Max Hartmann
@max-meteo.bsky.social
weather & climate stuff (focus on southern Germany and Alps)
meteorologist
chronically resilient (with ME/CFS)
meteorologist
chronically resilient (with ME/CFS)
Reposted by Max Hartmann
The big special report on the Hunga Tonga eruption is out:
juser.fz-juelich.de/record/10491...
After a couple years of arguing whether the net effect of aerosols+water vapor was warming or cooling, it includes this banger of a model ensemble that literally does cooling then warming.
juser.fz-juelich.de/record/10491...
After a couple years of arguing whether the net effect of aerosols+water vapor was warming or cooling, it includes this banger of a model ensemble that literally does cooling then warming.
December 19, 2025 at 2:53 PM
The big special report on the Hunga Tonga eruption is out:
juser.fz-juelich.de/record/10491...
After a couple years of arguing whether the net effect of aerosols+water vapor was warming or cooling, it includes this banger of a model ensemble that literally does cooling then warming.
juser.fz-juelich.de/record/10491...
After a couple years of arguing whether the net effect of aerosols+water vapor was warming or cooling, it includes this banger of a model ensemble that literally does cooling then warming.
In addition to the world's oceans, the positive sea surface temperature anomalies in the #Mediterranean are also no longer quite as high.
#SST
#SST
🌊📉 Sea surface temperatures have… come back down.
After the big global jump in 2023/24, SSTs are now back at below pre-jump levels in November (climatereanalyzer.org/clim/sst_dai...).
Climate surprise or expected? What role does climate variability play? Let’s try to unpack 👇
After the big global jump in 2023/24, SSTs are now back at below pre-jump levels in November (climatereanalyzer.org/clim/sst_dai...).
Climate surprise or expected? What role does climate variability play? Let’s try to unpack 👇
December 19, 2025 at 4:03 PM
In addition to the world's oceans, the positive sea surface temperature anomalies in the #Mediterranean are also no longer quite as high.
#SST
#SST
On Dec 24, an easterly weather pattern will settle over Central Europe. This will cause temperatures to drop significantly, especially at medium and higher altitudes. However, if there were currently snow over Eastern Europe, even colder air would probably reach us.
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December 18, 2025 at 10:59 AM
On Dec 24, an easterly weather pattern will settle over Central Europe. This will cause temperatures to drop significantly, especially at medium and higher altitudes. However, if there were currently snow over Eastern Europe, even colder air would probably reach us.
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1/4
Reposted by Max Hartmann
Before the 1990s, plane crashes caused by microbursts used to kill planeloads of people fairly regularly.
Dr. Ted Fujita and NCAR scientists figured out how to detect microbursts and warn pilots about them.
Since then? Zero airliner crashes from microbursts.
Dr. Ted Fujita and NCAR scientists figured out how to detect microbursts and warn pilots about them.
Since then? Zero airliner crashes from microbursts.
Exclusive: The Trump administration is moving to dismantle the National Center for Atmospheric Research in Colorado, according to a senior White House official, taking aim at one of the world's leading climate research labs.
Trump moves to dismantle major US climate research center in Colorado
The Trump administration is breaking up the National Center for Atmospheric Research, taking aim at one of the world's leading climate research labs.
bit.ly
December 17, 2025 at 3:47 AM
Before the 1990s, plane crashes caused by microbursts used to kill planeloads of people fairly regularly.
Dr. Ted Fujita and NCAR scientists figured out how to detect microbursts and warn pilots about them.
Since then? Zero airliner crashes from microbursts.
Dr. Ted Fujita and NCAR scientists figured out how to detect microbursts and warn pilots about them.
Since then? Zero airliner crashes from microbursts.
Reposted by Max Hartmann
🌊📉 Sea surface temperatures have… come back down.
After the big global jump in 2023/24, SSTs are now back at below pre-jump levels in November (climatereanalyzer.org/clim/sst_dai...).
Climate surprise or expected? What role does climate variability play? Let’s try to unpack 👇
After the big global jump in 2023/24, SSTs are now back at below pre-jump levels in November (climatereanalyzer.org/clim/sst_dai...).
Climate surprise or expected? What role does climate variability play? Let’s try to unpack 👇
December 15, 2025 at 10:40 AM
🌊📉 Sea surface temperatures have… come back down.
After the big global jump in 2023/24, SSTs are now back at below pre-jump levels in November (climatereanalyzer.org/clim/sst_dai...).
