Competing wind systems are prolonging unsettled conditions as the country transitions towards the dry season, with possible thunderstorms and temporary river level rises in vulnerable regions.
Bangladesh is expected to see a gradual decline in monsoon rainfall after October 10, with temperatures forecast to fall towards the end of the month as the country transitions to the dry season, while the risk of a cyclone developing in the Bay of Bengal remains high.
The Bangladesh Meteorological Department’s long-range forecast, signed by its director (current duty), Md. Mominul Islam, said two to three low-pressure systems could form over the Bay of Bengal in October, with one potentially intensifying into a depression or cyclone.
Heavy rainfall could also cause river levels to rise rapidly, at least temporarily, in parts of the country’s northern, northeastern and southeastern regions.
The southwest monsoon is expected to withdraw from Bangladesh during the first half of October. Rainfall may then decrease, while daytime and nighttime temperatures are forecast to decline during the second half of the month gradually.
The forecast also indicates thunderstorms are possible across the country for three to four days this month.
Meteorologist Md. Toriful Newaz Kabir said October marks the transition from the monsoon season to the dry season, with monsoon winds normally beginning to withdraw within the first 10 days of the month.
This year, however, monsoon activity has persisted into October, bringing rain to different parts of Bangladesh.
Kabir said a low-pressure system that recently developed near Myanmar and southeastern Bangladesh disrupted the normal movement of monsoon winds. Although the system has since become inactive, the monsoon flow has not completely ceased.
At the same time, westerly winds associated with winter weather are gradually moving towards Bangladesh. Temperatures are expected to decline as the monsoon winds withdraw and the westerlies arrive.
With the two wind systems currently competing for dominance, the monsoon flow has weakened, Kabir said. Intermittent moisture continues to produce clouds and rainfall in scattered areas, a pattern likely to persist for another four to five days.
The forecast indicates that Bangladesh will gradually move towards drier and cooler weather as October progresses, although possible thunderstorms and cyclone formation could complicate conditions.
Authorities are monitoring the Bay of Bengal for potential cyclonic developments, while residents of northern, northeastern and southeastern Bangladesh should remain alert to the possibility of sudden rises in river levels following heavy rainfall.
