More cut off lows recently?

[GHA]

One thing you can learn from sailing is don't trust the things that pop up in that incessant little voice in your head without checking, so when it says "I'm sure there's been more cut off lows down around Portugal/ Spain this year" we now have AI to ask to check for you! and maybe there has >>

Q> looking at the weather, have there been more cut off lows in the southern east of the north atlantic this year, 2024. Please provide clickable links formatted as full IP addresses instead of the normal superscript numbers wherever possible

Answer
Based on the available information, there has been an increase in cut-off lows, also known as deep depressions or DANAs (Depresión Aislada en Niveles Altos), in the southeastern North Atlantic region during 2024. This trend is consistent with recent observations and studies on changing weather patterns in the area.

Increased Frequency of Cut-Off Lows​

A study published in 2024 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2023GL104435 indicates that deep depression occurrences have significantly increased over the eastern side of the North Atlantic, while decreasing on the western side. This shift in the distribution of cut-off lows has important implications for weather patterns in Europe and North Africa.

Notable Events in 2024​

Several significant cut-off low events have been reported in the region during 2024:

1. On October 29, 2024, a severe DANA event caused widespread flooding in southeastern Spain, particularly in the province of Valencia. Rainfall exceeded 300 mm within 24 hours in many locations ClimaMeter - 2024/10/29 South-East Spain Floods.
2. In September 2024, Storm Boris, a cut-off low system, brought record-breaking rainfall to central Europe, causing extensive flooding Storm Boris and European flooding September 2024.

Factors Contributing to the Increase​

The increase in cut-off lows in the southeastern North Atlantic can be attributed to several factors:

1. Changes in Jet Stream Patterns: Research suggests that the northward shift of the summertime North Atlantic jet stream may be influencing the formation and movement of cut-off lows https://www.findaphd.com/phds/proje...ing-nature-of-summertime-european-flood-risk/.
2. Atmospheric Circulation Changes: Studies have shown that cut-off lows, particularly those located between the subtropical eastern North Atlantic and the western Mediterranean, are triggered by specific atmospheric circulation patterns Repeated Saharan dust intrusions raise questions about increasing frequency | Copernicus.
3. Climate Change: The increased frequency and intensity of these events may be linked to ongoing climate change, which is altering large-scale atmospheric circulation patterns.

Implications​

The rise in cut-off low occurrences in the southeastern North Atlantic has significant implications for weather patterns and associated risks:

1. Increased Flood Risk: As seen in the 2024 events, these systems can bring intense rainfall and heighten the risk of flooding in affected areas.
2. Weather Prediction Challenges: Cut-off lows are notoriously difficult to forecast accurately, earning them the nickname "weatherman's woe" Cut-off low - Wikipedia.
3. Long-lasting Impacts: These systems can remain stationary for days, potentially leading to prolonged periods of unsettled weather and associated hazards.

The trend of increasing cut-off lows in the southeastern North Atlantic during 2024 highlights the need for continued monitoring and research to better understand and predict these impactful weather systems.

 

[NormanS]

I've no idea what a cut-off low is. If it's a deep depression, why not just call it that? Here it's been about 1040 for several days. Mostly cold crisp clear and sunny.

 

[RunAgroundHard]

I've no idea what a cut-off low is. If it's a deep depression, why not just call it that? Here it's been about 1040 for several days. Mostly cold crisp clear and sunny.

A cut off low is not a deep depression, but it could be.

Cut-off low - Wikipedia

 

[GHA]

A cut off low is not a deep depression, but it could be.

Cut-off low - Wikipedia

Cut off lows are a nightmare doing any passage planning & seem near impossible for the models to predict, away from the polar front jetstream steering them they just seem to wander about doing what the want randomly, watched one not that long ago dump a load of rain on Iberian peninsula, head across the atlantic towards the Caribbean then come back and dump a load more!
Though sometimes the 500mB might hint at something forming before it shows on the grib surface models which can be a heads up to be ready to get up the west coast of portugal with some south in the wind if that's where u r heading.

 

[Puffin10032]

I've no idea what a cut-off low is. If it's a deep depression, why not just call it that? Here it's been about 1040 for several days. Mostly cold crisp clear and sunny.

They happen when the jet stream creates a loop which eventually touches itself and and a circular part detaches. A good analogy is how oxbow lakes form when a river's meander gets very extreme.

 

[GHA]

They happen when the jet stream creates a loop which eventually touches itself and and a circular part detaches. A good analogy is how oxbow lakes form when a river's meander gets very extreme.

Not always though, sometimes they seem to just pop up from nowhere or a low over north africa will decide to head out to sea.
How to get past a cut-off low pressure system – a true weather router's dilemma

 

[Puffin10032]

Not always though, sometimes they seem to just pop up from nowhere or a low over north africa will decide to head out to sea.
How to get past a cut-off low pressure system – a true weather router's dilemma

So one name for two different phenomena?

