EDIT: 2016 blog for the medicane season is now up. Comments can be left without giving any details at all.

http://quantumoverlord.blogspot.co.uk/2016/09/medicane-season-2016.html

the bay of Biscay storm has been written up; I'd particularly appreciate critism of this post.

So for those following last year, I'm pretty interested in medicanes and I'd appreciate any more expert insight as we enter the 'unofficial 2016 season'. Medicanes are most likely between September and January, this is because unlike conventional tropical storms they derive their energy from the warm air rather than the warm SSTs. September to January is the period when there is the biggest contrast between warmer air at the surface and cold air in the upper troposphere. Of all the months September has the highest medicane frequency.

My blog post from the 2015 season is available here for anyone interested.

http://quantumoverlord.blogspot.co.uk/2015/10/medicane-season-2015-to-be-updated.html

I'm not sure if all the storms are shown there, I believe I recorded 6 potential candidates last year.

Anyway we start the season with this:

At the moment its a disorganised system of thunderstorms, but it could develop into a medicane. Thoughts?

Personally I'd give this one a 30% chance of forming into a tropical like system. The UKMO and NAVGEM both try to develop a warm core as the system moves south:

Problem is its very close to land which massively hinders any tropical like development.

The WRF shows rapid tropical intensification around 75 hours

This would be a major medicane (potentially cat 1 level). Although please note that the WRF tends to exaggerate the possibility of medicane development. Very exciting times ahead though!

I've been away for a week with only minimal internet access so I've been out of the loop weatherwise. I'd like to thank Gav P for bringing this to my attention.

Yesterday's satellite image. I'm not sure this counts as a medicane though for obvious reasons. But I'm going to include it in the 2016 season since structurally it resembles medicanes.  

The name of this storm was officially called Subtropical storm Stephanine

https://en.wikipedia.org/wiki/Subtropical_Storm_Stephanie

But it does look a lot like a medicane and has more charatistics of a medicane than of a normal tropical or subtropical storm. For example, it formed at the peak of the 'unofficial medicane season' which I said was roughly September to January, but medicane frequency is by far the highest in September, it had a very short life typical of a medicane and a small wind radius. I think if anything its a justification to extend the 'medicane sub basin' to also include the bay of Biscay.

I'd appreciate any thoughts, but I'm going to 'officially unofficially' call this storm the first medicane of the 2016 season.

Eye wall of Stephanine at her peak intensity.

Phase space diagram for Stephanie

Definitely a tropical like system, albeit with a very short life.

Another beautiful image of Stephanie

Area of disturbance developing in the SW med.

Could be a candidate for a potential medicane. I'd put development probability as fairly low though, none of the models really do anything with it. Still worth watching.

Area of convection near the Balaric isles.

I think the probability of this developing into a medicane is very low (<20%) but will keep watching. Nearly at the end of the most active month of the medicane season and absolutely nothing to speak of, with the exception of that system in the bay of Biscay which I'm including.

2016 blog for the medicane season is now up. Comments can be left without giving any details at all.

http://quantumoverlord.blogspot.co.uk/2016/09/medicane-season-2016.html

the bay of Biscay storm has been written up; I'd particularly appreciate critism of this post.

What would you say is the threshold SST for a warm core to develop? Seas in the Med currently vary between 21 and 27.

For medicanes tropical-like development can happen at 15C although a more reasonable benchmark is probably 18-20C. Its notable in any case that this is significantly lower than the 26.5C required for regular tropical cyclones. Stephanie intensified over waters at 23C which is easily warm enough for medicane development.

September is the peak of the season partly because the sees are so warm at this time of year, but you also get the meterological conditions necessary for them to develop (for example cold air advected at the upper levels). By contrast there has never been a medicane recorded to have formed in May or June. Its actually quite interesting how common they are in September compared to how rare they are in August.

Area of convection near the Balaric isles.

I think the probability of this developing into a medicane is very low (<20%) but will keep watching. Nearly at the end of the most active month of the medicane season and absolutely nothing to speak of, with the exception of that system in the bay of Biscay which I'm including.

