MONTHLY BULLETIN FOR SERBIA

MARCH 2019

Belgrade, the 5th of April 2019

Division for Climate Monitoring and Climate Forecast

Department of National Center for Climate Change, Climate Model Development and Disaster

Risk Assessment

web: http://www.hidmet.gov.rs

mail: office@hidmet.gov.rs

Republic Hydrometeorological Service of Serbia

Kneza Viseslava 66

11000 Belgrade

Republic of Serbia

� Fifth warmest and sixth driest March for Serbia � Third warmest for Sombor, Loznica and Belgrade � Record dry March for Palic, Crni Vrh and Sombor, second

driest for Vranje � Mean maximum monthly air temperature surpassed on Palic,

Sombor, Novi Sad, Veliko Gradiste and Negotin

Air temperature

Mean monthly air temperature

March 2019 ranks as the fifth warmest for Serbia in the period from 1951 to 2019 (Figure 1) and the third warmest for Sombor, Loznica and Belgrade (Figure 2).

Figure 1. Rank of the warmest and coldest March for Serbia for the 1951-2019 base period

Figure 2. Rank of the 15 warmest March for Belgrade for the 1888-2019 period

Mean March air temperature ranged from 7,1ºC in Pozega to 11,4ºC in Belgrade, and on the mountains from 0,4ºC at Kopaonik to 5,1ºC at Crni Vrh (Figure 3).

Departure of the mean monthly air temperature from the normal1 for the 1981–2010 base period bilo je od 1,8ºC u Požegi do 4,3ºC na Crnom Vrhu (Slika 4).

Mean March air temperature, based on the percentile method2, was in the categories of warm and very warm across most of Serbia, normal category in Pozega, and extremely warm on Palic, Sombor, Novi Sad, Veliko Gradiste and Negotin (Figure 5).

1 Term normal refers to climatological standard normal, that is, the average value of a particular climate element, calculated for the period from January 1, 1981 to December 31, 2010 2 nth percentile of a variable refers to the value of the observed variable below which there is n percent of data previously arranged in an ascending order

Figure 5. Spatial distribution of the mean monthly air temperature using percentile

method during March 2019

Figure 3. Spatial distribution of mean monthly air temperature (ºC) during March 2019

Figure 4. Spatial distribution of mean monthly air temperature anomaly (ºC) during March

2019

Mean daily air temperature in Belgrade, based on the percentile method was in the normal category most of March. At the beginning of first decade and mid-month, mean daily air temperature was in the categories warm to extremely warm (Figure 6).

Figure 6. Monthly course of the mean daily air temperature in Belgrade during March 2019

Maximum air temperature

Mean maximum air temperature in March ranged from 15,8ºC on Palic to 17,8ºC in Leskovac, whereas Belgrade observed mean maximum air temperature of 16,9ºC. On the mountains, mean maximum air temperature in March ranged from 4,7ºC at Kopaonik to 11,4ºC in Sjenica.

Mean maximum monthly air temperature was surpassed at five stations (Chart 1).

Chart 1.

MMS station

Tsrmax March 2019 (ºC)

Surpassed maximum

entire series (ºC)

Year of the observed maximum Tsrmax

Palic 15.8 15.7 1990

Sombor 16.5 16.4 1990

Novi Sad 16.7 16.5 1990

Veliko Gradiste 17.1 16.9 1990

Negotin 17.8 17.3 1990

Based on the percentile method, mean maximum monthly air temperature was in the categories of very warm and extremely warm, and at Kopaonik it fell under the warm category.

The highest maximum daily air temperature of 26,6ºC was observed on March 17 in Loznica, the same day Belgrade observed the highest maximum daily air temperature of 24,5ºC.

Heat wave3 was recorded in the period from March 4 to 11 in Sjenica, Vranje, Leskovac and Kursumlija.

One summer day4 was observed in Sjenica, while Kopaonik observed 4 summer days. In the remainder of the country, there weren’t any ice days.

Minimum air temperature

Mean minimum air temperature in March ranged from 0,0ºC in Pozega and Dimitrovgrad to 6,3ºC in Belgrade, and on the mountains from -3,1ºC at Kopaonik to 1,3ºC at Crni Vrh.

