Staff Reporter:
Bangladesh is likely to experience another relatively dry month in November, following a significant rainfall deficit in October, although the possibility of one to two cyclones developing over the Bay of Bengal remains, according to the Bangladesh Meteorological Department (BMD).
The country received an average of just 57mm of rainfall in October against the normal 179mm, registering a deficit of 68 percent.
The dry conditions are expected to persist in November, with rainfall forecast to remain below normal across all eight divisions.
According to the BMD’s November long-range forecast, the country may receive 5-40mm of rainfall in different divisions, compared with their respective monthly averages of 6-44mm.
The number of rainy days is also expected to remain limited to two to four days across the divisions.
A comparison of the two months shows that rainfall remained substantially below normal in October, while November is also expected to see limited precipitation, signalling a continuation of predominantly dry weather.
In October, Chattogram recorded the highest rainfall deficit at 80.6 percent, followed by Dhaka at 79.9 percent. Sylhet had the lowest deficit at 58.3 percent.
Barishal received the highest recorded rainfall of 133mm, while Dhaka recorded only 32mm.
For November, Barishal is forecast to receive 30-40mm of rainfall against its normal 44mm, while Chattogram may get 35-40mm against 39mm. Dhaka and Sylhet are each expected to receive 15-25mm, Mymensingh and Rajshahi 10-15mm, Khulna 15-25mm and Rangpur 5-10mm.
Despite the prospect of limited rainfall, two to three low-pressure systems may develop over the Bay of Bengal during November, with one or two potentially intensifying into cyclones.
Temperatures are expected to gradually decline during the month, although both daytime and nighttime temperatures may remain above normal.
This follows a warmer-than-usual October, when the country’s monthly maximum, minimum and mean temperatures were respectively 1.8, 0.4 and 1.1 degrees Celsius above normal.
October also witnessed mild heat waves in parts of the country on October 12-14, 22 and 26-28. Sylhet recorded the month’s highest temperature at 37.8 degrees Celsius on October 17, while Tetulia registered the lowest at 15.4 degrees Celsius on October 27.
The southwest monsoon withdrew from Bangladesh on October 9. During the month, two low-pressure systems formed over the Bay of Bengal, one of which intensified into Severe Cyclonic Storm Arnab before making landfall along India’s Andhra Pradesh coast on October 28.
Unlike October’s notable rainfall deficit and intermittent heat wave conditions, November is expected to bring a gradual seasonal cooling trend, though above-normal temperatures may persist.
The BMD also forecast that the country’s major rivers would maintain normal flows during November.
Average daily evaporation is expected to range between 2.5 and 4.5mm, with daily sunshine lasting four to six hours.
