midget cyclone over Thyrrenian Sea

[DanieleItalyRm]

Warm core cyclone over THYrrenian sea (FINJAS [met.fu-berlin]) show a tropical characteristics, outflow, spiral band, convection in the center:
998 hpa
I Think this is a subtropical depression; convection top -40°C and only 15-16°C sea surface.

SAT: http://en.sat24.com/HD/en/it/visual
CAM: (60 km from midget cyclonic center) http://www.vedetta.org/index.php/only-w ... i-san-vito





yesterday 17/01/17 (about 190 km in diameter; 50/70 km extende the max winds from the center)


today 18/01/17 (about 90 km in diameter)

[DanieleItalyRm]

the system weakening in the next hours (about 90 km in diameter; 30/40 km extende the max winds from the center):


The desert and the cyclone..

[DanieleItalyRm]

evening 19:00, extremly midget-central convection, and bands (35 km in diameter; 10/15 km extende the max winds from the center)

[chaser1]

Any analysis suggesting what max. winds might have been at the surface? These spin up's fascinate me, given both their very short lives but often rapid organization.

[DanieleItalyRm]

Any analysis suggesting what max winds might have been at the surface? .

only 25/30 kt max wind; However,
none has passed through the extremly small center for real datas.

[chaser1]

Wild.... certainly would've assumed something appearing as well defined on Satellite would've translated to higher surface winds? I wonder if that end result is essentially that common or if its development (and demise) were so quick that stronger winds simply stayed aloft or just above the surface??

[Digital-TC-Chaser]

http://www.sat.dundee.ac.uk/gallery/gal ... 128&size=s

[chaser1]

http://www.sat.dundee.ac.uk/gallery/gallery_image.php?id=2128&size=s

"dead link"; takes one to a UK Satellite site requiring an account ID and password

[Digital-TC-Chaser]

http://www.sat.dundee.ac.uk/gallery/gallery_image.php?id=2128&size=s

"dead link"; takes one to a UK Satellite site requiring an account ID and password

Sorry did not think a sign up was needed.

[chaser1]

Awesome and fascinating up close shot there!

[DanieleItalyRm]

Wild.... certainly would've assumed something appearing as well defined on Satellite would've translated to higher surface winds? I wonder if that end result is essentially that common or if its development (and demise) were so quick that stronger winds simply stayed aloft or just above the surface??

[DanieleItalyRm]

19 January 2017: Another interesting 35 kt cyclone developed the next day, 19 January, over Adriatic Sea and landfall over Gargano (Apulia)
Also in this case the model show a warm core; Unfortunately, high-resolution Ir images are not available in the most 'interesting hours (05:00 / 05:30);
The convection around the center was more strong than 18 January system.
It rapidly weakened at landfall during the morning.

[chaser1]

They certainly have a fairly decent size wind field with them. Nearly like rapid little tropical depressions that form, then dissipate. I"m curious, in terms of "lifespan".... how long do these mesoscale-like systems tend to last?

[DanieleItalyRm]

They certainly have a fairly decent size wind field with them. Nearly like rapid little tropical depressions that form, then dissipate. I"m curious, in terms of "lifespan".... how long do these mesoscale-like systems tend to last?

This depends on Shear and other factors. Sometimes they last a 6-10h. but in other cases also 2/4 day. ...
Sometimes these have a very rapid tropical development, more 'rapidly than a normal tropical cyclone. Their ideal condition are often restricted in an old cut off. Perhaps that's why they are also small (like Vince 2005 or Grace 2009) and burn quickly the necessary fuel.

(However, in this 17-18 january case it was a subtropical development).

[chaser1]

Hmmmm?? Interesting stuff! Thanks Danielle
Basically, "looks" nearly tropical but "acts" baroclinic. Of course, we've seen a few occasions where cold lows over time found a way to transition into respectable tropical cyclones. That process certainly takes a bit of time and of course is occurring over relatively warm water. What is the warmest that those SST's get up there, in the area of the Thyrrenian Sea when these odd spin-up lows try and develop?

[Alyono]

Hmmmm?? Interesting stuff! Thanks Danielle
Basically, "looks" nearly tropical but "acts" baroclinic. Of course, we've seen a few occasions where cold lows over time found a way to transition into respectable tropical cyclones. That process certainly takes a bit of time and of course is occurring over relatively warm water. What is the warmest that those SST's get up there, in the area of the Thyrrenian Sea when these odd spin-up lows try and develop?

SSTs are not what is important. It is the difference between the SST and tropopause temperatures that dictates whether or not tropical development occurs. An unusually cold tropopause results in development