Drought pressures intensified in the U.S. Plains hard red winter wheat fields in the past week with rain forecast this week only for the northern portions of the belt while many parched western areas will likely remain dry, meteorologists said.

The weekly U.S. Drought Monitor, issued on Thursday by state and federal climate experts, said nearly 36 percent of the High Plains from Kansas to North Dakota was in moderate to exceptional drought, up from 28 percent a week ago.

"Much-above-normal temperatures accelerated crop-water demands on the Plains and further reduced already-dire mountain snowpacks over much of the West," the drought monitor said.

The drought is expanding just as hard red winter wheat moves into its key growth phase. That is the major wheat variety grown in the United States, the world's top food exporter.

The central and southern Plains have received 33 percent of normal rainfall during the past 90 days, Eric Luebehusen, lead author of the Drought Monitor, told Reuters on Thursday. Last week's average temperature in many spots was 10 degrees or more Fahrenheit above normal.

"To be seeing 90-degree temperatures in Texas, Oklahoma and Kansas in early April is disconcerting, causing crops to break dormancy rapidly and accelerating crop water and pasture water demands," Luebehusen said.

In Kansas, the top wheat growing state, authorities on Monday said HRW wheat condition had slipped 5 points during March to a range of 39 percent good to excellent. The wheat, planted last fall and just out of dormancy, is now setting heads on their stems and moving into the most active growth phase to fill out the grain.

The National Weather Service six to 10-day forecast for the April 7-11 period currently calls near- to below-normal temperatures across the northern and western U.S., while warmer-than-normal weather is to continue in the central and southern Plains.

Private forecasters said the best chance for rain is the middle of next week for the northern HRW wheat belt - Kansas, Colorado, Nebraska. The parched southern region will miss the rain.

"At this point it looks like the north only is going to get up to a half inch of rain - that's as good as it's going to get," said Drew Lerner, president of World Weather Inc.