As northward onset of the rainy Summer Monsoon proceeded nearly on schedule, pre-season thunderstorms have struck unusually far to the north and west this week on the Indian Subcontinent.
Strong thunderstorms swept over parts of northwestern India and Pakistan on Tuesday, whipping up powerful winds and dust storms while also unleashing blinding downpours, but the storm also gave welcome cooling rain following weeks of sweltering heat.
Tuesday, powerful thunderstorms roared through Rawalpindi, Pakistan, whipping the Islamabad airport with winds to 70 mph. These storms, which churned up clouds of thick dust, also broke an intense heat wave, as the high Tuesday was 111 degrees. In the nearby foothills, 3 inches of rain soaked Murree, yielding about half of the normal June rainfall.
Drenching thunderstorms also pelted the Lahore area. In nearby India, rainfall of 2 inches doused Amritsar Tuesday.
Strong storms along the Himalayas unleashed flooding cloudbursts, damaging winds and hail, according to the India Meteorological Department (IMD) website. High winds struck parts of Jammu, "uprooting many trees," damaging electrical infrastructure and unleashing hail. Crops and fruit trees were damaged.
Rainfall of 4.5 inches doused Jogindernagar in the 24 hours ended Wednesday, the IMD New Delhi website indicated.
Meanwhile, New Delhi was still awaiting its first widespread soaking rain of the month; the only effect so far has been trimmed daytime heat and stray thunderstorms. Historical average Monsoon onset in India's capital region is near the last week of June.
The Indian Monsoon "officially" began in the southern state of Kerala as of June 1, the IMD website showed, making it a "normal" start to the rain-giving weather phenomenon. As of Wednesday, the leading edge of the Monsoon's northward advance in India stretched across central India from Gujarat state in the west to West Bengal in the east, then north to the eastern Himalayas. Thus, onset was taking place within a few days either side of the historical onset date, according to the IMD website.
The opening days of the Monsoon have already seen widespread torrential rainfall and some flooding at Mumbai and along the west coast of India. Estimated rainfall at Mumbai since the start of June has been almost 15 inches, most of which as fallen since the June 8 start of the Monsoon. This amount was about two-thirds what normally falls in the average month of June.
Farther south on the west coast, about 20 inches of rain has already pelted Ratnagiri.
Going forward through at least the start of next week, AccuWeather.com forecasters expect further northward advance of the Monsoon on the Subcontinent, as typically happens during mid to late June. At the same time, widespread pre-monsoon showers and thunderstorms are anticipated over northwestern India and much of Pakistan.
Impacts will, on one hand, include a continued break from the usual pre-monsoon heat, a potential early start to the summer growing season. On the other hand, strong thunderstorms will threaten localized flooding, damaging winds and isolated large hail.