By Marc Frank
HAVANA (Reuters) - The first of 50 Cuban sugar mills open this week with prospects of reaching last season's production in doubt due to irregular weather caused by the El Nino phenomenon, sources close to the industry said.
Cuba produced 1.9 million tonnes of raw sugar during the last harvest which ended in May, with AZCUBA, the state sugar monopoly, forecasting at the time an 8 percent to 10 percent increase for 2015-16.
However, that was before the government reported rainfall through August was the lowest since 1901. Only 10 percent of Cuban plantations are irrigated and the industry mainly uses decades-old equipment for harvesting, transport and milling.
Precipitation has increased since August, and Cuban forecasters predict the phenomenon known as El Nino, which contributed to the drought, will now result in more humid weather and rainfall than normal during the harvest.
The problem is the sugar cane now needs dry and cool temperatures to increase yield.
An October estimate of cane found there was around 10 percent less tonnage available for milling than planned, a local agricultural expert with ties to the industry said.
"It will be a miracle if we top last season's output," he said, requesting anonymity to protect his access to information. "If forecasts of more rain and humidity prove true that will further reduce cane yields and efficiency."
AZCUBA usually announces its production plan before the harvest begins, but has been mostly quiet since May.
Company spokesperson Dionis Perez said earlier this month that it would be a "special" harvest and that the industry hoped to make up for less cane through improved efficiency.
The drought has been particularly damaging in eastern Cuba, which produced more than 600,000 tonnes of raw sugar during the last harvest.
The Communist Party daily Granma on Monday reported there was "much less cane" available in eastern Santiago de Cuba, while in eastern Las Tunas province local officials said in September there was 11 percent less cane than the previous year.
Cuba consumes between 600,000 and 700,000 tonnes of sugar a year and has an agreement to sell China 400,000 tonnes annually.
Sugar was long Cuba's most important industry and export with output reaching 8 million tonnes in 1991, but today it ranks eighth in exports behind sectors such as tourism, tobacco, nickel and pharmaceuticals.
(Editing by Daniel Trotta and Marguerita Choy)