Mediterranean: 90M

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Re: TS 90M

#41 Postby 1900hurricane » Mon Oct 31, 2016 8:48 am

DanieleItalyRm wrote:
1900hurricane wrote:
TheEuropean wrote:
Thx, I see some 60 kts there, right?

It's hard to tell between 55 kt and 60 kt in that image, but yes, there does appear to be a few barbs indicating winds greater than 50 kt.


You Can send an email from sab noaa with ascat wind? T2.0 intensity more incorrect.

The Satellite Analysis Branch isn't an agency that will issue full advisories on tropical cyclones. Their only concern is issuing bulletins based solely on the Dvorak Technique. It is up to the agencies warning on tropical cyclones to incorporate all the given data, including ASCAT, and come up with an intensity estimate. Unfortunately, there does not seem to be an agency designated to put out advisories on tropical or subtropical cyclones in the Mediterranean Sea.
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Re: TS 90M

#42 Postby DanieleItalyRm » Mon Oct 31, 2016 10:58 am

......Image
Last edited by DanieleItalyRm on Mon Oct 31, 2016 11:52 am, edited 3 times in total.
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Re: TS 90M

#43 Postby wxman57 » Mon Oct 31, 2016 11:28 am

I can't find anything on satellite now. Could see the low at 10Z but it has accelerated ENE and is hard to locate now. May not be much left of it.
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Re: TS 90M

#44 Postby DanieleItalyRm » Mon Oct 31, 2016 11:38 am

1900hurricane wrote:
DanieleItalyRm wrote:
1900hurricane wrote:It's hard to tell between 55 kt and 60 kt in that image, but yes, there does appear to be a few barbs indicating winds greater than 50 kt.


You Can send an email from sab noaa with ascat wind? T2.0 intensity more incorrect.

The Satellite Analysis Branch isn't an agency that will issue full advisories on tropical cyclones. Their only concern is issuing bulletins based solely on the Dvorak Technique. It is up to the agencies warning on tropical cyclones to incorporate all the given data, including ASCAT, and come up with an intensity estimate. Unfortunately, there does not seem to be an agency designated to put out advisories on tropical or subtropical cyclones in the Mediterranean Sea.



It's depressing to see current bulletins chase Invest 15-25 kt intensity and ignore a 60KT tropical storm.
If this was located in the Nort west Atlantic it would be well chased.
We are in 2016, every year the same bad story for the Mediterranean systems.
Now 90M dissipated.
I thank all of you for giving attention to this storm.
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Re: Mediterranean: 90M

#45 Postby bg1 » Mon Oct 31, 2016 5:30 pm

It's happening guys!! So excited to track an official 90M again.

And it's gone before I can enjoy it.
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Re: Mediterranean: 90M

#46 Postby DanieleItalyRm » Wed Nov 02, 2016 12:42 pm

I wanted to ask something important
As could be born an official cyclones tracking center for the Mediterranean sea? How can 'solve These conflicts that go on from years? Mediterranean has more many systems of the South Atlantic Ocean; it is obvious That These cyclones are just as TC Karl (nov.1980), TC Vince (oct.2005), TC Grace (oct.2009), TC Chris (jun.2012), TC Alex (january 2016) and many others, all in subtropical latitudine and over sea surface (19-25°C), extratropical or subtropical in origin but become in tropical cyclones
.

Image

Strong Winds and heavy rains in the 90M transit: In Calabria, South Greece and Crete torrential rains Caused problems. In Additions, the maritime and air transport experienced serious problems for over 24 hours.

Viannos floods (Crete)
https://www.youtube.com/watch?v=D1ngUMKJBRg&feature=youtu.be

Malta sea storm:
https://www.youtube.com/watch?v=PZDJDvJgIjo
http://www.meteoweb.eu/video-gallery/maltempo-ciclone-al-sud-la-tempesta-nella-baia-di-st-julian-a-malta/id/189423733/

Image

Image
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Re: Mediterranean: 90M

#47 Postby Vince_and_Grace_fan » Fri Nov 04, 2016 2:25 am

Hi everybody!
I am a meteorology student in Hungary, and I interested in tropical cyclones, particulary that occur near Europe, and also the tropical-like systems over the Mediteranean Sea.
I wrote a brief summary from this cyclone on my Wunderground blog: https://www.wunderground.com/blog/Zivip ... ranean-sea
This is of course not official, just my opinion. But I think, this cyclone became a real tropical storm for a short time, and also was subtropical before it.
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Re: Mediterranean: 90M

#48 Postby Hypercane_Kyle » Fri Nov 04, 2016 9:52 pm

So I'm really confused as to what these cyclones are classified as. Are they officially considered tropical cyclones? Why aren't there advisories for them?
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My posts are my own personal opinion, defer to the National Hurricane Center (NHC) and other NOAA products for decision making during hurricane season.

