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Data Source: The Columbia International Research Institute for Climate and Society.

Analytical Brief

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20 May 2020. Summary:
• Flooding continues to be extreme along portions of the Sava River and river levels are still rising in locations downstream of Šabac. Rising waters along the Sava River continue to threaten villages especially between Šabac and Beograde. Of particular concern is a power plant located in the town of Obrenovac which supplies power to half of Serbia. The town has already experienced significant flooding, and water levels are expected to continue to rise and put the power plant at increased risk.
• In addition to the Sava River, the next greatest threat is the Dunav (Danube) River. Numerous tributaries that flow into the Danube, including the Sava River, are experiencing elevated conditions. As water continues to flow from these tributaries into the Dunav, water levels will continue to rise in the Dunav. Of additional concern is the city of Beograde (Belgrade), which is at the confluence of two major rivers that are experiencing water level rises- the Sava and the Dunav. Current flood forecasts from the Serbia Hydrometeorological Service indicate river levels will approach Very significant water stage.
• Although significant rains are not expected through 23 May, water will continue to flow downstream, and river levels will remain elevated along the Sava River through at least 23 May. In general river levels in west Serbia will continue to decrease (with the exception of the Dunav), while water levels will continue to rise downstream. Please see below all of the latest information from the Serbia Hydrometeorological Service and inputs provided from JRC (Joint Research Centre).
Weather Forecast for Serbia from 20 May to 23 - No anomalous rains are expected through 23 May. Light showers will still be possible through 23 May but should not contribute to river levels nor impede any response.Latest Report Provided from JRC (Joint Research Centre)The following is a summary from the national hydrological services provided from JRC:

Serbia: According to the Hydrometeorological Service of Serbia several gauging stations in the Velika Morava, Sava, Jasenica and Mlava exceed the extraordinary flood defense level. Consulting the hydrographs of key locations in those basins, one can see that the water levels are decreasing since yesterday. In the Main Danube, however, water levels are increasing and are currently above the regular defense level. There is no national forecast published.

Bosnia Herzegovina: According to national information most water levels in the Serbian Republic show a stagnating or decreasing tendency. However, they are still above extraordinary flood defense level at some locations of the Sava, Una and Vrbas River. Besides, the limit of regular flood defense level is exceeded in the Sana River
Romania: The Romanian National Institute of Hydrology and Water Management is reporting risk of major flooding for the main Danube(downstream of the Iron Gate) as well as in the Vedea River. Additionally, there is a risk of flooding and rapid increase of water levels (without significant damage) reported for the Danube tributaries Jiu, Moldova andNeajlov.

Poland: According to national information of IMGW a large number of hydrological warnings and alarms are currently active. The main river basins affected are the Upper and Middle Wisla, the Upper and Middle Odra and the San. Most threshold exceedances are located at the main river reaches. Comparing to previous reports it is visible that the flood wave has started to propagate downstream through the main rivers.
Croatia: According to the today’s information by the Croatian Meteorological and Hydrological Service water levels of most stations in the Sava exceed the up to third alert level by now. The water levels are still increasing in the Sava at Crnac, Jasenovac and Mackovac. This could be particularly critical at Jasenovac as there the third alarm level is already exceeded. Also in the River Una the third alarm level is exceeded, however, the water levels are showing a falling tendency. In the main Danube and in the Drava River the first alarm level is exceeded at several locations, most of them show an increasing tendency.

Bulgaria: Most reporting points in Bulgaria show falling water levels, however they are still higher than normal at some locations. The only situation where water levels are still high and show an increasing tendency is found in the Lower Ogosta. Compared to last week, water levels at various gauging stations have dropped to a normal level.
Slovakia: Compared to last Friday, the hydrological situation in Slovakia calmed down largely according to the Hydrometeorological Institute of Slovakia, which released only two minor hydrological warnings for today

Current River ConditionsSummary:
• Extreme hydrological events and conditions: Sava River
• Significant water stage rise: Velika Mrava, Mlava, Kolubara sa pritokama, Dunav nizvodno od Smedereva, Dunav od Novog Sada do Smedereva
• http://www.meteoalarm.rs/eng/hidro_alarm.php
• http://www.hidmet.gov.rs/index_eng.php

Forecast Conditions – Rivers on May 22Summary: Water in the tributaries to the north, south and west of the Dunav will continue to generally decrease from 20 to 22 May (with the exception of the Sava). As water from all of these tributaries empties into the Danuv, water levels are expected to increase to ‘Very Significant stage rise’.
• Extreme hydrological events and conditions: Sava River
• Very Significant water stage rise: Dunav nizvodno od Smedereva, Dunav od Novog Sada do Smedereva
• Significant water stage rise: Kolubara sa Pritokama, Dunav do Novog Sada

List of Rising Rivers Summary: According to the Serbia Hydrometeorological Service, here are the latest trends for rivers across Serbia.: http://www.hidmet.gov.rs/eng/hidrologija/radio.php
• DUNAV: Currently at significant water stage. Rising.
• TISA: Currently No Warning. Slight rising in some locations
• SAVA: Currently at Extreme hydrological events and conditions. Upstream Šabac slight falling, downstream slight rising
• DRINA: Currently No Warning. Falling.
• MORAVA: Currently no warning. upsream Bagrdan falling, downstream stagnation
Sava River Forecast TrendsSummary: The river that is currently the greatest flood threat is the Sava River. Upstream of Šabac
river levels are falling and conditions are slowly improving. However, river levels are expected to
continue to rise downstream and are currently a threat to Beograd.

Below are displayed past conditions (solid blue) and forecasted river levels (dashed lines). As can be
seen, river levels are expected to continue to decrease at Sremska Mitrovica and Šabac:, but increase
at Beograd through 24 May.



Dunav River Forecast TrendsSummary: Water levels are expected to increase over the next 5 days across much of the Dunav River. Currently of greatest concern is near Belgrade and downstream of Belgrade, as the Sava River flows into the Dunav River right at Belgrade.
NOVI SAD (upstream of Beograde)

PANCEVO (downstream of Beograde)
Sources:- http://www.thestar.com/news/world/2014/05/19/flooding_forces_evacuation_of_12_serbian_villages_along_sava_river.html
- http://www.meteoalarm.rs/eng/hidro_alarm.php
- http://www.hidmet.gov.rs/index_eng.php

IRI/CPC Plume / Based Probalistic ENSO Forecast

Data Source: The Columbia International Research Institute for Climate and Society.

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