Climate surprise or expected? What role does climate variability play? Let’s try to unpack 👇
After the big global jump in 2023/24, SSTs are now back at below pre-jump levels in November (climatereanalyzer.org/clim/sst_dai...).
Climate surprise or expected? What role does climate variability play? Let’s try to unpack 👇
Reposted by Max Hartmann
By the finest of margins, ERA5 shows a reversal of the daily-mean 10 hPa 60°N zonal-mean zonal winds on 28 November to –0.13 m/s.
That nominally ties with 28 Nov 1968 as the earliest major sudden stratospheric warming on record in ERA5 post-1958 (when stratospheric observations increased).
That nominally ties with 28 Nov 1968 as the earliest major sudden stratospheric warming on record in ERA5 post-1958 (when stratospheric observations increased).
December 8, 2025 at 8:13 PM
By the finest of margins, ERA5 shows a reversal of the daily-mean 10 hPa 60°N zonal-mean zonal winds on 28 November to –0.13 m/s.
That nominally ties with 28 Nov 1968 as the earliest major sudden stratospheric warming on record in ERA5 post-1958 (when stratospheric observations increased).
That nominally ties with 28 Nov 1968 as the earliest major sudden stratospheric warming on record in ERA5 post-1958 (when stratospheric observations increased).
Reposted by Max Hartmann
Proud to share our new paper in npj Clim. Atmos. Sci. (@SpringerNature)!
Our findings:
1️⃣ reduce uncertainty in mid-latitude climate projections
2️⃣ increase confidence that #ClimateModels correctly predict a future poleward shift of the #JetStream
Read the paper here 👉 rdcu.be/eS73b
#ClimateScience
Our findings:
1️⃣ reduce uncertainty in mid-latitude climate projections
2️⃣ increase confidence that #ClimateModels correctly predict a future poleward shift of the #JetStream
Read the paper here 👉 rdcu.be/eS73b
#ClimateScience
Jet stream response to future Arctic sea ice loss not underestimated by climate models
npj Climate and Atmospheric Science - Jet stream response to future Arctic sea ice loss not underestimated by climate models
rdcu.be
December 9, 2025 at 8:07 PM
Proud to share our new paper in npj Clim. Atmos. Sci. (@SpringerNature)!
Our findings:
1️⃣ reduce uncertainty in mid-latitude climate projections
2️⃣ increase confidence that #ClimateModels correctly predict a future poleward shift of the #JetStream
Read the paper here 👉 rdcu.be/eS73b
#ClimateScience
Our findings:
1️⃣ reduce uncertainty in mid-latitude climate projections
2️⃣ increase confidence that #ClimateModels correctly predict a future poleward shift of the #JetStream
Read the paper here 👉 rdcu.be/eS73b
#ClimateScience
Reposted by Max Hartmann
New evidence suggests weather persistence is increasing in the northern mid– and high latitudes due to climate change.
So far, I’ve been skeptical as the signal seems small compared to natural variability, but maybe it’s time to update my thinking.
www.nature.com/articles/s43...
So far, I’ve been skeptical as the signal seems small compared to natural variability, but maybe it’s time to update my thinking.
www.nature.com/articles/s43...
Enhanced weather persistence due to amplified Arctic warming - Communications Earth & Environment
Weather persistence, in terms of duration of surface-air temperature anomalies across all weather types and seasons in Northern Hemisphere mid-latitudes, has increased in recent decades due to Arctic ...
www.nature.com
December 9, 2025 at 6:38 AM
New evidence suggests weather persistence is increasing in the northern mid– and high latitudes due to climate change.
So far, I’ve been skeptical as the signal seems small compared to natural variability, but maybe it’s time to update my thinking.
www.nature.com/articles/s43...
So far, I’ve been skeptical as the signal seems small compared to natural variability, but maybe it’s time to update my thinking.
www.nature.com/articles/s43...
The sudden stratospheric warming (SSW) at the end of November is indirectly responsible for the current and continuing extremely mild phase in Europe. A thread about the consequences of the unusually early SSW and other interactions.
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December 7, 2025 at 10:21 AM
The sudden stratospheric warming (SSW) at the end of November is indirectly responsible for the current and continuing extremely mild phase in Europe. A thread about the consequences of the unusually early SSW and other interactions.