Based on the percentile method, mean minimum monthly air temperature was in the categories of normal and warm in most of the country, very warm in Valjevo, Belgrade and Crni Vrh.

The lowest minimum daily air temperature of -13,6ºC was observed on March 13 in Sjenica. In March, Belgrade observed the lowest daily air temperature of 0,6ºC on the same day, March 13.

Frost days5 were recorded across the entire country, apart from Belgrade. In the lowland, their number ranged from 2 frost days in Loznica to 15 days in Dimitrovgrad, and in the upland from 10 days at Zlatibor to 24 days at Kopaonik. The recorded number of frost days was from 3 to 9 days below the March average in most of the country.

One day with severe frost6 was observed in Sjenica.

Figure 7 depicts the monthly course of the mean, maximum and minimum daily air temperature for Belgrade during March.

3 Heat wave, according to the percentile method, is a period during which maximum daily air temperature is in the warm and very warm categories for 5 days or longer 4 Ice day is defined as the day with maximum air temperature below 0°С 5 Frost day is defined as the day with minimum air temperature lower than 0°С 6 Day with severe frost is defined as the day with the minimum air temperature below -10°С

Figure 7. Monthly course of mean, maximum and minimum daily air temperature during March for Belgrade

PRECIPITATION

March 2019 ranks as the sixth driest for Serbia in a period from 1951 to 2019 (Figure 8), driest on record for Palic (Figure 9), Crni Vrh and Sombor (Figure 10) and second driest in Vranje.

Figure 8. Rank of the wettest and driest March for Serbia for the 1951-2019 base period

Figure 9. The smallest March precipitation in Palic for the period 1936-2019

Figure 10. The smallest March precipitation in Sombor for the period 1931-2019

The observed precipitation sums in March ranged from 1,0 mm on Palić to 37,8 mm in Loznica, whereas Belgrade received 11,5 mm of precipitation (Figure 11).

Precipitation totals relative to the normal for the 1981-2010 base period ranged from 3% on Palic to 69% in Sjenica (Figure 12).

Based on the percentile method, precipitation sums were in the following categories: dry and very dry category in most of the country, normal category in Loznica and Sjenica, and extremely dry on Palic, Sombor, Banatski Karlovac, Veliko Gradiste, Crni Vrh, Leskovac and Vranje (Figure 13).

Figure 11. Spatial distribution of the monthly precipitation sums (mm)

Figure 12. Spatial distribution of the monthly precipitation sums in the percentages of normal for the

1981–2010 base period

The highest daily precipitation sum of 24,9 mm was registered on March 12 in Sjenica. Belgrade observed maximum daily precipitation sum of 5,4 mm on March 9.

Number of days with precipitation in March ranged from 2 days in Kikinda and Kursumlija to 10 days at Kopaonik, which is 4 to 11 days below the March average. Crni Vrh observed record-breaking number of days with precipitation, total of 5 days, which is the fewest number of days ever recorded at that station in March. The previous record, total of 6 days, was registered in March 2012.

Snow cover was observed in the mountain areas, as well as Kraljevo, Kursumlija and Dimitrovgrad. In the upland, there were 10 to 13 days with the snow cover, at Kopaonik 31 day, whereas in the lowland, one day with snow cover was recorded.

The highest snow depth of 99cm was measured at Kopaonik, whereas in the lowland, Dimitrovgrad recorded 6 cm of snow on March 12.

Figure 14 shows assessment of the air temperature and precipitation sums for Serbia for March based on the tercile distribution relative to the 1981-2010 base period. It can be noted that March 2019 was marked by air temperature above the upper tercile boundary and precipitation sums below lower tercile.

Figure 13. Monthly precipitation sums according to the percentile method

Figure 14. Assessment of air temperature and precipitation in March for Serbia with the accompanying terciles in

relation to the 1981-2010 base period

Figures 15, 16 and 17 show daily and cumulative precipitation sums with averaged normals 1981-2010 for March for Belgrade, Loznica and Kopaonik.

