One to three low-pressure systems are likely to develop over the Bay of Bengal in October and one of them may intensify into a depression or a cyclone, according to the long-range weather forecast for October.

The forecast of Bangladesh Meteorological Department prepared after analysis of regional and global climate data suggests that Bangladesh may experience two to four days of moderate to severe thunderstorms with lightning and three to five days of light to moderate thunderstorms in different parts of the country.

Overall rainfall in October is expected to remain normal, said the forecast.

Low pressure area likely to form over Bay on Oct 24: BMD

Day and night temperatures may gradually decline as the month progresses, though both are expected to stay slightly above the seasonal average.

Major rivers are likely to maintain normal flow conditions during the month.

However, due to heavy rainfall, flashflood-like situation may occur in the northern, northeastern, and southeastern hilly regions.

The report also noted that average daily evaporation may range between 2.25 and 4.25 millimeters while average sunshine duration could vary from 5 to 7 hours per day.

The forecast was prepared after analyzing weather observations, upper-air patterns, various weather charts, and climate models.

Inputs were also taken from global forecasting and climate centers recognized by the World Meteorological Organization (WMO), including ECMWF, JMA, NOAA, IRI–Columbia University, APEC Climate Centre (APCC), RIMES, and C3S, the BMD said.