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Re: Mediterranean: 90M

#49 Postby DanieleItalyRm » Sat Nov 05, 2016 8:27 am

Vince_and_Grace_fan wrote:Hi everybody!
I am a meteorology student in Hungary, and I interested in tropical cyclones, particulary that occur near Europe, and also the tropical-like systems over the Mediteranean Sea.
I wrote a brief summary from this cyclone on my Wunderground blog: https://www.wunderground.com/blog/Zivip ... ranean-sea
This is of course not official, just my opinion. But I think, this cyclone became a real tropical storm for a short time, and also was subtropical before it.



I agree with your analysis. I'm glad we scored the same path of 90M.
90M has developed over more warm water than TCAlex developed in January 2016 . Advice this study for who still believes in old meteorological concepts:

" Revisiting the 26.5°C Sea Surface Temperature Threshold for Tropical Cyclone Development, 2014".


A high sea surface temperature is generally accepted to be one of the necessary ingredients for tropical cyclone development, indicative of the potential for surface heat and moisture fluxes capable of fueling a self-sustaining circulation. Although the minimum 26.5°C threshold for tropical cyclogenesis has become a mainstay in research and education, the fact that a nonnegligible fraction of storm formation events (about 5%) occur over cooler waters casts some doubt on the robustness of this estimate. Tropical cyclogenesis over subthreshold sea surface temperatures is associated with low tropopause heights, indicative of the presence of a cold trough aloft. To focus on this type of development environment, the applicability of the 26.5°C threshold is investigated for tropical transitions from baroclinic precursor disturbances in all basins between 1989 and 2013. Although the threshold performs well in the majority of cases without appreciable environmental baroclinicity, the potential for development is underestimated by up to 27% for systems undergoing tropical transition. An alternative criterion of a maximum 22.5°C difference between the tropopause-level and 850-hPa equivalent potential temperatures (defined as the coupling index) is proposed for this class of development. When combined with the standard 26.5°C sea surface temperature threshold for precursor-free environments, error rates are reduced to 3%–6% for all development types. The addition of this physically relevant representation of the deep-tropospheric state to the ingredients-based conceptual model for tropical cyclogenesis improves the representation of the important tropical transition-based subset of development events.
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Re: Mediterranean: 90M

#50 Postby AJC3 » Sun Nov 06, 2016 9:31 pm

DanieleItalyRm wrote:
Vince_and_Grace_fan wrote:Hi everybody!
I am a meteorology student in Hungary, and I interested in tropical cyclones, particulary that occur near Europe, and also the tropical-like systems over the Mediteranean Sea.
I wrote a brief summary from this cyclone on my Wunderground blog: https://www.wunderground.com/blog/Zivip ... ranean-sea
This is of course not official, just my opinion. But I think, this cyclone became a real tropical storm for a short time, and also was subtropical before it.


I agree with your analysis. I'm glad we scored the same path of 90M.
90M has developed over more warm water than TCAlex developed in January 2016 . Advice this study for who still believes in old meteorological concepts:

" Revisiting the 26.5°C Sea Surface Temperature Threshold for Tropical Cyclone Development, 2014".

A high sea surface temperature is generally accepted to be one of the necessary ingredients for tropical cyclone development, indicative of the potential for surface heat and moisture fluxes capable of fueling a self-sustaining circulation. Although the minimum 26.5°C threshold for tropical cyclogenesis has become a mainstay in research and education, the fact that a nonnegligible fraction of storm formation events (about 5%) occur over cooler waters casts some doubt on the robustness of this estimate. Tropical cyclogenesis over subthreshold sea surface temperatures is associated with low tropopause heights, indicative of the presence of a cold trough aloft. To focus on this type of development environment, the applicability of the 26.5°C threshold is investigated for tropical transitions from baroclinic precursor disturbances in all basins between 1989 and 2013. Although the threshold performs well in the majority of cases without appreciable environmental baroclinicity, the potential for development is underestimated by up to 27% for systems undergoing tropical transition. An alternative criterion of a maximum 22.5°C difference between the tropopause-level and 850-hPa equivalent potential temperatures (defined as the coupling index) is proposed for this class of development. When combined with the standard 26.5°C sea surface temperature threshold for precursor-free environments, error rates are reduced to 3%–6% for all development types. The addition of this physically relevant representation of the deep-tropospheric state to the ingredients-based conceptual model for tropical cyclogenesis improves the representation of the important tropical transition-based subset of development events.