 

[capnsensible]

So one name for two different phenomena?

Called a DANA in spain and well known for looong time.

 

[NormanS]

They happen when the jet stream creates a loop which eventually touches itself and and a circular part detaches. A good analogy is how oxbow lakes form when a river's meander gets very extreme.

I do like your analogy, which even I can understand. Thanks.

 

[GHA]

So one name for two different phenomena?

Only ever it as a low south of the jetstream regardless of the formation mechanism. Same thing, different birth.

 

[GHA]

Called a DANA in spain and well known for looong time.

istr that last one to batter Spain was formed as puffin said by the upper air rossby waves getting messed up..

"In summary, a DANA is a specific type of cut-off low that is particularly notable for its effects on weather patterns in Spain and similar climates."

 

[capnsensible]

In Spain, cut-off lows are often referred to as DANA ( Depresion Aislada en Niveles Altos , 'Isolated Upper-Level Depression'), stresses the characteristic of upper-level lows, differentiating them from other lows, such as thermal lows originating in lower atmosphere levels during the summer months.

That's from wiki.

 

[GHA]

In Spain, cut-off lows are often referred to as DANA ( Depresion Aislada en Niveles Altos , 'Isolated Upper-Level Depression'), stresses the characteristic of upper-level lows, differentiating them from other lows, such as thermal lows originating in lower atmosphere levels during the summer months.

That's from wiki.

Get on an AI if you are interested in digging deeper into the subject, it will produce all the links to academic sites & scientific published work.
a hoover is a vacuum cleaner but not all vacuum cleaners are hoovers..

Embracing being mistaken is so productive to education

 

[capnsensible]

Get on an AI if you are interested in digging deeper into the subject, it will produce all the links to academic sites & scientific published work.
a hoover is a vacuum cleaner but not all vacuum cleaners are hoovers..

Embracing being mistaken is so productive to education


View attachment 186652

If you are so right, I believe you can edit wiki.

In the meantime, I'm gonna stick with many decades of known knowns, written by those that study these things for a living and are very, very good.

No offence.

 

[robp]

Called a DANA in spain and well known for looong time.

Or Gota Fria. That's what hit us (lightly this time) and Valencia!

 

[GHA]

If you are so right, I believe you can edit wiki.

In the meantime, I'm gonna stick with many decades of known knowns, written by those that study these things for a living and are very, very good.

No offence.

Every day a schoolday, there's always more to it when you dig deeper
Helps to keep a open mind, the universe is subjective place which won't give a straight answer, much depends on scale.

Answer
No, not every cut-off low is a DANA. While both terms refer to similar weather phenomena, there are some key differences:

Cut-off Low​

A cut-off low is a broader meteorological term used globally to describe a closed upper-level low pressure system that has become separated from the main westerly flow
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. These systems can occur in various parts of the world, including:

• Southern hemisphere: South Africa, Namibia, South America, and southern Australia
• Northern hemisphere: Southern Europe, France, China, Siberia, North Pacific, Northeastern United States, and the northeast Atlantic
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DANA​

DANA, which stands for "Depresión Aislada en Niveles Altos" (Isolated Depression at High Altitudes), is a term specifically used in Spain and some other Mediterranean regions
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. It refers to a particular type of cut-off low that occurs in this area and has some specific characteristics:

1. It forms when cold air at high altitudes becomes detached from the polar jet stream and moves over the warm Mediterranean Sea
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2. The interaction between the cold air aloft and the warm, moist air near the surface creates a highly unstable atmosphere
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3. DANAs are known for causing severe weather events, including heavy rainfall, flooding, and sometimes even tornadoes
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Key Differences​

1. Geographic specificity: While cut-off lows can occur globally, DANAs are specifically associated with the Mediterranean region, particularly Spain
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2. Terminology: DANA is a Spanish acronym, whereas cut-off low is an English term used more broadly in meteorology
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3. Intensity: DANAs are often associated with more severe weather events due to their interaction with the warm Mediterranean Sea
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In essence, a DANA can be considered a specific type of cut-off low that occurs in the Mediterranean region, but not all cut-off lows are DANAs
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.Link addresses:
DANA Weather Phenomenon & Valencia Flood | Rain Viewer Blog
What makes a 'DANA' storm like the one causing deadly flooding in Spain?
Cold drop - Wikipedia
Cut-off low - Wikipedia
What is DANA, the weather phenomenon behind Spain's deadliest floods in decades?

 

[capnsensible]

Or Gota Fria. That's what hit us (lightly this time) and Valencia!

Literally, cold drop.

 

[GHA]

this will take a bit of wading through, & probably bring nothing of use to a day on the water bar maybe keeping an open mind as to just how volatile the global weather is, but still interesting, the few words I can understand anyway
https://sites.krieger.jhu.edu/waugh/files/2015/07/Ndarana_Waugh_2010.pdf