New Delhi: The power ministry is preparing to issue an advisory asking utilities and states to strengthen preparedness amid erratic weather conditions and their potential impact on electricity demand and generation, people aware of the development said.The move follows a review meeting Thursday with state officials, generation and transmission companies to assess challenges to power supply arising from El Nino conditions and forecasts of a deficient monsoon. The ministry has advised states to maintain adequate coal inventories and ensure sufficient water supplies for thermal power plants, one of the people said. Utilities may also be directed to complete preventive maintenance to minimise forced and partial outages.Power demand rose sharply in May and June, with peak demand touching the projected 271 GW in May and exceeding 250 GW during the last two weeks of June. The government has projected peak demand of 247-278 GW over the next three months, amid forecasts of below-normal rainfall, a government official had earlier told ET.