November 2018 in N.E. Italy. Close to the record for high temperatures.

November (in Italy) has just finished with colder air coming from eastern Europe, which has caused a decrease in temperatures especially in the north.

However, these few days of temperatures below the long term averages are not enough to reduce the (significant) positive anomaly recorded in N.E. Italy during the last month. 

Related to the previous historical analysis made for Treviso, in this article I am going to analyse the temperatures observed during November 2018 and compared with the long term average (1981-2010).

To notice that the average (for both minimum and maximum temperatures) is computed on a monthly basis, thus the 10-day average is not considered (the first week of the month has a higher long term average temperature than the last one), which would have led to a more robust analysis to determine the significance of the daily temperature anomaly .

This analysis is focused on comparing November 2018 with the previous ones, considering the overall monthly average temperatures (thus between maximum and minimum values), and on computing the daily temperature anomaly in the past month in both minimum and maximum values, being conscius that its ‘significance’ cannot be quantified in a precise way because of the above mentioned limitation.

Regarding the daily analysis, in Figure1 the daily temperature anomalies (for both maximum and minimum values) are shown, considering a long term average of (4.6/12.7 °C).

Figure1. Max (top) and min (bottom) daily temperature anomaly referred to the long term maximum and minimum averages in Treviso. Positive anomaly (red), negative anomaly (blue).

It is clear how only in few days temperatures below the average occurred and the positive anomaly is observed especially in the minimum values. In fact, though we can’t exactly quantify the significance of this anomaly, the overall analysis shows how the positive difference from the monthly mean is not counterbalanced by negative anomalies. For the minimum temperatures, 13 days have recorded values 5 °C above the average, instead the same negative anomaly was never observed.

Regarding the maximum temperatures, the magnitude of the positive anomaly is lower. This might be due to the overcast conditions observed in the first week of the month, when the southerly winds caused prolonged rainfall events limiting the solar radiation and thus, an increase in the maximum temperatures.

However, November 2018 (in Treviso) has been the second warmest since 1973 (Figure2). 

Figure2. Comparison of the deviation in the average November temperatures from the long term average (1981-2010). Deviation equal or above 0.5 °C (red), between -0.5/+0.5 °C (green), below -0.5 °C (blue).

The plot shows the temperature deviation for each November and it is clear how November 2018 has the second highest anomaly (+2.79 °C). The warmest November occurred in 2014 (+3.84 °C) and the third one in 2002 (+2.74 °C). Interesting, as mentioned in a first analysis , how since the 00s there are no months observing values below the average (deviation bigger than -0.5 °C), with most years observing a significant (positive) anomaly.

November 2018 has shown as average minimum and maximum values : +8.5/ 14.4 °C, thus, respectively, (+3.9/+1.69 °C) above the long term average. This confirms what shown previously with the daily analysis, where the most significant anomalies are observed in the minimum temperatures.

We will see how December will be, though for the next few days no cold spells are expected and temperatures will increase (again) towards values above the average, even if without reaching the positive anomalies observed in November.

References

Published by

edof93

I am Edoardo and I am passionate about weather analysis and forecasing. I would like to share my knowledge and to learn more with others (both International and Italian community).

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