KYIV (Reuters) - An abnormal heatwave seen in Ukraine in the last few weeks will begin to ease on Thursday making way for rain in most of the country, the state weather forecaster said on Wednesday.

Record high temperatures have had a negative impact on Ukraine's grain and oilseed crops and led to widespread electricity cuts.

"We can call this heatwave abnormal as many temperature records were broken," Natalia Ptukha from Ukraine's state weather forecasting centre told a televised briefing.

She said the expected cold snap would not be drastic and a new period of warming could arrive in as little as a week.

Agricultural producers group the Ukrainian Agrarian Council said on Tuesday that this year's corn yield could fall by 30-35% because of the extreme heat and drought.

The state weather forecaster also said the country's harvest of late crops could decline by 20-30% in central, southern and eastern regions owing to the extreme heat.

It said 30% to 50% of the overall area under late crops could be affected by drought.

(Reporting by Pavel Polityuk; editing by Jason Neely)