Torrential rain in France could cut wheat yields in the European Union's biggest grower but better conditions in countries including Germany are keeping western Europe on course for another large harvest this year.

Forecasters have in recent weeks increased their expectations for EU soft wheat production, with the European Commission raising its outlook by more than 2 million tonnes in late May to 145.1 million tonnes.

But flooding in the past week in some of France's biggest grain belts south of Paris has put further strain on crops already facing the threat of disease, pushing Euronext wheat futures prices <0#BL2:> to their highest in months.

"The biggest impact could be that on yields from the combination of rain and fusarium disease," Paul Gaffet of consultancy ODA Groupe said.

The heavy rain and a lack of sunshine may have harmed the wheat during flowering while soggy conditions could now breed fusarium, also known as head blight or scab, that can damage wheat yield and quality.

ODA already cut its French crop forecast by 1 million tonnes to 38.3 million last month due to yellow-dwarf virus, another crop disease, and expects to remove another 1.5 million tonnes after the downpours, he said.

Fellow consultants Agritel estimate about a quarter of French wheat production is currently at high risk from fusarium.

Grain quality could also be affected by damp conditions, but the situation was less critical than in 2014 when summer rain left no time for quality to recover, analysts said.

The extent of crop damage will depend on the weather until harvesting, with analysts watching out for storms spreading from the northeast that could bring more heavy rain this week.

However, in Germany torrential rain hit the south but spared major grain belts.

"Overall I do not see a negative impact from the rain and it could even be positive in areas with poor soil and low moisture-retaining properties," one German analyst said.

"North German wheat export regions did not suffer from the heaviest rain."

Germany's 2016 wheat crop will fall by 3.7 percent on last year to 25.57 million tonnes, partly because of a switch to rapeseed, Germany's farm cooperatives association forecasts.

Also, substantial rain last week in Poland helped crops in dry areas, Wojtek Sabaranski of analysts Sparks Polska said.

But Sparks Polska has reduced its forecast for Poland's wheat crop in 2016 to 10.7 million tonnes from around 11 million seen last month due to recent dryness.

Meanwhile wet weather in Britain has increased disease risks but the EU's third-biggest producer remains on track for a crop size similar to last year's 16.4 million tonnes.

"Disease is still probably the biggest threat but the fungicides are generally quite effective so there is not a major problem there," said Susan Twining of crop consultants ADAS.

"We do need to have some decent bright weather now to drive yields," she added.