Northern and southern extremes of the country are yet again being brought under influence of an incoming western disturbance and an eastern wave respectively translating into heavy rain, snowfall, high winds, lightning and hail over respective regions.
India Meteorological Department (IMD) said a passing easterly wave will trigger isolated heavy rainfall over south Tamil Nadu and Kerala & Mahe on Tuesday. Scattered to moderate rainfall, thunderstorms and lightning are likely over Tamil Nadu, Puducherry & Karaikal on Monday and Tuesday; over Kerala & Mahe; Lakshadweep; and South Interior Karnataka on Tuesday and Wednesday.
Rain for North-West
Incoming western disturbance, despite being located more than 3,500 km to over Iraq this (Sunday) morning, will cause strong surface winds (20-30 km/hr) to prevail over the Indo-Gangetic Plains including New Delhi tomorrow and the day-after (Monday and Tuesday). Thus, it would be able to influence weather over North-West India even as travels in for almost a week.
The IMD said scattered to fairly widespread light to moderate rainfall/snowfall is likely over Jammu-Kashmir-Ladakh; Himachal Pradesh; and Uttarakhand until Friday (March 14). Isolated light to moderate rainfall is likely over Punjab for three days from Wednesday; over Haryana on Thursday and Friday; and West Uttar Pradesh on Friday in line its easterly track over North-West India .Thunderstorms may roll out over Jammu & Kashmir and Himachal Pradesh tomorrow (Monday).
Western disturbance impact
Mostly known for weather-generating capacity during winter over North and North-West India, western disturbances outlive the season and arrive in their one and twos even into the spring. They relent with arrival of the south-west monsoon in June that also witnesses a reversal of winds. In contrast, easterly waves travel across the Bay of Bengal towards Sri Lanka and South India and carry a rain-head upfront directed mainly at east coasts of Sri Lanka and Tamil Nadu. Often, they feature a cyclonic circulation or a low-pressure area, even a cyclone, and extends moderate to heavy rainfall cover to west over Kerala as well.
To the south, an easterly wave and its accompaniment of clouds and moisture (white and green over the Bay of Bengal) travel towards the dry region (in golden yellow) of Sri Lanka and South Indian Peninsula.
| Photo Credit: www.meteologix.com/in
Rainfall spurt in south
A preceding easterly wave last week had occasioned a rainfall spurt over South Peninsula and surplus rainfall. Records have since taken a tumble since, though meteorological subdivisions of Lakshadweep (+281 per cent); Tamil Nadu, Puducherry & Karaikal (+94 per cent); and Kerala & Mahe (+34 per cent) have posted a surplus so far during pre-monsoon (March 1 to 8).
North-West India has returned an above-normal rainfall of eight per cent, the only one among core geographic regions to post any, helped by some heavy rainfall/snowfall (even avalanches) over hill states of Uttarakhand (+145 per cent) and Himachal Pradesh (+72 per cent). Rest of meteorological subdivisions here are either just-normal/below normal during this period.
Worst over Central India
Central India continued to be the worst-hit with practically no rain (-100 per cent) across all meteorological subdivisions and a large deficit (-99 per cent) for West Madhya Pradesh, that alone received a sprinkling, if any. Rainfall record for East & North-East India also took a turn for worse with no rain for plains of West Bengal lately; large deficits for Bihar, Jharkhand and Nagaland-Manipur-Mizoram-Tripura; and shortfall in Arunachal Pradesh, Assam & Meghalaya; and hills of West Bengal & Sikkim.
Thunderstorms in east
Towards the east, a cyclonic circulation has been stationed over Assam for more than the past week or so, anchoring seasonal thunderstorms over East & North-East India. On Sunday morning, it also featured a trough extending to the south and cutting into Bangladesh. It may bring isolated to scattered light to moderate rainfall/snowfall, thunderstorms, and lightning over Arunachal Pradesh, Assam & Meghalaya; Nagaland; and hills of West Bengal and Sikkim.
