Genoa. May spring be one unstable season it is well known, but the swing experienced in Liguria in April just ended was actually something extraordinary. This is confirmed by the data collected by the experts Arpal weather center: last month the average daily temperature calculated on a regional scale it has broken climatological records several times over the last twenty yearsboth the maximum and the minimum.
“In the first half of the month – he explains Barbara Turatomanager of the meteorological and hydrological service of Arpal – temperatures have been above average, then dropped heavily below average and then returned above average again in the last few days. These oscillations are actually not anomalous in passing seasons. In spring it begins to open brings of the African high pressure, but that of the Atlantic which brings in cold air remains open. It’s a fairly typical exchange for April, although perhaps not so drastic.”
In the graph that shows the thermal trend compared to the climatology, the black line – that is, the succession of average daily temperature values in Liguria – surpasses historical peaks upwards three times: on April 8th with 16.6 degrees, on April 16th with 19.1 degrees (the highest figure) and April 30 with 17.8 degrees. The April 23on the contrary, have been achieved on average 5.2 degrees, by far the lowest point in the historical series for that day. A notable leapeven if April, in the reference period, has in the past given temperatures even more unbalanced towards the extremes.
“Despite this – he observes Turato – if we see how the month went overall, we find that April had a regional average temperature of around 12.3 degrees, a figure which is still above the climatological average of 11.8 degrees”. In other words, the late winter tailspin was not enough to compensate for the unseasonal heat of the first two weeks, recording apositive thermal anomaly of about half a degree. It should be underlined that recent years had instead seen a negative anomaly, standing respectively at 10.1 degrees in 2021, 11.1 degrees in 2022 and 11.5 degrees in 2023, while 2020 was similar to this year (average of 12.4 degrees).
From the point of view of rainfall there were no particular phenomena: “The average cumulative figure from the beginning of the year is well above average thanks to the big jump between March and April which brought us very close to the highs of the last twenty years, almost all of which were achieved in 2014. This month the rainfall increased a little more but in an overall moderate manner”, explains the meteorologist. From the graph we can see how the black line, the one relating to the values for 2024, is well beyond the range of climatic normality, even if we cannot speak of a record.
What will happen in the next few weeks and when will the feared summer heat waves arrive? It’s hard to say: “As early as next week the situation should be resolved: temperatures will tend to recover, going slightly above average, the rain will follow the seasonal average and all in all the weather will settle down – he explains further Turato -. But the closer we get to the summer season, the more the scenario becomes unpredictable. While in winter anticyclonic rises and significant thermal anomalies are clearly visible, in summer the noisy thunderstorm signal prevails. Beyond 10 days the models are no longer able to return reliable forecasts.”
