DES MOINES, Iowa (AP) _ Reports of the death of the Midwest by drought are premature, analysts said Thursday, and a Federal Reserve analyst backed away from an earlier warning the drought could stop a recovery by farm banks.

''Farmers look like they have some staying power. Farm bankers, too,'' said George Gregorash, banking analysis officer of the Federal Reserve Bank of Chicago, who surveyed agricultural banks in Iowa, Wisconsin, northern Illinois and northern Indiana this week.

''Everybody didn't feel panicky - the people in the know, rather than us in Chicago eating our corn flakes and wondering how much the cost of a box will go up,'' Gregorash said in a telephone interview.

Just two weeks earlier, preparing an annual review of the performance of Midwest farm banks, Gregorash made a more dismal assessment, which was distributed this week by the Chicago Fed.

''The current drought conditions in the Midwest could make the 1987 gains short-lived,'' Gregorash said in that Fed statement.

But after surveying bankers, Gregorash said, ''the news is fairly good.''

Jerald Barnard, director of the University of Iowa's Institute of Economic Research, said that while some farmers may suffer and crop production will fall because of the drought, he expects no major impact on the national economy unless the drought is repeated next year.

''I think there's a reason to have some moderation in this,'' he said in a telephone interview from his Iowa City office. ''We're not likely to see a disaster, on one side, and we're also not likely to see the crops come through unscathed.''

At Iowa State University in Ames, researchers at the Center for Agricultural and Rural Development said that because of the great variation in the impact of the drought, the impact could be disastrous on some farmers while others would benefit. It recommended any government relief programs be tailored to target assistance to just those farmers hurt by the drought.

All of the analysts say the final impact of the drought is unknown and point to the huge fluctuations in commodity markets each time rain falls in the Farm Belt or is even forecast as signs of the uncertainty.

''The vagaries of weather have really got us on a roller coaster,'' Gregorash said.

ISU said the best that can be hoped for, through a shift to ideal conditions for the rest of the growing season, is average national corn yields dropping 15.6 percent to 100 bushels an acre, soybeans dropping 9.1 percent to 30 bushels an acre and wheat dropping 6 percent to 36 bushels an acre. Average normal yields are 118 1/2 bushels an acre of corn, 33 of soybeans and 38.3 of wheat, said research associate Patrick Westhoff.

The most severe forecast, one comparable to a drought intensifying to the proportions of Dust Bowl days, would reduce yields of corn by 40 percent, soybeans by 27 percent and wheat by about 15 percent.

A moderate scenario, based on a slight intensifying of current drought conditions, would fall exactly midway between the best and worst outlook and would reflect conditions as severe as any drought of the past 25 years, Westhoff said.

For farmers whose losses are held to a minimum, the rising prices caused by widespread damage to other crops would turn into a windfall, analysts said.

In the moderate damage analysis, prices would not rise above levels already seen earlier this year at the height of the drought rally on farm markets.

Westhoff says the midway drought damage price outlook is for an average $3.10 a bushel corn in the 1988-89 crop year, against the normal $1.90; about $10 soybeans, against $6.75; and about $4 wheat, as opposed to a normal $3.10.