[1/6]
[1/6]
Reposted by Max Hartmann
Record warmth still over southern Europe/northern Africa↙️ ... but in 150 hours with arctic air from Greenland follows record cold ↘️
November 16, 2025 at 10:27 AM
Record warmth still over southern Europe/northern Africa↙️ ... but in 150 hours with arctic air from Greenland follows record cold ↘️
Reposted by Max Hartmann
If CO2 emissions go to zero in 2050 (top), the sinks (green) will bring atmospheric CO2 back down (middle), & temperature will stabalise at ~1.7°C (bottom).
Going to zero today will keep us <1.5°C
Constant emissions leads to 2.6°C, rising rapidly thereafter.
www.nature.com/articles/s41...
Going to zero today will keep us <1.5°C
Constant emissions leads to 2.6°C, rising rapidly thereafter.
www.nature.com/articles/s41...
November 14, 2025 at 8:23 AM
If CO2 emissions go to zero in 2050 (top), the sinks (green) will bring atmospheric CO2 back down (middle), & temperature will stabalise at ~1.7°C (bottom).
Going to zero today will keep us <1.5°C
Constant emissions leads to 2.6°C, rising rapidly thereafter.
www.nature.com/articles/s41...
Going to zero today will keep us <1.5°C
Constant emissions leads to 2.6°C, rising rapidly thereafter.
www.nature.com/articles/s41...
Eine noch meridionalere Zirkulation als in den kommenden Tagen geht kaum. In der Nordhemisphere zwischen Amerika und Europa gibt es einen gewaltigen Austausch von polaren und subtropischen Luftmassen.
polarwx.com
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polarwx.com
1/4
November 10, 2025 at 12:05 PM
Eine noch meridionalere Zirkulation als in den kommenden Tagen geht kaum. In der Nordhemisphere zwischen Amerika und Europa gibt es einen gewaltigen Austausch von polaren und subtropischen Luftmassen.
polarwx.com
1/4
polarwx.com
1/4
Diese Woche gab es auf manchen Bergstationen in den Alpen neue November-Wärmerekorde. Nächste Woche kommen weitere hinzu. Mit voraussichtlich 15 bis 17 °C im 850-hpa-Niveau (Alpennordseite) und Südföhn ist es wohl sogar noch eine Spur wärmer.
wetterzentrale.de
wetterzentrale.de
November 8, 2025 at 10:13 AM
Diese Woche gab es auf manchen Bergstationen in den Alpen neue November-Wärmerekorde. Nächste Woche kommen weitere hinzu. Mit voraussichtlich 15 bis 17 °C im 850-hpa-Niveau (Alpennordseite) und Südföhn ist es wohl sogar noch eine Spur wärmer.
wetterzentrale.de
wetterzentrale.de
Reposted by Max Hartmann
Nach vier bei uns recht durchschnittlich temperierten Monaten zum Mittel 1991-2020 schickt sich der November an, wieder mal im roten Bereich zu drehen. Die detaillierte Monatsprognose für Europa:
www.orniwetter.info/monatsprogno...
www.orniwetter.info/monatsprogno...
November 1, 2025 at 11:53 AM
Nach vier bei uns recht durchschnittlich temperierten Monaten zum Mittel 1991-2020 schickt sich der November an, wieder mal im roten Bereich zu drehen. Die detaillierte Monatsprognose für Europa:
www.orniwetter.info/monatsprogno...
www.orniwetter.info/monatsprogno...
Reposted by Max Hartmann
🌀Melissa wird in 3-4 Stunden auf Jamaika treffen. In den letzten Stunden hat sich der Sturm weiter verstärkt, soeben wurden 896 hPa im Auge gemessen und 290 km/h knapp außerhalb.
Damit könnte Melissa der stärkste Sturm der Messgeschichte werden, der im Atlantik auf Land trifft. 🇯🇲
Damit könnte Melissa der stärkste Sturm der Messgeschichte werden, der im Atlantik auf Land trifft. 🇯🇲
October 28, 2025 at 1:16 PM
🌀Melissa wird in 3-4 Stunden auf Jamaika treffen. In den letzten Stunden hat sich der Sturm weiter verstärkt, soeben wurden 896 hPa im Auge gemessen und 290 km/h knapp außerhalb.
Damit könnte Melissa der stärkste Sturm der Messgeschichte werden, der im Atlantik auf Land trifft. 🇯🇲
Damit könnte Melissa der stärkste Sturm der Messgeschichte werden, der im Atlantik auf Land trifft. 🇯🇲
Reposted by Max Hartmann
Last week the German Meteorological Society warned that "the 3-degree limit could be exceeded as early as 2050".