Figure 15. Daily and cumulative precipitation in Belgrade

Figure 16. Daily and cumulative precipitation in Loznica

Figure 17. Daily and cumulative precipitation on Kopaonik

Cloud cover, bright and cloudy days

Mean March cloud cover in Serbia ranged from 3/10 to 5/10. The observed cloud cover was 1/10 to 3/10 below the March average. Figures 18, 19 and 20 show average daily cloud cover in March for Belgrade, Valјevo and Vranje.

Figure 18. Mean daily cloud cover in Belgrade

Figure 19. Mean daily cloud cover in Valjevo

Figure 20. Mean daily cloud cover in Vranje

Number of bright days in March in Serbia ranged from 6 days in Sombor and Kikinda to 13 days in Krusevac. In most of the country, observed number of bright days was 3 to 8 days above the average. Number of cloudy days in March ranged from 2 days in Vranje to 9 days in Valjevo. Vranje observed record low number of cloudy days. The previous record, total of 3 days, was registered March 1953, 1990 and 2000. Number of cloudy days in most of the country was 4 to 10 days below the March average.

SUNSHINE DURATION (INSOLATION)

Sunshine duration in March ranged from 171,6 hours in Zaječar to 239,1 hours in Banatski Karlovac (Figure 21).

March insolation ranged from 123% at Zlatibor to 158% in Negotin and Požega relative to the normal for the 1981-2010 base period (Figure 22).

Figure 21. Insolation, expressed in hours during

March 2019 Figure 22. Insolation expressed in the percentages of

normal during March 2019

*Note: Climate analysis of the meteorological elements was done based on the provisionary data obtained from 28 main meteorological stations.

APPENDIX

Overview of the synoptic situation*

Altering of impact of ridge from western Europe and incursion of cold and wet air at the cyclone periphery from north of the continent along with opening of the upper air trough and its passage across Serbia further east. Changeable weather with light precipitation.

The beginning of the month was marked by geopotential drop as well as abrupt upper air trough passage at the periphery of the cyclone from north of the continent, simultaneously on the ground passage of the accompanying atmospheric front took place. Weather was changeable, with seldom occurrence of rain and scattered snow at high mountains.

Period from March 3 to 11 was marked by abrupt altering of influence of cyclone from north and ridge from the western Europe. As a result of this synoptic, shift in circulation from northwesterly-westerly to southwesterly and then again westerly took place. In the same period, anticyclone remained on the ground disrupted by weakened atmospheric fronts within the cyclone from the north of the continent. Weather was changeably cloudy, warm, with scattered light rain.

Significant change in weather took place on March 11 and 12 with passage of the cold atmospheric front on the ground within the cyclone from the north of the continent, followed by upper air trough. Weather was cloudy, colder with more precipitation, in the hilly-mountainous regions and on the mountains snow was recorded.

Trend of the altering influence of ridge from west and spatial upper air trough from north of the continent continued from March 13 to 18. Influence of the anticyclone on the ground in the given period was disrupted by impact of the weakened frontal disruptions at the cyclone periphery from northwest of Europe. Consequently, weather was changeable, with scattered rain or showers of short duration, apart from March 13 and 17 when it was predominantly sunny.

On March 18, geopotential dropped and circulation shifted to southwesterly given the deeper incursion of new wet and cold air from north across the western Europe as well as opening of the upper air trough followed by upper air cyclone in the western Mediterranean. On March 20, center of the upper air cyclone moved. Consequently, cloud cover increased, temperature dropped and patches of intermittent light rain were observed.

On March 20, at the end of the day, rise of geopotential took place given the strengthening of the ridge impact from west and anticyclone on the ground. Impact of the ridge along with anticyclone remained until March 25, hence the weather was predominantly sunny and warm.

Geopotential drop, circulation shift along with abrupt passage of the upper air trough at the periphery of the cyclone from the north of the continent took place in the period from March 25 to 28. Simultaneously, series of atmospheric fronts passed across Serbia within the aforementioned cyclone disrupting anticyclone. Weather was changeable, with scattered rain, on the mountains with light snow.

Period from March 28 until the end of month was characterized by geopotential rise owing to the strengthening of the ridge influence from west, whilst anticyclone was established on the ground. It was predominantly sunny weather with cold mornings, at most places with occurrence of ground frost.

* National Center for Hydrometeorlogical Early Warning System