Ciao,

dopo mesi di indagine ho avuto finalmente una risposta dall'ESSL (European Severe Storm Laboratory) a proposito dei fenomeni convettivi che hanno interessato la Sicilia a dicembre 2005 (due trombe d'aria e forti precipitazioni accompagnate anche da raffiche di vento intense). Ecco il testo (spero che tutti sappiano l'inglese):

Dear Stefano,
storms like these are not classified as tropical storms. Dynamically, they are more
similar to "polar lows", and some authors name them "meso-cyclones" (not to be
confused with the use of "mesocyclone" in severe thunderstorm research). Most
polar lows also show the hurricane-like eye.
I remember that there were several cases of such storms in the Mediterranean
region over the last 5-10 years, but I have not kept a record of them. One older case
I found in the literature occurred from 26-28 January 1982; it was described by
Billing, H., I. Haupt, and W. Tonn, 1983: Evolution of a hurricane-like cyclone
in the Mediterranean Sea. Beitr. Phys. Atmosph., 56, 508-510.
Do you have a list of such events? This might provide a basis for a future study on
their occurrence.
BTW, who in the USA told you to ask your question to the ESSL (just being curious)?
At the moment, the ESSL is still a network of scientists. A proposal for developing the
ESWD database (and founding the ESSL as an institution) is currently under evaluation
at the European Commission. If this project will be funded, it will be a major step
forward.
Best regards,
Nikolai

Ho inviato comunque la lista dei sospetti "TLC" sono curioso di sapere se sono effettivamente tempeste tropicali,tempeste ibride o normali cicloni extratropicali.

Ste