September to December period constitutes the second major rainfall season in Uganda. During the 47th Greater Horn of Africa Climate Outlook Forum (GHACOF47) for the Greater Horn of Africa that was held at Zanzibar Beach Resort in Zanzibar, Republic of Tanzania from 21st – 22nd August 2017, the national, regional and international climate scientists reviewed the current state of the global climate systems and their implications on the seasonal rainfall over the Greater Horn of Africa.

It was observed that the major physical conditions that are likely to influence the evolution of weather conditions over Uganda and the rest of the region for the forecast period of September to December 2017 will include:

  • The predicted neutral phase of Indian Ocean Dipole and neutral ENSO conditions in the central and eastern Pacific Ocean (No El Niño and no La Niña);
  • The influence of regional circulation patterns, topographical features, and large inland water bodies.

Based on the above considerations as well as details of the climatology of Uganda and scientific tools for climate analysis, Uganda National Meteorological Authority (UNMA) has downscaled the regional forecast and come up with the following detailed forecast:

  • Overall, there is an increased likelihood of above normal (above average) rainfall over much of Uganda, while near normal (average) rainfall over south western Uganda and near normal to below normal rainfall conditions over Karamoja regions.

The seasonal forecast issued for September to December 2017 across regions of Uganda is detailed in  September to December 2017 Seasonal Rainfall Update

The June, July and August forecast period is generally part of the dry season over most parts of south western, central, Lake Victoria basin and some parts of eastern region but a continuation of rainfall season for much of the northern Uganda. It generally marks the end of the first rainfall season for the southern sector of the country and is usually a harvest season for crops.

Following the conclusion of the 46th Climate Outlook Forum for the Greater Horn of Africa held in Khartoum, Republic of Sudan from 15th – 16th May 2017, the national, regional and international climate scientists reviewed the state of the global climate system and its implications on the seasonal rainfall over the East African region. It was observed that the major physical conditions likely to influence the weather conditions over Uganda and the rest of the east African region for the forecast period of June to August 2017 are as follows:

  1. The weak positive phase of Indian Ocean Dipole (IOD) that has significant influence on regional climate;
  2. The neutral conditions of Sea Surface Temperatures (SSTs) over the equatorial Pacific Ocean with a heightened likelihood of El Niño episode to start developing during the second half of 2017 with a 60% chance of at least a weak El Niño by the end of the year which calls for close monitoring;
  3. The influence of regional circulation patterns, topographical features and large inland water bodies.

Based on the above considerations as well as details of the climatology of Uganda and scientific tools for climate analysis, Uganda National Meteorological Authority (UNMA) under Ministry of Water and Environment has downscaled the regional forecast and come up with the following detailed forecast:-

Overall, there is an increased likelihood of near normal tending to above normal rainfall over the northern and some parts of eastern region, while the rest of the country is expected to experience below normal rainfall punctuated with occasional light rainfall conditions.

The seasonal forecast issued for June to August 2017 across regions of Uganda is detailed in June to August 2017 Seasonal Rainfall Update

UNMA normally issues timely seasonal climate forecasts just before the beginning of each rainfall season in Uganda. The seasons are March, April and May (MAM), June, July and August (JJA) and September, October, November and December (SOND). The climate forecast in every season provides indications of the expected performance of seasonal rains including the onset and cessation dates and proposed advisories for the different sectors of the economy. The expected impacts from the forecast are also highlighted for the purposes of advancing appropriate safeguarding planning strategies and decision making for various sectors.

The MAM period constitutes the first major rainfall season over Uganda and overall, there is an increased probability for above normal rainfall for western sector of Uganda, normal rainfall for central, Lake Victoria Basin, south-eastern, and central-northern Uganda, and below normal rainfall for Karamoja region and some parts of Lango and Acholi regions. It should be noted that the onset of seasonal rains is expected to be characterised by thunderstorms and hailstorms over some parts of the country as well as dry-spells during the course of the seasonal rainfall performance.

