Rain deficiency 100% in 6 states, 2 UTS, says IMD

At least six states and two Union territories have recorded a nearly 100% rain deficiency in January after a large deficit in December the two peak winter months for north India and the season is likely to end on a dry note, weather experts said.

The rain deficiency has come amid spells of dense to very dense fog, and cold day and cold wave conditions over the northern plains for at least two weeks, with experts attributing the lack of winter precipitation largely to the absence of strong western disturbances (WDS) over the region.

North India is seeing a unique situation, experts said, with western disturbances not touching the country at all as they sweep by through more northern latitudes.

Generally, five to seven WDS impact north India between December and January. This winter, however, no active WD has impacted the region.

"The jet stream is also moving north of India. WDS form along with jet stream instability but that instability is not within the Indian region. They are all moving north of India," said M Rajeevan, former secretary, ministry of earth sciences.

On Monday, a WD could be seen in satellite images above the Indian region, when seen on a map. Jet stream winds of 240 to 250 kmph at 12.6km above mean sea level are also prevailing over the plains of North India. This is causing cold air to subside, which in turn is strengthening cold wave/cold day conditions over the region.

Similar intensity of jet stream is likely to continue for the next three-four days, the IMD warned.