasting or called for greater use of AI.
The Level 5 emergency heavy rain warnings issued for Ishikawa and Toyama on the morning of the 27th were triggered by record-breaking rainfall from a linear rain band. However, the JMA was unable to predict the first band that formed in the early morning hours or warn in advance that danger was imminent. The same thing happened during the August 13 Chiba downpour, highlighting ongoing problems with forecast accuracy.
According to the JMA, linear rain bands formed three times in Ishikawa on the 27th — at 3:08 a.m., 6:19 a.m., and 8:48 a.m. — and twice in Toyama, at 2:58 a.m. and 6:08 a.m.
The JMA issues both a “half-day-ahead forecast” and an “imminent forecast,” the latter indicating a heightened chance of a linear rain band forming within three hours, to urge caution. The imminent forecast in particular is a newly launched, higher-precision service that only began operating this past May.
Source: asahi.com / Original article here
What people said
If they tried to predict every single one of these, there'd be no end to it
It'll just end up like the boy who cried wolf anyway
Yeah, that's right!
They're just predicting based on past data
Once decades' worth of data piles up, they'll probably start getting it right
if resources get diverted to flood-damage response and it causes a labor shortage, will small regional sash (window frame) manufacturers lose work? Go under?
Toyama's actually a major sash-manufacturing region, you know
So? Does that mean less work?
That's a troll, don't engage.
Maybe that's it
Once enough data builds up over time, it'll gradually start hitting the mark
I mean, they're already using AI for this, aren't they?
AI makes plenty of mistakes too
And hey, perfect liability shield, right?
There's no way a perfect prediction is even possible
You'd think they could at least get "rain or shine" right. The past few years, sites like tenki.jp keep forecasting sunny and it rains, or forecasting rain and it's blazing sunny all day. And they want you to pay for premium on top of that lol
tenki.jp's quality has been the same since it launched decades ago
It's never once actually helped me but I still check it out of habit
The economic analysts on TV predicting the Nikkei average get way less flak.
Makes you want to say their accuracy's dropping — that's how little I trust them
Of course accuracy tanks the moment something outside their usual patterns shows up
Linear rain bands are actually the easier case, since the near-term is relatively predictable
Recent guerrilla downpours (sudden, localized cloudbursts) feel like rain clouds just spawn out of nowhere
They're too busy DMing people on X for video footage to post, no way they've got time for that
Nobody's buying it anyway, so who cares
Bought some new rice today. Miyazaki-grown Koshihikari, ¥1,999 before tax.
With that in mind, well, get a load of this lol
[Weather] JMA issues 12-hour-advance linear rain band forecast — risk of major flood disaster surging in Shizuoka, Aichi, Gifu, and Mie prefectures [Gure★]
https://asahi.5ch.io/test/read.cgi/newsplus/1787818778/
Maybe that's actually a sign of progress — the remaining hard cases are just the ones that are genuinely hard to predict
Dangerous cold fronts too
A normal cold front's no big deal, but the dangerous kind can spawn tornadoes
Knowing a few hours ahead could let people evacuate at night before it hits, though
If rough guessing is good enough, even an amateur can spot a nasty-looking rain cloud
There's tons of information out there now
With humidity like a sauna, a typhoon nearby, and a weather map showing rain clouds ready to dump — heavy rain is basically guaranteed
It's actually weirder to be caught off guard
They pop up out of nowhere sometimes though
Might need data on terrain, whether there's a data center or factory nearby, highways, and other heat sources from human activity too
When I'm bored I check the rain radar sometimes, and even on a clearly sunny day there are red patches of rain clouds popping up here and there — it's just hopeless. Even if they could predict it, the infrastructure still isn't built to withstand torrential rain anyway
my parents' house had water under the floor
Namu Amida Butsu (a Buddhist prayer, roughly "rest in peace")
*This article is compiled from excerpts and a summary of the 5ch (Breaking News+) thread “[JMA] Linear Rain Band Forecast Missed Again — This Time in Hokuriku, Following Chiba.”
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