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#HeavyRain

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Fortsettelse av samtale
anlomedad

Does heavy rain occur more often in the late summer evening hours than in the early evening?
3/

I dug in some more.
I don't know the first thing about statistics so I don't know how to professionally put a figure to significance.
But I noticed that many of my positives, where late evening rain occurs more often than early evening rain, only had minor differences in occurrences in comparison.
This still means that late evening strong-ish rain larger than early evening rain is very common – contrary to the expert opinion.
But if I want to figure out what the underlying weather physics might be, I need to constrain the selection further.
So I took the number of events where Late Evening strong rain with 4-10mm/hour comes "out of the blue", meaning has no preceding strong rain (here >=4mm, open end!) in the early evening hours
and compared the number to
the station's number of events where an early evening has a 4-10mm event.
The difference of late versus early is then expressed as % of the total number of events of 4-10mm rain.
And if this is 12.5% or higher, I call it significant.

4-10mm per EVENING hour occurs once per summer in July-August, so is quite rare, but the events since 2005 are still numerous enough to do something with them. (The Alpine region gets plenty more evening events tho!)
Rain >=10mm/hour is too rare, occurring only every 3rd year or so, which is an average of only 8 summer evening events per station. Too few to compare early and late events.

The screenshot shows the % significance on the left hand side and the 25 station locations on the map.
I zoomed into the 10 most significant stations in Google Earth and noticed that all but one are located a few kilometres East of a slightly elevated and forested strip of land.
This might be a pointer – or it might not 😁

It is promising to see a clear cluster in the mid West and mid East of the country, also suggesting an underlying physical reason, as opposed to the late summer evening events being a mere fluke.

Next step is to grab evening event dates and look at them in context of the wider weather system synopsis:
dwd.de/EN/ourservices/wetterla
The data is linked to where it says "Download of the weather type classification data and additional forecast data (txt, 2MB, " on the right-hand side.

#ClimateChange#ExtremeWeather#heavyRain
Fortsettelse av samtale
anlomedad

2/2

Does heavy rain occur more often in late evening hours when people have gone to bed?
I felt like it did. And I find night-time flooding particularly scary.
But a meteorologist told me, my feelings were wrong! 😁

So I checked 556 German stations reporting hourly rain since 2005.

Turns out, my feelings are A-okay! 😁 💃🏽
The map shows 374 stations as purple which support my feelings. 😍

July and August are the months where heavy rains occur more often (defined as 4mm per hour, see above for why), so I counted 4mm events in these 2 months in each reporting hour since 2005.
Interesting bit on the side:
the 4mm events start after lunch, the mornings rarely see heavy rain. So ride your bike to work! 🖖🏽
The peak of event count is always mid afternoon, say 16 to 17 hour, afterwards the event count declines.

I defined Late Evening as 22 to 00 hour, Early Evening as 19 to 21.
Counting the events in July and in August in these hourly groups has the following results:
374 have more events in the late evenings,
182 have fewer events in the late evenings.

July is the month where stations have more late evening events:
July 253 vs August 228 stations.
For 109 stations, both months have more late events than early events.

Now I'll show him the data and ask him what physics is behind this feature.
? Warm air rises, while the cooler air descends, and when they meet and either air parcel is full of water,
the water bomb explodes 💥 , from the molecular friction or something else sciency 😁 ?

source:
opendata.dwd.de/climate_enviro

#ClimateChange#ExtremeWeather#heavyRain
anlomedad

Does heavy rain occur more often during the night?
My impression was so. 3 Examples: Texas Chain Rain Massacre, Australia Deluge in their autumn, Belgium & Germany July 2021 #Bernd

The heatmaps show 2 weather stations affected by Bernd, Ahrweiler and Kall-Sistig.
Kahler Asten is not too far from them, it's where I grew up.
Warnemünde is on the Baltic Coast in East Germany, where I now live.

Last week was my first conscious heavy rain event, in fact a little like Bernd 2021, come to think of it, but now in the East with hardly any elevation, no steep narrow valleys or creeks.
Warnemünde got 4 to 9mm of rain per hour so I took 4mm as threshold for heavy rain.
Top row heatmaps is mm averaged on months where such events occurred,
bottom row is the monthly counts of the events.

Ahrweiler and Kall-Sistig are reporting hourly rain since 2004, the other 2 since 1995.

What do I see?
Looking primarily at the bottom heatmaps, the event count
I see that heavy rain doesn't occur in the winter months.
Doesn't occur in the wee hours.
Doesn't occur when we commute to work.

Does occur
* during summer months
* on our way home from work
* during lunch break and
* all afternoon
* late night is more likely than wee hours
* The 2 stations at higher elevation, Kall-Sistig and Kahler Asten, have a definite second peak count in the late night hours,
apart from the mid afternoon peaks they share with the low-lying stations.

I'm no meteorologist but I can hazard a guess why there's a higher likelihood for heavy rain events in the late hours than in the wee or early morning hours – at locations where elevation is a rainmaker.
Temperature at high-er elevations cools down fast when the sun goes to sleep. The land stays warm for a while longer.
But the warm air rises, while the cooler air descends, I guess, and when they meet and either air parcel is full of water,
the water bomb explodes 💥 , from the molecular friction or something sciency 😁

Data: opendata.dwd.de/climate_enviro

#heavyRain#Flood#ClimateChange
anlomedad

Blatten got 119mm precipitation on April 16.
Nearby Grächen's
122mm ranked 3rd highest since 1861,
and came as 60 cm snow, ranking 8th since 1966.

The event is not mentioned as factor in accelerated Nesthorn / Birch glacier collapse, but why not – despite its significance – at least merits noting a reason, doesn't it?

Until I hear otherwise 😁, I am going to connect the event to the acceleration from May 14 onwards, and to the final collapse.
Data from:
meteoschweiz.admin.ch/service-=

www.meteoschweiz.admin.chDaten ohne Programmierkenntnisse herunterladenBodenmessdaten und homogene Messreihen der einzelnen Stationen mit erläuternden Metadaten ohne Programmierkenntnisse herunterladen.
#Blatten#KleinNesthorn#BirchGlacier
JdeB [216.91 ppm]

873 #ClimateEmergency #HeavyRain #India

"India: Cloudburst in Uttarakhand, Char Dham Yatra Suspended | Subscribe to Firstpost | N18G" [ ± 1-3 min]
by Firstpost

youtube.com/shorts/095AZMI8T0Q

Quote by Fp:
"Jun 29, 2025
Cloudburst and heavy rains triggered landslides in Uttarakhand, leading to the suspension of the Char Dham Yatra. The cloudburst washed away a labourers’ campsite in Uttarkashi, after which at least nine people went missing. Search and rescue operations are underway."

#TakeCareForLife #TakeCareForEarth
#StopBurningThings #StopEcoside
#StopThePlunder #StopRapingNature
#ClimateBreakDown

YouTubeIndia: Cloudburst in Uttarakhand, Char Dham Yatra Suspended | Subscribe to Firstpost | N18GAv Firstpost
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