As a heat wave started to build from the international border along the West in Gujarat and Rajasthan, global weather models have made available the first full forecasts for the South-West monsoon season (June-September).

The Busan-based APEC Climate Centre continues to favour decent precipitation during April, May and June, but suspects that the first localised rain deficits would start emerging in July and more so in August.

Summer showers

These could get reversed in September. The International Research Institute for Climate and Society at Columbia University tends to agree with these forecasts for the most part.

The European Centre for Medium-Range Weather Forecasts sees a normal monsoon for the country as a whole this year, while the UK Met Office tends to classify it as normal to slightly below normal.

Quarterly forecasts

In quarterly forecasts, the APEC Climate Centre shows April-June leaving a deficit in Jammu & Kashmir and adjoining Himachal Pradesh, while July-September might point to a spot of bother in North Coastal Tamil Nadu (around Chennai).

Forecast for April shows normal to above normal rainfall for the South Peninsula — including in South Interior Karnataka, North Interior Karnataka, Tamil Nadu and Kerala.

It will be mostly normal for the rest of the country.

Positive for peninsula

Most parts of Kerala and adjoining South Tamil Nadu could receive, what the South Korean agency predicts, excess summer showers in April.

Monday’s satellite pictures showed clouds massing up over Sri Lanka and spilling into adjoining Tamil Nadu.

May forecasts too show positive trends for not just the South Peninsula but also for the adjoining North and Central India extending into parts of even South-West Uttar Pradesh.

Wet June seen

Normal rainfall is being forecast for the rest of the country except Jammu & Kashmir, which could return a deficit.

Meanwhile, excess showers are forecast for the West Coast from Kerala, Coastal Karnataka to Goa.

The two summer months of April and May are likely to be followed by what looks like a wet June with even Jammu & Kashmir getting its due.

June and July

Excess showers would lash not just the West Coast including Mumbai but also the entire East India. East Madhya Pradesh, Chhattisgarh, Odisha, Jharkhand and Bengal are seen benefiting from this spell.

In contrast, the rainiest months, July and August, might just fail to measure up with likely deficit cropping up over North Coastal Tamil Nadu and later over Telangana and western parts of Saurashtra and Gujarat.

The rest of the country — including Madhya Pradesh, Maharashtra, Uttar Pradesh, Rajasthan, East India and South Peninsula — is forecast to witness mostly normal rainfall.

September would turn out to be good for entire northern half of the country (including Rajasthan and Gujarat), while pockets of deficit are likely to crop up in Arunachal Pradesh, South Bengal, South Kerala and adjoining Tamil Nadu.