Daniele, my friend...

As always, it is good to see your posts on this subject. You and I have had this same conversation before in the "Xandra" (2014) thread.

viewtopic.php?f=31&t=116987

It's now apparent (or at least it should be apparent) to those who study such things that the 26C threshold only works in a standard or seasonal "MDR-type" barotropic environment. My thoughts there are similarly relevant here, so I will repeat them...

"The traditional low end SST threshold of 26-27C (79-81F) assumes a barotropic atmosphere typical of the deep tropics. Generally, in absence of cold core TUTT cells or troughs that show some reflection down into the mid levels, this type of atmosphere features 500MB temperatures of -4C to -6C. Since instability is a function of temperatures both at the surface and aloft, obviously traditional SST thresholds for TC formation will rarely apply to "medcanes", given their formation north in the range between 30-37N.

I think a decent rule of thumb here might be to look for a temperature difference of no less than 30C between SST/near surface air mass and 500MB when looking at true TC processes (i.e latent heat feedback from convection). In other words, when your SSTs drop to, say...20C, as long as 500MB temps have cooled to at least -10C or lower, and in absence of a significant intrusion of a dry and/or cool (polar) air mass at the time, the local atmosphere, would still support TC formation, at least thermodynamically."

Since your proposal looks at 850MB-tropopause and mine looks at near surface-500MB, I think it would be interesting to compare the two alternative thresholds (or similarly less stringent alternatives) for this subset of developments.

This is a FANTASTIC opportunity for a comprehensive M.S. thesis just waiting to be written!
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Re: Mediterranean: 90M

#51 Postby DanieleItalyRm » Tue Dec 20, 2016 4:44 am

AJC3 wrote:
Daniele, my friend...

As always, it is good to see your posts on this subject. You and I have had this same conversation before in the "Xandra" (2014) thread.

viewtopic.php?f=31&t=116987

It's now apparent (or at least it should be apparent) to those who study such things that the 26C threshold only works in a standard or seasonal "MDR-type" barotropic environment. My thoughts there are similarly relevant here, so I will repeat them...

"The traditional low end SST threshold of 26-27C (79-81F) assumes a barotropic atmosphere typical of the deep tropics. Generally, in absence of cold core TUTT cells or troughs that show some reflection down into the mid levels, this type of atmosphere features 500MB temperatures of -4C to -6C. Since instability is a function of temperatures both at the surface and aloft, obviously traditional SST thresholds for TC formation will rarely apply to "medcanes", given their formation north in the range between 30-37N.

I think a decent rule of thumb here might be to look for a temperature difference of no less than 30C between SST/near surface air mass and 500MB when looking at true TC processes (i.e latent heat feedback from convection). In other words, when your SSTs drop to, say...20C, as long as 500MB temps have cooled to at least -10C or lower, and in absence of a significant intrusion of a dry and/or cool (polar) air mass at the time, the local atmosphere, would still support TC formation, at least thermodynamically."

Since your proposal looks at 850MB-tropopause and mine looks at near surface-500MB, I think it would be interesting to compare the two alternative thresholds (or similarly less stringent alternatives) for this subset of developments.

This is a FANTASTIC opportunity for a comprehensive M.S. thesis just waiting to be written!


AJC3,
Thank you very much for your reply, which unfortunately I read late. I remember our discussions many years ago. I'm glad that someone begins to understand the dynamics of Medicanes, which are similar to those of the North Atlantic cyclones, as Vince 2005, Grace 2009 or Alex 2016. I think like you; You probably more 'competent than me in physics and dynamic meteorology.
Sorry for my English; Soon, I hope somebody does a correct theory, because all the studies that exist today,
compare a Medicanes with a common tropical cyclones surroundings, and this is wrong.
Daniele Bianchino
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