This year, Bhutan is expected to experience a summer with slightly higher temperatures and increased rainfall. According to the National Centre for Hydrology and Meteorology (NCHM), the monsoon will begin on June 5. The monsoon season, running from June to September, is likely to see above-average rainfall.
The NCHM presented its forecast to officials from various sectors during the 10th National Climate Outlook Forum, held in Thimphu on May 22. The onset of the monsoon refers to the start of the season marked by significant rainfall and changes in atmospheric and oceanic conditions, determined by criteria such as rainfall amount, wind speed, and humidity levels.
Drivers of the Monsoon
Bhutan experiences two monsoons: the winter monsoon and the summer monsoon. The drivers of these monsoons include western disturbances, cyclones, the El Niño-Southern Oscillation (ENSO), and the Indian Ocean Dipole (IOD).
For June to September (JJAS) 2024, the National Outlook suggests slightly above-normal precipitation based on CPT GCMs and station data. Temperature predictions indicate normal maximum temperatures and slightly above-normal minimum temperatures.
Regional Outlook
The South Asian Climate Outlook Forum (SASCOF) suggests that rainfall will be slightly above normal this year, and temperatures will also be above normal across the region.
ENSO and IOD Phases
The ENSO phases for JJAS 2024 are expected to range from neutral to La Niña, according to probabilities issued in May. ENSO is a recurring climate pattern involving changes in the temperature of waters in the central and eastern tropical Pacific Ocean:
El Niño: A warming of the ocean surface, or above-average sea surface temperatures (SST), in the central and eastern tropical Pacific Ocean.
La Niña: A cooling of the ocean surface, or below-average SST, in the central and eastern tropical Pacific Ocean.
Neutral: Neither El Niño nor La Niña, with tropical Pacific SSTs generally close to average.
The National Outlook for JJAS 2024 also suggests a positive IOD, indicating more monsoon rain due to warmer sea surface temperatures in the western Indian Ocean relative to the east. A negative IOD would result in cooler sea surface temperatures in the western Indian Ocean relative to the east.
Bhutan’s Weather Predictions
The consensus forecast for JJAS 2024 in Bhutan indicates slightly above-normal rainfall, with maximum and minimum temperatures likely to be slightly above normal.
An NCHM official noted that while the above-normal rainfall poses some concerns for certain sectors, it can also positively impact agriculture and hydropower. However, forecasts are not foolproof, and it is vital to remain vigilant and prepared by monitoring the monsoon onset and staying updated with regular forecasts to ensure timely adjustments and decision-making.
Pangrizampa College of Astrology Forecast
The Pangrizampa College of Astrology has made similar weather predictions, suggesting severe storms and heavy rainfall in the northern regions of the country. The college also predicts abundant agricultural yields but warns of a higher incidence of contagious diseases due to increased rainfall. To mitigate this risk, Sonam Rinchen, Vice Principal of Pangrizampa College of Astrology, advises performing rituals such as kurim and reciting prayers.
Previous Year’s Climate Outlook
Last year’s national climate outlook accurately predicted slightly below-normal rainfall levels. However, there was a discrepancy between the predicted and actual temperature readings. The outlook forecasted a slightly above-normal temperature of 21.75°C, while the recorded average temperature was 20.87°C, which fell below normal levels.
The highest 24-hour rainfall last year was recorded in Bhur, Gelephu, on August 13, at 306mm. The highest temperature was 38.5°C in Phuentsholing on July 5.
Meanwhile, the deputy chief statistical officer from NCHM, Ugyen Chophel said that while the rainfall outlook is above-normal, it poses some concerns for certain sectors, and can also have positive impacts on agriculture and hydropower.
“It is crucial to note that forecasts are not foolproof, and therefore, it is vital to remain vigilant and prepared by monitoring the onset of the monsoon and staying updated with regular forecasts to ensure timely adjustments and decision-making,” he expressed.
By Sangay Rabten, Thimphu