While not possible to fully rule out, the assessed warming scenarios we published in the IPCC AR6 report find this to be extremely unlikely.
While not possible to fully rule out, the assessed warming scenarios we published in the IPCC AR6 report find this to be extremely unlikely.
September 28, 2025 at 8:47 PM
Last week the German Meteorological Society warned that "the 3-degree limit could be exceeded as early as 2050".
While not possible to fully rule out, the assessed warming scenarios we published in the IPCC AR6 report find this to be extremely unlikely.
While not possible to fully rule out, the assessed warming scenarios we published in the IPCC AR6 report find this to be extremely unlikely.
Reposted by Max Hartmann
Before-and-after satellite imagery shows multiple large burn scars from the recent major wildfires in Portugal and Spain.
August 25, 2025 at 5:37 PM
Before-and-after satellite imagery shows multiple large burn scars from the recent major wildfires in Portugal and Spain.
Menschen mit schwerem #ME/CFS können nicht mehr für ihre Rechte einstehen. 🛌
Kannst du für sie demonstrieren gehen? 🚶🚶♀️
In diesen Städten hast du am Wochenende die Chance dazu: München, Berlin, Köln, Frankfurt a.M., Konstanz
Die genauen Termine 👉 mecfs-info.my.canva.site#severe-me-cf...
Kannst du für sie demonstrieren gehen? 🚶🚶♀️
In diesen Städten hast du am Wochenende die Chance dazu: München, Berlin, Köln, Frankfurt a.M., Konstanz
Die genauen Termine 👉 mecfs-info.my.canva.site#severe-me-cf...
August 6, 2025 at 6:31 PM
Menschen mit schwerem #ME/CFS können nicht mehr für ihre Rechte einstehen. 🛌
Kannst du für sie demonstrieren gehen? 🚶🚶♀️
In diesen Städten hast du am Wochenende die Chance dazu: München, Berlin, Köln, Frankfurt a.M., Konstanz
Die genauen Termine 👉 mecfs-info.my.canva.site#severe-me-cf...
Kannst du für sie demonstrieren gehen? 🚶🚶♀️
In diesen Städten hast du am Wochenende die Chance dazu: München, Berlin, Köln, Frankfurt a.M., Konstanz
Die genauen Termine 👉 mecfs-info.my.canva.site#severe-me-cf...
What an inverse #SST temperature trend this summer!
At the beginning of July, the western #Mediterranean #Sea was as warm as it was during the hottest years in mid-August. And now we are pretty much back to the average for the years 1982-2015 even
source: apps.socib.es/subregmed-indicators/
At the beginning of July, the western #Mediterranean #Sea was as warm as it was during the hottest years in mid-August. And now we are pretty much back to the average for the years 1982-2015 even
source: apps.socib.es/subregmed-indicators/
August 6, 2025 at 10:31 AM
What an inverse #SST temperature trend this summer!
At the beginning of July, the western #Mediterranean #Sea was as warm as it was during the hottest years in mid-August. And now we are pretty much back to the average for the years 1982-2015 even
source: apps.socib.es/subregmed-indicators/
At the beginning of July, the western #Mediterranean #Sea was as warm as it was during the hottest years in mid-August. And now we are pretty much back to the average for the years 1982-2015 even
source: apps.socib.es/subregmed-indicators/
Reposted by Max Hartmann
A pleasure to be on BBC Radio Scotland this morning talking about Storm Floris – which even gave me the fun opportunity to distinguish between the real meteorological term "bomb cyclone" and the perhaps more 'pseudo-meteorological' term "heat dome" 😄
August 4, 2025 at 9:05 AM
A pleasure to be on BBC Radio Scotland this morning talking about Storm Floris – which even gave me the fun opportunity to distinguish between the real meteorological term "bomb cyclone" and the perhaps more 'pseudo-meteorological' term "heat dome" 😄
Reposted by Max Hartmann
Bis zu 50 Grad in Italien? Wieder mal wird geistert eine Headline durch alle Medien.
- Einordnung: 50 Grad gibt es höchstens lokal in Sizilien. Sonst eher max. 40-45 Grad.
- die Quelle ilmeteo.it macht solche Aussendungen immer wieder
- deutsche Medien übernehmen ungefiltert
orf.at/stories/3400...
- Einordnung: 50 Grad gibt es höchstens lokal in Sizilien. Sonst eher max. 40-45 Grad.
- die Quelle ilmeteo.it macht solche Aussendungen immer wieder
- deutsche Medien übernehmen ungefiltert
orf.at/stories/3400...
