No heat wave until this weekend, says IMD

Dynamical weather models are in good agreement that a cloud-and-rain-bearing Madden-Julian Oscillation (MJO) wave will propagate eastward from East Africa to the Indian Ocean during the early part of this month, an update from the Climate Prediction Centre of the US National Weather Service said.

As the enhanced phase of the MJO propagates east to the Indian Ocean, it predicts an increase in convection and reduction in wind shear during the week May 5-11, an ensemble model run said. These might set up a conducive environment for a low-pressure area to build over the South Arabian Sea.

Widespread rain, says IMD

An extended outlook by India Meteorological Department (IMD) has predicted scattered to fairly widespread rainfall/thunderstorm over the South-West Peninsula and the Lakshadweep Islands and isolated rainfall/thunderstorms over the remaining parts of the South Peninsula during May 9-11.

This would suggest a perk-up in the ongoing pre-monsoon and thunderstorm season over the region currently driven by a cyclonic circulation over North Interior Karnataka and a trough that runs into it from South Kerala. Kerala has already recorded surplus rainfall so far during the pre-monsoon season from April 1.

The Chennai Meteorological Centre of the IMD said several places in Kerala recorded moderate to heavy rainfall on Monday. The rainfall figures are (in cm): Mancompu-8; Kanjirappally-7; Kottayam-6; Myladumpara and Ottappalam-3; Alappuzha, Punalur, and Kozha-2 each, mostly over Central Kerala.

More rain forecast

The North-South trough over South Peninsula may trigger light/moderate scattered to fairly widespread rain/thunder over Kerala, Mahe, Lakshadweep and Coastal and South Interior Karnataka on Tuesday. In addition, isolated rain/thundershower may lash the rest of the South Peninsula into the weekend.

Isolated heavy rainfall is likely over Kerala, Mahe and Coastal and South Interior Karnataka from today and tomorrow (Tuesday and Wednesday).

To the country’s East, the Kal Baishakhi season of thunderstorms is in full swing with an ‘incendiary’ trough connecting a cyclonic circulation over West Uttar Pradesh with Assam across East Uttar Pradesh, Bihar and the hills of West Bengal, and fuelling a flare-up of intense lightning and thunderstorms.

Flare-up in North-East

Strong southerly/southwesterly winds have been blowing from the Bay of Bengal to East and North-East India Sunday, triggering isolated to scattered rainfall/thunderstorm activity. This will acquire further momentum with scattered to widespread rain/thundershower being forecast until Thursday.

In this (Tuesday) morning’s update, the IMD said isolated heavy rainfall is likely over Assam and Meghalaya until Friday; hills of West Bengal and Sikkim today and the plains both today and tomorrow (Tuesday and Wednesday). In addition, Odisha and Arunachal Pradesh are expected to be under the weather during this phase.

Thunderstorm and lightning accompanied with gusty winds are likely over most parts of these until the weekend.

Western disturbances

Meanwhile, back-to-back western disturbances may bring isolated to scattered rain/thunder over the hills of North-West India today (Tuesday). Its intensity and distribution are likely to increase with light to moderate scattered/fairly widespread rainfall/thundershower next two days.

In this manner, rain and cloud cover will keep the heatwave away over most parts of the country. As a result, heatwaves have been comparably fewer this year and far in-between.

Isolated heavy rainfall is also very likely over Uttarakhand on Thursday, while isolated to scattered rain with thunderstorm and lightning is also forecast over the plains of North-West India (Punjab, Rajasthan, Haryana, Delhi and West Uttar Pradesh during the next five days.

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