During the 45th Climate Outlook Forum for the Greater Horn of Africa held in Addis Ababa, Ethiopia from 5 to 8th February 2017, the national, regional and international climate scientists reviewed the state of the global climate system and its implications on the seasonal rainfall over the East African region. It was observed that the major physical conditions likely to influence the weather conditions over Uganda and the rest of the East African region for the forecast period of March to May 2017 are as follows:

  1. The predicted neutral phase of Indian Ocean Dipole and neutral ENSO conditions in the central and eastern Pacific Ocean (No El Niño and no La Niña);
  2. The influence of regional circulation patterns, topographical features and large inland water bodies.

Based on the above considerations as well as details of the climatology of Uganda and scientific tools for climate analysis, Uganda National Meteorological Authority (UNMA) in the Ministry of Water and Environment, has come up with the detailed forecast issued on 17th day of February 2017 for March, April and May (MAM) 2017 period: March to May 2017 Seasonal Rainfall Forecast

The Highest significant wave height of 19 meters (62.3 feet) measured by a buoy in the North Atlantic has been certified by the World Meteorological Organization (WMO) expert committee as a new world record significant wave height. The wave was taller than a six-storey building. It was recorded by an automated buoy at 0600 UTC on 4th February 2013 in the North Atlantic Ocean between Iceland and the United Kingdom (approximately 59° N, 11° W).  According to WMO Expert committee, this wave was due to the passage of a very strong cold front, which produced winds of up to 43.8 knots (50.4 miles per hour) over the area.

Representational Image. (Source: REUTERS/Mark Kauzlarich)

The previous record of 18.275 meters (59.96 feet) was measured on 8th December 2007, also in the North Atlantic. The WMO Commission for Climatology’s Extremes Evaluation Committee classified it as“the highest significant wave height as measured by a buoy”. The Committee consisted of scientists from the United Kingdom, Britain, Canada, the United States of America and Spain.

“This is the first time we have ever measured a wave of 19 meters. It is a remarkable record,” said WMO Assistant Secretary-General Wenjian Zhang. “It highlights the importance of meteorological and ocean observations and forecasts to ensure the safety of the global maritime industry and to protect the lives of crew and passengers on busy shipping lanes,” he said. Dr. Zhang also recognized the need for high quality and extensive ocean records to help in our understanding of weather/ocean interactions. He further said that, “despite the huge strides in satellite technology, the sustained observations and data records from moored and drifting buoys and ships still play a major role in this respect”.

The new world record will be added to the official WMO archive of weather and climate extremes which is being constantly updated and expanded thanks to continued improvements in instrumentation, technology and analysis. 

More on this story. https://public.wmo.int/en/media/press-release/19-meter-wave-sets-new-record-highest-significant-wave-height-measured-buoy

September to December period constitutes the second major rainfall season in Uganda. During the 44th Climate Outlook Forum (COF44) for the Greater Horn of Africa that was held at Speke Resort Hotel Munyonyo from 29th to 30th August 2016, the national, regional and international climate scientists reviewed the current state of the global climate systems and their implications on the seasonal rainfall over the east African region. It was observed that the major physical conditions that are likely to influence the evolution of weather conditions over Uganda and the rest of the region for the forecast period of September to December 2016 will be mostly La Niña conditions over equatorial eastern pacific Ocean that are predicted to persist during the rest of the 2016 and early months of 2017. It should be noted that when La Niña occurs, most parts of Uganda receive suppressed rainfall. Other conditions include:-

  1. The Indian Ocean Dipole (IOD) that has significant influence on regional climate is also predicted to be in the negative phase during the forecast period;
  2. The influence of regional circulation patterns, topographical features and large inland water bodies.

Based on the current La Niña conditions as well as details of the climatology and scientific tools for climate analysis, Uganda National Meteorological Authority (UNMA) in the Ministry of Water and Environment, has come up with the detailed forecast as illustrated in the figure below:

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