Nächste Hitzewelle: Bis zu 50 Grad in Italien
Italien steuert auf eine der intensivsten Hitzewellen des Sommers 2025 zu. Das afrikanische Hochdruckgebiet, von Meteorologinnen und Meteorologen „Kamel“ genannt, wird in den kommenden Tagen zu einem ...
orf.at
July 22, 2025 at 8:28 AM
Bis zu 50 Grad in Italien? Wieder mal wird geistert eine Headline durch alle Medien.
- Einordnung: 50 Grad gibt es höchstens lokal in Sizilien. Sonst eher max. 40-45 Grad.
- die Quelle ilmeteo.it macht solche Aussendungen immer wieder
- deutsche Medien übernehmen ungefiltert
orf.at/stories/3400...
- Einordnung: 50 Grad gibt es höchstens lokal in Sizilien. Sonst eher max. 40-45 Grad.
- die Quelle ilmeteo.it macht solche Aussendungen immer wieder
- deutsche Medien übernehmen ungefiltert
orf.at/stories/3400...
Reposted by Max Hartmann
#GoodNews am Morgen: Es sieht bis Ende Juli nach gaaaanz normalem mitteleuropäischem #Sommerwetter aus. Mal sehr warm, mal etwas kühler. Dazu sorgen zeitweilige Niederschläge zumindest dafür, dass die Dürresituation nicht weiter eskaliert. Also weder Ussel- noch Horror-/Hitze-Jahrtausendsommer ...
July 15, 2025 at 5:32 AM
#GoodNews am Morgen: Es sieht bis Ende Juli nach gaaaanz normalem mitteleuropäischem #Sommerwetter aus. Mal sehr warm, mal etwas kühler. Dazu sorgen zeitweilige Niederschläge zumindest dafür, dass die Dürresituation nicht weiter eskaliert. Also weder Ussel- noch Horror-/Hitze-Jahrtausendsommer ...
Summer is far from over, but one thing can already be said: the dormouse rule for the Alpine region has pretty much failed this year. Here is the general weather situation from 27.6 to 8.7. (average geopotential height 500 mb)
psl.noaa.gov/data/composi...
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psl.noaa.gov/data/composi...
🧵1/6
July 14, 2025 at 12:06 PM
Summer is far from over, but one thing can already be said: the dormouse rule for the Alpine region has pretty much failed this year. Here is the general weather situation from 27.6 to 8.7. (average geopotential height 500 mb)
psl.noaa.gov/data/composi...
🧵1/6
psl.noaa.gov/data/composi...
🧵1/6
Reposted by Max Hartmann
Temperature Update for June 2025
Third warmest June in the instrumental record.
Similar conditions to May, but sharply cooler than earlier in 2025.
Neutral conditions in the Pacific.
2025 is very likely to be the 2nd or 3rd warmest year.
berkeleyearth.org/june-2025-te...
🧵
Third warmest June in the instrumental record.
Similar conditions to May, but sharply cooler than earlier in 2025.
Neutral conditions in the Pacific.
2025 is very likely to be the 2nd or 3rd warmest year.
berkeleyearth.org/june-2025-te...
🧵
July 11, 2025 at 12:40 PM
Temperature Update for June 2025
Third warmest June in the instrumental record.
Similar conditions to May, but sharply cooler than earlier in 2025.
Neutral conditions in the Pacific.
2025 is very likely to be the 2nd or 3rd warmest year.
berkeleyearth.org/june-2025-te...
🧵
Third warmest June in the instrumental record.
Similar conditions to May, but sharply cooler than earlier in 2025.
Neutral conditions in the Pacific.
2025 is very likely to be the 2nd or 3rd warmest year.
berkeleyearth.org/june-2025-te...
🧵
Reposted by Max Hartmann
6/über uns sind auch Balsam für die geschundene Seele. Gute Bücher gibt es wenige, über einige berichtete ich hier auch, aber dieses von Lotte Habermann-Horstmeier, „das Handbuch“ ist besonders zu empfehlen. Es enthält alles, was irgendwie im MECFS-Kontext relevant ist. Ich
July 6, 2025 at 9:32 AM
6/über uns sind auch Balsam für die geschundene Seele. Gute Bücher gibt es wenige, über einige berichtete ich hier auch, aber dieses von Lotte Habermann-Horstmeier, „das Handbuch“ ist besonders zu empfehlen. Es enthält alles, was irgendwie im MECFS-Kontext relevant ist. Ich