Italy is one of the strangest countries in the world for what it concerns its weather. This is due to its latitude span, its landscape and all the geographical characteristics that make it one of the most incredibly complex countries for weather forecasts.
Italy runs from a low latitude of little less than 37°N to a little more than 47°N. And, most important, its climates are so different and present so many variations in a country no bigger than 300000 square kilometers. Examples to explain this are the Pianura Padana (the Padana Plain), a typical subcontinental region, with rain mostly during the spring and autumn, and with cold winters. But right next to it, in Liguria (Genua), at almost the same latitude, the climate is Mediterranean, that is, never cold, rainy mostly in spring and autumn, and with mild winters. The 'separator' for these two kind of climates are the Alps. In fact, the Alps have a great concern in climate definition. Alps create a natural barrier to cold winds from the North for the Padana plain, and this luckily avoids the Padana plain to have a more continental climate, instead of subcontinental.
Taking Sicily as an example, we could say that its climate is more subtropical in nature, tending to desertic. Rainfall amounts in Sicily near this region to a morelike semi-desertic region, like the Northern coasts of Africa. Most of the South of Italy, is a warm temperate climate region, where rain falls in winter, and summers are hot and dry. Nonetheless, this region is in winter very exposed to cold winds from the NorthEast, coming from Russian Plains, which provoke heavy snowfalls in the inner mountains (the Appennins).
This prevailing weather pattern is due to the motion of the Azores High, which in Winter moves down in latitude, and in summer moves north, then blocking the prevailing west-east jet flow, in which storm systems are located. But in these last years, this weather pattern seems to have changed a bit: The Azores High seems to have moved too far north, then making winters in Northern Italy dryer, and in Southern Italy wetter (flow from NorthEast), and summers wet and colder in Northern Italy and extremely dry in Southern Italy. No correct answer has yet been given, the factors that could have affected this change are many. But it is a fact that weather has considerably modelled itself in these last 5-10 years.
While travelling in the Alps, I found out the incredible amount of snow still residing on them, and this wouldn't be incredible if this snow had accumulated during time this winter. The incredible fact is that from mid-January till mid-April, no drop of water fell in Northern Italy. So, there could be two possible explanations for this evidence: one is that there has fallen lots and lots of snow during autumn and the beginnings of winter. But looking at charts, it doesn't look like there has been a considerable difference in snowfall amounts between the last years. So, discarded this possibility, there is only one left: weather has been cold.
In effect, weather has been cold. The Azores High has prevailingly stationned in Western Europe during this winter, though enabling a N-NE flow towards Southern Europe travelling from Scandinavia and Eastern Europe. Northern Italy has been in this flow for the whole rainless period; weather systems were included in this flow, but they crashed against the Alps, pouring down heavy rain and snow North of the Alps (ie: in Southern Germany, Austria), and giving windy, clear and cold days to the Padana Plains and to the Southern section of the Alps.
On the contrary, rain fell in southern Italy, where weather seemed normal. No great amounts have though fallen, but nothing compared to the almost null precipitation Northern Italy had to cope with in winter months.
Now spring has begun, rains have begun coming down, no real thunderstorm has yet happened, and all 'chasers' in Italy are waiting for Thunderstorm season to happen. It is to pinpoint a difference between last year's and this year's beginning of season: last year was quite poor in thunderstorms, there have been not many at all, and mostly concentrated in the summer period (normally they would concentrate in spring). That has been a signal of changing weather pattern. But this year, compared to last year, is nothing ever seen to me. Having had three months of no precipitation, and up-to-day (1st decade of May), when precipitations have seriously begun, no thunderstorm has yet happened, when last year, towards the end of March, thunderstorms were already happening, at a low rate, but happening, is all this a thing that makes us think: what, how and when is this weather changing? What are the causes of this change? What will the consecuences be? And what can we expect from the future?
Another consideration is temperature. As said before, the position of the Azores High, kept a continuous N-NW to S-SE flow prevailing in the considered rainless period. The temperatures, up to day, are still lower than normal. Being already in almost mid-May, there have been only 5, or, to exceed, 6 days of morelike summery weather (hot and humid), while in normality, May is already more summery like than springy. April has been really cold compared to normal. Temperatures kept at a constant rate of around 3 degrees Celsius below normal. And, again, this is all comprehended in a vaste weather pattern that affected Western Europe this year in winter, and that will affect it again in summer and the times to come. So, as a forecast, I could say to expect a wet and not hot summer period, where a prevailing N-NE flow will bring rain, thunder and cold weather to Northern Italy, a situation that has been happening for the last three years.
Italian weather, already complicated by itself, has become even more complicated. Unluckily, there is no real good Weather Bureau in Italy, forecasts are most of the times wrong, and though there is a lot of people that are working in a serious research direction, they are still few, and not much help is given to them, when there should be more and more help given to predict any possible weather complication, be it on a large-scale pattern or concentrated in a small area of a few tens of kilometres. As an ending point, I would like to remind a confirmed extremization of the weather, with that meaning a big change in weather pattern in the matter of few hours to no more than two to three days. That is: a rapid change from summer to winter conditions, a change from dry to extremely wet, from humid to drought, extreme downpours of snow or rain, and so on. This is the bigger risk a weather forecaster should face, and these are the risks research must be pointed towards, in order to prevent extreme damage and losses of human lives.
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