A well-marked low-pressure area over north-west Bay of Bengal off Odisha coast may move slowly northwards and concentrate into a depression by Thursday, India Meteorological Department (IMD) said on Wednesday afternoon.
The system pushed the northern limit of the monsoon to Mumbai, Ahilyanagar, Adilabad, Dantewada, Rayagada, Agartala and Goalpara. The monsoon shear zone was aligned in readiness along a line linking Ratnagiri and Jath (Maharashtra); Nalgonda (Telangana) and Rajamahendravaram (Andhra Pradesh) over South Peninsula.
Monsoon shear zone
Shear zone exists in the higher atmosphere, and serves as monsoon playground populated by helpful circulations. Isolated extremely heavy rainfall is likely over Kerala and Mahe for three days; Coastal and South Interior Karnataka as well as Tamil Nadu, Puducherry and Karaikal, for two days. Thunder squalls with winds reaching 50-60 km/hr in speed and gusting to 70 km/hr are likely over Karnataka, Coastal Andhra Pradesh and Yanam; and Rayalaseema. Isolated heavy rainfall has been forecast over Madhya Maharashtra, Konkan and Goa.
Heavy rainfall warned
TO east, isolated extremely heavy rainfall is likely over Assam and Meghalaya for two days; Nagaland, Manipur, Mizoram and Tripura on Thursday; and Arunachal Pradesh, hills of West Bengal and Sikkim on Friday. Isolated heavy to very heavy rainfall is likely over hills of West Bengal and Sikkim for our days; for seven days over Assam and Meghalaya; and North-Eastern States.
Western disturbances
A western disturbance was draped along Sriganganagar and Karnal in Rajasthan and Haryana while its successor in the form of trough linked Kerman and Zahedan (Iran); Quetta and Multan (Pakistan); and Sriganganagar (West Rajasthan). These may trigger moderate to severe air turbulence over North-West India across Chandigarh, Sriganganagar, Karnal, Bikaner, Dewa, Jodhpur, Udaipur, New Delhi, Agro, Kota, Kanpur, Jhansi, Bhopal, Jabalpur, Allahabad, Raipur and Singrauli.
Circulations galore
Cyclonic circulations lay in wait over south Punjab and central Rajasthan. A trough ran out from west Rajasthan to north Chhattisgarh across east Rajasthan and Madhya Pradesh. A third circulation lay over north-east Madhya Pradesh. Isolated heavy rainfall is likely over Uttarakhand for next five days. Dust storm is likely over West Rajasthan for three days.
Violent weather
Scattered to fairly widespread rainfall, thunderstorms, lightning and gusty winds are likely over Jammu and Kashmir; Ladakh; Himachal Pradesh; Uttarakhand; Punjab; Haryana; Chandigarh; and Delhi. Dangerous thunder squalls are likely over Rajasthan, Jammu, Kashmir and Ladakh also for three days; and Haryana, Chandigarh and Delhi on Friday.