TULSA, Okla. (AP) — While the sporadic rain that's fallen on much of Oklahoma during the past two days has heartened the state's wheat growers and ranchers, it will take 10 to 20 inches of precipitation to bring the state out of a 13-month drought, forecasters said Thursday.

Up to an inch of rain had fallen in parts of the state by Thursday, with areas in western and central Oklahoma getting the most precipitation, said Gary McManus, an associate state climatologist with the Oklahoma Climatological Survey.

"In general, we just need more of these types of situations," McManus said. "For some folks, this is the first good rain they're having.

"We are so far down over the last 13 months now that we have a long way to catch up."

The western and central portions of Oklahoma remain in an exceptional drought, which is the worst drought category listed by the U.S. Drought Monitor. The rest of the state was either in an extreme drought, the second worst stage, or a severe drought, the third worst. The drought monitor has five drought stages.

Oklahoma has experienced unusually dry, hot weather since the spring, and triple-digit temperatures over the summer fueled dozens of wildfires, prompted burn bans and led to water rationing in some communities.

Farmers welcomed any amount of rain.

"Until we get a significant drought-busting rain, we (need) to have a half-inch to an inch of rain on a regular basis to keep the wheat growing," said Tim Bartram, executive director of the Oklahoma Wheat Growers Association, who also farms about 300 acres in Guthrie.

Kim Anderson, a crop marketing specialist with the Oklahoma Cooperative Extension in Stillwater, said a lack of moisture below the soil's surface could jeopardize the winter wheat crop, which is planted in the fall and harvested in the spring. The state has had a below-average wheat crop for four out of the past six years because of drought.

"The wheat producers are in survival mode and praying for a miracle," Anderson said. "Farmers are naturally optimistic, but I don't think anybody is anticipating an average crop (this season)."

Copyright 2011 The Associated Press.