I happened to be in Ibiza when this storm occurred overnight. Strobing lightning, torrential rain. Totally fantastic. Next day back to warm sunshine. Can confirm that the sea temperatures were still lovely, much warmer than the hotel pools. Summer wanders on in the SW Med.

Things are stirring of the east coast of Spain, Quantum

http://en.sat24.com/en

Very quiet season so far. Some chances of developments by the end of the week possibly with a northeasterly setting in across europe.

Yes it has indeed been very quiet; I think, as you say, the lack of northerly incursions are partly to blame. The peak of the medicane season has also now passed so we would expect them to become less frequent.

This has caught my interest, a frontal system that may attempt to transition to a tropical-like system. I would put the odds of that happening very low though (~10%) due to a lack of cold air in the upper troposphere and strong interaction with land.

Things are stirring of the east coast of Spain, Quantum

http://en.sat24.com/en

 

I'd rate the odds that it transitions as only 10%; the conditions are just not conductive to medicanes at the moment. Ill keep tabs on it though.

Extratropical low has moved over the Med. Odds of developing into a tropical like storm are <10% in my opinion. Thought I'd mention it as the current season has been so boring so far.

I see there was a so-called medicane on 15 Jan 1995; are there ever hurricanes this late, over the warmer waters? I think at the date this one is listed the sea temps were somewhere between 15 and 17 C. How much energy this provides for an anything-cane is dubious. I suspect it was categorised due to its clear cyclonic centre. What was the MSLP at the 'eye'? I'm sceptical about this, Q, but I'd love to be wrong because it's a fascinating topic.

I see there was a so-called medicane on 15 Jan 1995; are there ever hurricanes this late, over the warmer waters? I think at the date this one is listed the sea temps were somewhere between 15 and 17 C. How much energy this provides for an anything-cane is dubious. I suspect it was categorised due to its clear cyclonic centre. What was the MSLP at the 'eye'? I'm sceptical about this, Q, but I'd love to be wrong because it's a fascinating topic.

For a hurricane those temperatures are too cold, but for a medicane its only borderline and therefore credible one could develop when temps are that cold. What its worth pointing out is that as you move further north the temperature of the upper troposphere decreases too; since it is the vertical gradient that is important, the temperatures do not need to be as high for places further north. Even for actual atlantic hurricanes very far north forming systems do so over colder waters such as Hurricane vince which formed over waters of 24C (very cold for a hurricane).

As far as medicanes go, its also true that medicanes, unlike hurricanes derive a lot of their energy from the air at the surface rather than the sea; so SSTs are not as important for medicanes as they are for hurricanes. The January storm which you speak of by the way is still 'in season', I defined the medicane season to be September to January; again for systems further north the seasons tend to start and finish later when the SSTs are still warm but you can get cold air in the upper troposphere.

TL:DR yes that 1995 storm was a medicane in my opinion and a strong one at that.

 

For a hurricane those temperatures are too cold, but for a medicane its only borderline and therefore credible one could develop when temps are that cold. What its worth pointing out is that as you move further north the temperature of the upper troposphere decreases too; since it is the vertical gradient that is important, the temperatures do not need to be as high for places further north. Even for actual atlantic hurricanes very far north forming systems do so over colder waters such as Hurricane vince which formed over waters of 24C (very cold for a hurricane).

As far as medicanes go, its also true that medicanes, unlike hurricanes derive a lot of their energy from the air at the surface rather than the sea; so SSTs are not as important for medicanes as they are for hurricanes. The January storm which you speak of by the way is still 'in season', I defined the medicane season to be September to January; again for systems further north the seasons tend to start and finish later when the SSTs are still warm but you can get cold air in the upper troposphere.

TL:DR yes that 1995 storm was a medicane in my opinion and a strong one at that.

 

Thank you- succinct. Does the tropospheric latitudinal gradient keep pace with changes at the surface- if it's slower, as I suspect (not opining strongly here- I don't know but the Med is relatively landlocked compared to the open Atlantic), won't the vertical thermal gradient be reduced, especially say, in mid-autumn, when the Med region has lost all that late summer heat?