LAHORE - Prevailing atmospheric conditions may cause erratic monsoon and summer in Pakistan, experts say.

Oceanic, atmospheric and surface climatic conditions indicate uncertainties in weather pattern till the El Niño comes to neutral phase in June, said Director Pakistan Meteorological Department Muhammad Ajmal Shad.

“The region is currently under the influence of El Nino. Through this phenomenon, when the surface temperature in the Pacific Ocean rises, more rains are expected.

“El Nino is decreasing and it is likely to come to neutral phase in June. That can be followed by La Nina, drop in surface temperature of Pacific. La Nina suppresses rainfall. But it will not affect monsoon rains as the season will pass until La Nina can make any impact”, he added.

Shaukat Ali Awan, a meteorological expert, said: “El Nino is one of the factors. There are other factors that decide intensity of monsoon. Intense heating in plains of the country and Tibet pull monsoon incursions from Bay of Bengal. That in Southern Hemisphere provides pushing force.”

Like March, April is expected to be wetter than normal. As such the month will not be that hot. Frequent spells of rainfall and isolated hailstorms associated with windstorm may hamper the harvesting and threshing of wheat and sowing of cotton.

“May and first half of June are likely to remain drier and hotter than normal. Lack of rains and abundance of sunshine will cause the mercury to rise above normal level. That will increase the probability of occurrence of heat waves over plains and coastal belt of the country. Due to intense heating, monsoon onset is expected to be early during second half of June,” Shaukat Awan said. “Extreme weather events cannot be ruled out which may lead to floods,” he added.

Heat wave conditions in Gilgit-Baltistan and Chitral may accelerate glacier melting and trigger GLOF events in summer.

Meanwhile, a westerly wave is likely to enter upper parts of the country on Saturday and persist for 2 to 3 days. It is likely to give rain thunderstorm with gusty winds at scattered places of FATA, Khyber Pakhtunkhwa, Islamabad, upper Punjab (Rawalpindi, Gujranwala, Sargodha, Lahore and Faisalabad divisions), Gilgit- Baltistan and Kashmir and at isolated places in Northeast Balochistan (Quetta, Zhob, Sibbi divisions), Sukkur division, South Punjab (DG Khan, Multan, Bahawalpur, Sahiwal divisions).

Scattered rain-thunderstorm may cause landslides in Malakand, Hazara divisions, Gilgit- Baltistan and Kashmir from Sunday to Wednesday.